This BlockingQueue implementation restricts its elements to instances of some class E that implements the Delay interface. null elements are not allowed. Elements on the queue are ordered by the amount of delay remaining. The element whose getdelay( ) method returns the smallest value is the first to be removed from the queue. No element may be removed, however, until its getdelay( ) method returns zero or a negative number.

Figure 16-81. java.util.concurrent.DelayQueue<E extends Delayed>

public class DelayQueue<E extends Delayed> extends java.util.AbstractQueue<E> 
        implements BlockingQueue<E> {
// Public Constructors
     public DelayQueue( );  
     public DelayQueue(java.util.Collection<? extends E> c);  
// Public Instance Methods
     public E peek( );  
     public E poll( );  
// Methods Implementing BlockingQueue
     public boolean add(E o);  
     public int drainTo(java.util.Collection<? super E> c);  
     public int drainTo(java.util.Collection<? super E> c, int maxElements);  
     public boolean offer(E o);  
     public boolean offer(E o, long timeout, TimeUnit unit);  
     public E poll(long timeout, TimeUnit unit) throws InterruptedException;  
     public void put(E o);  
     public int remainingCapacity( );  
     public E take( ) throws InterruptedException;  
// Methods Implementing Collection
     public void clear( );  
     public java.util.Iterator<E> iterator( );  
     public boolean remove(Object o);  
     public int size( );  
     public Object[ ] toArray( );  
     public <T> T[ ] toArray(T[ ] array);  
}