public class ArrayBlockingQueue<E> extends AbstractQueue<E>
implements BlockingQueue<E>, java.io.Serializable {
final Object[] items;
int takeIndex;
int putIndex;
int count;
final ReentrantLock lock; /**notEmpty条件对象，用于通知take方法队列已有元素，可执行获取操作 */
private final Condition notEmpty;
private final Condition notFull; 迭代器 */
transient Itrs itrs = null;
public void put(E e) throws InterruptedException {
checkNotNull(e);
final ReentrantLock lock = this.lock; // ？？？？？？？？
lock.lockInterruptibly();
try {
while (count == items.length) //将当前调用线程挂起，添加到notFull条件队列中等待唤醒
notFull.await();
enqueue(e);//如果队列没有满直接添加。。 } finally {
lock.unlock();
}
}
}为甚么类的属性里没有ReentrantLock lock = new ReentrantLock();
却可以在put()中直接指定ReentrantLock lock=this.lock;?
/**
* Creates an {@code ArrayBlockingQueue} with the given (fixed)
* capacity and the specified access policy.
*
* @param capacity the capacity of this queue
* @param fair if {@code true} then queue accesses for threads blocked
* on insertion or removal, are processed in FIFO order;
* if {@code false} the access order is unspecified.
* @throws IllegalArgumentException if {@code capacity < 1}
*/
public ArrayBlockingQueue(int capacity, boolean fair) {
if (capacity <= 0)
throw new IllegalArgumentException();
this.items = new Object[capacity];
lock = new ReentrantLock(fair);
notEmpty = lock.newCondition();
notFull = lock.newCondition();
}构造方法里面初始化了lock对象