JUC-10-ReadWriteLock read-write lock

Like ReadWriteLock Lock is an interface that provides the operating mechanism readLock and writeLock other kinds of locks, one for read-only lock is a write lock

 

      

 

 

Mutually exclusive principles:

Read - can coexist,

Read - write can not coexist,

Write - write can not coexist.

 

 

 

 

package com.wf.zhang.juc;

import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * ReadWritelock Read-Write Lock
 *
 *
 * Write / read-write needs "exclusive"
 *
 * Do not need to read exclusive
 */
public class TestReadWriterlock {

    public static void main(String[] args) {
        RW ReadWriterlockDemo = new new ReadWriterlockDemo ();
         // a thread write 
        new new the Thread ( new new the Runnable () {
            @Override
            public void run() {
                rw.set((int) (Math.random() * 101));
            }
        },"写锁").start();


        @ 100 threads read 
        for ( int I = 0; I <= 100; I ++ ) {

            new Thread(new Runnable() {
                @Override
                public void run() {
                    rw.get();
                }
            }).start();
        }

    }
}

class ReadWriterlockDemo {

    private int number = 0;

    private ReadWriteLock readWriteLock = new ReentrantReadWriteLock();

    //读
    public void get() {
        readWriteLock.readLock().lock();
        try {

            System.out.println(Thread.currentThread().getName() + " 读" + number);
        } finally {
            readWriteLock.readLock().unlock();
        }
    }

    //写
    public void set(int number) {
        this.number = number;
        readWriteLock.writeLock().lock();
        try {

            System.out.println(Thread.currentThread().getName() + " 写 " +number);
        } finally {
            readWriteLock.writeLock().unlock();
        }
    }
}