背景

上文JDK8中的HashMap源码写了HashMap，这次写ConcurrentHashMap

ConcurrentHashMap源码

/**
     * Maps the specified key to the specified value in this table.
     * Neither the key nor the value can be null.
     *
     * <p>The value can be retrieved by calling the {@code get} method
     * with a key that is equal to the original key.
     *
     * @param key key with which the specified value is to be associated
     * @param value value to be associated with the specified key
     * @return the previous value associated with {@code key}, or
     *         {@code null} if there was no mapping for {@code key}
     * @throws NullPointerException if the specified key or value is null
     */
    public V put(K key, V value) {
        return putVal(key, value, false);
    }

    /** Implementation for put and putIfAbsent */
    final V putVal(K key, V value, boolean onlyIfAbsent) {
        if (key == null || value == null) throw new NullPointerException();
        int hash = spread(key.hashCode());
        int binCount = 0;
        for (Node<K,V>[] tab = table;;) {
            Node<K,V> f; int n, i, fh;
            //tab为空，则初始化
            if (tab == null || (n = tab.length) == 0)
                tab = initTable();
            else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) { //该槽为空，则尝试插入
                if (casTabAt(tab, i, null,
                             new Node<K,V>(hash, key, value, null)))
                    break;                   // no lock when adding to empty bin
            }
            else if ((fh = f.hash) == MOVED) //正在移动，
                tab = helpTransfer(tab, f);
            else {
                V oldVal = null;
                synchronized (f) { //对该槽进行加锁
                    if (tabAt(tab, i) == f) {
                        if (fh >= 0) {
                            binCount = 1;
                            for (Node<K,V> e = f;; ++binCount) {
                                K ek;
                                if (e.hash == hash &&
                                    ((ek = e.key) == key ||
                                     (ek != null && key.equals(ek)))) {
                                    oldVal = e.val;
                                    if (!onlyIfAbsent)
                                        e.val = value;
                                    break;
                                }
                                Node<K,V> pred = e;
                                if ((e = e.next) == null) {
                                    pred.next = new Node<K,V>(hash, key,
                                                              value, null);
                                    break;
                                }
                            }
                        }
                        else if (f instanceof TreeBin) {
                            Node<K,V> p;
                            binCount = 2;
                            if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key,
                                                           value)) != null) {
                                oldVal = p.val;
                                if (!onlyIfAbsent)
                                    p.val = value;
                            }
                        }
                    }
                }
                if (binCount != 0) {
                    if (binCount >= TREEIFY_THRESHOLD)
                        treeifyBin(tab, i);
                    if (oldVal != null)
                        return oldVal;
                    break;
                }
            }
        }
        addCount(1L, binCount);
        return null;
    }
/**
     * Returns the value to which the specified key is mapped,
     * or {@code null} if this map contains no mapping for the key.
     *
     * <p>More formally, if this map contains a mapping from a key
     * {@code k} to a value {@code v} such that {@code key.equals(k)},
     * then this method returns {@code v}; otherwise it returns
     * {@code null}.  (There can be at most one such mapping.)
     *
     * @throws NullPointerException if the specified key is null
     */
    public V get(Object key) {
        Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek;
        //获得hash值
        int h = spread(key.hashCode());
        //表非空，且该处不为空
        if ((tab = table) != null && (n = tab.length) > 0 &&
            (e = tabAt(tab, (n - 1) & h)) != null) {
            if ((eh = e.hash) == h) { //判断第1个
                if ((ek = e.key) == key || (ek != null && key.equals(ek)))
                    return e.val;
            }
            else if (eh < 0) //eh<0，找其他的
                return (p = e.find(h, key)) != null ? p.val : null;
            while ((e = e.next) != null) { //遍历
                if (e.hash == h &&
                    ((ek = e.key) == key || (ek != null && key.equals(ek))))
                    return e.val;
            }
        }
        return null;
    }

ConcurrentHashMap代码太多了，粘了好几次粘不上来。只粘几个方法吧。

阅后感

ConcurrentHashMap通过几个原子操作尽量减少加锁操作。

扩容部分没有看太明白，尤其时扩容时进行get操作。后续再继续学习。

/* * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. * * * * * * * * * * * * * * * * * * * * */
/* * * * * * * Written by Doug Lea with assistance from members of JCP JSR-166 * Expert Group and released to the public domain, as explained at * http://creativecommons.org/publicdomain/zero/1.0/ */
package java.util.concurrent;
import java.io.ObjectStreamField;import java.io.Serializable;import java.lang.reflect.ParameterizedType;import java.lang.reflect.Type;import java.util.AbstractMap;import java.util.Arrays;import java.util.Collection;import java.util.Comparator;import java.util.Enumeration;import java.util.HashMap;import java.util.Hashtable;import java.util.Iterator;import java.util.Map;import java.util.NoSuchElementException;import java.util.Set;import java.util.Spliterator;import java.util.concurrent.ConcurrentMap;import java.util.concurrent.ForkJoinPool;import java.util.concurrent.atomic.AtomicReference;import java.util.concurrent.locks.LockSupport;import java.util.concurrent.locks.ReentrantLock;import java.util.function.BiConsumer;import java.util.function.BiFunction;import java.util.function.BinaryOperator;import java.util.function.Consumer;import java.util.function.DoubleBinaryOperator;import java.util.function.Function;import java.util.function.IntBinaryOperator;import java.util.function.LongBinaryOperator;import java.util.function.ToDoubleBiFunction;import java.util.function.ToDoubleFunction;import java.util.function.ToIntBiFunction;import java.util.function.ToIntFunction;import java.util.function.ToLongBiFunction;import java.util.function.ToLongFunction;import java.util.stream.Stream;
/** * A hash table supporting full concurrency of retrievals and * high expected concurrency for updates. This class obeys the * same functional specification as {@link java.util.Hashtable}, and * includes versions of methods corresponding to each method of * {@code Hashtable}. However, even though all operations are * thread-safe, retrieval operations do not entail locking, * and there is not any support for locking the entire table * in a way that prevents all access. This class is fully * interoperable with {@code Hashtable} in programs that rely on its * thread safety but not on its synchronization details. * * Retrieval operations (including {@code get}) generally do not * block, so may overlap with update operations (including {@code put} * and {@code remove}). Retrievals reflect the results of the most * recently completed update operations holding upon their * onset. (More formally, an update operation for a given key bears a * happens-before relation with any (non-null) retrieval for * that key reporting the updated value.) For aggregate operations * such as {@code putAll} and {@code clear}, concurrent retrievals may * reflect insertion or removal of only some entries. Similarly, * Iterators, Spliterators and Enumerations return elements reflecting the * state of the hash table at some point at or since the creation of the * iterator/enumeration. They do not throw {@link * java.util.ConcurrentModificationException ConcurrentModificationException}. * However, iterators are designed to be used by only one thread at a time. * Bear in mind that the results of aggregate status methods including * {@code size}, {@code isEmpty}, and {@code containsValue} are typically * useful only when a map is not undergoing concurrent updates in other threads. * Otherwise the results of these methods reflect transient states * that may be adequate for monitoring or estimation purposes, but not * for program control. * * The table is dynamically expanded when there are too many * collisions (i.e., keys that have distinct hash codes but fall into * the same slot modulo the table size), with the expected average * effect of maintaining roughly two bins per mapping (corresponding * to a 0.75 load factor threshold for resizing). There may be much * variance around this average as mappings are added and removed, but * overall, this maintains a commonly accepted time/space tradeoff for * hash tables. However, resizing this or any other kind of hash * table may be a relatively slow operation. When possible, it is a * good idea to provide a size estimate as an optional {@code * initialCapacity} constructor argument. An additional optional * {@code loadFactor} constructor argument provides a further means of * customizing initial table capacity by specifying the table density * to be used in calculating the amount of space to allocate for the * given number of elements. Also, for compatibility with previous * versions of this class, constructors may optionally specify an * expected {@code concurrencyLevel} as an additional hint for * internal sizing. Note that using many keys with exactly the same * {@code hashCode()} is a sure way to slow down performance of any * hash table. To ameliorate impact, when keys are {@link Comparable}, * this class may use comparison order among keys to help break ties. * * A {@link Set} projection of a ConcurrentHashMap may be created * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed * (using {@link #keySet(Object)} when only keys are of interest, and the * mapped values are (perhaps transiently) not used or all take the * same mapping value. * * A ConcurrentHashMap can be used as scalable frequency map (a * form of histogram or multiset) by using {@link * java.util.concurrent.atomic.LongAdder} values and initializing via * {@link #computeIfAbsent computeIfAbsent}. For example, to add a count * to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use * {@code freqs.computeIfAbsent(k -> new LongAdder()).increment();} * * This class and its views and iterators implement all of the * optional methods of the {@link Map} and {@link Iterator} * interfaces. * * Like {@link Hashtable} but unlike {@link HashMap}, this class * does not allow {@code null} to be used as a key or value. * * ConcurrentHashMaps support a set of sequential and parallel bulk * operations that, unlike most {@link Stream} methods, are designed * to be safely, and often sensibly, applied even with maps that are * being concurrently updated by other threads; for example, when * computing a snapshot summary of the values in a shared registry. * There are three kinds of operation, each with four forms, accepting * functions with Keys, Values, Entries, and (Key, Value) arguments * and/or return values. Because the elements of a ConcurrentHashMap * are not ordered in any particular way, and may be processed in * different orders in different parallel executions, the correctness * of supplied functions should not depend on any ordering, or on any * other objects or values that may transiently change while * computation is in progress; and except for forEach actions, should * ideally be side-effect-free. Bulk operations on {@link java.util.Map.Entry} * objects do not support method {@code setValue}. * * <ul> * <li> forEach: Perform a given action on each element. * A variant form applies a given transformation on each element * before performing the action.</li> * * <li> search: Return the first available non-null result of * applying a given function on each element; skipping further * search when a result is found.</li> * * <li> reduce: Accumulate each element. The supplied reduction * function cannot rely on ordering (more formally, it should be * both associative and commutative). There are five variants: * * <ul> * * <li> Plain reductions. (There is not a form of this method for * (key, value) function arguments since there is no corresponding * return type.)</li> * * <li> Mapped reductions that accumulate the results of a given * function applied to each element.</li> * * <li> Reductions to scalar doubles, longs, and ints, using a * given basis value.</li> * * </ul> * </li> * </ul> * * These bulk operations accept a {@code parallelismThreshold} * argument. Methods proceed sequentially if the current map size is * estimated to be less than the given threshold. Using a value of * {@code Long.MAX_VALUE} suppresses all parallelism. Using a value * of {@code 1} results in maximal parallelism by partitioning into * enough subtasks to fully utilize the {@link * ForkJoinPool#commonPool()} that is used for all parallel * computations. Normally, you would initially choose one of these * extreme values, and then measure performance of using in-between * values that trade off overhead versus throughput. * * The concurrency properties of bulk operations follow * from those of ConcurrentHashMap: Any non-null result returned * from {@code get(key)} and related access methods bears a * happens-before relation with the associated insertion or * update. The result of any bulk operation reflects the * composition of these per-element relations (but is not * necessarily atomic with respect to the map as a whole unless it * is somehow known to be quiescent). Conversely, because keys * and values in the map are never null, null serves as a reliable * atomic indicator of the current lack of any result. To * maintain this property, null serves as an implicit basis for * all non-scalar reduction operations. For the double, long, and * int versions, the basis should be one that, when combined with * any other value, returns that other value (more formally, it * should be the identity element for the reduction). Most common * reductions have these properties; for example, computing a sum * with basis 0 or a minimum with basis MAX_VALUE. * * Search and transformation functions provided as arguments * should similarly return null to indicate the lack of any result * (in which case it is not used). In the case of mapped * reductions, this also enables transformations to serve as * filters, returning null (or, in the case of primitive * specializations, the identity basis) if the element should not * be combined. You can create compound transformations and * filterings by composing them yourself under this "null means * there is nothing there now" rule before using them in search or * reduce operations. * * Methods accepting and/or returning Entry arguments maintain * key-value associations. They may be useful for example when * finding the key for the greatest value. Note that "plain" Entry * arguments can be supplied using {@code new * AbstractMap.SimpleEntry(k,v)}. * * Bulk operations may complete abruptly, throwing an * exception encountered in the application of a supplied * function. Bear in mind when handling such exceptions that other * concurrently executing functions could also have thrown * exceptions, or would have done so if the first exception had * not occurred. * * Speedups for parallel compared to sequential forms are common * but not guaranteed. Parallel operations involving brief functions * on small maps may execute more slowly than sequential forms if the * underlying work to parallelize the computation is more expensive * than the computation itself. Similarly, parallelization may not * lead to much actual parallelism if all processors are busy * performing unrelated tasks. * * All arguments to all task methods must be non-null. * * This class is a member of the * <a href="{@docRoot}/../technotes/guides/collections/index.html"> * Java Collections Framework</a>. * * @since 1.5 * @author Doug Lea * @param <K> the type of keys maintained by this map * @param <V> the type of mapped values */public class ConcurrentHashMap<K,V> extends AbstractMap<K,V> implements ConcurrentMap<K,V>, Serializable { private static final long serialVersionUID = 7249069246763182397L;
