java DelayQueue的原理浅析

public DelayQueue() {}
public DelayQueue(Collection<? extends E> c) {
 this.addAll(c);
}

public interface Delayed extends Comparable<Delayed> {
 /**
  * Returns the remaining delay associated with this object, in the
  * given time unit.
  *
  * @param unit the time unit
  * @return the remaining delay; zero or negative values indicate
  * that the delay has already elapsed
  */
 long getDelay(TimeUnit unit);
}

public class DelayQueue<E extends Delayed>extends AbstractQueue<E>implements BlockingQueue<E>