Package com.google.common.collect
Class EvictingQueue<E>
- java.lang.Object
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- com.google.common.collect.ForwardingObject
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- com.google.common.collect.ForwardingCollection<E>
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- com.google.common.collect.ForwardingQueue<E>
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- com.google.common.collect.EvictingQueue<E>
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- All Implemented Interfaces:
Serializable,Iterable<E>,Collection<E>,Queue<E>
@GwtCompatible public final class EvictingQueue<E> extends ForwardingQueue<E> implements Serializable
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. This queue orders elements FIFO (first-in-first-out). This data structure is logically equivalent to a circular buffer (i.e., cyclic buffer or ring buffer).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
- Author:
- Kurt Alfred Kluever
- See Also:
- Serialized Form
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description booleanadd(E e)Adds the given element to this queue.booleanaddAll(Collection<? extends E> collection)static <E> EvictingQueue<E>create(int maxSize)Creates and returns a new evicting queue that will hold up tomaxSizeelements.protected Queue<E>delegate()Returns the backing delegate instance that methods are forwarded to.booleanoffer(E e)Adds the given element to this queue.intremainingCapacity()Returns the number of additional elements that this queue can accept without evicting; zero if the queue is currently full.Object[]toArray()-
Methods inherited from class com.google.common.collect.ForwardingQueue
element, peek, poll, remove, standardOffer, standardPeek, standardPoll
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Methods inherited from class com.google.common.collect.ForwardingCollection
clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRemoveAll, standardRetainAll, standardToArray, standardToArray, standardToString, toArray
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Methods inherited from class com.google.common.collect.ForwardingObject
toString
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.Collection
clear, contains, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, remove, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArray
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Method Detail
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create
public static <E> EvictingQueue<E> create(int maxSize)
Creates and returns a new evicting queue that will hold up tomaxSizeelements.When
maxSizeis zero, elements will be evicted immediately after being added to the queue.
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remainingCapacity
public int remainingCapacity()
Returns the number of additional elements that this queue can accept without evicting; zero if the queue is currently full.- Since:
- 16.0
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delegate
protected Queue<E> delegate()
Description copied from class:ForwardingObjectReturns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such asForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.- Specified by:
delegatein classForwardingQueue<E>
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offer
@CanIgnoreReturnValue 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.
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add
@CanIgnoreReturnValue 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:
addin interfaceCollection<E>- Specified by:
addin interfaceQueue<E>- Overrides:
addin classForwardingCollection<E>- Returns:
truealways
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addAll
@CanIgnoreReturnValue public boolean addAll(Collection<? extends E> collection)
- Specified by:
addAllin interfaceCollection<E>- Overrides:
addAllin classForwardingCollection<E>
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toArray
public Object[] toArray()
- Specified by:
toArrayin interfaceCollection<E>- Overrides:
toArrayin classForwardingCollection<E>
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