/* * Overview: * * The primary design goal of this hash table is to maintain * concurrent readability (typically method get(), but also * iterators and related methods) while minimizing update * contention. Secondary goals are to keep space consumption about * the same or better than java.util.HashMap, and to support high * initial insertion rates on an empty table by many threads. * * This map usually acts as a binned (bucketed) hash table. Each * key-value mapping is held in a Node. Most nodes are instances * of the basic Node class with hash, key, value, and next * fields. However, various subclasses exist: TreeNodes are * arranged in balanced trees, not lists. TreeBins hold the roots * of sets of TreeNodes. ForwardingNodes are placed at the heads * of bins during resizing. ReservationNodes are used as * placeholders while establishing values in computeIfAbsent and * related methods. The types TreeBin, ForwardingNode, and * ReservationNode do not hold normal user keys, values, or * hashes, and are readily distinguishable during search etc * because they have negative hash fields and null key and value * fields. (These special nodes are either uncommon or transient, * so the impact of carrying around some unused fields is * insignificant.) * * The table is lazily initialized to a power-of-two size upon the * first insertion. Each bin in the table normally contains a * list of Nodes (most often, the list has only zero or one Node). * Table accesses require volatile/atomic reads, writes, and * CASes. Because there is no other way to arrange this without * adding further indirections, we use intrinsics * (sun.misc.Unsafe) operations. * * We use the top (sign) bit of Node hash fields for control * purposes -- it is available anyway because of addressing * constraints. Nodes with negative hash fields are specially * handled or ignored in map methods. * * Insertion (via put or its variants) of the first node in an * empty bin is performed by just CASing it to the bin. This is * by far the most common case for put operations under most * key/hash distributions. Other update operations (insert, * delete, and replace) require locks. We do not want to waste * the space required to associate a distinct lock object with * each bin, so instead use the first node of a bin list itself as * a lock. Locking support for these locks relies on builtin * "synchronized" monitors. * * Using the first node of a list as a lock does not by itself * suffice though: When a node is locked, any update must first * validate that it is still the first node after locking it, and * retry if not. Because new nodes are always appended to lists, * once a node is first in a bin, it remains first until deleted * or the bin becomes invalidated (upon resizing). * * The main disadvantage of per-bin locks is that other update * operations on other nodes in a bin list protected by the same * lock can stall, for example when user equals() or mapping * functions take a long time. However, statistically, under * random hash codes, this is not a common problem. Ideally, the * frequency of nodes in bins follows a Poisson distribution * (http://en.wikipedia.org/wiki/Poisson_distribution) with a * parameter of about 0.5 on average, given the resizing threshold * of 0.75, although with a large variance because of resizing * granularity. Ignoring variance, the expected occurrences of * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The * first values are: * * 0: 0.60653066 * 1: 0.30326533 * 2: 0.07581633 * 3: 0.01263606 * 4: 0.00157952 * 5: 0.00015795 * 6: 0.00001316 * 7: 0.00000094 * 8: 0.00000006 * more: less than 1 in ten million * * Lock contention probability for two threads accessing distinct * elements is roughly 1 / (8 * #elements) under random hashes. * * Actual hash code distributions encountered in practice * sometimes deviate significantly from uniform randomness. This * includes the case when N > (1<<30), so some keys MUST collide. * Similarly for dumb or hostile usages in which multiple keys are * designed to have identical hash codes or ones that differs only * in masked-out high bits. So we use a secondary strategy that * applies when the number of nodes in a bin exceeds a * threshold. These TreeBins use a balanced tree to hold nodes (a * specialized form of red-black trees), bounding search time to * O(log N). Each search step in a TreeBin is at least twice as * slow as in a regular list, but given that N cannot exceed * (1<<64) (before running out of addresses) this bounds search * steps, lock hold times, etc, to reasonable constants (roughly * 100 nodes inspected per operation worst case) so long as keys * are Comparable (which is very common -- String, Long, etc). * TreeBin nodes (TreeNodes) also maintain the same "next" * traversal pointers as regular nodes, so can be traversed in * iterators in the same way. * * The table is resized when occupancy exceeds a percentage * threshold (nominally, 0.75, but see below). Any thread * noticing an overfull bin may assist in resizing after the * initiating thread allocates and sets up the replacement array. * However, rather than stalling, these other threads may proceed * with insertions etc. The use of TreeBins shields us from the * worst case effects of overfilling while resizes are in * progress. Resizing proceeds by transferring bins, one by one, * from the table to the next table. However, threads claim small * blocks of indices to transfer (via field transferIndex) before * doing so, reducing contention. A generation stamp in field * sizeCtl ensures that resizings do not overlap. Because we are * using power-of-two expansion, the elements from each bin must * either stay at same index, or move with a power of two * offset. We eliminate unnecessary node creation by catching * cases where old nodes can be reused because their next fields * won't change. On average, only about one-sixth of them need * cloning when a table doubles. The nodes they replace will be * garbage collectable as soon as they are no longer referenced by * any reader thread that may be in the midst of concurrently * traversing table. Upon transfer, the old table bin contains * only a special forwarding node (with hash field "MOVED") that * contains the next table as its key. On encountering a * forwarding node, access and update operations restart, using * the new table. * * Each bin transfer requires its bin lock, which can stall * waiting for locks while resizing. However, because other * threads can join in and help resize rather than contend for * locks, average aggregate waits become shorter as resizing * progresses. The transfer operation must also ensure that all * accessible bins in both the old and new table are usable by any * traversal. This is arranged in part by proceeding from the * last bin (table.length - 1) up towards the first. Upon seeing * a forwarding node, traversals (see class Traverser) arrange to * move to the new table without revisiting nodes. To ensure that * no intervening nodes are skipped even when moved out of order, * a stack (see class TableStack) is created on first encounter of * a forwarding node during a traversal, to maintain its place if * later processing the current table. The need for these * save/restore mechanics is relatively rare, but when one * forwarding node is encountered, typically many more will be. * So Traversers use a simple caching scheme to avoid creating so * many new TableStack nodes. (Thanks to Peter Levart for * suggesting use of a stack here.) * * The traversal scheme also applies to partial traversals of * ranges of bins (via an alternate Traverser constructor) * to support partitioned aggregate operations. Also, read-only * operations give up if ever forwarded to a null table, which * provides support for shutdown-style clearing, which is also not * currently implemented. * * Lazy table initialization minimizes footprint until first use, * and also avoids resizings when the first operation is from a * putAll, constructor with map argument, or deserialization. * These cases attempt to override the initial capacity settings, * but harmlessly fail to take effect in cases of races. * * The element count is maintained using a specialization of * LongAdder. We need to incorporate a specialization rather than * just use a LongAdder in order to access implicit * contention-sensing that leads to creation of multiple * CounterCells. The counter mechanics avoid contention on * updates but can encounter cache thrashing if read too * frequently during concurrent access. To avoid reading so often, * resizing under contention is attempted only upon adding to a * bin already holding two or more nodes. Under uniform hash * distributions, the probability of this occurring at threshold * is around 13%, meaning that only about 1 in 8 puts check * threshold (and after resizing, many fewer do so). * * TreeBins use a special form of comparison for search and * related operations (which is the main reason we cannot use * existing collections such as TreeMaps). TreeBins contain * Comparable elements, but may contain others, as well as * elements that are Comparable but not necessarily Comparable for * the same T, so we cannot invoke compareTo among them. To handle * this, the tree is ordered primarily by hash value, then by * Comparable.compareTo order if applicable. On lookup at a node, * if elements are not comparable or compare as 0 then both left * and right children may need to be searched in the case of tied * hash values. (This corresponds to the full list search that * would be necessary if all elements were non-Comparable and had * tied hashes.) On insertion, to keep a total ordering (or as * close as is required here) across rebalancings, we compare * classes and identityHashCodes as tie-breakers. The red-black * balancing code is updated from pre-jdk-collections * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) * based in turn on Cormen, Leiserson, and Rivest "Introduction to * Algorithms" (CLR). * * TreeBins also require an additional locking mechanism. While * list traversal is always possible by readers even during * updates, tree traversal is not, mainly because of tree-rotations * that may change the root node and/or its linkages. TreeBins * include a simple read-write lock mechanism parasitic on the * main bin-synchronization strategy: Structural adjustments * associated with an insertion or removal are already bin-locked * (and so cannot conflict with other writers) but must wait for * ongoing readers to finish. Since there can be only one such * waiter, we use a simple scheme using a single "waiter" field to * block writers. However, readers need never block. If the root * lock is held, they proceed along the slow traversal path (via * next-pointers) until the lock becomes available or the list is * exhausted, whichever comes first. These cases are not fast, but * maximize aggregate expected throughput. * * Maintaining API and serialization compatibility with previous * versions of this class introduces several oddities. Mainly: We * leave untouched but unused constructor arguments refering to * concurrencyLevel. We accept a loadFactor constructor argument, * but apply it only to initial table capacity (which is the only * time that we can guarantee to honor it.) We also declare an * unused "Segment" class that is instantiated in minimal form * only when serializing. * * Also, solely for compatibility with previous versions of this * class, it extends AbstractMap, even though all of its methods * are overridden, so it is just useless baggage. * * This file is organized to make things a little easier to follow * while reading than they might otherwise: First the main static * declarations and utilities, then fields, then main public * methods (with a few factorings of multiple public methods into * internal ones), then sizing methods, trees, traversers, and * bulk operations. */
/* ---------------- Constants -------------- */
/** * The largest possible table capacity. This value must be * exactly 1<<30 to stay within Java array allocation and indexing * bounds for power of two table sizes, and is further required * because the top two bits of 32bit hash fields are used for * control purposes. */ private static final int MAXIMUM_CAPACITY = 1 << 30;
/** * The default initial table capacity. Must be a power of 2 * (i.e., at least 1) and at most MAXIMUM_CAPACITY. */ private static final int DEFAULT_CAPACITY = 16;
/** * The largest possible (non-power of two) array size. * Needed by toArray and related methods. */ static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/** * The default concurrency level for this table. Unused but * defined for compatibility with previous versions of this class. */ private static final int DEFAULT_CONCURRENCY_LEVEL = 16;
/** * The load factor for this table. Overrides of this value in * constructors affect only the initial table capacity. The * actual floating point value isn't normally used -- it is * simpler to use expressions such as {@code n - (n >>> 2)} for * the associated resizing threshold. */ private static final float LOAD_FACTOR = 0.75f;
/** * The bin count threshold for using a tree rather than list for a * bin. Bins are converted to trees when adding an element to a * bin with at least this many nodes. The value must be greater * than 2, and should be at least 8 to mesh with assumptions in * tree removal about conversion back to plain bins upon * shrinkage. */ static final int TREEIFY_THRESHOLD = 8;
/** * The bin count threshold for untreeifying a (split) bin during a * resize operation. Should be less than TREEIFY_THRESHOLD, and at * most 6 to mesh with shrinkage detection under removal. */ static final int UNTREEIFY_THRESHOLD = 6;
/** * The smallest table capacity for which bins may be treeified. * (Otherwise the table is resized if too many nodes in a bin.) * The value should be at least 4 * TREEIFY_THRESHOLD to avoid * conflicts between resizing and treeification thresholds. */ static final int MIN_TREEIFY_CAPACITY = 64;
/** * Minimum number of rebinnings per transfer step. Ranges are * subdivided to allow multiple resizer threads. This value * serves as a lower bound to avoid resizers encountering * excessive memory contention. The value should be at least * DEFAULT_CAPACITY. */ private static final int MIN_TRANSFER_STRIDE = 16;
/** * The number of bits used for generation stamp in sizeCtl. * Must be at least 6 for 32bit arrays. */ private static int RESIZE_STAMP_BITS = 16;
/** * The maximum number of threads that can help resize. * Must fit in 32 - RESIZE_STAMP_BITS bits. */ private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1;
/** * The bit shift for recording size stamp in sizeCtl. */ private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS;
/* * Encodings for Node hash fields. See above for explanation. */ static final int MOVED = -1; // hash for forwarding nodes static final int TREEBIN = -2; // hash for roots of trees static final int RESERVED = -3; // hash for transient reservations static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash
/** Number of CPUS, to place bounds on some sizings */ static final int NCPU = Runtime.getRuntime().availableProcessors();
/** For serialization compatibility. */ private static final ObjectStreamField[] serialPersistentFields = { new ObjectStreamField("segments", Segment[].class), new ObjectStreamField("segmentMask", Integer.TYPE), new ObjectStreamField("segmentShift", Integer.TYPE) };
/* ---------------- Nodes -------------- */
/** * Key-value entry. This class is never exported out as a * user-mutable Map.Entry (i.e., one supporting setValue; see * MapEntry below), but can be used for read-only traversals used * in bulk tasks. Subclasses of Node with a negative hash field * are special, and contain null keys and values (but are never * exported). Otherwise, keys and vals are never null. */ static class Node<K,V> implements Map.Entry<K,V> { final int hash; final K key; volatile V val; volatile Node<K,V> next;
Node(int hash, K key, V val, Node<K,V> next) { this.hash = hash; this.key = key; this.val = val; this.next = next; }
public final K getKey() { return key; } public final V getValue() { return val; } public final int hashCode() { return key.hashCode() ^ val.hashCode(); } public final String toString(){ return key + "=" + val; } public final V setValue(V value) { throw new UnsupportedOperationException(); }
public final boolean equals(Object o) { Object k, v, u; Map.Entry<?,?> e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?,?>)o).getKey()) != null && (v = e.getValue()) != null && (k == key || k.equals(key)) && (v == (u = val) || v.equals(u))); }
/** * Virtualized support for map.get(); overridden in subclasses. */ Node<K,V> find(int h, Object k) { Node<K,V> e = this; if (k != null) { do { K ek; if (e.hash == h && ((ek = e.key) == k || (ek != null && k.equals(ek)))) return e; } while ((e = e.next) != null); } return null; } }
/* ---------------- Static utilities -------------- */
/** * Spreads (XORs) higher bits of hash to lower and also forces top * bit to 0. Because the table uses power-of-two masking, sets of * hashes that vary only in bits above the current mask will * always collide. (Among known examples are sets of Float keys * holding consecutive whole numbers in small tables.) So we * apply a transform that spreads the impact of higher bits * downward. There is a tradeoff between speed, utility, and * quality of bit-spreading. Because many common sets of hashes * are already reasonably distributed (so don't benefit from * spreading), and because we use trees to handle large sets of * collisions in bins, we just XOR some shifted bits in the * cheapest possible way to reduce systematic lossage, as well as * to incorporate impact of the highest bits that would otherwise * never be used in index calculations because of table bounds. */ static final int spread(int h) { return (h ^ (h >>> 16)) & HASH_BITS; }
/** * Returns a power of two table size for the given desired capacity. * See Hackers Delight, sec 3.2 */ private static final int tableSizeFor(int c) { int n = c - 1; n |= n >>> 1; n |= n >>> 2; n |= n >>> 4; n |= n >>> 8; n |= n >>> 16; return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; }
/** * Returns x's Class if it is of the form "class C implements * Comparable<C>", else null. */ static Class<?> comparableClassFor(Object x) { if (x instanceof Comparable) { Class<?> c; Type[] ts, as; Type t; ParameterizedType p; if ((c = x.getClass()) == String.class) // bypass checks return c; if ((ts = c.getGenericInterfaces()) != null) { for (int i = 0; i < ts.length; ++i) { if (((t = ts[i]) instanceof ParameterizedType) && ((p = (ParameterizedType)t).getRawType() == Comparable.class) && (as = p.getActualTypeArguments()) != null && as.length == 1 && as[0] == c) // type arg is c return c; } } } return null; }
/** * Returns k.compareTo(x) if x matches kc (k's screened comparable * class), else 0. */ @SuppressWarnings({"rawtypes","unchecked"}) // for cast to Comparable static int compareComparables(Class<?> kc, Object k, Object x) { return (x == null || x.getClass() != kc ? 0 : ((Comparable)k).compareTo(x)); }
/* ---------------- Table element access -------------- */
/* * Volatile access methods are used for table elements as well as * elements of in-progress next table while resizing. All uses of * the tab arguments must be null checked by callers. All callers * also paranoically precheck that tab's length is not zero (or an * equivalent check), thus ensuring that any index argument taking * the form of a hash value anded with (length - 1) is a valid * index. Note that, to be correct wrt arbitrary concurrency * errors by users, these checks must operate on local variables, * which accounts for some odd-looking inline assignments below. * Note that calls to setTabAt always occur within locked regions, * and so in principle require only release ordering, not * full volatile semantics, but are currently coded as volatile * writes to be conservative. */
@SuppressWarnings("unchecked") static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) { return (Node<K,V>)U.getObjectVolatile(tab, ((long)i << ASHIFT) + ABASE); }
static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i, Node<K,V> c, Node<K,V> v) { return U.compareAndSwapObject(tab, ((long)i << ASHIFT) + ABASE, c, v); }
static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) { U.putObjectVolatile(tab, ((long)i << ASHIFT) + ABASE, v); }
/* ---------------- Fields -------------- */
/** * The array of bins. Lazily initialized upon first insertion. * Size is always a power of two. Accessed directly by iterators. */ transient volatile Node<K,V>[] table;
/** * The next table to use; non-null only while resizing. */ private transient volatile Node<K,V>[] nextTable;
/** * Base counter value, used mainly when there is no contention, * but also as a fallback during table initialization * races. Updated via CAS. */ private transient volatile long baseCount;
/** * Table initialization and resizing control. When negative, the * table is being initialized or resized: -1 for initialization, * else -(1 + the number of active resizing threads). Otherwise, * when table is null, holds the initial table size to use upon * creation, or 0 for default. After initialization, holds the * next element count value upon which to resize the table. */ private transient volatile int sizeCtl;
/** * The next table index (plus one) to split while resizing. */ private transient volatile int transferIndex;
/** * Spinlock (locked via CAS) used when resizing and/or creating CounterCells. */ private transient volatile int cellsBusy;
/** * Table of counter cells. When non-null, size is a power of 2. */ private transient volatile CounterCell[] counterCells;
// views private transient KeySetView<K,V> keySet; private transient ValuesView<K,V> values; private transient EntrySetView<K,V> entrySet;

