Package org.jctools.channels

Class OffHeapFixedMessageSizeRingBuffer

java.lang.Object

org.jctools.channels.proxy.ProxyChannelRingBuffer

org.jctools.channels.OffHeapFixedMessageSizeRingBuffer

Direct Known Subclasses:

MpscFFLamportOffHeapFixedSizeRingBuffer, MpscOffHeapFixedSizeRingBuffer, SpscOffHeapFixedSizeRingBuffer

public abstract class OffHeapFixedMessageSizeRingBuffer
extends ProxyChannelRingBuffer

Channel protocol: - Fixed message size - 'null' indicator in message preceding byte (potentially use same for type mapping in future) - Use FF algorithm relying on indicator to support in place detection of next element existence

Field Summary

Fields

Modifier and Type	Field	Description
protected long	bufferAddress
private java.nio.ByteBuffer	buffy
protected long	consumerIndexAddress
static int	HEADER_SIZE
protected long	mask
static byte	MESSAGE_INDICATOR_SIZE
protected int	messageSize
protected long	producerIndexAddress
static int	READ_ACQUIRE_INDICATOR
static int	READ_RELEASE_INDICATOR
protected int	referenceMessageSize
protected java.lang.Object[]	references
static int	WRITE_ACQUIRE_INDICATOR
static int	WRITE_RELEASE_INDICATOR

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

EOF

Constructor Summary

Constructors

Modifier	Constructor	Description
	OffHeapFixedMessageSizeRingBuffer(int capacity, int primitiveMessageSize, int referenceMessageSize)
protected	OffHeapFixedMessageSizeRingBuffer(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
protected long	arrayIndexForCursor(long currentHead)
protected static long	arrayIndexForCursor(long mask, int referenceMessageSize, long currentHead)
int	capacity()
protected long	consumerReferenceArrayIndex(long offset)	Get the position index of the consumer in the reference array
protected static java.lang.Object[]	createReferenceArray(int capacity, int referenceMessageSize)
static int	getRequiredArraySize(int capacity, int primitiveMessageSize)
static int	getRequiredBufferSize(int capacity, int messageSize)
boolean	isEmpty()
protected boolean	isReadReleased(long offset)
protected long	lpConsumerIndex()
protected long	lpProducerIndex()
protected long	lvConsumerIndex()
protected long	lvProducerIndex()
protected long	offsetForIndex(long currentHead)
protected static long	offsetForIndex(long bufferAddress, long mask, int messageSize, long currentHead)
protected long	producerReferenceArrayIndex(long offset)	Get the position index of the producer in the reference array
protected abstract long	readAcquire()	Acquire an offset to read from
protected void	readAcquireState(long offset)
protected java.lang.Object	readReference(long offset)	Read a reference at the given position
protected abstract void	readRelease(long offset)	Release the offset from reading
protected void	readReleaseState(long offset)
protected long	relativeIndexForOffset(long offset)
protected static long	relativeIndexForOffset(long bufferAddress, int messageSize, long offset)	Computes an index relative to the buffer start for an offset.
int	size()
protected void	soConsumerIndex(long value)
protected void	soProducerIndex(long value)
protected abstract long	writeAcquire()	Acquire an offset to write to.
protected void	writeAcquireState(long offset)
protected void	writeReference(long offset, java.lang.Object reference)	Write a reference to the given position
protected abstract void	writeRelease(long offset)
protected void	writeReleaseState(long offset)

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

writeRelease

Methods inherited from class java.lang.Object

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

Field Detail

READ_RELEASE_INDICATOR

public static final int READ_RELEASE_INDICATOR

See Also:

Constant Field Values

READ_ACQUIRE_INDICATOR

public static final int READ_ACQUIRE_INDICATOR

See Also:

Constant Field Values

WRITE_RELEASE_INDICATOR

public static final int WRITE_RELEASE_INDICATOR

See Also:

Constant Field Values

WRITE_ACQUIRE_INDICATOR

public static final int WRITE_ACQUIRE_INDICATOR

See Also:

Constant Field Values

MESSAGE_INDICATOR_SIZE

public static final byte MESSAGE_INDICATOR_SIZE

See Also:

