E - the type of elements held in this collectionpublic final class SingleConsumerQueue<E>
extends java.util.AbstractQueue<E>
implements java.util.Queue<E>, java.io.Serializable
null elements.
A SingleConsumerQueue is an appropriate choice when many producer threads will share
access to a common collection and a single consumer thread drains it. This collection is useful
in scenarios such as implementing flat combining, actors, or lock amortization.
This implementation employs combination to transfer elements between threads that are producing concurrently. This approach avoids contention on the queue by combining colliding operations that have identical semantics. When a pair of producers collide, the task of performing the combined set of operations is delegated to one of the threads and the other thread optionally waits for its operation to be completed. This decision of whether to wait for completion is determined by constructing either a linearizable or optimistic queue.
Iterators are weakly consistent, returning elements reflecting the state of the queue at
some point at or since the creation of the iterator. They do not throw ConcurrentModificationException, and may proceed concurrently with other operations.
Elements contained in the queue since the creation of the iterator will be returned exactly once.
Beware that it is the responsibility of the caller to ensure that a consumer has exclusive read access to the queue. This implementation does not include fail-fast behavior to guard against incorrect consumer usage.
Beware that, unlike in most collections, the size method is NOT a
constant-time operation. Because of the asynchronous nature of these queues, determining the
current number of elements requires a traversal of the elements, and so may report inaccurate
results if this collection is modified during traversal.
Warning: This class is scheduled for removal in version 3.0.0.
| Modifier and Type | Method and Description |
|---|---|
boolean |
add(E e) |
boolean |
addAll(java.util.Collection<? extends E> c) |
boolean |
contains(java.lang.Object o) |
boolean |
isEmpty() |
java.util.Iterator<E> |
iterator() |
static <E> SingleConsumerQueue<E> |
linearizable()
Creates a queue with a linearizable backoff strategy.
|
boolean |
offer(E e) |
static <E> SingleConsumerQueue<E> |
optimistic()
Creates a queue with an optimistic backoff strategy.
|
E |
peek() |
E |
poll() |
int |
size() |
containsAll, remove, removeAll, retainAll, toArray, toArray, toStringclone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, waitpublic static <E> SingleConsumerQueue<E> optimistic()
E - the type of elements held in this collectionpublic static <E> SingleConsumerQueue<E> linearizable()
E - the type of elements held in this collectionpublic boolean isEmpty()
public int size()
public boolean contains(java.lang.Object o)
public boolean add(E e)
public boolean addAll(java.util.Collection<? extends E> c)