/* ---------------- Public operations -------------- */
/** * Creates a new, empty map with the default initial table size (16). */ public ConcurrentHashMap() { }
/** * Creates a new, empty map with an initial table size * accommodating the specified number of elements without the need * to dynamically resize. * * @param initialCapacity The implementation performs internal * sizing to accommodate this many elements. * @throws IllegalArgumentException if the initial capacity of * elements is negative */ public ConcurrentHashMap(int initialCapacity) { if (initialCapacity < 0) throw new IllegalArgumentException(); int cap = ((initialCapacity >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : tableSizeFor(initialCapacity + (initialCapacity >>> 1) + 1)); this.sizeCtl = cap; }
/** * Creates a new map with the same mappings as the given map. * * @param m the map */ public ConcurrentHashMap(Map<? extends K, ? extends V> m) { this.sizeCtl = DEFAULT_CAPACITY; putAll(m); }
/** * Creates a new, empty map with an initial table size based on * the given number of elements ({@code initialCapacity}) and * initial table density ({@code loadFactor}). * * @param initialCapacity the initial capacity. The implementation * performs internal sizing to accommodate this many elements, * given the specified load factor. * @param loadFactor the load factor (table density) for * establishing the initial table size * @throws IllegalArgumentException if the initial capacity of * elements is negative or the load factor is nonpositive * * @since 1.6 */ public ConcurrentHashMap(int initialCapacity, float loadFactor) { this(initialCapacity, loadFactor, 1); }
/** * Creates a new, empty map with an initial table size based on * the given number of elements ({@code initialCapacity}), table * density ({@code loadFactor}), and number of concurrently * updating threads ({@code concurrencyLevel}). * * @param initialCapacity the initial capacity. The implementation * performs internal sizing to accommodate this many elements, * given the specified load factor. * @param loadFactor the load factor (table density) for * establishing the initial table size * @param concurrencyLevel the estimated number of concurrently * updating threads. The implementation may use this value as * a sizing hint. * @throws IllegalArgumentException if the initial capacity is * negative or the load factor or concurrencyLevel are * nonpositive */ public ConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel) { if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) throw new IllegalArgumentException(); if (initialCapacity < concurrencyLevel) // Use at least as many bins initialCapacity = concurrencyLevel; // as estimated threads long size = (long)(1.0 + (long)initialCapacity / loadFactor); int cap = (size >= (long)MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : tableSizeFor((int)size); this.sizeCtl = cap; }
// Original (since JDK1.2) Map methods
/** * {@inheritDoc} */ public int size() { long n = sumCount(); return ((n < 0L) ? 0 : (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int)n); }
/** * {@inheritDoc} */ public boolean isEmpty() { return sumCount() <= 0L; // ignore transient negative values }
/** * Returns the value to which the specified key is mapped, * or {@code null} if this map contains no mapping for the key. * * More formally, if this map contains a mapping from a key * {@code k} to a value {@code v} such that {@code key.equals(k)}, * then this method returns {@code v}; otherwise it returns * {@code null}. (There can be at most one such mapping.) * * @throws NullPointerException if the specified key is null */ public V get(Object key) { Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek; //获得hash值 int h = spread(key.hashCode()); //表非空，且该处不为空 if ((tab = table) != null && (n = tab.length) > 0 && (e = tabAt(tab, (n - 1) & h)) != null) { if ((eh = e.hash) == h) { //判断第1个 if ((ek = e.key) == key || (ek != null && key.equals(ek))) return e.val; } else if (eh < 0) //eh<0，找其他的 return (p = e.find(h, key)) != null ? p.val : null; while ((e = e.next) != null) { //遍历 if (e.hash == h && ((ek = e.key) == key || (ek != null && key.equals(ek)))) return e.val; } } return null; }
/** * Tests if the specified object is a key in this table. * * @param key possible key * @return {@code true} if and only if the specified object * is a key in this table, as determined by the * {@code equals} method; {@code false} otherwise * @throws NullPointerException if the specified key is null */ public boolean containsKey(Object key) { return get(key) != null; }
/** * Returns {@code true} if this map maps one or more keys to the * specified value. Note: This method may require a full traversal * of the map, and is much slower than method {@code containsKey}. * * @param value value whose presence in this map is to be tested * @return {@code true} if this map maps one or more keys to the * specified value * @throws NullPointerException if the specified value is null */ public boolean containsValue(Object value) { if (value == null) throw new NullPointerException(); Node<K,V>[] t; if ((t = table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) { V v; if ((v = p.val) == value || (v != null && value.equals(v))) return true; } } return false; }
/** * Maps the specified key to the specified value in this table. * Neither the key nor the value can be null. * * The value can be retrieved by calling the {@code get} method * with a key that is equal to the original key. * * @param key key with which the specified value is to be associated * @param value value to be associated with the specified key * @return the previous value associated with {@code key}, or * {@code null} if there was no mapping for {@code key} * @throws NullPointerException if the specified key or value is null */ public V put(K key, V value) { return putVal(key, value, false); }
/** Implementation for put and putIfAbsent */ final V putVal(K key, V value, boolean onlyIfAbsent) { if (key == null || value == null) throw new NullPointerException(); int hash = spread(key.hashCode()); int binCount = 0; for (Node<K,V>[] tab = table;;) { Node<K,V> f; int n, i, fh; //tab为空，则初始化 if (tab == null || (n = tab.length) == 0) tab = initTable(); else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) { //该槽为空，则尝试插入 if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value, null))) break; // no lock when adding to empty bin } else if ((fh = f.hash) == MOVED) //正在移动， tab = helpTransfer(tab, f); else { V oldVal = null; synchronized (f) { //对该槽进行加锁 if (tabAt(tab, i) == f) { if (fh >= 0) { binCount = 1; for (Node<K,V> e = f;; ++binCount) { K ek; if (e.hash == hash && ((ek = e.key) == key || (ek != null && key.equals(ek)))) { oldVal = e.val; if (!onlyIfAbsent) e.val = value; break; } Node<K,V> pred = e; if ((e = e.next) == null) { pred.next = new Node<K,V>(hash, key, value, null); break; } } } else if (f instanceof TreeBin) { Node<K,V> p; binCount = 2; if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key, value)) != null) { oldVal = p.val; if (!onlyIfAbsent) p.val = value; } } } } if (binCount != 0) { if (binCount >= TREEIFY_THRESHOLD) treeifyBin(tab, i); if (oldVal != null) return oldVal; break; } } } addCount(1L, binCount); return null; }
/** * Copies all of the mappings from the specified map to this one. * These mappings replace any mappings that this map had for any of the * keys currently in the specified map. * * @param m mappings to be stored in this map */ public void putAll(Map<? extends K, ? extends V> m) { tryPresize(m.size()); for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) putVal(e.getKey(), e.getValue(), false); }
/** * Removes the key (and its corresponding value) from this map. * This method does nothing if the key is not in the map. * * @param key the key that needs to be removed * @return the previous value associated with {@code key}, or * {@code null} if there was no mapping for {@code key} * @throws NullPointerException if the specified key is null */ public V remove(Object key) { return replaceNode(key, null, null); }
/** * Implementation for the four public remove/replace methods: * Replaces node value with v, conditional upon match of cv if * non-null. If resulting value is null, delete. */ final V replaceNode(Object key, V value, Object cv) { int hash = spread(key.hashCode()); for (Node<K,V>[] tab = table;;) { Node<K,V> f; int n, i, fh; if (tab == null || (n = tab.length) == 0 || (f = tabAt(tab, i = (n - 1) & hash)) == null) break; else if ((fh = f.hash) == MOVED) tab = helpTransfer(tab, f); else { V oldVal = null; boolean validated = false; synchronized (f) { if (tabAt(tab, i) == f) { if (fh >= 0) { validated = true; for (Node<K,V> e = f, pred = null;;) { K ek; if (e.hash == hash && ((ek = e.key) == key || (ek != null && key.equals(ek)))) { V ev = e.val; if (cv == null || cv == ev || (ev != null && cv.equals(ev))) { oldVal = ev; if (value != null) e.val = value; else if (pred != null) pred.next = e.next; else setTabAt(tab, i, e.next); } break; } pred = e; if ((e = e.next) == null) break; } } else if (f instanceof TreeBin) { validated = true; TreeBin<K,V> t = (TreeBin<K,V>)f; TreeNode<K,V> r, p; if ((r = t.root) != null && (p = r.findTreeNode(hash, key, null)) != null) { V pv = p.val; if (cv == null || cv == pv || (pv != null && cv.equals(pv))) { oldVal = pv; if (value != null) p.val = value; else if (t.removeTreeNode(p)) setTabAt(tab, i, untreeify(t.first)); } } } } } if (validated) { if (oldVal != null) { if (value == null) addCount(-1L, -1); return oldVal; } break; } } } return null; }
/** * Removes all of the mappings from this map. */ public void clear() { long delta = 0L; // negative number of deletions int i = 0; Node<K,V>[] tab = table; while (tab != null && i < tab.length) { int fh; Node<K,V> f = tabAt(tab, i); if (f == null) ++i; else if ((fh = f.hash) == MOVED) { tab = helpTransfer(tab, f); i = 0; // restart } else { synchronized (f) { if (tabAt(tab, i) == f) { Node<K,V> p = (fh >= 0 ? f : (f instanceof TreeBin) ? ((TreeBin<K,V>)f).first : null); while (p != null) { --delta; p = p.next; } setTabAt(tab, i++, null); } } } } if (delta != 0L) addCount(delta, -1); }
/** * Returns a {@link Set} view of the keys contained in this map. * The set is backed by the map, so changes to the map are * reflected in the set, and vice-versa. The set supports element * removal, which removes the corresponding mapping from this map, * via the {@code Iterator.remove}, {@code Set.remove}, * {@code removeAll}, {@code retainAll}, and {@code clear} * operations. It does not support the {@code add} or * {@code addAll} operations. * * The view's iterators and spliterators are * <a href="package-summary.html#Weakly">weakly consistent</a>. * * The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}, * {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}. * * @return the set view */ public KeySetView<K,V> keySet() { KeySetView<K,V> ks; return (ks = keySet) != null ? ks : (keySet = new KeySetView<K,V>(this, null)); }
/** * Returns a {@link Collection} view of the values contained in this map. * The collection is backed by the map, so changes to the map are * reflected in the collection, and vice-versa. The collection * supports element removal, which removes the corresponding * mapping from this map, via the {@code Iterator.remove}, * {@code Collection.remove}, {@code removeAll}, * {@code retainAll}, and {@code clear} operations. It does not * support the {@code add} or {@code addAll} operations. * * The view's iterators and spliterators are * <a href="package-summary.html#Weakly">weakly consistent</a>. * * The view's {@code spliterator} reports {@link Spliterator#CONCURRENT} * and {@link Spliterator#NONNULL}. * * @return the collection view */ public Collection<V> values() { ValuesView<K,V> vs; return (vs = values) != null ? vs : (values = new ValuesView<K,V>(this)); }
/** * Returns a {@link Set} view of the mappings contained in this map. * The set is backed by the map, so changes to the map are * reflected in the set, and vice-versa. The set supports element * removal, which removes the corresponding mapping from the map, * via the {@code Iterator.remove}, {@code Set.remove}, * {@code removeAll}, {@code retainAll}, and {@code clear} * operations. * * The view's iterators and spliterators are * <a href="package-summary.html#Weakly">weakly consistent</a>. * * The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}, * {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}. * * @return the set view */ public Set<Map.Entry<K,V>> entrySet() { EntrySetView<K,V> es; return (es = entrySet) != null ? es : (entrySet = new EntrySetView<K,V>(this)); }
/** * Returns the hash code value for this {@link Map}, i.e., * the sum of, for each key-value pair in the map, * {@code key.hashCode() ^ value.hashCode()}. * * @return the hash code value for this map */ public int hashCode() { int h = 0; Node<K,V>[] t; if ((t = table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) h += p.key.hashCode() ^ p.val.hashCode(); } return h; }
/** * Returns a string representation of this map. The string * representation consists of a list of key-value mappings (in no * particular order) enclosed in braces ("{@code {}}"). Adjacent * mappings are separated by the characters {@code ", "} (comma * and space). Each key-value mapping is rendered as the key * followed by an equals sign ("{@code =}") followed by the * associated value. * * @return a string representation of this map */ public String toString() { Node<K,V>[] t; int f = (t = table) == null ? 0 : t.length; Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f); StringBuilder sb = new StringBuilder(); sb.append('{'); Node<K,V> p; if ((p = it.advance()) != null) { for (;;) { K k = p.key; V v = p.val; sb.append(k == this ? "(this Map)" : k); sb.append('='); sb.append(v == this ? "(this Map)" : v); if ((p = it.advance()) == null) break; sb.append(',').append(' '); } } return sb.append('}').toString(); }
/** * Compares the specified object with this map for equality. * Returns {@code true} if the given object is a map with the same * mappings as this map. This operation may return misleading * results if either map is concurrently modified during execution * of this method. * * @param o object to be compared for equality with this map * @return {@code true} if the specified object is equal to this map */ public boolean equals(Object o) { if (o != this) { if (!(o instanceof Map)) return false; Map<?,?> m = (Map<?,?>) o; Node<K,V>[] t; int f = (t = table) == null ? 0 : t.length; Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f); for (Node<K,V> p; (p = it.advance()) != null; ) { V val = p.val; Object v = m.get(p.key); if (v == null || (v != val && !v.equals(val))) return false; } for (Map.Entry<?,?> e : m.entrySet()) { Object mk, mv, v; if ((mk = e.getKey()) == null || (mv = e.getValue()) == null || (v = get(mk)) == null || (mv != v && !mv.equals(v))) return false; } } return true; }
/** * Stripped-down version of helper class used in previous version, * declared for the sake of serialization compatibility */ static class Segment<K,V> extends ReentrantLock implements Serializable { private static final long serialVersionUID = 2249069246763182397L; final float loadFactor; Segment(float lf) { this.loadFactor = lf; } }
/** * Saves the state of the {@code ConcurrentHashMap} instance to a * stream (i.e., serializes it). * @param s the stream * @throws java.io.IOException if an I/O error occurs * @serialData * the key (Object) and value (Object) * for each key-value mapping, followed by a null pair. * The key-value mappings are emitted in no particular order. */ private void writeObject(java.io.ObjectOutputStream s) throws java.io.IOException { // For serialization compatibility // Emulate segment calculation from previous version of this class int sshift = 0; int ssize = 1; while (ssize < DEFAULT_CONCURRENCY_LEVEL) { ++sshift; ssize <<= 1; } int segmentShift = 32 - sshift; int segmentMask = ssize - 1; @SuppressWarnings("unchecked") Segment<K,V>[] segments = (Segment<K,V>[]) new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL]; for (int i = 0; i < segments.length; ++i) segments[i] = new Segment<K,V>(LOAD_FACTOR); s.putFields().put("segments", segments); s.putFields().put("segmentShift", segmentShift); s.putFields().put("segmentMask", segmentMask); s.writeFields();
Node<K,V>[] t; if ((t = table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) { s.writeObject(p.key); s.writeObject(p.val); } } s.writeObject(null); s.writeObject(null); segments = null; // throw away }
/** * Reconstitutes the instance from a stream (that is, deserializes it). * @param s the stream * @throws ClassNotFoundException if the class of a serialized object * could not be found * @throws java.io.IOException if an I/O error occurs */ private void readObject(java.io.ObjectInputStream s) throws java.io.IOException, ClassNotFoundException { /* * To improve performance in typical cases, we create nodes * while reading, then place in table once size is known. * However, we must also validate uniqueness and deal with * overpopulated bins while doing so, which requires * specialized versions of putVal mechanics. */ sizeCtl = -1; // force exclusion for table construction s.defaultReadObject(); long size = 0L; Node<K,V> p = null; for (;;) { @SuppressWarnings("unchecked") K k = (K) s.readObject(); @SuppressWarnings("unchecked") V v = (V) s.readObject(); if (k != null && v != null) { p = new Node<K,V>(spread(k.hashCode()), k, v, p); ++size; } else break; } if (size == 0L) sizeCtl = 0; else { int n; if (size >= (long)(MAXIMUM_CAPACITY >>> 1)) n = MAXIMUM_CAPACITY; else { int sz = (int)size; n = tableSizeFor(sz + (sz >>> 1) + 1); } @SuppressWarnings("unchecked") Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n]; int mask = n - 1; long added = 0L; while (p != null) { boolean insertAtFront; Node<K,V> next = p.next, first; int h = p.hash, j = h & mask; if ((first = tabAt(tab, j)) == null) insertAtFront = true; else { K k = p.key; if (first.hash < 0) { TreeBin<K,V> t = (TreeBin<K,V>)first; if (t.putTreeVal(h, k, p.val) == null) ++added; insertAtFront = false; } else { int binCount = 0; insertAtFront = true; Node<K,V> q; K qk; for (q = first; q != null; q = q.next) { if (q.hash == h && ((qk = q.key) == k || (qk != null && k.equals(qk)))) { insertAtFront = false; break; } ++binCount; } if (insertAtFront && binCount >= TREEIFY_THRESHOLD) { insertAtFront = false; ++added; p.next = first; TreeNode<K,V> hd = null, tl = null; for (q = p; q != null; q = q.next) { TreeNode<K,V> t = new TreeNode<K,V> (q.hash, q.key, q.val, null, null); if ((t.prev = tl) == null) hd = t; else tl.next = t; tl = t; } setTabAt(tab, j, new TreeBin<K,V>(hd)); } } } if (insertAtFront) { ++added; p.next = first; setTabAt(tab, j, p); } p = next; } table = tab; sizeCtl = n - (n >>> 2); baseCount = added; } }
// ConcurrentMap methods
/** * {@inheritDoc} * * @return the previous value associated with the specified key, * or {@code null} if there was no mapping for the key * @throws NullPointerException if the specified key or value is null */ public V putIfAbsent(K key, V value) { return putVal(key, value, true); }
/** * {@inheritDoc} * * @throws NullPointerException if the specified key is null */ public boolean remove(Object key, Object value) { if (key == null) throw new NullPointerException(); return value != null && replaceNode(key, null, value) != null; }
/** * {@inheritDoc} * * @throws NullPointerException if any of the arguments are null */ public boolean replace(K key, V oldValue, V newValue) { if (key == null || oldValue == null || newValue == null) throw new NullPointerException(); return replaceNode(key, newValue, oldValue) != null; }
/** * {@inheritDoc} * * @return the previous value associated with the specified key, * or {@code null} if there was no mapping for the key * @throws NullPointerException if the specified key or value is null */ public V replace(K key, V value) { if (key == null || value == null) throw new NullPointerException(); return replaceNode(key, value, null); }
// Overrides of JDK8+ Map extension method defaults
/** * Returns the value to which the specified key is mapped, or the * given default value if this map contains no mapping for the * key. * * @param key the key whose associated value is to be returned * @param defaultValue the value to return if this map contains * no mapping for the given key * @return the mapping for the key, if present; else the default value * @throws NullPointerException if the specified key is null */ public V getOrDefault(Object key, V defaultValue) { V v; return (v = get(key)) == null ? defaultValue : v; }
public void forEach(BiConsumer<? super K, ? super V> action) { if (action == null) throw new NullPointerException(); Node<K,V>[] t; if ((t = table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) { action.accept(p.key, p.val); } } }
public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { if (function == null) throw new NullPointerException(); Node<K,V>[] t; if ((t = table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) { V oldValue = p.val; for (K key = p.key;;) { V newValue = function.apply(key, oldValue); if (newValue == null) throw new NullPointerException(); if (replaceNode(key, newValue, oldValue) != null || (oldValue = get(key)) == null) break; } } } }
