This abstract class provides a framework for simple Queue implementations. A concrete subclass must implement offer( ), peek( ), and poll( ) and must also implement the inherited size( ) and iterator( ) methods of the Collection interface. The Iterator returned by iterator( ) must support the remove( ) operation.

Figure 16-4. java.util.AbstractQueue<E>

public abstract class AbstractQueue<E> extends AbstractCollection<E> implements Queue<E> {
// Protected Constructors
     protected AbstractQueue( );  
// Methods Implementing Collection
     public boolean add(E o);  
     public boolean addAll(Collection<? extends E> c);  
     public void clear( );  
// Methods Implementing Queue
     public E element( );  
     public E remove( );  
}

Subclasses

PriorityQueue, java.util.concurrent.ArrayBlockingQueue, java.util.concurrent.ConcurrentLinkedQueue, java.util.concurrent.DelayQueue, java.util.concurrent.LinkedBlockingQueue, java.util.concurrent.PriorityBlockingQueue, java.util.concurrent.SynchronousQueue