Package org.jctools.channels.mpsc

Class MpscFFLamportOffHeapFixedSizeRingBuffer

java.lang.Object

org.jctools.channels.proxy.ProxyChannelRingBuffer

org.jctools.channels.OffHeapFixedMessageSizeRingBuffer

org.jctools.channels.mpsc.MpscFFLamportOffHeapFixedSizeRingBuffer

public final class MpscFFLamportOffHeapFixedSizeRingBuffer
extends OffHeapFixedMessageSizeRingBuffer

A Multi-Producer-Single-Consumer ring buffer. This implies that any thread may call the write methods, but only a single thread may call reads for correctness to maintained.
This implementation follows patterns for False Sharing protection.
This implementation is using the Fast Flow method for polling from the queue (with minor change to correctly publish the index) and an extension of the Leslie Lamport concurrent queue algorithm (originated by Martin Thompson) on the producer side.

Field Summary

Fields

Modifier and Type	Field	Description
private long	consumerIndexCacheAddress

Fields inherited from class org.jctools.channels.OffHeapFixedMessageSizeRingBuffer

bufferAddress, consumerIndexAddress, HEADER_SIZE, mask, MESSAGE_INDICATOR_SIZE, messageSize, producerIndexAddress, READ_ACQUIRE_INDICATOR, READ_RELEASE_INDICATOR, referenceMessageSize, references, WRITE_ACQUIRE_INDICATOR, WRITE_RELEASE_INDICATOR

Fields inherited from class org.jctools.channels.proxy.ProxyChannelRingBuffer

EOF

Constructor Summary

Constructors

Modifier	Constructor	Description
	MpscFFLamportOffHeapFixedSizeRingBuffer(int capacity, int primitiveMessageSize, int referenceMessageSize)
protected	MpscFFLamportOffHeapFixedSizeRingBuffer(java.nio.ByteBuffer buff, int capacity, boolean isProducer, boolean isConsumer, boolean initialize, int primitiveMessageSize, java.lang.Object[] references, int referenceMessageSize)	This is to be used for an IPC queue with the direct buffer used being a memory mapped file.

Method Summary

Modifier and Type	Method	Description
private boolean	casProducerIndex(long expected, long update)
private long	lpConsumerIndexCache()
protected long	readAcquire()	Acquire an offset to read from
protected void	readRelease(long offset)	Release the offset from reading
private long	slowPathWriteAcquire(long wrapPoint)
private void	spConsumerIndexCache(long value)
private static void	spReadReleaseState(long offset)
protected long	writeAcquire()	Acquire an offset to write to.
protected void	writeRelease(long offset)
protected void	writeRelease(long offset, int callTypeId)	Ordered store of the callTypeId for the message at offset

Methods inherited from class org.jctools.channels.OffHeapFixedMessageSizeRingBuffer

arrayIndexForCursor, arrayIndexForCursor, capacity, consumerReferenceArrayIndex, createReferenceArray, getRequiredArraySize, getRequiredBufferSize, isEmpty, isReadReleased, lpConsumerIndex, lpProducerIndex, lvConsumerIndex, lvProducerIndex, offsetForIndex, offsetForIndex, producerReferenceArrayIndex, readAcquireState, readReference, readReleaseState, relativeIndexForOffset, relativeIndexForOffset, size, soConsumerIndex, soProducerIndex, writeAcquireState, writeReference, writeReleaseState

Methods inherited from class java.lang.Object

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

Field Detail

consumerIndexCacheAddress

private final long consumerIndexCacheAddress

Constructor Detail

MpscFFLamportOffHeapFixedSizeRingBuffer

public MpscFFLamportOffHeapFixedSizeRingBuffer(int capacity,
                                               int primitiveMessageSize,
                                               int referenceMessageSize)

MpscFFLamportOffHeapFixedSizeRingBuffer

protected MpscFFLamportOffHeapFixedSizeRingBuffer(java.nio.ByteBuffer buff,
                                                  int capacity,
                                                  boolean isProducer,
                                                  boolean isConsumer,
                                                  boolean initialize,
                                                  int primitiveMessageSize,
                                                  java.lang.Object[] references,
                                                  int referenceMessageSize)

This is to be used for an IPC queue with the direct buffer used being a memory mapped file.

Parameters:

buff -

capacity -

Method Detail

slowPathWriteAcquire

private long slowPathWriteAcquire(long wrapPoint)

writeAcquire

protected final long writeAcquire()

Description copied from class: ProxyChannelRingBuffer

Acquire an offset to write to. If there's no space available a wait strategy may be used.

Specified by:

writeAcquire in class OffHeapFixedMessageSizeRingBuffer

Returns:

a base address for a message acquired to be written, or EOF if none is available

writeRelease

protected final void writeRelease(long offset)

Specified by:

writeRelease in class OffHeapFixedMessageSizeRingBuffer

Parameters:

offset - the base address of a message that we are done writing and can be read now

writeRelease

protected final void writeRelease(long offset,
                                  int callTypeId)

Description copied from class: ProxyChannelRingBuffer

Ordered store of the callTypeId for the message at offset

Specified by:

writeRelease in class ProxyChannelRingBuffer

Parameters:

offset - the offset that was released for writing

callTypeId - A unique ID for the call

readAcquire

protected final long readAcquire()

Description copied from class: ProxyChannelRingBuffer

Acquire an offset to read from

Specified by:

readAcquire in class OffHeapFixedMessageSizeRingBuffer

Returns:

a base address for a message acquired to be read, or EOF if none is available

readRelease

protected final void readRelease(long offset)

Description copied from class: ProxyChannelRingBuffer

Release the offset from reading

Specified by:

readRelease in class OffHeapFixedMessageSizeRingBuffer

Parameters:

offset - the base address of a message that we are done reading and can be overwritten now

casProducerIndex

private boolean casProducerIndex(long expected,
                                 long update)

lpConsumerIndexCache

private long lpConsumerIndexCache()

spConsumerIndexCache

private void spConsumerIndexCache(long value)

spReadReleaseState

private static void spReadReleaseState(long offset)