/** * If the specified key is not already associated with a value, * attempts to compute its value using the given mapping function * and enters it into this map unless {@code null}. The entire * method invocation is performed atomically, so the function is * applied at most once per key. Some attempted update operations * on this map by other threads may be blocked while computation * is in progress, so the computation should be short and simple, * and must not attempt to update any other mappings of this map. * * @param key key with which the specified value is to be associated * @param mappingFunction the function to compute a value * @return the current (existing or computed) value associated with * the specified key, or null if the computed value is null * @throws NullPointerException if the specified key or mappingFunction * is null * @throws IllegalStateException if the computation detectably * attempts a recursive update to this map that would * otherwise never complete * @throws RuntimeException or Error if the mappingFunction does so, * in which case the mapping is left unestablished */ public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) { if (key == null || mappingFunction == null) throw new NullPointerException(); int h = spread(key.hashCode()); V val = null; int binCount = 0; for (Node<K,V>[] tab = table;;) { Node<K,V> f; int n, i, fh; if (tab == null || (n = tab.length) == 0) tab = initTable(); else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { Node<K,V> r = new ReservationNode<K,V>(); synchronized (r) { if (casTabAt(tab, i, null, r)) { binCount = 1; Node<K,V> node = null; try { if ((val = mappingFunction.apply(key)) != null) node = new Node<K,V>(h, key, val, null); } finally { setTabAt(tab, i, node); } } } if (binCount != 0) break; } else if ((fh = f.hash) == MOVED) tab = helpTransfer(tab, f); else { boolean added = false; synchronized (f) { if (tabAt(tab, i) == f) { if (fh >= 0) { binCount = 1; for (Node<K,V> e = f;; ++binCount) { K ek; V ev; if (e.hash == h && ((ek = e.key) == key || (ek != null && key.equals(ek)))) { val = e.val; break; } Node<K,V> pred = e; if ((e = e.next) == null) { if ((val = mappingFunction.apply(key)) != null) { added = true; pred.next = new Node<K,V>(h, key, val, null); } break; } } } else if (f instanceof TreeBin) { binCount = 2; TreeBin<K,V> t = (TreeBin<K,V>)f; TreeNode<K,V> r, p; if ((r = t.root) != null && (p = r.findTreeNode(h, key, null)) != null) val = p.val; else if ((val = mappingFunction.apply(key)) != null) { added = true; t.putTreeVal(h, key, val); } } } } if (binCount != 0) { if (binCount >= TREEIFY_THRESHOLD) treeifyBin(tab, i); if (!added) return val; break; } } } if (val != null) addCount(1L, binCount); return val; }
/** * If the value for the specified key is present, attempts to * compute a new mapping given the key and its current mapped * value. The entire method invocation is performed atomically. * Some attempted update operations on this map by other threads * may be blocked while computation is in progress, so the * computation should be short and simple, and must not attempt to * update any other mappings of this map. * * @param key key with which a value may be associated * @param remappingFunction the function to compute a value * @return the new value associated with the specified key, or null if none * @throws NullPointerException if the specified key or remappingFunction * is null * @throws IllegalStateException if the computation detectably * attempts a recursive update to this map that would * otherwise never complete * @throws RuntimeException or Error if the remappingFunction does so, * in which case the mapping is unchanged */ public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) { if (key == null || remappingFunction == null) throw new NullPointerException(); int h = spread(key.hashCode()); V val = null; int delta = 0; int binCount = 0; for (Node<K,V>[] tab = table;;) { Node<K,V> f; int n, i, fh; if (tab == null || (n = tab.length) == 0) tab = initTable(); else if ((f = tabAt(tab, i = (n - 1) & h)) == null) break; else if ((fh = f.hash) == MOVED) tab = helpTransfer(tab, f); else { synchronized (f) { if (tabAt(tab, i) == f) { if (fh >= 0) { binCount = 1; for (Node<K,V> e = f, pred = null;; ++binCount) { K ek; if (e.hash == h && ((ek = e.key) == key || (ek != null && key.equals(ek)))) { val = remappingFunction.apply(key, e.val); if (val != null) e.val = val; else { delta = -1; Node<K,V> en = e.next; if (pred != null) pred.next = en; else setTabAt(tab, i, en); } break; } pred = e; if ((e = e.next) == null) break; } } else if (f instanceof TreeBin) { binCount = 2; TreeBin<K,V> t = (TreeBin<K,V>)f; TreeNode<K,V> r, p; if ((r = t.root) != null && (p = r.findTreeNode(h, key, null)) != null) { val = remappingFunction.apply(key, p.val); if (val != null) p.val = val; else { delta = -1; if (t.removeTreeNode(p)) setTabAt(tab, i, untreeify(t.first)); } } } } } if (binCount != 0) break; } } if (delta != 0) addCount((long)delta, binCount); return val; }
/** * Attempts to compute a mapping for the specified key and its * current mapped value (or {@code null} if there is no current * mapping). The entire method invocation is performed atomically. * Some attempted update operations on this map by other threads * may be blocked while computation is in progress, so the * computation should be short and simple, and must not attempt to * update any other mappings of this Map. * * @param key key with which the specified value is to be associated * @param remappingFunction the function to compute a value * @return the new value associated with the specified key, or null if none * @throws NullPointerException if the specified key or remappingFunction * is null * @throws IllegalStateException if the computation detectably * attempts a recursive update to this map that would * otherwise never complete * @throws RuntimeException or Error if the remappingFunction does so, * in which case the mapping is unchanged */ public V compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) { if (key == null || remappingFunction == null) throw new NullPointerException(); int h = spread(key.hashCode()); V val = null; int delta = 0; int binCount = 0; for (Node<K,V>[] tab = table;;) { Node<K,V> f; int n, i, fh; if (tab == null || (n = tab.length) == 0) tab = initTable(); else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { Node<K,V> r = new ReservationNode<K,V>(); synchronized (r) { if (casTabAt(tab, i, null, r)) { binCount = 1; Node<K,V> node = null; try { if ((val = remappingFunction.apply(key, null)) != null) { delta = 1; node = new Node<K,V>(h, key, val, null); } } finally { setTabAt(tab, i, node); } } } if (binCount != 0) break; } else if ((fh = f.hash) == MOVED) tab = helpTransfer(tab, f); else { synchronized (f) { if (tabAt(tab, i) == f) { if (fh >= 0) { binCount = 1; for (Node<K,V> e = f, pred = null;; ++binCount) { K ek; if (e.hash == h && ((ek = e.key) == key || (ek != null && key.equals(ek)))) { val = remappingFunction.apply(key, e.val); if (val != null) e.val = val; else { delta = -1; Node<K,V> en = e.next; if (pred != null) pred.next = en; else setTabAt(tab, i, en); } break; } pred = e; if ((e = e.next) == null) { val = remappingFunction.apply(key, null); if (val != null) { delta = 1; pred.next = new Node<K,V>(h, key, val, null); } break; } } } else if (f instanceof TreeBin) { binCount = 1; TreeBin<K,V> t = (TreeBin<K,V>)f; TreeNode<K,V> r, p; if ((r = t.root) != null) p = r.findTreeNode(h, key, null); else p = null; V pv = (p == null) ? null : p.val; val = remappingFunction.apply(key, pv); if (val != null) { if (p != null) p.val = val; else { delta = 1; t.putTreeVal(h, key, val); } } else if (p != null) { delta = -1; if (t.removeTreeNode(p)) setTabAt(tab, i, untreeify(t.first)); } } } } if (binCount != 0) { if (binCount >= TREEIFY_THRESHOLD) treeifyBin(tab, i); break; } } } if (delta != 0) addCount((long)delta, binCount); return val; }
/** * If the specified key is not already associated with a * (non-null) value, associates it with the given value. * Otherwise, replaces the value with the results of the given * remapping function, or removes if {@code null}. The entire * method invocation is performed atomically. Some attempted * update operations on this map by other threads may be blocked * while computation is in progress, so the computation should be * short and simple, and must not attempt to update any other * mappings of this Map. * * @param key key with which the specified value is to be associated * @param value the value to use if absent * @param remappingFunction the function to recompute a value if present * @return the new value associated with the specified key, or null if none * @throws NullPointerException if the specified key or the * remappingFunction is null * @throws RuntimeException or Error if the remappingFunction does so, * in which case the mapping is unchanged */ public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) { if (key == null || value == null || remappingFunction == null) throw new NullPointerException(); int h = spread(key.hashCode()); V val = null; int delta = 0; int binCount = 0; for (Node<K,V>[] tab = table;;) { Node<K,V> f; int n, i, fh; if (tab == null || (n = tab.length) == 0) tab = initTable(); else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { if (casTabAt(tab, i, null, new Node<K,V>(h, key, value, null))) { delta = 1; val = value; break; } } else if ((fh = f.hash) == MOVED) tab = helpTransfer(tab, f); else { synchronized (f) { if (tabAt(tab, i) == f) { if (fh >= 0) { binCount = 1; for (Node<K,V> e = f, pred = null;; ++binCount) { K ek; if (e.hash == h && ((ek = e.key) == key || (ek != null && key.equals(ek)))) { val = remappingFunction.apply(e.val, value); if (val != null) e.val = val; else { delta = -1; Node<K,V> en = e.next; if (pred != null) pred.next = en; else setTabAt(tab, i, en); } break; } pred = e; if ((e = e.next) == null) { delta = 1; val = value; pred.next = new Node<K,V>(h, key, val, null); break; } } } else if (f instanceof TreeBin) { binCount = 2; TreeBin<K,V> t = (TreeBin<K,V>)f; TreeNode<K,V> r = t.root; TreeNode<K,V> p = (r == null) ? null : r.findTreeNode(h, key, null); val = (p == null) ? value : remappingFunction.apply(p.val, value); if (val != null) { if (p != null) p.val = val; else { delta = 1; t.putTreeVal(h, key, val); } } else if (p != null) { delta = -1; if (t.removeTreeNode(p)) setTabAt(tab, i, untreeify(t.first)); } } } } if (binCount != 0) { if (binCount >= TREEIFY_THRESHOLD) treeifyBin(tab, i); break; } } } if (delta != 0) addCount((long)delta, binCount); return val; }
// Hashtable legacy methods
/** * Legacy method testing if some key maps into the specified value * in this table. This method is identical in functionality to * {@link #containsValue(Object)}, and exists solely to ensure * full compatibility with class {@link java.util.Hashtable}, * which supported this method prior to introduction of the * Java Collections framework. * * @param value a value to search for * @return {@code true} if and only if some key maps to the * {@code value} argument in this table as * determined by the {@code equals} method; * {@code false} otherwise * @throws NullPointerException if the specified value is null */ public boolean contains(Object value) { return containsValue(value); }
/** * Returns an enumeration of the keys in this table. * * @return an enumeration of the keys in this table * @see #keySet() */ public Enumeration<K> keys() { Node<K,V>[] t; int f = (t = table) == null ? 0 : t.length; return new KeyIterator<K,V>(t, f, 0, f, this); }
/** * Returns an enumeration of the values in this table. * * @return an enumeration of the values in this table * @see #values() */ public Enumeration<V> elements() { Node<K,V>[] t; int f = (t = table) == null ? 0 : t.length; return new ValueIterator<K,V>(t, f, 0, f, this); }
// ConcurrentHashMap-only methods
/** * Returns the number of mappings. This method should be used * instead of {@link #size} because a ConcurrentHashMap may * contain more mappings than can be represented as an int. The * value returned is an estimate; the actual count may differ if * there are concurrent insertions or removals. * * @return the number of mappings * @since 1.8 */ public long mappingCount() { long n = sumCount(); return (n < 0L) ? 0L : n; // ignore transient negative values }
/** * Creates a new {@link Set} backed by a ConcurrentHashMap * from the given type to {@code Boolean.TRUE}. * * @param <K> the element type of the returned set * @return the new set * @since 1.8 */ public static <K> KeySetView<K,Boolean> newKeySet() { return new KeySetView<K,Boolean> (new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE); }
/** * Creates a new {@link Set} backed by a ConcurrentHashMap * from the given type to {@code Boolean.TRUE}. * * @param initialCapacity The implementation performs internal * sizing to accommodate this many elements. * @param <K> the element type of the returned set * @return the new set * @throws IllegalArgumentException if the initial capacity of * elements is negative * @since 1.8 */ public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) { return new KeySetView<K,Boolean> (new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE); }
/** * Returns a {@link Set} view of the keys in this map, using the * given common mapped value for any additions (i.e., {@link * Collection#add} and {@link Collection#addAll(Collection)}). * This is of course only appropriate if it is acceptable to use * the same value for all additions from this view. * * @param mappedValue the mapped value to use for any additions * @return the set view * @throws NullPointerException if the mappedValue is null */ public KeySetView<K,V> keySet(V mappedValue) { if (mappedValue == null) throw new NullPointerException(); return new KeySetView<K,V>(this, mappedValue); }
/* ---------------- Special Nodes -------------- */
/** * A node inserted at head of bins during transfer operations. */ static final class ForwardingNode<K,V> extends Node<K,V> { final Node<K,V>[] nextTable; ForwardingNode(Node<K,V>[] tab) { super(MOVED, null, null, null); this.nextTable = tab; }
Node<K,V> find(int h, Object k) { // loop to avoid arbitrarily deep recursion on forwarding nodes outer: for (Node<K,V>[] tab = nextTable;;) { Node<K,V> e; int n; if (k == null || tab == null || (n = tab.length) == 0 || (e = tabAt(tab, (n - 1) & h)) == null) return null; for (;;) { int eh; K ek; if ((eh = e.hash) == h && ((ek = e.key) == k || (ek != null && k.equals(ek)))) return e; if (eh < 0) { if (e instanceof ForwardingNode) { tab = ((ForwardingNode<K,V>)e).nextTable; continue outer; } else return e.find(h, k); } if ((e = e.next) == null) return null; } } } }
/** * A place-holder node used in computeIfAbsent and compute */ static final class ReservationNode<K,V> extends Node<K,V> { ReservationNode() { super(RESERVED, null, null, null); }
Node<K,V> find(int h, Object k) { return null; } }
/* ---------------- Table Initialization and Resizing -------------- */
/** * Returns the stamp bits for resizing a table of size n. * Must be negative when shifted left by RESIZE_STAMP_SHIFT. */ static final int resizeStamp(int n) { return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1)); }
/** * Initializes table, using the size recorded in sizeCtl. */ private final Node<K,V>[] initTable() { Node<K,V>[] tab; int sc; while ((tab = table) == null || tab.length == 0) { if ((sc = sizeCtl) < 0) Thread.yield(); // lost initialization race; just spin else if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { try { if ((tab = table) == null || tab.length == 0) { int n = (sc > 0) ? sc : DEFAULT_CAPACITY; @SuppressWarnings("unchecked") Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n]; table = tab = nt; sc = n - (n >>> 2); } } finally { sizeCtl = sc; } break; } } return tab; }
/** * Adds to count, and if table is too small and not already * resizing, initiates transfer. If already resizing, helps * perform transfer if work is available. Rechecks occupancy * after a transfer to see if another resize is already needed * because resizings are lagging additions. * * @param x the count to add * @param check if <0, don't check resize, if <= 1 only check if uncontended */ private final void addCount(long x, int check) { CounterCell[] as; long b, s; if ((as = counterCells) != null || !U.compareAndSwapLong(this, BASECOUNT, b = baseCount, s = b + x)) { CounterCell a; long v; int m; boolean uncontended = true; if (as == null || (m = as.length - 1) < 0 || (a = as[ThreadLocalRandom.getProbe() & m]) == null || !(uncontended = U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x))) { fullAddCount(x, uncontended); return; } if (check <= 1) return; s = sumCount(); } if (check >= 0) { Node<K,V>[] tab, nt; int n, sc; while (s >= (long)(sc = sizeCtl) && (tab = table) != null && (n = tab.length) < MAXIMUM_CAPACITY) { int rs = resizeStamp(n); if (sc < 0) { if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 || sc == rs + MAX_RESIZERS || (nt = nextTable) == null || transferIndex <= 0) break; if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) transfer(tab, nt); } else if (U.compareAndSwapInt(this, SIZECTL, sc, (rs << RESIZE_STAMP_SHIFT) + 2)) transfer(tab, null); s = sumCount(); } } }
/** * Helps transfer if a resize is in progress. */ final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) { Node<K,V>[] nextTab; int sc; if (tab != null && (f instanceof ForwardingNode) && (nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) { int rs = resizeStamp(tab.length); while (nextTab == nextTable && table == tab && (sc = sizeCtl) < 0) { if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 || sc == rs + MAX_RESIZERS || transferIndex <= 0) break; if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) { transfer(tab, nextTab); break; } } return nextTab; } return table; }
/** * Tries to presize table to accommodate the given number of elements. * * @param size number of elements (doesn't need to be perfectly accurate) */ private final void tryPresize(int size) { int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : tableSizeFor(size + (size >>> 1) + 1); int sc; while ((sc = sizeCtl) >= 0) { Node<K,V>[] tab = table; int n; if (tab == null || (n = tab.length) == 0) { n = (sc > c) ? sc : c; if (U.compareAndSwapInt(this, SIZECTL, sc, -1)) { try { if (table == tab) { @SuppressWarnings("unchecked") Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n]; table = nt; sc = n - (n >>> 2); } } finally { sizeCtl = sc; } } } else if (c <= sc || n >= MAXIMUM_CAPACITY) break; else if (tab == table) { int rs = resizeStamp(n); if (sc < 0) { Node<K,V>[] nt; if ((sc >>> RESIZE_STAMP_SHIFT) != rs || sc == rs + 1 || sc == rs + MAX_RESIZERS || (nt = nextTable) == null || transferIndex <= 0) break; if (U.compareAndSwapInt(this, SIZECTL, sc, sc + 1)) transfer(tab, nt); } else if (U.compareAndSwapInt(this, SIZECTL, sc, (rs << RESIZE_STAMP_SHIFT) + 2)) transfer(tab, null); } } }
/** * Moves and/or copies the nodes in each bin to new table. See * above for explanation. */ private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) { int n = tab.length, stride; if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) stride = MIN_TRANSFER_STRIDE; // subdivide range if (nextTab == null) { // initiating try { @SuppressWarnings("unchecked") Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1]; nextTab = nt; } catch (Throwable ex) { // try to cope with OOME sizeCtl = Integer.MAX_VALUE; return; } nextTable = nextTab; transferIndex = n; } int nextn = nextTab.length; ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab); boolean advance = true; boolean finishing = false; // to ensure sweep before committing nextTab for (int i = 0, bound = 0;;) { Node<K,V> f; int fh; while (advance) { int nextIndex, nextBound; if (--i >= bound || finishing) advance = false; else if ((nextIndex = transferIndex) <= 0) { i = -1; advance = false; } else if (U.compareAndSwapInt (this, TRANSFERINDEX, nextIndex, nextBound = (nextIndex > stride ? nextIndex - stride : 0))) { bound = nextBound; i = nextIndex - 1; advance = false; } } if (i < 0 || i >= n || i + n >= nextn) { int sc; if (finishing) { nextTable = null; table = nextTab; sizeCtl = (n << 1) - (n >>> 1); return; } if (U.compareAndSwapInt(this, SIZECTL, sc = sizeCtl, sc - 1)) { if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT) return; finishing = advance = true; i = n; // recheck before commit } } else if ((f = tabAt(tab, i)) == null) advance = casTabAt(tab, i, null, fwd); else if ((fh = f.hash) == MOVED) advance = true; // already processed else { synchronized (f) { if (tabAt(tab, i) == f) { Node<K,V> ln, hn; if (fh >= 0) { int runBit = fh & n; Node<K,V> lastRun = f; for (Node<K,V> p = f.next; p != null; p = p.next) { int b = p.hash & n; if (b != runBit) { runBit = b; lastRun = p; } } if (runBit == 0) { ln = lastRun; hn = null; } else { hn = lastRun; ln = null; } for (Node<K,V> p = f; p != lastRun; p = p.next) { int ph = p.hash; K pk = p.key; V pv = p.val; if ((ph & n) == 0) ln = new Node<K,V>(ph, pk, pv, ln); else hn = new Node<K,V>(ph, pk, pv, hn); } setTabAt(nextTab, i, ln); setTabAt(nextTab, i + n, hn); setTabAt(tab, i, fwd); advance = true; } else if (f instanceof TreeBin) { TreeBin<K,V> t = (TreeBin<K,V>)f; TreeNode<K,V> lo = null, loTail = null; TreeNode<K,V> hi = null, hiTail = null; int lc = 0, hc = 0; for (Node<K,V> e = t.first; e != null; e = e.next) { int h = e.hash; TreeNode<K,V> p = new TreeNode<K,V> (h, e.key, e.val, null, null); if ((h & n) == 0) { if ((p.prev = loTail) == null) lo = p; else loTail.next = p; loTail = p; ++lc; } else { if ((p.prev = hiTail) == null) hi = p; else hiTail.next = p; hiTail = p; ++hc; } } ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) : (hc != 0) ? new TreeBin<K,V>(lo) : t; hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) : (lc != 0) ? new TreeBin<K,V>(hi) : t; setTabAt(nextTab, i, ln); setTabAt(nextTab, i + n, hn); setTabAt(tab, i, fwd); advance = true; } } } } } }
