public class Queue {

	private LinkedList<Object> list = new LinkedList<Object>() ;

	private final int minSize = 0 ; ;

	private final int maxSize ;

	private AtomicInteger count = new AtomicInteger(0) ;

	public Queue(int size){

		this.maxSize = size ;

	}

	private final Object lock = new Object() ;

	public void put(Object o){

		synchronized(lock){

			while(size() == this.maxSize){

				try {

					lock.wait();

				} catch (InterruptedException e) {

					e.printStackTrace();

				}

			}

			list.add(o) ;

			//计数器增加

			count.incrementAndGet() ;

			//通知唤醒

			lock.notify();

		}

	}

	private int size(){

		return count.get() ;

	}

	public Object take(){

		Object res = null ;

		synchronized(lock){

			while(size() == this.minSize){

				try {

					lock.wait();

				} catch (InterruptedException e) {

					e.printStackTrace();

				}

			}

			res = list.removeFirst();

			//计数器减1

			count.decrementAndGet() ;

			lock.notify();

		}

		return res ;

	}

	public static void main(String[] args) {

		final Queue mq = new Queue(3) ;

		mq.put("a");

		mq.put("b");

		mq.put("c");

		new Thread(new Runnable() {

			@Override

			public void run() {

				mq.put("g");

				System.out.println("put1 secceseful");

				mq.put("f");

				System.out.println("put2 secceseful");

			}

		}).start();

		new Thread(new Runnable() {

			@Override

			public void run() {

				System.out.println("take value = "+mq.take() );

			}

		}).start();

	}

}

take value = a

put1 secceseful