Package rx.internal.util.atomic

Class SpscAtomicArrayQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

rx.internal.util.atomic.AtomicReferenceArrayQueue<E>

rx.internal.util.atomic.SpscAtomicArrayQueue<E>

Type Parameters:

E -

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>, java.util.Queue<E>

public final class SpscAtomicArrayQueue<E>
extends AtomicReferenceArrayQueue<E>

A Single-Producer-Single-Consumer queue backed by a pre-allocated buffer.

This implementation is a mashup of the Fast Flow algorithm with an optimization of the offer method taken from the BQueue algorithm (a variation on Fast Flow), and adjusted to comply with Queue.offer semantics with regards to capacity.
For convenience the relevant papers are available in the resources folder:
2010 - Pisa - SPSC Queues on Shared Cache Multi-Core Systems.pdf
2012 - Junchang- BQueue- Efficient and Practical Queuing.pdf
This implementation is wait free.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) java.util.concurrent.atomic.AtomicLong	consumerIndex
(package private) int	lookAheadStep
private static java.lang.Integer	MAX_LOOK_AHEAD_STEP
(package private) java.util.concurrent.atomic.AtomicLong	producerIndex
(package private) long	producerLookAhead

Fields inherited from class rx.internal.util.atomic.AtomicReferenceArrayQueue

buffer, mask

Constructor Summary

Constructors

Constructor	Description
SpscAtomicArrayQueue(int capacity)

Method Summary

Modifier and Type	Method	Description
boolean	isEmpty()
private long	lvConsumerIndex()
private long	lvProducerIndex()
boolean	offer(E e)
E	peek()
E	poll()
int	size()
private void	soConsumerIndex(long newIndex)
private void	soProducerIndex(long newIndex)

Methods inherited from class rx.internal.util.atomic.AtomicReferenceArrayQueue

calcElementOffset, calcElementOffset, clear, iterator, lpElement, lpElement, lvElement, lvElement, soElement, soElement, spElement, spElement, svElement

Methods inherited from class java.util.AbstractQueue

add, addAll, element, remove

Methods inherited from class java.util.AbstractCollection

contains, containsAll, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

contains, containsAll, equals, hashCode, parallelStream, remove, removeAll, removeIf, retainAll, spliterator, stream, toArray, toArray, toArray

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

MAX_LOOK_AHEAD_STEP

private static final java.lang.Integer MAX_LOOK_AHEAD_STEP

producerIndex

final java.util.concurrent.atomic.AtomicLong producerIndex

producerLookAhead

long producerLookAhead

consumerIndex

final java.util.concurrent.atomic.AtomicLong consumerIndex

lookAheadStep

final int lookAheadStep

Constructor Detail

SpscAtomicArrayQueue

public SpscAtomicArrayQueue(int capacity)

Method Detail

offer

public boolean offer(E e)

poll

public E poll()

peek

public E peek()

size

public int size()

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in class java.util.AbstractCollection<E>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Collection<E>

Overrides:

isEmpty in class java.util.AbstractCollection<E>

soProducerIndex

private void soProducerIndex(long newIndex)

soConsumerIndex

private void soConsumerIndex(long newIndex)

lvConsumerIndex

private long lvConsumerIndex()

lvProducerIndex

private long lvProducerIndex()