/* ---------------- Counter support -------------- */
/** * A padded cell for distributing counts. Adapted from LongAdder * and Striped64. See their internal docs for explanation. */ @sun.misc.Contended static final class CounterCell { volatile long value; CounterCell(long x) { value = x; } }
final long sumCount() { CounterCell[] as = counterCells; CounterCell a; long sum = baseCount; if (as != null) { for (int i = 0; i < as.length; ++i) { if ((a = as[i]) != null) sum += a.value; } } return sum; }
// See LongAdder version for explanation private final void fullAddCount(long x, boolean wasUncontended) { int h; if ((h = ThreadLocalRandom.getProbe()) == 0) { ThreadLocalRandom.localInit(); // force initialization h = ThreadLocalRandom.getProbe(); wasUncontended = true; } boolean collide = false; // True if last slot nonempty for (;;) { CounterCell[] as; CounterCell a; int n; long v; if ((as = counterCells) != null && (n = as.length) > 0) { if ((a = as[(n - 1) & h]) == null) { if (cellsBusy == 0) { // Try to attach new Cell CounterCell r = new CounterCell(x); // Optimistic create if (cellsBusy == 0 && U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { boolean created = false; try { // Recheck under lock CounterCell[] rs; int m, j; if ((rs = counterCells) != null && (m = rs.length) > 0 && rs[j = (m - 1) & h] == null) { rs[j] = r; created = true; } } finally { cellsBusy = 0; } if (created) break; continue; // Slot is now non-empty } } collide = false; } else if (!wasUncontended) // CAS already known to fail wasUncontended = true; // Continue after rehash else if (U.compareAndSwapLong(a, CELLVALUE, v = a.value, v + x)) break; else if (counterCells != as || n >= NCPU) collide = false; // At max size or stale else if (!collide) collide = true; else if (cellsBusy == 0 && U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { try { if (counterCells == as) {// Expand table unless stale CounterCell[] rs = new CounterCell[n << 1]; for (int i = 0; i < n; ++i) rs[i] = as[i]; counterCells = rs; } } finally { cellsBusy = 0; } collide = false; continue; // Retry with expanded table } h = ThreadLocalRandom.advanceProbe(h); } else if (cellsBusy == 0 && counterCells == as && U.compareAndSwapInt(this, CELLSBUSY, 0, 1)) { boolean init = false; try { // Initialize table if (counterCells == as) { CounterCell[] rs = new CounterCell[2]; rs[h & 1] = new CounterCell(x); counterCells = rs; init = true; } } finally { cellsBusy = 0; } if (init) break; } else if (U.compareAndSwapLong(this, BASECOUNT, v = baseCount, v + x)) break; // Fall back on using base } }
/* ---------------- Conversion from/to TreeBins -------------- */
/** * Replaces all linked nodes in bin at given index unless table is * too small, in which case resizes instead. */ private final void treeifyBin(Node<K,V>[] tab, int index) { Node<K,V> b; int n, sc; if (tab != null) { if ((n = tab.length) < MIN_TREEIFY_CAPACITY) tryPresize(n << 1); else if ((b = tabAt(tab, index)) != null && b.hash >= 0) { synchronized (b) { if (tabAt(tab, index) == b) { TreeNode<K,V> hd = null, tl = null; for (Node<K,V> e = b; e != null; e = e.next) { TreeNode<K,V> p = new TreeNode<K,V>(e.hash, e.key, e.val, null, null); if ((p.prev = tl) == null) hd = p; else tl.next = p; tl = p; } setTabAt(tab, index, new TreeBin<K,V>(hd)); } } } } }
/** * Returns a list on non-TreeNodes replacing those in given list. */ static <K,V> Node<K,V> untreeify(Node<K,V> b) { Node<K,V> hd = null, tl = null; for (Node<K,V> q = b; q != null; q = q.next) { Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val, null); if (tl == null) hd = p; else tl.next = p; tl = p; } return hd; }
/* ---------------- TreeNodes -------------- */
/** * Nodes for use in TreeBins */ static final class TreeNode<K,V> extends Node<K,V> { TreeNode<K,V> parent; // red-black tree links TreeNode<K,V> left; TreeNode<K,V> right; TreeNode<K,V> prev; // needed to unlink next upon deletion boolean red;
TreeNode(int hash, K key, V val, Node<K,V> next, TreeNode<K,V> parent) { super(hash, key, val, next); this.parent = parent; }
Node<K,V> find(int h, Object k) { return findTreeNode(h, k, null); }
/** * Returns the TreeNode (or null if not found) for the given key * starting at given root. */ final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) { if (k != null) { TreeNode<K,V> p = this; do { int ph, dir; K pk; TreeNode<K,V> q; TreeNode<K,V> pl = p.left, pr = p.right; if ((ph = p.hash) > h) p = pl; else if (ph < h) p = pr; else if ((pk = p.key) == k || (pk != null && k.equals(pk))) return p; else if (pl == null) p = pr; else if (pr == null) p = pl; else if ((kc != null || (kc = comparableClassFor(k)) != null) && (dir = compareComparables(kc, k, pk)) != 0) p = (dir < 0) ? pl : pr; else if ((q = pr.findTreeNode(h, k, kc)) != null) return q; else p = pl; } while (p != null); } return null; } }
/* ---------------- TreeBins -------------- */
/** * TreeNodes used at the heads of bins. TreeBins do not hold user * keys or values, but instead point to list of TreeNodes and * their root. They also maintain a parasitic read-write lock * forcing writers (who hold bin lock) to wait for readers (who do * not) to complete before tree restructuring operations. */ static final class TreeBin<K,V> extends Node<K,V> { TreeNode<K,V> root; volatile TreeNode<K,V> first; volatile Thread waiter; volatile int lockState; // values for lockState static final int WRITER = 1; // set while holding write lock static final int WAITER = 2; // set when waiting for write lock static final int READER = 4; // increment value for setting read lock
/** * Tie-breaking utility for ordering insertions when equal * hashCodes and non-comparable. We don't require a total * order, just a consistent insertion rule to maintain * equivalence across rebalancings. Tie-breaking further than * necessary simplifies testing a bit. */ static int tieBreakOrder(Object a, Object b) { int d; if (a == null || b == null || (d = a.getClass().getName(). compareTo(b.getClass().getName())) == 0) d = (System.identityHashCode(a) <= System.identityHashCode(b) ? -1 : 1); return d; }
/** * Creates bin with initial set of nodes headed by b. */ TreeBin(TreeNode<K,V> b) { super(TREEBIN, null, null, null); this.first = b; TreeNode<K,V> r = null; for (TreeNode<K,V> x = b, next; x != null; x = next) { next = (TreeNode<K,V>)x.next; x.left = x.right = null; if (r == null) { x.parent = null; x.red = false; r = x; } else { K k = x.key; int h = x.hash; Class<?> kc = null; for (TreeNode<K,V> p = r;;) { int dir, ph; K pk = p.key; if ((ph = p.hash) > h) dir = -1; else if (ph < h) dir = 1; else if ((kc == null && (kc = comparableClassFor(k)) == null) || (dir = compareComparables(kc, k, pk)) == 0) dir = tieBreakOrder(k, pk); TreeNode<K,V> xp = p; if ((p = (dir <= 0) ? p.left : p.right) == null) { x.parent = xp; if (dir <= 0) xp.left = x; else xp.right = x; r = balanceInsertion(r, x); break; } } } } this.root = r; assert checkInvariants(root); }
/** * Acquires write lock for tree restructuring. */ private final void lockRoot() { if (!U.compareAndSwapInt(this, LOCKSTATE, 0, WRITER)) contendedLock(); // offload to separate method }
/** * Releases write lock for tree restructuring. */ private final void unlockRoot() { lockState = 0; }
/** * Possibly blocks awaiting root lock. */ private final void contendedLock() { boolean waiting = false; for (int s;;) { if (((s = lockState) & ~WAITER) == 0) { if (U.compareAndSwapInt(this, LOCKSTATE, s, WRITER)) { if (waiting) waiter = null; return; } } else if ((s & WAITER) == 0) { if (U.compareAndSwapInt(this, LOCKSTATE, s, s | WAITER)) { waiting = true; waiter = Thread.currentThread(); } } else if (waiting) LockSupport.park(this); } }
/** * Returns matching node or null if none. Tries to search * using tree comparisons from root, but continues linear * search when lock not available. */ final Node<K,V> find(int h, Object k) { if (k != null) { for (Node<K,V> e = first; e != null; ) { int s; K ek; if (((s = lockState) & (WAITER|WRITER)) != 0) { if (e.hash == h && ((ek = e.key) == k || (ek != null && k.equals(ek)))) return e; e = e.next; } else if (U.compareAndSwapInt(this, LOCKSTATE, s, s + READER)) { TreeNode<K,V> r, p; try { p = ((r = root) == null ? null : r.findTreeNode(h, k, null)); } finally { Thread w; if (U.getAndAddInt(this, LOCKSTATE, -READER) == (READER|WAITER) && (w = waiter) != null) LockSupport.unpark(w); } return p; } } } return null; }
/** * Finds or adds a node. * @return null if added */ final TreeNode<K,V> putTreeVal(int h, K k, V v) { Class<?> kc = null; boolean searched = false; for (TreeNode<K,V> p = root;;) { int dir, ph; K pk; if (p == null) { first = root = new TreeNode<K,V>(h, k, v, null, null); break; } else if ((ph = p.hash) > h) dir = -1; else if (ph < h) dir = 1; else if ((pk = p.key) == k || (pk != null && k.equals(pk))) return p; else if ((kc == null && (kc = comparableClassFor(k)) == null) || (dir = compareComparables(kc, k, pk)) == 0) { if (!searched) { TreeNode<K,V> q, ch; searched = true; if (((ch = p.left) != null && (q = ch.findTreeNode(h, k, kc)) != null) || ((ch = p.right) != null && (q = ch.findTreeNode(h, k, kc)) != null)) return q; } dir = tieBreakOrder(k, pk); }
TreeNode<K,V> xp = p; if ((p = (dir <= 0) ? p.left : p.right) == null) { TreeNode<K,V> x, f = first; first = x = new TreeNode<K,V>(h, k, v, f, xp); if (f != null) f.prev = x; if (dir <= 0) xp.left = x; else xp.right = x; if (!xp.red) x.red = true; else { lockRoot(); try { root = balanceInsertion(root, x); } finally { unlockRoot(); } } break; } } assert checkInvariants(root); return null; }
/** * Removes the given node, that must be present before this * call. This is messier than typical red-black deletion code * because we cannot swap the contents of an interior node * with a leaf successor that is pinned by "next" pointers * that are accessible independently of lock. So instead we * swap the tree linkages. * * @return true if now too small, so should be untreeified */ final boolean removeTreeNode(TreeNode<K,V> p) { TreeNode<K,V> next = (TreeNode<K,V>)p.next; TreeNode<K,V> pred = p.prev; // unlink traversal pointers TreeNode<K,V> r, rl; if (pred == null) first = next; else pred.next = next; if (next != null) next.prev = pred; if (first == null) { root = null; return true; } if ((r = root) == null || r.right == null || // too small (rl = r.left) == null || rl.left == null) return true; lockRoot(); try { TreeNode<K,V> replacement; TreeNode<K,V> pl = p.left; TreeNode<K,V> pr = p.right; if (pl != null && pr != null) { TreeNode<K,V> s = pr, sl; while ((sl = s.left) != null) // find successor s = sl; boolean c = s.red; s.red = p.red; p.red = c; // swap colors TreeNode<K,V> sr = s.right; TreeNode<K,V> pp = p.parent; if (s == pr) { // p was s's direct parent p.parent = s; s.right = p; } else { TreeNode<K,V> sp = s.parent; if ((p.parent = sp) != null) { if (s == sp.left) sp.left = p; else sp.right = p; } if ((s.right = pr) != null) pr.parent = s; } p.left = null; if ((p.right = sr) != null) sr.parent = p; if ((s.left = pl) != null) pl.parent = s; if ((s.parent = pp) == null) r = s; else if (p == pp.left) pp.left = s; else pp.right = s; if (sr != null) replacement = sr; else replacement = p; } else if (pl != null) replacement = pl; else if (pr != null) replacement = pr; else replacement = p; if (replacement != p) { TreeNode<K,V> pp = replacement.parent = p.parent; if (pp == null) r = replacement; else if (p == pp.left) pp.left = replacement; else pp.right = replacement; p.left = p.right = p.parent = null; }
root = (p.red) ? r : balanceDeletion(r, replacement);
if (p == replacement) { // detach pointers TreeNode<K,V> pp; if ((pp = p.parent) != null) { if (p == pp.left) pp.left = null; else if (p == pp.right) pp.right = null; p.parent = null; } } } finally { unlockRoot(); } assert checkInvariants(root); return false; }
/* ------------------------------------------------------------ */ // Red-black tree methods, all adapted from CLR
static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root, TreeNode<K,V> p) { TreeNode<K,V> r, pp, rl; if (p != null && (r = p.right) != null) { if ((rl = p.right = r.left) != null) rl.parent = p; if ((pp = r.parent = p.parent) == null) (root = r).red = false; else if (pp.left == p) pp.left = r; else pp.right = r; r.left = p; p.parent = r; } return root; }
static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root, TreeNode<K,V> p) { TreeNode<K,V> l, pp, lr; if (p != null && (l = p.left) != null) { if ((lr = p.left = l.right) != null) lr.parent = p; if ((pp = l.parent = p.parent) == null) (root = l).red = false; else if (pp.right == p) pp.right = l; else pp.left = l; l.right = p; p.parent = l; } return root; }
static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root, TreeNode<K,V> x) { x.red = true; for (TreeNode<K,V> xp, xpp, xppl, xppr;;) { if ((xp = x.parent) == null) { x.red = false; return x; } else if (!xp.red || (xpp = xp.parent) == null) return root; if (xp == (xppl = xpp.left)) { if ((xppr = xpp.right) != null && xppr.red) { xppr.red = false; xp.red = false; xpp.red = true; x = xpp; } else { if (x == xp.right) { root = rotateLeft(root, x = xp); xpp = (xp = x.parent) == null ? null : xp.parent; } if (xp != null) { xp.red = false; if (xpp != null) { xpp.red = true; root = rotateRight(root, xpp); } } } } else { if (xppl != null && xppl.red) { xppl.red = false; xp.red = false; xpp.red = true; x = xpp; } else { if (x == xp.left) { root = rotateRight(root, x = xp); xpp = (xp = x.parent) == null ? null : xp.parent; } if (xp != null) { xp.red = false; if (xpp != null) { xpp.red = true; root = rotateLeft(root, xpp); } } } } } }
static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root, TreeNode<K,V> x) { for (TreeNode<K,V> xp, xpl, xpr;;) { if (x == null || x == root) return root; else if ((xp = x.parent) == null) { x.red = false; return x; } else if (x.red) { x.red = false; return root; } else if ((xpl = xp.left) == x) { if ((xpr = xp.right) != null && xpr.red) { xpr.red = false; xp.red = true; root = rotateLeft(root, xp); xpr = (xp = x.parent) == null ? null : xp.right; } if (xpr == null) x = xp; else { TreeNode<K,V> sl = xpr.left, sr = xpr.right; if ((sr == null || !sr.red) && (sl == null || !sl.red)) { xpr.red = true; x = xp; } else { if (sr == null || !sr.red) { if (sl != null) sl.red = false; xpr.red = true; root = rotateRight(root, xpr); xpr = (xp = x.parent) == null ? null : xp.right; } if (xpr != null) { xpr.red = (xp == null) ? false : xp.red; if ((sr = xpr.right) != null) sr.red = false; } if (xp != null) { xp.red = false; root = rotateLeft(root, xp); } x = root; } } } else { // symmetric if (xpl != null && xpl.red) { xpl.red = false; xp.red = true; root = rotateRight(root, xp); xpl = (xp = x.parent) == null ? null : xp.left; } if (xpl == null) x = xp; else { TreeNode<K,V> sl = xpl.left, sr = xpl.right; if ((sl == null || !sl.red) && (sr == null || !sr.red)) { xpl.red = true; x = xp; } else { if (sl == null || !sl.red) { if (sr != null) sr.red = false; xpl.red = true; root = rotateLeft(root, xpl); xpl = (xp = x.parent) == null ? null : xp.left; } if (xpl != null) { xpl.red = (xp == null) ? false : xp.red; if ((sl = xpl.left) != null) sl.red = false; } if (xp != null) { xp.red = false; root = rotateRight(root, xp); } x = root; } } } } }
/** * Recursive invariant check */ static <K,V> boolean checkInvariants(TreeNode<K,V> t) { TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right, tb = t.prev, tn = (TreeNode<K,V>)t.next; if (tb != null && tb.next != t) return false; if (tn != null && tn.prev != t) return false; if (tp != null && t != tp.left && t != tp.right) return false; if (tl != null && (tl.parent != t || tl.hash > t.hash)) return false; if (tr != null && (tr.parent != t || tr.hash < t.hash)) return false; if (t.red && tl != null && tl.red && tr != null && tr.red) return false; if (tl != null && !checkInvariants(tl)) return false; if (tr != null && !checkInvariants(tr)) return false; return true; }
private static final sun.misc.Unsafe U; private static final long LOCKSTATE; static { try { U = sun.misc.Unsafe.getUnsafe(); Class<?> k = TreeBin.class; LOCKSTATE = U.objectFieldOffset (k.getDeclaredField("lockState")); } catch (Exception e) { throw new Error(e); } } }
/* ----------------Table Traversal -------------- */
/** * Records the table, its length, and current traversal index for a * traverser that must process a region of a forwarded table before * proceeding with current table. */ static final class TableStack<K,V> { int length; int index; Node<K,V>[] tab; TableStack<K,V> next; }
/** * Encapsulates traversal for methods such as containsValue; also * serves as a base class for other iterators and spliterators. * * Method advance visits once each still-valid node that was * reachable upon iterator construction. It might miss some that * were added to a bin after the bin was visited, which is OK wrt * consistency guarantees. Maintaining this property in the face * of possible ongoing resizes requires a fair amount of * bookkeeping state that is difficult to optimize away amidst * volatile accesses. Even so, traversal maintains reasonable * throughput. * * Normally, iteration proceeds bin-by-bin traversing lists. * However, if the table has been resized, then all future steps * must traverse both the bin at the current index as well as at * (index + baseSize); and so on for further resizings. To * paranoically cope with potential sharing by users of iterators * across threads, iteration terminates if a bounds checks fails * for a table read. */ static class Traverser<K,V> { Node<K,V>[] tab; // current table; updated if resized Node<K,V> next; // the next entry to use TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes int index; // index of bin to use next int baseIndex; // current index of initial table int baseLimit; // index bound for initial table final int baseSize; // initial table size
Traverser(Node<K,V>[] tab, int size, int index, int limit) { this.tab = tab; this.baseSize = size; this.baseIndex = this.index = index; this.baseLimit = limit; this.next = null; }
/** * Advances if possible, returning next valid node, or null if none. */ final Node<K,V> advance() { Node<K,V> e; if ((e = next) != null) e = e.next; for (;;) { Node<K,V>[] t; int i, n; // must use locals in checks if (e != null) return next = e; if (baseIndex >= baseLimit || (t = tab) == null || (n = t.length) <= (i = index) || i < 0) return next = null; if ((e = tabAt(t, i)) != null && e.hash < 0) { if (e instanceof ForwardingNode) { tab = ((ForwardingNode<K,V>)e).nextTable; e = null; pushState(t, i, n); continue; } else if (e instanceof TreeBin) e = ((TreeBin<K,V>)e).first; else e = null; } if (stack != null) recoverState(n); else if ((index = i + baseSize) >= n) index = ++baseIndex; // visit upper slots if present } }
/** * Saves traversal state upon encountering a forwarding node. */ private void pushState(Node<K,V>[] t, int i, int n) { TableStack<K,V> s = spare; // reuse if possible if (s != null) spare = s.next; else s = new TableStack<K,V>(); s.tab = t; s.length = n; s.index = i; s.next = stack; stack = s; }
/** * Possibly pops traversal state. * * @param n length of current table */ private void recoverState(int n) { TableStack<K,V> s; int len; while ((s = stack) != null && (index += (len = s.length)) >= n) { n = len; index = s.index; tab = s.tab; s.tab = null; TableStack<K,V> next = s.next; s.next = spare; // save for reuse stack = next; spare = s; } if (s == null && (index += baseSize) >= n) index = ++baseIndex; } }
/** * Base of key, value, and entry Iterators. Adds fields to * Traverser to support iterator.remove. */ static class BaseIterator<K,V> extends Traverser<K,V> { final ConcurrentHashMap<K,V> map; Node<K,V> lastReturned; BaseIterator(Node<K,V>[] tab, int size, int index, int limit, ConcurrentHashMap<K,V> map) { super(tab, size, index, limit); this.map = map; advance(); }
public final boolean hasNext() { return next != null; } public final boolean hasMoreElements() { return next != null; }
public final void remove() { Node<K,V> p; if ((p = lastReturned) == null) throw new IllegalStateException(); lastReturned = null; map.replaceNode(p.key, null, null); } }
static final class KeyIterator<K,V> extends BaseIterator<K,V> implements Iterator<K>, Enumeration<K> { KeyIterator(Node<K,V>[] tab, int index, int size, int limit, ConcurrentHashMap<K,V> map) { super(tab, index, size, limit, map); }
public final K next() { Node<K,V> p; if ((p = next) == null) throw new NoSuchElementException(); K k = p.key; lastReturned = p; advance(); return k; }
public final K nextElement() { return next(); } }
static final class ValueIterator<K,V> extends BaseIterator<K,V> implements Iterator<V>, Enumeration<V> { ValueIterator(Node<K,V>[] tab, int index, int size, int limit, ConcurrentHashMap<K,V> map) { super(tab, index, size, limit, map); }
public final V next() { Node<K,V> p; if ((p = next) == null) throw new NoSuchElementException(); V v = p.val; lastReturned = p; advance(); return v; }
