Class ForwardingQueue<E extends @Nullable java.lang.Object>

  • All Implemented Interfaces:
    java.lang.Iterable<E>, java.util.Collection<E>, java.util.Queue<E>
    Direct Known Subclasses:
    EvictingQueue, ForwardingBlockingQueue, ForwardingDeque

    public abstract class ForwardingQueue<E extends @Nullable java.lang.Object>
    extends ForwardingCollection<E>
    implements java.util.Queue<E>
    A queue which forwards all its method calls to another queue. Subclasses should override one or more methods to modify the behavior of the backing queue as desired per the decorator pattern.

    Warning: The methods of ForwardingQueue forward indiscriminately to the methods of the delegate. For example, overriding ForwardingCollection.add(E) alone will not change the behavior of offer(E) which can lead to unexpected behavior. In this case, you should override offer as well, either providing your own implementation, or delegating to the provided standardOffer method.

    default method warning: This class does not forward calls to default methods. Instead, it inherits their default implementations. When those implementations invoke methods, they invoke methods on the ForwardingQueue.

    The standard methods are not guaranteed to be thread-safe, even when all of the methods that they depend on are thread-safe.

    Mike Bostock, Louis Wasserman