Package com.google.common.collect

Class EvictingQueue<E>

  • All Implemented Interfaces:
    java.lang.Iterable<E>, java.util.Collection<E>, java.util.Queue<E>
    @Beta
@GwtIncompatible("java.util.ArrayDeque")
public final class EvictingQueue<E>
extends ForwardingQueue<E>
    A non-blocking queue which automatically evicts elements from the head of the queue when attempting to add new elements onto the queue and it is full.

    An evicting queue must be configured with a maximum size. Each time an element is added to a full queue, the queue automatically removes its head element. This is different from conventional bounded queues, which either block or reject new elements when full.

    This class is not thread-safe, and does not accept null elements.

    Since:
    15.0

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean add​(E e)
      Adds the given element to this queue.
      boolean addAll​(java.util.Collection<? extends E> collection)  
      boolean contains​(java.lang.Object object)  
      static <E> EvictingQueue<E> create​(int maxSize)
      Creates and returns a new evicting queue that will hold up to maxSize elements.
      boolean offer​(E e)
      Adds the given element to this queue.
      boolean remove​(java.lang.Object object)  

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

      • Methods inherited from interface java.util.Collection

        clear, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray, toArray

      • Methods inherited from interface java.lang.Iterable

        forEach

    • Method Detail

      • create

        public static <E> EvictingQueue<E> create​(int maxSize)
        Creates and returns a new evicting queue that will hold up to maxSize elements.

        When maxSize is zero, elements will be evicted immediately after being added to the queue.

      • offer

        public boolean offer​(E e)
        Adds the given element to this queue. If the queue is currently full, the element at the head of the queue is evicted to make room.
        Specified by:
        offer in interface java.util.Queue<E>
        Overrides:
        offer in class ForwardingQueue<E>
        Returns:
        true always

      • add

        public boolean add​(E e)
        Adds the given element to this queue. If the queue is currently full, the element at the head of the queue is evicted to make room.
        Specified by:
        add in interface java.util.Collection<E>
        Specified by:
        add in interface java.util.Queue<E>
        Overrides:
        add in class ForwardingCollection<E>
        Returns:
        true always

      • addAll

        public boolean addAll​(java.util.Collection<? extends E> collection)
        Specified by:
        addAll in interface java.util.Collection<E>
        Overrides:
        addAll in class ForwardingCollection<E>

      • contains

        public boolean contains​(java.lang.Object object)
        Specified by:
        contains in interface java.util.Collection<E>
        Overrides:
        contains in class ForwardingCollection<E>

      • remove

        public boolean remove​(java.lang.Object object)
        Specified by:
        remove in interface java.util.Collection<E>
        Overrides:
        remove in class ForwardingCollection<E>