public final V nextElement() { return next(); } }
static final class EntryIterator<K,V> extends BaseIterator<K,V> implements Iterator<Map.Entry<K,V>> { EntryIterator(Node<K,V>[] tab, int index, int size, int limit, ConcurrentHashMap<K,V> map) { super(tab, index, size, limit, map); }
public final Map.Entry<K,V> next() { Node<K,V> p; if ((p = next) == null) throw new NoSuchElementException(); K k = p.key; V v = p.val; lastReturned = p; advance(); return new MapEntry<K,V>(k, v, map); } }
/** * Exported Entry for EntryIterator */ static final class MapEntry<K,V> implements Map.Entry<K,V> { final K key; // non-null V val; // non-null final ConcurrentHashMap<K,V> map; MapEntry(K key, V val, ConcurrentHashMap<K,V> map) { this.key = key; this.val = val; this.map = map; } public K getKey() { return key; } public V getValue() { return val; } public int hashCode() { return key.hashCode() ^ val.hashCode(); } public String toString() { return key + "=" + val; }
public boolean equals(Object o) { Object k, v; Map.Entry<?,?> e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?,?>)o).getKey()) != null && (v = e.getValue()) != null && (k == key || k.equals(key)) && (v == val || v.equals(val))); }
/** * Sets our entry's value and writes through to the map. The * value to return is somewhat arbitrary here. Since we do not * necessarily track asynchronous changes, the most recent * "previous" value could be different from what we return (or * could even have been removed, in which case the put will * re-establish). We do not and cannot guarantee more. */ public V setValue(V value) { if (value == null) throw new NullPointerException(); V v = val; val = value; map.put(key, value); return v; } }
static final class KeySpliterator<K,V> extends Traverser<K,V> implements Spliterator<K> { long est; // size estimate KeySpliterator(Node<K,V>[] tab, int size, int index, int limit, long est) { super(tab, size, index, limit); this.est = est; }
public Spliterator<K> trySplit() { int i, f, h; return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : new KeySpliterator<K,V>(tab, baseSize, baseLimit = h, f, est >>>= 1); }
public void forEachRemaining(Consumer<? super K> action) { if (action == null) throw new NullPointerException(); for (Node<K,V> p; (p = advance()) != null;) action.accept(p.key); }
public boolean tryAdvance(Consumer<? super K> action) { if (action == null) throw new NullPointerException(); Node<K,V> p; if ((p = advance()) == null) return false; action.accept(p.key); return true; }
public long estimateSize() { return est; }
public int characteristics() { return Spliterator.DISTINCT | Spliterator.CONCURRENT | Spliterator.NONNULL; } }
static final class ValueSpliterator<K,V> extends Traverser<K,V> implements Spliterator<V> { long est; // size estimate ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit, long est) { super(tab, size, index, limit); this.est = est; }
public Spliterator<V> trySplit() { int i, f, h; return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h, f, est >>>= 1); }
public void forEachRemaining(Consumer<? super V> action) { if (action == null) throw new NullPointerException(); for (Node<K,V> p; (p = advance()) != null;) action.accept(p.val); }
public boolean tryAdvance(Consumer<? super V> action) { if (action == null) throw new NullPointerException(); Node<K,V> p; if ((p = advance()) == null) return false; action.accept(p.val); return true; }
public long estimateSize() { return est; }
public int characteristics() { return Spliterator.CONCURRENT | Spliterator.NONNULL; } }
static final class EntrySpliterator<K,V> extends Traverser<K,V> implements Spliterator<Map.Entry<K,V>> { final ConcurrentHashMap<K,V> map; // To export MapEntry long est; // size estimate EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit, long est, ConcurrentHashMap<K,V> map) { super(tab, size, index, limit); this.map = map; this.est = est; }
public Spliterator<Map.Entry<K,V>> trySplit() { int i, f, h; return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h, f, est >>>= 1, map); }
public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) { if (action == null) throw new NullPointerException(); for (Node<K,V> p; (p = advance()) != null; ) action.accept(new MapEntry<K,V>(p.key, p.val, map)); }
public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) { if (action == null) throw new NullPointerException(); Node<K,V> p; if ((p = advance()) == null) return false; action.accept(new MapEntry<K,V>(p.key, p.val, map)); return true; }
public long estimateSize() { return est; }
public int characteristics() { return Spliterator.DISTINCT | Spliterator.CONCURRENT | Spliterator.NONNULL; } }
// Parallel bulk operations
/** * Computes initial batch value for bulk tasks. The returned value * is approximately exp2 of the number of times (minus one) to * split task by two before executing leaf action. This value is * faster to compute and more convenient to use as a guide to * splitting than is the depth, since it is used while dividing by * two anyway. */ final int batchFor(long b) { long n; if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b) return 0; int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4 return (b <= 0L || (n /= b) >= sp) ? sp : (int)n; }
/** * Performs the given action for each (key, value). * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param action the action * @since 1.8 */ public void forEach(long parallelismThreshold, BiConsumer<? super K,? super V> action) { if (action == null) throw new NullPointerException(); new ForEachMappingTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, action).invoke(); }
/** * Performs the given action for each non-null transformation * of each (key, value). * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case the action is not applied) * @param action the action * @param the return type of the transformer * @since 1.8 */ public void forEach(long parallelismThreshold, BiFunction<? super K, ? super V, ? extends U> transformer, Consumer<? super U> action) { if (transformer == null || action == null) throw new NullPointerException(); new ForEachTransformedMappingTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, transformer, action).invoke(); }
/** * Returns a non-null result from applying the given search * function on each (key, value), or null if none. Upon * success, further element processing is suppressed and the * results of any other parallel invocations of the search * function are ignored. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param searchFunction a function returning a non-null * result on success, else null * @param the return type of the search function * @return a non-null result from applying the given search * function on each (key, value), or null if none * @since 1.8 */ public U search(long parallelismThreshold, BiFunction<? super K, ? super V, ? extends U> searchFunction) { if (searchFunction == null) throw new NullPointerException(); return new SearchMappingsTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, searchFunction, new AtomicReference()).invoke(); }
/** * Returns the result of accumulating the given transformation * of all (key, value) pairs using the given reducer to * combine values, or null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case it is not combined) * @param reducer a commutative associative combining function * @param the return type of the transformer * @return the result of accumulating the given transformation * of all (key, value) pairs * @since 1.8 */ public U reduce(long parallelismThreshold, BiFunction<? super K, ? super V, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceMappingsTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all (key, value) pairs using the given reducer to * combine values, and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all (key, value) pairs * @since 1.8 */ public double reduceToDouble(long parallelismThreshold, ToDoubleBiFunction<? super K, ? super V> transformer, double basis, DoubleBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceMappingsToDoubleTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all (key, value) pairs using the given reducer to * combine values, and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all (key, value) pairs * @since 1.8 */ public long reduceToLong(long parallelismThreshold, ToLongBiFunction<? super K, ? super V> transformer, long basis, LongBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceMappingsToLongTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all (key, value) pairs using the given reducer to * combine values, and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all (key, value) pairs * @since 1.8 */ public int reduceToInt(long parallelismThreshold, ToIntBiFunction<? super K, ? super V> transformer, int basis, IntBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceMappingsToIntTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Performs the given action for each key. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param action the action * @since 1.8 */ public void forEachKey(long parallelismThreshold, Consumer<? super K> action) { if (action == null) throw new NullPointerException(); new ForEachKeyTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, action).invoke(); }
/** * Performs the given action for each non-null transformation * of each key. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case the action is not applied) * @param action the action * @param the return type of the transformer * @since 1.8 */ public void forEachKey(long parallelismThreshold, Function<? super K, ? extends U> transformer, Consumer<? super U> action) { if (transformer == null || action == null) throw new NullPointerException(); new ForEachTransformedKeyTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, transformer, action).invoke(); }
/** * Returns a non-null result from applying the given search * function on each key, or null if none. Upon success, * further element processing is suppressed and the results of * any other parallel invocations of the search function are * ignored. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param searchFunction a function returning a non-null * result on success, else null * @param the return type of the search function * @return a non-null result from applying the given search * function on each key, or null if none * @since 1.8 */ public U searchKeys(long parallelismThreshold, Function<? super K, ? extends U> searchFunction) { if (searchFunction == null) throw new NullPointerException(); return new SearchKeysTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, searchFunction, new AtomicReference()).invoke(); }
/** * Returns the result of accumulating all keys using the given * reducer to combine values, or null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param reducer a commutative associative combining function * @return the result of accumulating all keys using the given * reducer to combine values, or null if none * @since 1.8 */ public K reduceKeys(long parallelismThreshold, BiFunction<? super K, ? super K, ? extends K> reducer) { if (reducer == null) throw new NullPointerException(); return new ReduceKeysTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all keys using the given reducer to combine values, or * null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case it is not combined) * @param reducer a commutative associative combining function * @param the return type of the transformer * @return the result of accumulating the given transformation * of all keys * @since 1.8 */ public U reduceKeys(long parallelismThreshold, Function<? super K, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceKeysTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all keys using the given reducer to combine values, and * the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all keys * @since 1.8 */ public double reduceKeysToDouble(long parallelismThreshold, ToDoubleFunction<? super K> transformer, double basis, DoubleBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceKeysToDoubleTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all keys using the given reducer to combine values, and * the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all keys * @since 1.8 */ public long reduceKeysToLong(long parallelismThreshold, ToLongFunction<? super K> transformer, long basis, LongBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceKeysToLongTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all keys using the given reducer to combine values, and * the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all keys * @since 1.8 */ public int reduceKeysToInt(long parallelismThreshold, ToIntFunction<? super K> transformer, int basis, IntBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceKeysToIntTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Performs the given action for each value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param action the action * @since 1.8 */ public void forEachValue(long parallelismThreshold, Consumer<? super V> action) { if (action == null) throw new NullPointerException(); new ForEachValueTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, action).invoke(); }
/** * Performs the given action for each non-null transformation * of each value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case the action is not applied) * @param action the action * @param the return type of the transformer * @since 1.8 */ public void forEachValue(long parallelismThreshold, Function<? super V, ? extends U> transformer, Consumer<? super U> action) { if (transformer == null || action == null) throw new NullPointerException(); new ForEachTransformedValueTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, transformer, action).invoke(); }
/** * Returns a non-null result from applying the given search * function on each value, or null if none. Upon success, * further element processing is suppressed and the results of * any other parallel invocations of the search function are * ignored. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param searchFunction a function returning a non-null * result on success, else null * @param the return type of the search function * @return a non-null result from applying the given search * function on each value, or null if none * @since 1.8 */ public U searchValues(long parallelismThreshold, Function<? super V, ? extends U> searchFunction) { if (searchFunction == null) throw new NullPointerException(); return new SearchValuesTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, searchFunction, new AtomicReference()).invoke(); }
/** * Returns the result of accumulating all values using the * given reducer to combine values, or null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param reducer a commutative associative combining function * @return the result of accumulating all values * @since 1.8 */ public V reduceValues(long parallelismThreshold, BiFunction<? super V, ? super V, ? extends V> reducer) { if (reducer == null) throw new NullPointerException(); return new ReduceValuesTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all values using the given reducer to combine values, or * null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case it is not combined) * @param reducer a commutative associative combining function * @param the return type of the transformer * @return the result of accumulating the given transformation * of all values * @since 1.8 */ public U reduceValues(long parallelismThreshold, Function<? super V, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceValuesTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all values using the given reducer to combine values, * and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all values * @since 1.8 */ public double reduceValuesToDouble(long parallelismThreshold, ToDoubleFunction<? super V> transformer, double basis, DoubleBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceValuesToDoubleTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all values using the given reducer to combine values, * and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all values * @since 1.8 */ public long reduceValuesToLong(long parallelismThreshold, ToLongFunction<? super V> transformer, long basis, LongBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceValuesToLongTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all values using the given reducer to combine values, * and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all values * @since 1.8 */ public int reduceValuesToInt(long parallelismThreshold, ToIntFunction<? super V> transformer, int basis, IntBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceValuesToIntTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Performs the given action for each entry. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param action the action * @since 1.8 */ public void forEachEntry(long parallelismThreshold, Consumer<? super Map.Entry<K,V>> action) { if (action == null) throw new NullPointerException(); new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table, action).invoke(); }
/** * Performs the given action for each non-null transformation * of each entry. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case the action is not applied) * @param action the action * @param the return type of the transformer * @since 1.8 */ public void forEachEntry(long parallelismThreshold, Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) { if (transformer == null || action == null) throw new NullPointerException(); new ForEachTransformedEntryTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, transformer, action).invoke(); }
/** * Returns a non-null result from applying the given search * function on each entry, or null if none. Upon success, * further element processing is suppressed and the results of * any other parallel invocations of the search function are * ignored. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param searchFunction a function returning a non-null * result on success, else null * @param the return type of the search function * @return a non-null result from applying the given search * function on each entry, or null if none * @since 1.8 */ public U searchEntries(long parallelismThreshold, Function<Map.Entry<K,V>, ? extends U> searchFunction) { if (searchFunction == null) throw new NullPointerException(); return new SearchEntriesTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, searchFunction, new AtomicReference()).invoke(); }
/** * Returns the result of accumulating all entries using the * given reducer to combine values, or null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param reducer a commutative associative combining function * @return the result of accumulating all entries * @since 1.8 */ public Map.Entry<K,V> reduceEntries(long parallelismThreshold, BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) { if (reducer == null) throw new NullPointerException(); return new ReduceEntriesTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all entries using the given reducer to combine values, * or null if none. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element, or null if there is no transformation (in * which case it is not combined) * @param reducer a commutative associative combining function * @param the return type of the transformer * @return the result of accumulating the given transformation * of all entries * @since 1.8 */ public U reduceEntries(long parallelismThreshold, Function<Map.Entry<K,V>, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceEntriesTask<K,V,U> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all entries using the given reducer to combine values, * and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all entries * @since 1.8 */ public double reduceEntriesToDouble(long parallelismThreshold, ToDoubleFunction<Map.Entry<K,V>> transformer, double basis, DoubleBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceEntriesToDoubleTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all entries using the given reducer to combine values, * and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all entries * @since 1.8 */ public long reduceEntriesToLong(long parallelismThreshold, ToLongFunction<Map.Entry<K,V>> transformer, long basis, LongBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceEntriesToLongTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }
/** * Returns the result of accumulating the given transformation * of all entries using the given reducer to combine values, * and the given basis as an identity value. * * @param parallelismThreshold the (estimated) number of elements * needed for this operation to be executed in parallel * @param transformer a function returning the transformation * for an element * @param basis the identity (initial default value) for the reduction * @param reducer a commutative associative combining function * @return the result of accumulating the given transformation * of all entries * @since 1.8 */ public int reduceEntriesToInt(long parallelismThreshold, ToIntFunction<Map.Entry<K,V>> transformer, int basis, IntBinaryOperator reducer) { if (transformer == null || reducer == null) throw new NullPointerException(); return new MapReduceEntriesToIntTask<K,V> (null, batchFor(parallelismThreshold), 0, 0, table, null, transformer, basis, reducer).invoke(); }

