package com.alibaba.dubbo.common.utils;
import java.util.LinkedHashMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class LRUCache<K, V> extends LinkedHashMap<K, V> {
private static final long serialVersionUID = -5167631809472116969L;
private static final float DEFAULT_LOAD_FACTOR = 0.75f;
private static final int DEFAULT_MAX_CAPACITY = 1000;
private volatile int maxCapacity;
private final Lock lock = new ReentrantLock();
public LRUCache() {
this(DEFAULT_MAX_CAPACITY);
}
public LRUCache(int maxCapacity) {
super(16, DEFAULT_LOAD_FACTOR, true);
this.maxCapacity = maxCapacity;
}
@Override
protected boolean removeEldestEntry(java.util.Map.Entry<K, V> eldest) {
return size() > maxCapacity;
}
@Override
public boolean containsKey(Object key) {
try {
lock.lock();
return super.containsKey(key);
} finally {
lock.unlock();
}
}
@Override
public V get(Object key) {
try {
lock.lock();
return super.get(key);
} finally {
lock.unlock();
}
}
@Override
public V put(K key, V value) {
try {
lock.lock();
return super.put(key, value);
} finally {
lock.unlock();
}
}
@Override
public V remove(Object key) {
try {
lock.lock();
return super.remove(key);
} finally {
lock.unlock();
}
}
@Override
public int size() {
try {
lock.lock();
return super.size();
} finally {
lock.unlock();
}
}
@Override
public void clear() {
try {
lock.lock();
super.clear();
} finally {
lock.unlock();
}
}
public int getMaxCapacity() {
return maxCapacity;
}
public void setMaxCapacity(int maxCapacity) {
this.maxCapacity = maxCapacity;
}
}