org.jctools.queues.atomic

Class SpmcAtomicArrayQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

org.jctools.queues.atomic.SpmcAtomicArrayQueue<E>

Type Parameters:

E -

All Implemented Interfaces:

Iterable<E>, Collection<E>, Queue<E>, QueueProgressIndicators

public final class SpmcAtomicArrayQueue<E>
extends AbstractQueue<E>
implements QueueProgressIndicators

A single-producer multiple-consumer AtomicReferenceArray-backed queue.

Author:

akarnokd

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicReferenceArray<E>	buffer
protected int	mask

Constructor Summary

Constructors

Constructor and Description
SpmcAtomicArrayQueue(int capacity)

Method Summary

Modifier and Type	Method and Description
protected int	calcElementOffset(long index)
protected int	calcElementOffset(long index, int mask)
protected boolean	casHead(long expect, long newValue)
void	clear()
long	currentConsumerIndex() This method has no concurrent visibility semantics.
long	currentProducerIndex() This method has no concurrent visibility semantics.
boolean	isEmpty()
Iterator<E>	iterator()
protected E	lpElement(AtomicReferenceArray<E> buffer, int offset)
protected E	lpElement(int offset)
protected long	lvConsumerIndex()
protected E	lvElement(AtomicReferenceArray<E> buffer, int offset)
protected E	lvElement(int offset)
protected long	lvProducerIndex()
protected long	lvProducerIndexCache()
boolean	offer(E e)
E	peek()
E	poll()
int	size()
protected void	soElement(AtomicReferenceArray<E> buffer, int offset, E value)
protected void	soElement(int offset, E value)
protected void	soTail(long v)
protected void	spElement(AtomicReferenceArray<E> buffer, int offset, E value)
protected void	spElement(int offset, E value)
protected void	svElement(AtomicReferenceArray<E> buffer, int offset, E value)
protected void	svProducerIndexCache(long v)

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

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

buffer

protected final AtomicReferenceArray<E> buffer

mask

protected final int mask

Constructor Detail

SpmcAtomicArrayQueue

public SpmcAtomicArrayQueue(int capacity)

Method Detail

offer

public boolean offer(E e)

Specified by:

offer in interface Queue<E>

poll

public E poll()

Specified by:

poll in interface Queue<E>

peek

public E peek()

Specified by:

peek in interface Queue<E>

size

public int size()

Specified by:

size in interface Collection<E>

Specified by:

size in class AbstractCollection<E>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Collection<E>

Overrides:

isEmpty in class AbstractCollection<E>

currentProducerIndex

public long currentProducerIndex()

Description copied from interface: QueueProgressIndicators

This method has no concurrent visibility semantics. The value returned may be negative. Under normal circumstances 2 consecutive calls to this method can offer an idea of progress made by producer threads by subtracting the 2 results though in extreme cases (if producers have progressed by more than 2^64) this may also fail.
This value will normally indicate number of elements passed into the queue, but may under some circumstances be a derivative of that figure. This method should not be used to derive size or emptiness.

Specified by:

currentProducerIndex in interface QueueProgressIndicators

Returns:

the current value of the producer progress index

currentConsumerIndex

public long currentConsumerIndex()

Description copied from interface: QueueProgressIndicators

This method has no concurrent visibility semantics. The value returned may be negative. Under normal circumstances 2 consecutive calls to this method can offer an idea of progress made by consumer threads by subtracting the 2 results though in extreme cases (if consumers have progressed by more than 2^64) this may also fail.
This value will normally indicate number of elements taken out of the queue, but may under some circumstances be a derivative of that figure. This method should not be used to derive size or emptiness.

Specified by:

currentConsumerIndex in interface QueueProgressIndicators

Returns:

the current value of the consumer progress index

lvProducerIndexCache

protected final long lvProducerIndexCache()

svProducerIndexCache

protected final void svProducerIndexCache(long v)

lvConsumerIndex

protected final long lvConsumerIndex()

casHead

protected final boolean casHead(long expect,
                                long newValue)

lvProducerIndex

protected final long lvProducerIndex()

soTail

protected final void soTail(long v)

iterator

public Iterator<E> iterator()

Specified by:

iterator in interface Iterable<E>

Specified by:

iterator in interface Collection<E>

Specified by:

iterator in class AbstractCollection<E>

clear

public void clear()

Specified by:

clear in interface Collection<E>

Overrides:

clear in class AbstractQueue<E>

calcElementOffset

protected final int calcElementOffset(long index,
                                      int mask)

calcElementOffset

protected final int calcElementOffset(long index)

lvElement

protected final E lvElement(AtomicReferenceArray<E> buffer,
                            int offset)

lpElement

protected final E lpElement(AtomicReferenceArray<E> buffer,
                            int offset)

lpElement

protected final E lpElement(int offset)

spElement

protected final void spElement(AtomicReferenceArray<E> buffer,
                               int offset,
                               E value)

spElement

protected final void spElement(int offset,
                               E value)

soElement

protected final void soElement(AtomicReferenceArray<E> buffer,
                               int offset,
                               E value)

soElement

protected final void soElement(int offset,
                               E value)

svElement

protected final void svElement(AtomicReferenceArray<E> buffer,
                               int offset,
                               E value)

lvElement

protected final E lvElement(int offset)