/* ----------------Views -------------- */
/** * Base class for views. */ abstract static class CollectionView<K,V,E> implements Collection<E>, java.io.Serializable { private static final long serialVersionUID = 7249069246763182397L; final ConcurrentHashMap<K,V> map; CollectionView(ConcurrentHashMap<K,V> map) { this.map = map; }
/** * Returns the map backing this view. * * @return the map backing this view */ public ConcurrentHashMap<K,V> getMap() { return map; }
/** * Removes all of the elements from this view, by removing all * the mappings from the map backing this view. */ public final void clear() { map.clear(); } public final int size() { return map.size(); } public final boolean isEmpty() { return map.isEmpty(); }
// implementations below rely on concrete classes supplying these // abstract methods /** * Returns an iterator over the elements in this collection. * * The returned iterator is * <a href="package-summary.html#Weakly">weakly consistent</a>. * * @return an iterator over the elements in this collection */ public abstract Iterator<E> iterator(); public abstract boolean contains(Object o); public abstract boolean remove(Object o);
private static final String oomeMsg = "Required array size too large";
public final Object[] toArray() { long sz = map.mappingCount(); if (sz > MAX_ARRAY_SIZE) throw new OutOfMemoryError(oomeMsg); int n = (int)sz; Object[] r = new Object[n]; int i = 0; for (E e : this) { if (i == n) { if (n >= MAX_ARRAY_SIZE) throw new OutOfMemoryError(oomeMsg); if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) n = MAX_ARRAY_SIZE; else n += (n >>> 1) + 1; r = Arrays.copyOf(r, n); } r[i++] = e; } return (i == n) ? r : Arrays.copyOf(r, i); }
@SuppressWarnings("unchecked") public final <T> T[] toArray(T[] a) { long sz = map.mappingCount(); if (sz > MAX_ARRAY_SIZE) throw new OutOfMemoryError(oomeMsg); int m = (int)sz; T[] r = (a.length >= m) ? a : (T[])java.lang.reflect.Array .newInstance(a.getClass().getComponentType(), m); int n = r.length; int i = 0; for (E e : this) { if (i == n) { if (n >= MAX_ARRAY_SIZE) throw new OutOfMemoryError(oomeMsg); if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) n = MAX_ARRAY_SIZE; else n += (n >>> 1) + 1; r = Arrays.copyOf(r, n); } r[i++] = (T)e; } if (a == r && i < n) { r[i] = null; // null-terminate return r; } return (i == n) ? r : Arrays.copyOf(r, i); }
/** * Returns a string representation of this collection. * The string representation consists of the string representations * of the collection's elements in the order they are returned by * its iterator, enclosed in square brackets ({@code "[]"}). * Adjacent elements are separated by the characters {@code ", "} * (comma and space). Elements are converted to strings as by * {@link String#valueOf(Object)}. * * @return a string representation of this collection */ public final String toString() { StringBuilder sb = new StringBuilder(); sb.append('['); Iterator<E> it = iterator(); if (it.hasNext()) { for (;;) { Object e = it.next(); sb.append(e == this ? "(this Collection)" : e); if (!it.hasNext()) break; sb.append(',').append(' '); } } return sb.append(']').toString(); }
public final boolean containsAll(Collection<?> c) { if (c != this) { for (Object e : c) { if (e == null || !contains(e)) return false; } } return true; }
public final boolean removeAll(Collection<?> c) { if (c == null) throw new NullPointerException(); boolean modified = false; for (Iterator<E> it = iterator(); it.hasNext();) { if (c.contains(it.next())) { it.remove(); modified = true; } } return modified; }
public final boolean retainAll(Collection<?> c) { if (c == null) throw new NullPointerException(); boolean modified = false; for (Iterator<E> it = iterator(); it.hasNext();) { if (!c.contains(it.next())) { it.remove(); modified = true; } } return modified; }
}
/** * A view of a ConcurrentHashMap as a {@link Set} of keys, in * which additions may optionally be enabled by mapping to a * common value. This class cannot be directly instantiated. * See {@link #keySet() keySet()}, * {@link #keySet(Object) keySet(V)}, * {@link #newKeySet() newKeySet()}, * {@link #newKeySet(int) newKeySet(int)}. * * @since 1.8 */ public static class KeySetView<K,V> extends CollectionView<K,V,K> implements Set<K>, java.io.Serializable { private static final long serialVersionUID = 7249069246763182397L; private final V value; KeySetView(ConcurrentHashMap<K,V> map, V value) { // non-public super(map); this.value = value; }
/** * Returns the default mapped value for additions, * or {@code null} if additions are not supported. * * @return the default mapped value for additions, or {@code null} * if not supported */ public V getMappedValue() { return value; }
/** * {@inheritDoc} * @throws NullPointerException if the specified key is null */ public boolean contains(Object o) { return map.containsKey(o); }
/** * Removes the key from this map view, by removing the key (and its * corresponding value) from the backing map. This method does * nothing if the key is not in the map. * * @param o the key to be removed from the backing map * @return {@code true} if the backing map contained the specified key * @throws NullPointerException if the specified key is null */ public boolean remove(Object o) { return map.remove(o) != null; }
/** * @return an iterator over the keys of the backing map */ public Iterator<K> iterator() { Node<K,V>[] t; ConcurrentHashMap<K,V> m = map; int f = (t = m.table) == null ? 0 : t.length; return new KeyIterator<K,V>(t, f, 0, f, m); }
/** * Adds the specified key to this set view by mapping the key to * the default mapped value in the backing map, if defined. * * @param e key to be added * @return {@code true} if this set changed as a result of the call * @throws NullPointerException if the specified key is null * @throws UnsupportedOperationException if no default mapped value * for additions was provided */ public boolean add(K e) { V v; if ((v = value) == null) throw new UnsupportedOperationException(); return map.putVal(e, v, true) == null; }
/** * Adds all of the elements in the specified collection to this set, * as if by calling {@link #add} on each one. * * @param c the elements to be inserted into this set * @return {@code true} if this set changed as a result of the call * @throws NullPointerException if the collection or any of its * elements are {@code null} * @throws UnsupportedOperationException if no default mapped value * for additions was provided */ public boolean addAll(Collection<? extends K> c) { boolean added = false; V v; if ((v = value) == null) throw new UnsupportedOperationException(); for (K e : c) { if (map.putVal(e, v, true) == null) added = true; } return added; }
public int hashCode() { int h = 0; for (K e : this) h += e.hashCode(); return h; }
public boolean equals(Object o) { Set<?> c; return ((o instanceof Set) && ((c = (Set<?>)o) == this || (containsAll(c) && c.containsAll(this)))); }
public Spliterator<K> spliterator() { Node<K,V>[] t; ConcurrentHashMap<K,V> m = map; long n = m.sumCount(); int f = (t = m.table) == null ? 0 : t.length; return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n); }
public void forEach(Consumer<? super K> action) { if (action == null) throw new NullPointerException(); Node<K,V>[] t; if ((t = map.table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) action.accept(p.key); } } }
/** * A view of a ConcurrentHashMap as a {@link Collection} of * values, in which additions are disabled. This class cannot be * directly instantiated. See {@link #values()}. */ static final class ValuesView<K,V> extends CollectionView<K,V,V> implements Collection<V>, java.io.Serializable { private static final long serialVersionUID = 2249069246763182397L; ValuesView(ConcurrentHashMap<K,V> map) { super(map); } public final boolean contains(Object o) { return map.containsValue(o); }
public final boolean remove(Object o) { if (o != null) { for (Iterator<V> it = iterator(); it.hasNext();) { if (o.equals(it.next())) { it.remove(); return true; } } } return false; }
public final Iterator<V> iterator() { ConcurrentHashMap<K,V> m = map; Node<K,V>[] t; int f = (t = m.table) == null ? 0 : t.length; return new ValueIterator<K,V>(t, f, 0, f, m); }
public final boolean add(V e) { throw new UnsupportedOperationException(); } public final boolean addAll(Collection<? extends V> c) { throw new UnsupportedOperationException(); }
public Spliterator<V> spliterator() { Node<K,V>[] t; ConcurrentHashMap<K,V> m = map; long n = m.sumCount(); int f = (t = m.table) == null ? 0 : t.length; return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n); }
public void forEach(Consumer<? super V> action) { if (action == null) throw new NullPointerException(); Node<K,V>[] t; if ((t = map.table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) action.accept(p.val); } } }
/** * A view of a ConcurrentHashMap as a {@link Set} of (key, value) * entries. This class cannot be directly instantiated. See * {@link #entrySet()}. */ static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>> implements Set<Map.Entry<K,V>>, java.io.Serializable { private static final long serialVersionUID = 2249069246763182397L; EntrySetView(ConcurrentHashMap<K,V> map) { super(map); }
public boolean contains(Object o) { Object k, v, r; Map.Entry<?,?> e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?,?>)o).getKey()) != null && (r = map.get(k)) != null && (v = e.getValue()) != null && (v == r || v.equals(r))); }
public boolean remove(Object o) { Object k, v; Map.Entry<?,?> e; return ((o instanceof Map.Entry) && (k = (e = (Map.Entry<?,?>)o).getKey()) != null && (v = e.getValue()) != null && map.remove(k, v)); }
/** * @return an iterator over the entries of the backing map */ public Iterator<Map.Entry<K,V>> iterator() { ConcurrentHashMap<K,V> m = map; Node<K,V>[] t; int f = (t = m.table) == null ? 0 : t.length; return new EntryIterator<K,V>(t, f, 0, f, m); }
public boolean add(Entry<K,V> e) { return map.putVal(e.getKey(), e.getValue(), false) == null; }
public boolean addAll(Collection<? extends Entry<K,V>> c) { boolean added = false; for (Entry<K,V> e : c) { if (add(e)) added = true; } return added; }
public final int hashCode() { int h = 0; Node<K,V>[] t; if ((t = map.table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) { h += p.hashCode(); } } return h; }
public final boolean equals(Object o) { Set<?> c; return ((o instanceof Set) && ((c = (Set<?>)o) == this || (containsAll(c) && c.containsAll(this)))); }
public Spliterator<Map.Entry<K,V>> spliterator() { Node<K,V>[] t; ConcurrentHashMap<K,V> m = map; long n = m.sumCount(); int f = (t = m.table) == null ? 0 : t.length; return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m); }
public void forEach(Consumer<? super Map.Entry<K,V>> action) { if (action == null) throw new NullPointerException(); Node<K,V>[] t; if ((t = map.table) != null) { Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); for (Node<K,V> p; (p = it.advance()) != null; ) action.accept(new MapEntry<K,V>(p.key, p.val, map)); } }
}
// -------------------------------------------------------
/** * Base class for bulk tasks. Repeats some fields and code from * class Traverser, because we need to subclass CountedCompleter. */ @SuppressWarnings("serial") abstract static class BulkTask<K,V,R> extends CountedCompleter<R> { Node<K,V>[] tab; // same as Traverser Node<K,V> next; TableStack<K,V> stack, spare; int index; int baseIndex; int baseLimit; final int baseSize; int batch; // split control
BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) { super(par); this.batch = b; this.index = this.baseIndex = i; if ((this.tab = t) == null) this.baseSize = this.baseLimit = 0; else if (par == null) this.baseSize = this.baseLimit = t.length; else { this.baseLimit = f; this.baseSize = par.baseSize; } }
/** * Same as Traverser version */ final Node<K,V> advance() { Node<K,V> e; if ((e = next) != null) e = e.next; for (;;) { Node<K,V>[] t; int i, n; if (e != null) return next = e; if (baseIndex >= baseLimit || (t = tab) == null || (n = t.length) <= (i = index) || i < 0) return next = null; if ((e = tabAt(t, i)) != null && e.hash < 0) { if (e instanceof ForwardingNode) { tab = ((ForwardingNode<K,V>)e).nextTable; e = null; pushState(t, i, n); continue; } else if (e instanceof TreeBin) e = ((TreeBin<K,V>)e).first; else e = null; } if (stack != null) recoverState(n); else if ((index = i + baseSize) >= n) index = ++baseIndex; } }
private void pushState(Node<K,V>[] t, int i, int n) { TableStack<K,V> s = spare; if (s != null) spare = s.next; else s = new TableStack<K,V>(); s.tab = t; s.length = n; s.index = i; s.next = stack; stack = s; }
private void recoverState(int n) { TableStack<K,V> s; int len; while ((s = stack) != null && (index += (len = s.length)) >= n) { n = len; index = s.index; tab = s.tab; s.tab = null; TableStack<K,V> next = s.next; s.next = spare; // save for reuse stack = next; spare = s; } if (s == null && (index += baseSize) >= n) index = ++baseIndex; } }
/* * Task classes. Coded in a regular but ugly format/style to * simplify checks that each variant differs in the right way from * others. The null screenings exist because compilers cannot tell * that we've already null-checked task arguments, so we force * simplest hoisted bypass to help avoid convoluted traps. */ @SuppressWarnings("serial") static final class ForEachKeyTask<K,V> extends BulkTask<K,V,Void> { final Consumer<? super K> action; ForEachKeyTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Consumer<? super K> action) { super(p, b, i, f, t); this.action = action; } public final void compute() { final Consumer<? super K> action; if ((action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachKeyTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, action).fork(); } for (Node<K,V> p; (p = advance()) != null;) action.accept(p.key); propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachValueTask<K,V> extends BulkTask<K,V,Void> { final Consumer<? super V> action; ForEachValueTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Consumer<? super V> action) { super(p, b, i, f, t); this.action = action; } public final void compute() { final Consumer<? super V> action; if ((action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachValueTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, action).fork(); } for (Node<K,V> p; (p = advance()) != null;) action.accept(p.val); propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachEntryTask<K,V> extends BulkTask<K,V,Void> { final Consumer<? super Entry<K,V>> action; ForEachEntryTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Consumer<? super Entry<K,V>> action) { super(p, b, i, f, t); this.action = action; } public final void compute() { final Consumer<? super Entry<K,V>> action; if ((action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachEntryTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, action).fork(); } for (Node<K,V> p; (p = advance()) != null; ) action.accept(p); propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachMappingTask<K,V> extends BulkTask<K,V,Void> { final BiConsumer<? super K, ? super V> action; ForEachMappingTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, BiConsumer<? super K,? super V> action) { super(p, b, i, f, t); this.action = action; } public final void compute() { final BiConsumer<? super K, ? super V> action; if ((action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachMappingTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, action).fork(); } for (Node<K,V> p; (p = advance()) != null; ) action.accept(p.key, p.val); propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachTransformedKeyTask<K,V,U> extends BulkTask<K,V,Void> { final Function<? super K, ? extends U> transformer; final Consumer<? super U> action; ForEachTransformedKeyTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Function<? super K, ? extends U> transformer, Consumer<? super U> action) { super(p, b, i, f, t); this.transformer = transformer; this.action = action; } public final void compute() { final Function<? super K, ? extends U> transformer; final Consumer<? super U> action; if ((transformer = this.transformer) != null && (action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachTransformedKeyTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, transformer, action).fork(); } for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p.key)) != null) action.accept(u); } propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachTransformedValueTask<K,V,U> extends BulkTask<K,V,Void> { final Function<? super V, ? extends U> transformer; final Consumer<? super U> action; ForEachTransformedValueTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Function<? super V, ? extends U> transformer, Consumer<? super U> action) { super(p, b, i, f, t); this.transformer = transformer; this.action = action; } public final void compute() { final Function<? super V, ? extends U> transformer; final Consumer<? super U> action; if ((transformer = this.transformer) != null && (action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachTransformedValueTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, transformer, action).fork(); } for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p.val)) != null) action.accept(u); } propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachTransformedEntryTask<K,V,U> extends BulkTask<K,V,Void> { final Function<Map.Entry<K,V>, ? extends U> transformer; final Consumer<? super U> action; ForEachTransformedEntryTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) { super(p, b, i, f, t); this.transformer = transformer; this.action = action; } public final void compute() { final Function<Map.Entry<K,V>, ? extends U> transformer; final Consumer<? super U> action; if ((transformer = this.transformer) != null && (action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachTransformedEntryTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, transformer, action).fork(); } for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p)) != null) action.accept(u); } propagateCompletion(); } } }
@SuppressWarnings("serial") static final class ForEachTransformedMappingTask<K,V,U> extends BulkTask<K,V,Void> { final BiFunction<? super K, ? super V, ? extends U> transformer; final Consumer<? super U> action; ForEachTransformedMappingTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, BiFunction<? super K, ? super V, ? extends U> transformer, Consumer<? super U> action) { super(p, b, i, f, t); this.transformer = transformer; this.action = action; } public final void compute() { final BiFunction<? super K, ? super V, ? extends U> transformer; final Consumer<? super U> action; if ((transformer = this.transformer) != null && (action = this.action) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); new ForEachTransformedMappingTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, transformer, action).fork(); } for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p.key, p.val)) != null) action.accept(u); } propagateCompletion(); } } }
@SuppressWarnings("serial") static final class SearchKeysTask<K,V,U> extends BulkTask<K,V,U> { final Function<? super K, ? extends U> searchFunction; final AtomicReference result; SearchKeysTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Function<? super K, ? extends U> searchFunction, AtomicReference result) { super(p, b, i, f, t); this.searchFunction = searchFunction; this.result = result; } public final U getRawResult() { return result.get(); } public final void compute() { final Function<? super K, ? extends U> searchFunction; final AtomicReference result; if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { if (result.get() != null) return; addToPendingCount(1); new SearchKeysTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, searchFunction, result).fork(); } while (result.get() == null) { U u; Node<K,V> p; if ((p = advance()) == null) { propagateCompletion(); break; } if ((u = searchFunction.apply(p.key)) != null) { if (result.compareAndSet(null, u)) quietlyCompleteRoot(); break; } } } } }
@SuppressWarnings("serial") static final class SearchValuesTask<K,V,U> extends BulkTask<K,V,U> { final Function<? super V, ? extends U> searchFunction; final AtomicReference result; SearchValuesTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Function<? super V, ? extends U> searchFunction, AtomicReference result) { super(p, b, i, f, t); this.searchFunction = searchFunction; this.result = result; } public final U getRawResult() { return result.get(); } public final void compute() { final Function<? super V, ? extends U> searchFunction; final AtomicReference result; if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { if (result.get() != null) return; addToPendingCount(1); new SearchValuesTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, searchFunction, result).fork(); } while (result.get() == null) { U u; Node<K,V> p; if ((p = advance()) == null) { propagateCompletion(); break; } if ((u = searchFunction.apply(p.val)) != null) { if (result.compareAndSet(null, u)) quietlyCompleteRoot(); break; } } } } }
@SuppressWarnings("serial") static final class SearchEntriesTask<K,V,U> extends BulkTask<K,V,U> { final Function<Entry<K,V>, ? extends U> searchFunction; final AtomicReference result; SearchEntriesTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, Function<Entry<K,V>, ? extends U> searchFunction, AtomicReference result) { super(p, b, i, f, t); this.searchFunction = searchFunction; this.result = result; } public final U getRawResult() { return result.get(); } public final void compute() { final Function<Entry<K,V>, ? extends U> searchFunction; final AtomicReference result; if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { if (result.get() != null) return; addToPendingCount(1); new SearchEntriesTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, searchFunction, result).fork(); } while (result.get() == null) { U u; Node<K,V> p; if ((p = advance()) == null) { propagateCompletion(); break; } if ((u = searchFunction.apply(p)) != null) { if (result.compareAndSet(null, u)) quietlyCompleteRoot(); return; } } } } }
