@Beta @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 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.
| Modifier and Type | Method and Description |
|---|---|
boolean |
add(E e)
Adds the given element to this queue.
|
boolean |
addAll(Collection<? extends E> collection) |
boolean |
contains(Object object) |
static <E> EvictingQueue<E> |
create(int maxSize)
Creates and returns a new evicting queue that will hold up to
maxSize elements. |
protected Queue<E> |
delegate()
Returns the backing delegate instance that methods are forwarded to.
|
boolean |
offer(E e)
Adds the given element to this queue.
|
int |
remainingCapacity()
Returns the number of additional elements that this queue can accept without evicting; zero if the queue is currently full.
|
boolean |
remove(Object object) |
element, peek, poll, remove, standardOffer, standardPeek, standardPollclear, containsAll, isEmpty, iterator, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRemoveAll, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArraytoStringclone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitclear, containsAll, equals, hashCode, isEmpty, iterator, parallelStream, removeAll, removeIf, retainAll, size, spliterator, stream, toArray, toArraypublic 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.
public int remainingCapacity()
Returns the number of additional elements that this queue can accept without evicting; zero if the queue is currently full.
protected Queue<E> delegate()
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 as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
delegate in class ForwardingQueue<E>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.
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.
add in interface Collection<E>add in interface Queue<E>add in class ForwardingCollection<E>true alwayspublic boolean addAll(Collection<? extends E> collection)
addAll in interface Collection<E>addAll in class ForwardingCollection<E>public boolean contains(Object object)
contains in interface Collection<E>contains in class ForwardingCollection<E>public boolean remove(Object object)
remove in interface Collection<E>remove in class ForwardingCollection<E>