net.openhft.chronicle.queue.impl.single

Class SingleChronicleQueueExcerpts.StoreTailer

java.lang.Object

net.openhft.chronicle.queue.impl.single.SingleChronicleQueueExcerpts.StoreTailer

All Implemented Interfaces:

ExcerptCommon<ExcerptTailer>, ExcerptTailer, ExcerptContext, net.openhft.chronicle.wire.MarshallableIn, net.openhft.chronicle.wire.SourceContext

Enclosing class:

SingleChronicleQueueExcerpts

public static class SingleChronicleQueueExcerpts.StoreTailer
extends Object
implements ExcerptTailer, net.openhft.chronicle.wire.SourceContext, ExcerptContext

Tailer

Field Summary

Fields inherited from interface net.openhft.chronicle.wire.MarshallableIn

MARSHALLABLE_IN_INTERN_SIZE

Constructor Summary

Constructors

Constructor and Description
StoreTailer(SingleChronicleQueue queue)
StoreTailer(SingleChronicleQueue queue, net.openhft.chronicle.core.values.LongValue indexValue)

Method Summary

Modifier and Type	Method and Description
ExcerptTailer	afterLastWritten(ChronicleQueue queue) Wind this tailer to after the last entry which wrote an entry to the queue
int	cycle()
TailerDirection	direction()
ExcerptTailer	direction(TailerDirection direction) Set the direction of movement.
Runnable	getCloserJob() A task that will be run if a WeakReference referring this appender is registered with a clean-up task.
long	index()
boolean	moveToIndex(long index) Randomly select an Excerpt.
ExcerptTailer	originalToEnd()
boolean	peekDocument() peekDocument() can be used after a message has been found by toStart() or readingDocument().
ChronicleQueue	queue()
boolean	readAfterReplicaAcknowledged()
void	readAfterReplicaAcknowledged(boolean readAfterReplicaAcknowledged) Enterprise Queue only: if replication enabled, setting this to true on a source queue ensures that this tailer will not read until at least one of the sinks has acknowledged receipt of the excerpt.
boolean	readDocument(net.openhft.chronicle.wire.ReadMarshallable reader)
static net.openhft.chronicle.wire.MessageHistory	readHistory(net.openhft.chronicle.wire.DocumentContext dc, net.openhft.chronicle.wire.MessageHistory history)
net.openhft.chronicle.wire.DocumentContext	readingDocument() equivalent to MarshallableIn.readDocument(ReadMarshallable) but with out the use of a lambda expression.
net.openhft.chronicle.wire.DocumentContext	readingDocument(boolean includeMetaData)
void	releaseResources() Can be used to manually release resources when this StoreTailer is no longer used.
void	setCycle(int cycle)
int	sourceId()
TailerState	state()
boolean	striding()
ExcerptTailer	striding(boolean striding) When striding is enabled AND direction is BACKWARD, skip to the entries easiest to find, doesn't need to be every entry.
long	timeoutMS()
ExcerptTailer	toEnd() Wind to the last entry in the last cycle
ExcerptTailer	toStart() Replay from the first entry in the first cycle.
String	toString()
net.openhft.chronicle.wire.Wire	wire()
net.openhft.chronicle.wire.Wire	wireForIndex()

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.openhft.chronicle.wire.MarshallableIn

methodReader, methodReaderBuilder, readBytes, readBytes, readMap, readText, readText

Constructor Detail

StoreTailer

public StoreTailer(@NotNull
                   SingleChronicleQueue queue)

StoreTailer

public StoreTailer(@NotNull
                   SingleChronicleQueue queue,
                   net.openhft.chronicle.core.values.LongValue indexValue)

Method Detail

readHistory

@Nullable
public static net.openhft.chronicle.wire.MessageHistory readHistory(net.openhft.chronicle.wire.DocumentContext dc,
                                                                              net.openhft.chronicle.wire.MessageHistory history)

readDocument

public boolean readDocument(@NotNull
                            net.openhft.chronicle.wire.ReadMarshallable reader)

Specified by:

readDocument in interface net.openhft.chronicle.wire.MarshallableIn

readingDocument

@NotNull
public net.openhft.chronicle.wire.DocumentContext readingDocument()

Description copied from interface: ExcerptTailer

equivalent to MarshallableIn.readDocument(ReadMarshallable) but with out the use of a lambda expression.

This method is the ExcerptTailer equivalent of WireIn.readingDocument()

Specified by:

readingDocument in interface ExcerptTailer

Specified by:

readingDocument in interface net.openhft.chronicle.wire.MarshallableIn

Returns:

the document context

wire

public net.openhft.chronicle.wire.Wire wire()

Specified by:

wire in interface ExcerptContext

wireForIndex

public net.openhft.chronicle.wire.Wire wireForIndex()

Specified by:

wireForIndex in interface ExcerptContext

timeoutMS

public long timeoutMS()

Specified by:

timeoutMS in interface ExcerptContext

sourceId

public int sourceId()

Specified by:

sourceId in interface ExcerptCommon<ExcerptTailer>

Specified by:

sourceId in interface net.openhft.chronicle.wire.SourceContext

Returns:

the sourceId for the queue which created this.

toString

@NotNull
public String toString()

Overrides:

toString in class Object

readingDocument

@NotNull
public net.openhft.chronicle.wire.DocumentContext readingDocument(boolean includeMetaData)

Specified by:

readingDocument in interface ExcerptTailer

peekDocument

public boolean peekDocument()

Description copied from interface: ExcerptTailer

peekDocument() can be used after a message has been found by toStart() or readingDocument(). Until then only readingDocument() will find the first cycle.