@SuppressWarnings("serial") static final class SearchMappingsTask<K,V,U> extends BulkTask<K,V,U> { final BiFunction<? super K, ? super V, ? extends U> searchFunction; final AtomicReference result; SearchMappingsTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, BiFunction<? super K, ? super V, ? extends U> searchFunction, AtomicReference result) { super(p, b, i, f, t); this.searchFunction = searchFunction; this.result = result; } public final U getRawResult() { return result.get(); } public final void compute() { final BiFunction<? super K, ? super V, ? extends U> searchFunction; final AtomicReference result; if ((searchFunction = this.searchFunction) != null && (result = this.result) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { if (result.get() != null) return; addToPendingCount(1); new SearchMappingsTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, searchFunction, result).fork(); } while (result.get() == null) { U u; Node<K,V> p; if ((p = advance()) == null) { propagateCompletion(); break; } if ((u = searchFunction.apply(p.key, p.val)) != null) { if (result.compareAndSet(null, u)) quietlyCompleteRoot(); break; } } } } }
@SuppressWarnings("serial") static final class ReduceKeysTask<K,V> extends BulkTask<K,V,K> { final BiFunction<? super K, ? super K, ? extends K> reducer; K result; ReduceKeysTask<K,V> rights, nextRight; ReduceKeysTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, ReduceKeysTask<K,V> nextRight, BiFunction<? super K, ? super K, ? extends K> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.reducer = reducer; } public final K getRawResult() { return result; } public final void compute() { final BiFunction<? super K, ? super K, ? extends K> reducer; if ((reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new ReduceKeysTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, reducer)).fork(); } K r = null; for (Node<K,V> p; (p = advance()) != null; ) { K u = p.key; r = (r == null) ? u : u == null ? r : reducer.apply(r, u); } result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") ReduceKeysTask<K,V> t = (ReduceKeysTask<K,V>)c, s = t.rights; while (s != null) { K tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class ReduceValuesTask<K,V> extends BulkTask<K,V,V> { final BiFunction<? super V, ? super V, ? extends V> reducer; V result; ReduceValuesTask<K,V> rights, nextRight; ReduceValuesTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, ReduceValuesTask<K,V> nextRight, BiFunction<? super V, ? super V, ? extends V> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.reducer = reducer; } public final V getRawResult() { return result; } public final void compute() { final BiFunction<? super V, ? super V, ? extends V> reducer; if ((reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new ReduceValuesTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, reducer)).fork(); } V r = null; for (Node<K,V> p; (p = advance()) != null; ) { V v = p.val; r = (r == null) ? v : reducer.apply(r, v); } result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") ReduceValuesTask<K,V> t = (ReduceValuesTask<K,V>)c, s = t.rights; while (s != null) { V tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class ReduceEntriesTask<K,V> extends BulkTask<K,V,Map.Entry<K,V>> { final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer; Map.Entry<K,V> result; ReduceEntriesTask<K,V> rights, nextRight; ReduceEntriesTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, ReduceEntriesTask<K,V> nextRight, BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.reducer = reducer; } public final Map.Entry<K,V> getRawResult() { return result; } public final void compute() { final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer; if ((reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new ReduceEntriesTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, reducer)).fork(); } Map.Entry<K,V> r = null; for (Node<K,V> p; (p = advance()) != null; ) r = (r == null) ? p : reducer.apply(r, p); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") ReduceEntriesTask<K,V> t = (ReduceEntriesTask<K,V>)c, s = t.rights; while (s != null) { Map.Entry<K,V> tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceKeysTask<K,V,U> extends BulkTask<K,V,U> { final Function<? super K, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; U result; MapReduceKeysTask<K,V,U> rights, nextRight; MapReduceKeysTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceKeysTask<K,V,U> nextRight, Function<? super K, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.reducer = reducer; } public final U getRawResult() { return result; } public final void compute() { final Function<? super K, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceKeysTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, reducer)).fork(); } U r = null; for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p.key)) != null) r = (r == null) ? u : reducer.apply(r, u); } result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceKeysTask<K,V,U> t = (MapReduceKeysTask<K,V,U>)c, s = t.rights; while (s != null) { U tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceValuesTask<K,V,U> extends BulkTask<K,V,U> { final Function<? super V, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; U result; MapReduceValuesTask<K,V,U> rights, nextRight; MapReduceValuesTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceValuesTask<K,V,U> nextRight, Function<? super V, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.reducer = reducer; } public final U getRawResult() { return result; } public final void compute() { final Function<? super V, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceValuesTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, reducer)).fork(); } U r = null; for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p.val)) != null) r = (r == null) ? u : reducer.apply(r, u); } result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceValuesTask<K,V,U> t = (MapReduceValuesTask<K,V,U>)c, s = t.rights; while (s != null) { U tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceEntriesTask<K,V,U> extends BulkTask<K,V,U> { final Function<Map.Entry<K,V>, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; U result; MapReduceEntriesTask<K,V,U> rights, nextRight; MapReduceEntriesTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceEntriesTask<K,V,U> nextRight, Function<Map.Entry<K,V>, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.reducer = reducer; } public final U getRawResult() { return result; } public final void compute() { final Function<Map.Entry<K,V>, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceEntriesTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, reducer)).fork(); } U r = null; for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p)) != null) r = (r == null) ? u : reducer.apply(r, u); } result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceEntriesTask<K,V,U> t = (MapReduceEntriesTask<K,V,U>)c, s = t.rights; while (s != null) { U tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceMappingsTask<K,V,U> extends BulkTask<K,V,U> { final BiFunction<? super K, ? super V, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; U result; MapReduceMappingsTask<K,V,U> rights, nextRight; MapReduceMappingsTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceMappingsTask<K,V,U> nextRight, BiFunction<? super K, ? super V, ? extends U> transformer, BiFunction<? super U, ? super U, ? extends U> reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.reducer = reducer; } public final U getRawResult() { return result; } public final void compute() { final BiFunction<? super K, ? super V, ? extends U> transformer; final BiFunction<? super U, ? super U, ? extends U> reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceMappingsTask<K,V,U> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, reducer)).fork(); } U r = null; for (Node<K,V> p; (p = advance()) != null; ) { U u; if ((u = transformer.apply(p.key, p.val)) != null) r = (r == null) ? u : reducer.apply(r, u); } result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceMappingsTask<K,V,U> t = (MapReduceMappingsTask<K,V,U>)c, s = t.rights; while (s != null) { U tr, sr; if ((sr = s.result) != null) t.result = (((tr = t.result) == null) ? sr : reducer.apply(tr, sr)); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceKeysToDoubleTask<K,V> extends BulkTask<K,V,Double> { final ToDoubleFunction<? super K> transformer; final DoubleBinaryOperator reducer; final double basis; double result; MapReduceKeysToDoubleTask<K,V> rights, nextRight; MapReduceKeysToDoubleTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceKeysToDoubleTask<K,V> nextRight, ToDoubleFunction<? super K> transformer, double basis, DoubleBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Double getRawResult() { return result; } public final void compute() { final ToDoubleFunction<? super K> transformer; final DoubleBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { double r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceKeysToDoubleTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceKeysToDoubleTask<K,V> t = (MapReduceKeysToDoubleTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsDouble(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceValuesToDoubleTask<K,V> extends BulkTask<K,V,Double> { final ToDoubleFunction<? super V> transformer; final DoubleBinaryOperator reducer; final double basis; double result; MapReduceValuesToDoubleTask<K,V> rights, nextRight; MapReduceValuesToDoubleTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceValuesToDoubleTask<K,V> nextRight, ToDoubleFunction<? super V> transformer, double basis, DoubleBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Double getRawResult() { return result; } public final void compute() { final ToDoubleFunction<? super V> transformer; final DoubleBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { double r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceValuesToDoubleTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceValuesToDoubleTask<K,V> t = (MapReduceValuesToDoubleTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsDouble(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceEntriesToDoubleTask<K,V> extends BulkTask<K,V,Double> { final ToDoubleFunction<Map.Entry<K,V>> transformer; final DoubleBinaryOperator reducer; final double basis; double result; MapReduceEntriesToDoubleTask<K,V> rights, nextRight; MapReduceEntriesToDoubleTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceEntriesToDoubleTask<K,V> nextRight, ToDoubleFunction<Map.Entry<K,V>> transformer, double basis, DoubleBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Double getRawResult() { return result; } public final void compute() { final ToDoubleFunction<Map.Entry<K,V>> transformer; final DoubleBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { double r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceEntriesToDoubleTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsDouble(r, transformer.applyAsDouble(p)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceEntriesToDoubleTask<K,V> t = (MapReduceEntriesToDoubleTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsDouble(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceMappingsToDoubleTask<K,V> extends BulkTask<K,V,Double> { final ToDoubleBiFunction<? super K, ? super V> transformer; final DoubleBinaryOperator reducer; final double basis; double result; MapReduceMappingsToDoubleTask<K,V> rights, nextRight; MapReduceMappingsToDoubleTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceMappingsToDoubleTask<K,V> nextRight, ToDoubleBiFunction<? super K, ? super V> transformer, double basis, DoubleBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Double getRawResult() { return result; } public final void compute() { final ToDoubleBiFunction<? super K, ? super V> transformer; final DoubleBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { double r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceMappingsToDoubleTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceMappingsToDoubleTask<K,V> t = (MapReduceMappingsToDoubleTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsDouble(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceKeysToLongTask<K,V> extends BulkTask<K,V,Long> { final ToLongFunction<? super K> transformer; final LongBinaryOperator reducer; final long basis; long result; MapReduceKeysToLongTask<K,V> rights, nextRight; MapReduceKeysToLongTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceKeysToLongTask<K,V> nextRight, ToLongFunction<? super K> transformer, long basis, LongBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Long getRawResult() { return result; } public final void compute() { final ToLongFunction<? super K> transformer; final LongBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { long r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceKeysToLongTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsLong(r, transformer.applyAsLong(p.key)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceKeysToLongTask<K,V> t = (MapReduceKeysToLongTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsLong(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceValuesToLongTask<K,V> extends BulkTask<K,V,Long> { final ToLongFunction<? super V> transformer; final LongBinaryOperator reducer; final long basis; long result; MapReduceValuesToLongTask<K,V> rights, nextRight; MapReduceValuesToLongTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceValuesToLongTask<K,V> nextRight, ToLongFunction<? super V> transformer, long basis, LongBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Long getRawResult() { return result; } public final void compute() { final ToLongFunction<? super V> transformer; final LongBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { long r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceValuesToLongTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsLong(r, transformer.applyAsLong(p.val)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceValuesToLongTask<K,V> t = (MapReduceValuesToLongTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsLong(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceEntriesToLongTask<K,V> extends BulkTask<K,V,Long> { final ToLongFunction<Map.Entry<K,V>> transformer; final LongBinaryOperator reducer; final long basis; long result; MapReduceEntriesToLongTask<K,V> rights, nextRight; MapReduceEntriesToLongTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceEntriesToLongTask<K,V> nextRight, ToLongFunction<Map.Entry<K,V>> transformer, long basis, LongBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Long getRawResult() { return result; } public final void compute() { final ToLongFunction<Map.Entry<K,V>> transformer; final LongBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { long r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceEntriesToLongTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsLong(r, transformer.applyAsLong(p)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceEntriesToLongTask<K,V> t = (MapReduceEntriesToLongTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsLong(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceMappingsToLongTask<K,V> extends BulkTask<K,V,Long> { final ToLongBiFunction<? super K, ? super V> transformer; final LongBinaryOperator reducer; final long basis; long result; MapReduceMappingsToLongTask<K,V> rights, nextRight; MapReduceMappingsToLongTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceMappingsToLongTask<K,V> nextRight, ToLongBiFunction<? super K, ? super V> transformer, long basis, LongBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Long getRawResult() { return result; } public final void compute() { final ToLongBiFunction<? super K, ? super V> transformer; final LongBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { long r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceMappingsToLongTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceMappingsToLongTask<K,V> t = (MapReduceMappingsToLongTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsLong(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceKeysToIntTask<K,V> extends BulkTask<K,V,Integer> { final ToIntFunction<? super K> transformer; final IntBinaryOperator reducer; final int basis; int result; MapReduceKeysToIntTask<K,V> rights, nextRight; MapReduceKeysToIntTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceKeysToIntTask<K,V> nextRight, ToIntFunction<? super K> transformer, int basis, IntBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Integer getRawResult() { return result; } public final void compute() { final ToIntFunction<? super K> transformer; final IntBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { int r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceKeysToIntTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsInt(r, transformer.applyAsInt(p.key)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceKeysToIntTask<K,V> t = (MapReduceKeysToIntTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsInt(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceValuesToIntTask<K,V> extends BulkTask<K,V,Integer> { final ToIntFunction<? super V> transformer; final IntBinaryOperator reducer; final int basis; int result; MapReduceValuesToIntTask<K,V> rights, nextRight; MapReduceValuesToIntTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceValuesToIntTask<K,V> nextRight, ToIntFunction<? super V> transformer, int basis, IntBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Integer getRawResult() { return result; } public final void compute() { final ToIntFunction<? super V> transformer; final IntBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { int r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceValuesToIntTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsInt(r, transformer.applyAsInt(p.val)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceValuesToIntTask<K,V> t = (MapReduceValuesToIntTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsInt(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceEntriesToIntTask<K,V> extends BulkTask<K,V,Integer> { final ToIntFunction<Map.Entry<K,V>> transformer; final IntBinaryOperator reducer; final int basis; int result; MapReduceEntriesToIntTask<K,V> rights, nextRight; MapReduceEntriesToIntTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceEntriesToIntTask<K,V> nextRight, ToIntFunction<Map.Entry<K,V>> transformer, int basis, IntBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Integer getRawResult() { return result; } public final void compute() { final ToIntFunction<Map.Entry<K,V>> transformer; final IntBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { int r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceEntriesToIntTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsInt(r, transformer.applyAsInt(p)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceEntriesToIntTask<K,V> t = (MapReduceEntriesToIntTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsInt(t.result, s.result); s = t.rights = s.nextRight; } } } } }
@SuppressWarnings("serial") static final class MapReduceMappingsToIntTask<K,V> extends BulkTask<K,V,Integer> { final ToIntBiFunction<? super K, ? super V> transformer; final IntBinaryOperator reducer; final int basis; int result; MapReduceMappingsToIntTask<K,V> rights, nextRight; MapReduceMappingsToIntTask (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, MapReduceMappingsToIntTask<K,V> nextRight, ToIntBiFunction<? super K, ? super V> transformer, int basis, IntBinaryOperator reducer) { super(p, b, i, f, t); this.nextRight = nextRight; this.transformer = transformer; this.basis = basis; this.reducer = reducer; } public final Integer getRawResult() { return result; } public final void compute() { final ToIntBiFunction<? super K, ? super V> transformer; final IntBinaryOperator reducer; if ((transformer = this.transformer) != null && (reducer = this.reducer) != null) { int r = this.basis; for (int i = baseIndex, f, h; batch > 0 && (h = ((f = baseLimit) + i) >>> 1) > i;) { addToPendingCount(1); (rights = new MapReduceMappingsToIntTask<K,V> (this, batch >>>= 1, baseLimit = h, f, tab, rights, transformer, r, reducer)).fork(); } for (Node<K,V> p; (p = advance()) != null; ) r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val)); result = r; CountedCompleter<?> c; for (c = firstComplete(); c != null; c = c.nextComplete()) { @SuppressWarnings("unchecked") MapReduceMappingsToIntTask<K,V> t = (MapReduceMappingsToIntTask<K,V>)c, s = t.rights; while (s != null) { t.result = reducer.applyAsInt(t.result, s.result); s = t.rights = s.nextRight; } } } } }
// Unsafe mechanics private static final sun.misc.Unsafe U; private static final long SIZECTL; private static final long TRANSFERINDEX; private static final long BASECOUNT; private static final long CELLSBUSY; private static final long CELLVALUE; private static final long ABASE; private static final int ASHIFT;
static { try { U = sun.misc.Unsafe.getUnsafe(); Class<?> k = ConcurrentHashMap.class; SIZECTL = U.objectFieldOffset (k.getDeclaredField("sizeCtl")); TRANSFERINDEX = U.objectFieldOffset (k.getDeclaredField("transferIndex")); BASECOUNT = U.objectFieldOffset (k.getDeclaredField("baseCount")); CELLSBUSY = U.objectFieldOffset (k.getDeclaredField("cellsBusy")); Class<?> ck = CounterCell.class; CELLVALUE = U.objectFieldOffset (ck.getDeclaredField("value")); Class<?> ak = Node[].class; ABASE = U.arrayBaseOffset(ak); int scale = U.arrayIndexScale(ak); if ((scale & (scale - 1)) != 0) throw new Error("data type scale not a power of two"); ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); } catch (Exception e) { throw new Error(e); } }}

JDK8中的ConcurrentHashMap源码

背景

ConcurrentHashMap源码

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