Java并发之条件阻塞Condition的应用 Java并发之条件阻塞Condition的应用代码示例

public class ConditionCommunication {
	public static void main(String[] args) {
		Business bussiness = new Business();
		new Thread(new Runnable() {
			// 开启一个子线程
			@Override
			          public void run() {
				for (int i = 1; i <= 50; i++) {
					bussiness.sub(i);
				}
			}
		}
		).start();
		// main方法主线程
		for (int i = 1; i <= 50; i++) {
			bussiness.main(i);
		}
	}
}
class Business {
	Lock lock = new ReentrantLock();
	Condition condition = lock.newCondition();
	//Condition是在具体的lock之上的
	private Boolean bShouldSub = true;
	public void sub(int i) {
		lock.lock();
		try {
			while (!bShouldSub) {
				try {
					condition.await();
					//用condition来调用await方法
				}
				catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			for (int j = 1; j <= 10; j++) {
				System.out.println("sub thread sequence of " + j
				            + ", loop of " + i);
			}
			bShouldSub = false;
			condition.signal();
			//用condition来发出唤醒信号，唤醒某一个
		}
		finally {
			lock.unlock();
		}
	}
	public void main(int i) {
		lock.lock();
		try {
			while (bShouldSub) {
				try {
					condition.await();
					//用condition来调用await方法
				}
				catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			for (int j = 1; j <= 10; j++) {
				System.out.println("main thread sequence of " + j
				            + ", loop of " + i);
			}
			bShouldSub = true;
			condition.signal();
			//用condition来发出唤醒信号么，唤醒某一个
		}
		finally {
			lock.unlock();
		}
	}
}

class Buffer {
	final Lock lock = new ReentrantLock();
	//定义一个锁
	final Condition notFull = lock.newCondition();
	//定义阻塞队列满了的Condition
	final Condition notEmpty = lock.newCondition();
	//定义阻塞队列空了的Condition
	final Object[] items = new Object[10];
	//为了下面模拟，设置阻塞队列的大小为10，不要设太大
	int putptr, takeptr, count;
	//数组下标，用来标定位置的
	//往队列中存数据
	public void put(Object x) throws InterruptedException {
		lock.lock();
		//上锁
		try {
			while (count == items.length) {
				System.out.println(Thread.currentThread().getName() + " 被阻塞了，暂时无法存数据！");
				notFull.await();
				//如果队列满了，那么阻塞存数据这个线程，等待被唤醒
			}
			//如果没满，按顺序往数组中存
			items[putptr] = x;
			if (++putptr == items.length) //这是到达数组末端的判断，如果到了，再回到始端
			putptr = 0;
			++count;
			//消息数量
			System.out.println(Thread.currentThread().getName() + " 存好了值： " + x);
			notEmpty.signal();
			//好了，现在队列中有数据了，唤醒队列空的那个线程，可以取数据啦
		}
		finally {
			lock.unlock();
			//放锁
		}
	}
	//从队列中取数据
	public Object take() throws InterruptedException {
		lock.lock();
		//上锁
		try {
			while (count == 0) {
				System.out.println(Thread.currentThread().getName() + " 被阻塞了，暂时无法取数据！");
				notEmpty.await();
				//如果队列是空，那么阻塞取数据这个线程，等待被唤醒
			}
			//如果没空，按顺序从数组中取
			Object x = items[takeptr];
			if (++takeptr == items.length) //判断是否到达末端，如果到了，再回到始端
			takeptr = 0;
			--count;
			//消息数量
			System.out.println(Thread.currentThread().getName() + " 取出了值： " + x);
			notFull.signal();
			//好了，现在队列中有位置了，唤醒队列满的那个线程，可以存数据啦
			return x;
		}
		finally {
			lock.unlock();
			//放锁
		}
	}
}

public class BoundedBuffer {
	public static void main(String[] args) {
		Buffer buffer = new Buffer();
		for (int i = 0; i < 5; i ++) {
			//开启5个线程往缓冲区存数据
			new Thread(new Runnable() {
				@Override
				        public void run() {
					try {
						buffer.put(new Random().nextint(1000));
						//随机存数据
					}
					catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
			).start();
		}
		for (int i = 0; i < 10; i ++) {
			//开启10个线程从缓冲区中取数据
			new Thread(new Runnable() {
				@Override
				        public void run() {
					try {
						buffer.take();
						//从缓冲区取数据
					}
					catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
			).start();
		}
	}
}

public class ThreeConditionCommunication {
	public static void main(String[] args) {
		Business bussiness = new Business();
		new Thread(new Runnable() {
			// 开启一个子线程
			@Override
			          public void run() {
				for (int i = 1; i <= 50; i++) {
					bussiness.sub1(i);
				}
			}
		}
		).start();
		new Thread(new Runnable() {
			// 开启另一个子线程
			@Override
			      public void run() {
				for (int i = 1; i <= 50; i++) {
					bussiness.sub2(i);
				}
			}
		}
		).start();
		// main方法主线程
		for (int i = 1; i <= 50; i++) {
			bussiness.main(i);
		}
	}
	static class Business {
		Lock lock = new ReentrantLock();
		Condition condition1 = lock.newCondition();
		//Condition是在具体的lock之上的
		Condition condition2 = lock.newCondition();
		Condition conditionMain = lock.newCondition();
		private int bShouldSub = 0;
		public void sub1(int i) {
			lock.lock();
			try {
				while (bShouldSub != 0) {
					try {
						condition1.await();
						//用condition来调用await方法
					}
					catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
				for (int j = 1; j <= 10; j++) {
					System.out.println("sub1 thread sequence of " + j
					              + ", loop of " + i);
				}
				bShouldSub = 1;
				condition2.signal();
				//让线程2执行
			}
			finally {
				lock.unlock();
			}
		}
		public void sub2(int i) {
			lock.lock();
			try {
				while (bShouldSub != 1) {
					try {
						condition2.await();
						//用condition来调用await方法
					}
					catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
				for (int j = 1; j <= 10; j++) {
					System.out.println("sub2 thread sequence of " + j
					              + ", loop of " + i);
				}
				bShouldSub = 2;
				conditionMain.signal();
				//让主线程执行
			}
			finally {
				lock.unlock();
			}
		}
		public void main(int i) {
			lock.lock();
			try {
				while (bShouldSub != 2) {
					try {
						conditionMain.await();
						//用condition来调用await方法
					}
					catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
				for (int j = 1; j <= 5; j++) {
					System.out.println("main thread sequence of " + j
					              + ", loop of " + i);
				}
				bShouldSub = 0;
				condition1.signal();
				//让线程1执行
			}
			finally {
				lock.unlock();
			}
		}
	}
}