Specified by:

peekDocument in interface ExcerptTailer

Specified by:

peekDocument in interface net.openhft.chronicle.wire.MarshallableIn

Returns:

true if readingDocument() should be called, false if most likely it's not needed.

index

public long index()

Specified by:

index in interface ExcerptTailer

Specified by:

index in interface net.openhft.chronicle.wire.SourceContext

Returns:

provides an index that includes the cycle number

cycle

public int cycle()

Specified by:

cycle in interface ExcerptTailer

Returns:

the cycle this tailer is on, usually with chronicle-queue each cycle will have its own unique data file to store the excerpt

moveToIndex

public boolean moveToIndex(long index)

Description copied from interface: ExcerptTailer

Randomly select an Excerpt.

Specified by:

moveToIndex in interface ExcerptTailer

Parameters:

index - index to look up, the index includes the cycle number and a sequence number from with this cycle

Returns:

true if this is a valid entries.

toStart

@NotNull
public final ExcerptTailer toStart()

Description copied from interface: ExcerptTailer

Replay from the first entry in the first cycle.

Specified by:

toStart in interface ExcerptTailer

Returns:

this Excerpt

toEnd

@NotNull
public ExcerptTailer toEnd()

Description copied from interface: ExcerptTailer

Wind to the last entry in the last cycle

If the direction() == FORWARD, this will be 1 more than the last entry.

Otherwise the index will be the last entry.

This is not atomic with the appenders, in other words if a cycle has been added in the current millisecond, toEnd() may not see it, This is because for performance reasons, the queue.lastCycle() is cached, as finding the last cycle is expensive, it requires asking the directory for the Files.list() so, this cache is only refreshed if the call toEnd() is in a new millisecond. Hence a whole milliseconds with of data could be added to the chronicle-queue that toEnd() won’t see. For appenders that that are using the same queue instance ( and with then same JVM ), they can be informed that the last cycle has changed, this will yield better results, but atomicity can still not be guaranteed.

Specified by:

toEnd in interface ExcerptTailer

Returns:

this ExcerptTailer

striding

public ExcerptTailer striding(boolean striding)

Description copied from interface: ExcerptTailer

When striding is enabled AND direction is BACKWARD, skip to the entries easiest to find, doesn't need to be every entry.

Specified by:

striding in interface ExcerptTailer

Parameters:

striding - skip to the indexStride if that is easy, doesn't always happen.

Returns:

this ExcerptTailer

striding

public boolean striding()

Specified by:

striding in interface ExcerptTailer

Returns:

whether striding is enabled.

originalToEnd

@NotNull
public ExcerptTailer originalToEnd()

direction

public TailerDirection direction()

Specified by:

direction in interface ExcerptTailer

Returns:

the direction of movement after reading an entry.

direction

@NotNull
public ExcerptTailer direction(TailerDirection direction)

Description copied from interface: ExcerptTailer

Set the direction of movement.

Specified by:

direction in interface ExcerptTailer

Parameters:

direction - NONE, FORWARD, BACKWARD

Returns:

this

queue

@NotNull
public ChronicleQueue queue()

Specified by:

queue in interface ExcerptCommon<ExcerptTailer>

getCloserJob

public Runnable getCloserJob()

Description copied from interface: ExcerptTailer

A task that will be run if a WeakReference referring this appender is registered with a clean-up task.

Specified by:

getCloserJob in interface ExcerptTailer

Returns:

Task to release any associated resources

releaseResources

public void releaseResources()

Can be used to manually release resources when this StoreTailer is no longer used.

readAfterReplicaAcknowledged

public void readAfterReplicaAcknowledged(boolean readAfterReplicaAcknowledged)

Description copied from interface: ExcerptTailer

Enterprise Queue only: if replication enabled, setting this to true on a source queue ensures that this tailer will not read until at least one of the sinks has acknowledged receipt of the excerpt. This will block forever if no sinks acknowledge receipt.

Specified by:

readAfterReplicaAcknowledged in interface ExcerptTailer

Parameters:

readAfterReplicaAcknowledged - enable

readAfterReplicaAcknowledged

public boolean readAfterReplicaAcknowledged()

Specified by:

readAfterReplicaAcknowledged in interface ExcerptTailer

state

@NotNull
public TailerState state()

Specified by:

state in interface ExcerptTailer

afterLastWritten

@NotNull
public ExcerptTailer afterLastWritten(@NotNull
                                               ChronicleQueue queue)

Description copied from interface: ExcerptTailer

Wind this tailer to after the last entry which wrote an entry to the queue

Specified by:

afterLastWritten in interface ExcerptTailer

Parameters:

queue - which was written to.

Returns:

this ExcerptTailer

setCycle

public void setCycle(int cycle)