/** Main lock guarding all access */
private final ReentrantLock lock;
/** Condition for waiting takes */
private final Condition notEmpty;
/** Condition for waiting puts */
private final Condition notFull;
/**
 * Inserts the specified element at the tail of this queue, waiting
 * for space to become available if the queue is full.
 *
 * @throws InterruptedException {@inheritDoc}
 * @throws NullPointerException {@inheritDoc}
 */
public void put(E e) throws InterruptedException {
 if (e == null) throw new NullPointerException();
 final E[] items = this.items;
 final ReentrantLock lock = this.lock;
 lock.lockInterruptibly();
 try {
 try {
  while (count == items.length)
  notFull.await();
 } catch (InterruptedException ie) {
  notFull.signal(); // propagate to non-interrupted thread
  throw ie;
 }
 insert(e);
 } finally {
 lock.unlock();
 }
}
public E take() throws InterruptedException {
 final ReentrantLock lock = this.lock;
 lock.lockInterruptibly();
 try {
 try {
  while (count == 0)
  notEmpty.await();
 } catch (InterruptedException ie) {
  notEmpty.signal(); // propagate to non-interrupted thread
  throw ie;
 }
 E x = extract();
 return x;
 } finally {
 lock.unlock();
 }
}