Constant Field Values

HEADER_SIZE

public static final int HEADER_SIZE

buffy

private final java.nio.ByteBuffer buffy

bufferAddress

protected final long bufferAddress

consumerIndexAddress

protected final long consumerIndexAddress

producerIndexAddress

protected final long producerIndexAddress

mask

protected final long mask

messageSize

protected final int messageSize

references

protected final java.lang.Object[] references

referenceMessageSize

protected final int referenceMessageSize

Constructor Detail

OffHeapFixedMessageSizeRingBuffer

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

OffHeapFixedMessageSizeRingBuffer

protected OffHeapFixedMessageSizeRingBuffer(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 - in messages, actual capacity will be

primitiveMessageSize -

Method Detail

getRequiredBufferSize

public static int getRequiredBufferSize(int capacity,
                                        int messageSize)

createReferenceArray

protected static java.lang.Object[] createReferenceArray(int capacity,
                                                         int referenceMessageSize)

getRequiredArraySize

public static int getRequiredArraySize(int capacity,
                                       int primitiveMessageSize)

capacity

public final int capacity()

size

public final int size()

isEmpty

public final boolean isEmpty()

isReadReleased

protected final boolean isReadReleased(long offset)

writeReleaseState

protected final void writeReleaseState(long offset)

readReleaseState

protected final void readReleaseState(long offset)

writeAcquireState

protected final void writeAcquireState(long offset)

readAcquireState

protected final void readAcquireState(long offset)

offsetForIndex

protected final long offsetForIndex(long currentHead)

offsetForIndex

protected static long offsetForIndex(long bufferAddress,
                                     long mask,
                                     int messageSize,
                                     long currentHead)

relativeIndexForOffset

protected final long relativeIndexForOffset(long offset)

relativeIndexForOffset

protected static long relativeIndexForOffset(long bufferAddress,
                                             int messageSize,
                                             long offset)

Computes an index relative to the buffer start for an offset. This does not recover the original index because that is a very hard problem.

Parameters:

bufferAddress -

messageSize -

offset -

Returns:

lpConsumerIndex

protected final long lpConsumerIndex()

lvConsumerIndex

protected final long lvConsumerIndex()

soConsumerIndex

protected final void soConsumerIndex(long value)

lpProducerIndex

protected final long lpProducerIndex()

lvProducerIndex

protected final long lvProducerIndex()

soProducerIndex

protected final void soProducerIndex(long value)

arrayIndexForCursor

protected final long arrayIndexForCursor(long currentHead)

arrayIndexForCursor

protected static long arrayIndexForCursor(long mask,
                                          int referenceMessageSize,
                                          long currentHead)

consumerReferenceArrayIndex

protected long consumerReferenceArrayIndex(long offset)

Description copied from class: ProxyChannelRingBuffer

Get the position index of the consumer in the reference array

Specified by:

consumerReferenceArrayIndex in class ProxyChannelRingBuffer

Parameters:

offset - the current offset of the consumer returned from ProxyChannelRingBuffer.readAcquire()

Returns:

the consumer index

producerReferenceArrayIndex

protected long producerReferenceArrayIndex(long offset)

Description copied from class: ProxyChannelRingBuffer

Get the position index of the producer in the reference array

Specified by:

producerReferenceArrayIndex in class ProxyChannelRingBuffer

Parameters:

offset - the current offset of the producer returned from ProxyChannelRingBuffer.writeAcquire()

Returns:

the producer index

writeReference

protected void writeReference(long offset,
                              java.lang.Object reference)

Write a reference to the given position

Specified by:

writeReference in class ProxyChannelRingBuffer

Parameters:

offset - index into the reference array

reference -

readReference

protected java.lang.Object readReference(long offset)

Read a reference at the given position

Specified by:

readReference in class ProxyChannelRingBuffer

Parameters:

offset - index into the reference array

Returns:

readAcquire

protected abstract long readAcquire()

Description copied from class: ProxyChannelRingBuffer

Acquire an offset to read from

Specified by:

readAcquire in class ProxyChannelRingBuffer

Returns:

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

readRelease

protected abstract void readRelease(long offset)

Description copied from class: ProxyChannelRingBuffer

Release the offset from reading

Specified by:

readRelease in class ProxyChannelRingBuffer

Parameters:

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

writeAcquire

protected abstract 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 ProxyChannelRingBuffer

Returns:

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

writeRelease

protected abstract void writeRelease(long offset)

Parameters:

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