Java NIO - Condition

Condition用来实现对应Object的wati，notify，notifyAll三个方法。

在Condition中用await()替换wait()，用signal()替换notify() ，用signalAll()替换notifyAll()，传统线程之间的通讯Condition都可以实现。如下列子，我们实现一个读写操作，分为读写线程。

package chp3.condition;

import java.util.concurrent.locks.Condition;

import java.util.concurrent.locks.Lock;

import java.util.concurrent.locks.ReentrantLock;

public class BufferThread {

final Lock lock = new ReentrantLock();// 锁

final Condition notFull = lock.newCondition();// 写线程条件

final Condition notEmpty = lock.newCondition();// 读线程条件

final Object[] items = new Object[10];// 缓存队列

int putptr/* 写索引 */, takeptr/* 读索引 */, count/* 队列中存在的数据个数 */;

public void put(Object x) throws InterruptedException {

lock.lock();

try {

while (count == items.length) {

notFull.await();// 阻塞写线程

}

System.out.println("写入操作: index =  " + putptr + " value = " + x);

items[putptr++] = x;

if (putptr == items.length)

putptr = 0;// 如果写索引写到队列的最后一个位置了，那么置为0

++count;// 个数++

notEmpty.signal();// 唤醒读线程

} finally {

lock.unlock();

}

}

public Object take() throws InterruptedException {

lock.lock();

try {

while (count == 0)

// 如果队列为空

notEmpty.await();// 阻塞读线程

Object x = items[takeptr];// 取值

System.out.println("读取操作: index =" + takeptr + " vale = " + x);

if (++takeptr == items.length)

takeptr = 0;// 如果读索引读到队列的最后一个位置了，那么置为0

--count;// 个数--

notFull.signal();// 唤醒写线程

return x;

} finally {

lock.unlock();

}

}

public static void main(String[] args) {

final BufferThread bt = new BufferThread();

Thread t1 = new Thread(new Runnable() {

@Override

public void run() {

for (int i = 0; i < 250; i++)

	try {

bt.put(i);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

});

Thread t2 = new Thread(new Runnable() {

@Override

public void run() {

for (int i = 0; i < 230; i++)

	try {

bt.take();

} catch (InterruptedException e) {

e.printStackTrace();

}

}

});

t1.start();

t2.start();

}

}

参考：http://blog.csdn.net/ghsau/article/details/7481142