ArrayBlockingQueue

ArrayBlockingQueue实现,有容量限制的阻塞队列，实现原理如下

class BoundedBuffer {

   final Lock lock = new ReentrantLock();

   final Condition notFull  = lock.newCondition(); 

   final Condition notEmpty = lock.newCondition(); 



   final Object[] items = new Object[100];

   int putptr, takeptr, count;



   public void put(Object x) throws InterruptedException {

     lock.lock();

     try {

       while (count == items.length) 

         notFull.await();

       items[putptr] = x; 

       if (++putptr == items.length) putptr = 0;

       ++count;

       notEmpty.signal();

     } finally {

       lock.unlock();

     }

   }



   public Object take() throws InterruptedException {

     lock.lock();

     try {

       while (count == 0) 

         notEmpty.await();

       Object x = items[takeptr]; 

       if (++takeptr == items.length) takeptr = 0;

       --count;

       notFull.signal();

       return x;

     } finally {

       lock.unlock();

     }

   } 

 }