org.jctools.queues

Class ConcurrentCircularArrayQueue<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractQueue<E>

org.jctools.queues.ConcurrentCircularArrayQueue<E>

Type Parameters:

E -

All Implemented Interfaces:

Iterable<E>, Collection<E>, Queue<E>, MessagePassingQueue<E>

Direct Known Subclasses:

ConcurrentSequencedCircularArrayQueue, MpscArrayQueue, SpmcArrayQueue, SpscArrayQueue

public abstract class ConcurrentCircularArrayQueue<E>
extends AbstractQueue<E>

A concurrent access enabling class used by circular array based queues this class exposes an offset computation method along with differently memory fenced load/store methods into the underlying array. The class is pre-padded and the array is padded on either side to help with False sharing prvention. It is expected theat subclasses handle post padding.

Offset calculation is separate from access to enable the reuse of a give compute offset.

Load/Store methods using a buffer parameter are provided to allow the prevention of final field reload after a LoadLoad barrier.

Author:

nitsanw

Nested Class Summary

Nested classes/interfaces inherited from interface org.jctools.queues.MessagePassingQueue

MessagePassingQueue.Consumer<T>, MessagePassingQueue.ExitCondition, MessagePassingQueue.Supplier<T>, MessagePassingQueue.WaitStrategy

Field Summary

Fields

Modifier and Type	Field and Description
protected E[]	buffer
protected long	mask

Fields inherited from interface org.jctools.queues.MessagePassingQueue

UNBOUNDED_CAPACITY

Constructor Summary

Constructors

Constructor and Description
ConcurrentCircularArrayQueue(int capacity)

Method Summary

Modifier and Type	Method and Description
protected long	calcElementOffset(long index)
protected static long	calcElementOffset(long index, long mask)
int	capacity()
void	clear() Removes all items from the queue.
Iterator<E>	iterator()

Methods inherited from class java.util.AbstractQueue

add, addAll, element, remove

Methods inherited from class java.util.AbstractCollection

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jctools.queues.MessagePassingQueue

drain, drain, drain, fill, fill, fill, isEmpty, offer, peek, poll, relaxedOffer, relaxedPeek, relaxedPoll, size

Methods inherited from interface java.util.Queue

offer, peek, poll

Methods inherited from interface java.util.Collection

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

Methods inherited from interface java.lang.Iterable

forEach

Field Detail

mask

protected final long mask

buffer

protected final E[] buffer

Constructor Detail

ConcurrentCircularArrayQueue

public ConcurrentCircularArrayQueue(int capacity)

Method Detail

calcElementOffset

protected final long calcElementOffset(long index)

Parameters:

index - desirable element index

Returns:

the offset in bytes within the array for a given index.

calcElementOffset

protected static long calcElementOffset(long index,
                                        long mask)

Parameters:

index - desirable element index

mask -

Returns:

the offset in bytes within the array for a given index.

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()

Description copied from interface: MessagePassingQueue

Removes all items from the queue. Called from the consumer thread subject to the restrictions appropriate to the implementation and according to the Collection.clear() interface.

Specified by:

clear in interface Collection<E>

Specified by:

clear in interface MessagePassingQueue<E>

Overrides:

clear in class AbstractQueue<E>

capacity

public int capacity()

Returns:

the capacity of this queue or UNBOUNDED_CAPACITY if not bounded