net.openhft.chronicle.queue

Interface ExcerptAppender

All Superinterfaces:

ExcerptCommon<ExcerptAppender>, net.openhft.chronicle.wire.MarshallableOut

public interface ExcerptAppender
extends ExcerptCommon<ExcerptAppender>, net.openhft.chronicle.wire.MarshallableOut

The component that facilitates sequentially writing data to a ChronicleQueue.

NOTE: Appenders are NOT thread-safe, sharing the Appender between threads will lead to errors and unpredictable behaviour.

Author:

peter.lawrey

Nested Class Summary

Nested classes/interfaces inherited from interface net.openhft.chronicle.wire.MarshallableOut

net.openhft.chronicle.wire.MarshallableOut.Padding

Method Summary

Modifier and Type	Method and Description
long	batchAppend(int timeoutMS, BatchAppender batchAppender) Deprecated. This method is not recommended unless you really know what you are doing. Misuse of this API could corrupt your data or even worst cause the JVM or your application to crash.
int	cycle() Returns the cycle this appender is on.
default Runnable	getCloserJob() A task that will be run if a WeakReference referring this appender is registered with a clean-up task.
long	lastIndexAppended() Returns the index last written.
default <T> T	methodWriter(Class<T> tClass, Class... additional) Creates and returns a new writer proxy for the given interface tclass and the given additional interfaces.
default <T> net.openhft.chronicle.wire.VanillaMethodWriterBuilder<T>	methodWriterBuilder(Class<T> tClass) Creates and returns a new writer proxy for the given interface tclass.
void	padToCacheAlign(net.openhft.chronicle.wire.MarshallableOut.Padding padToCacheAlign) Sets the Padding to be used for this ExcerptAppender.
net.openhft.chronicle.wire.MarshallableOut.Padding	padToCacheAlignMode() Returns the current Padding used by this ExcerptAppender.
default void	pretouch() Pre-touches storage resources for the current queue so that appenders may exhibit more predictable latencies.
net.openhft.chronicle.wire.Wire	wire() Returns a raw wire for low level direct access.
default void	writeBytes(net.openhft.chronicle.bytes.Bytes bytes) Writes (i.e.
void	writeBytes(net.openhft.chronicle.bytes.BytesStore bytes) Writes (i.e.

Methods inherited from interface net.openhft.chronicle.queue.ExcerptCommon

queue, sourceId

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

methodWriter, recordHistory, writeBytes, writeDocument, writeDocument, writeMap, writeMessage, writeText, writingDocument, writingDocument

Method Detail

writeBytes

void writeBytes(@NotNull
                net.openhft.chronicle.bytes.BytesStore bytes)
         throws net.openhft.chronicle.wire.UnrecoverableTimeoutException

Writes (i.e. appends) the provided bytes to the queue.

Parameters:

bytes - to write to excerpt.

Throws:

net.openhft.chronicle.wire.UnrecoverableTimeoutException

writeBytes

default void writeBytes(@NotNull
                        net.openhft.chronicle.bytes.Bytes bytes)
                 throws net.openhft.chronicle.wire.UnrecoverableTimeoutException

Writes (i.e. appends) the provided bytes to the queue.

Parameters:

bytes - to write to excerpt.

Throws:

net.openhft.chronicle.wire.UnrecoverableTimeoutException

lastIndexAppended

long lastIndexAppended()

Returns the index last written.

The index includes the cycle and the sequence number.

Returns:

the index last written

Throws:

IllegalStateException - if no index is available

cycle

int cycle()

Returns the cycle this appender is on.

Usually with chronicle-queue each cycle will have its own unique data file to store the excerpts

Returns:

the cycle this appender is on

pretouch

default void pretouch()

Pre-touches storage resources for the current queue so that appenders may exhibit more predictable latencies.

Pre-touching involves accessing pages of files/memory that are likely accessed in a near future and may also involve accessing/acquiring future cycle files.

We suggest this code is called from a background thread [ not you main business thread ], it must be called from the same thread that created it, as the call to pretouch() is not thread safe. For example :

newSingleThreadScheduledExecutor().scheduleAtFixedRate(() -> queue.acquireAppender().pretouch(), 0, 1, TimeUnit.SECONDS);

padToCacheAlign

void padToCacheAlign(net.openhft.chronicle.wire.MarshallableOut.Padding padToCacheAlign)

Sets the Padding to be used for this ExcerptAppender.

Enable padding if near the end of a cache line, pad it so a following 4-byte int value will not split a cache line.

See Also:

MarshallableOut.Padding

padToCacheAlignMode

@NotNull
net.openhft.chronicle.wire.MarshallableOut.Padding padToCacheAlignMode()

Returns the current Padding used by this ExcerptAppender.

Specified by:

padToCacheAlignMode in interface net.openhft.chronicle.wire.MarshallableOut

Returns:

the current Padding used by this ExcerptAppender

getCloserJob

default Runnable getCloserJob()

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

Returns:

Task to release any associated resources

methodWriter

@NotNull
default <T> T methodWriter(@NotNull
                                    Class<T> tClass,
                                    Class... additional)

Creates and returns a new writer proxy for the given interface tclass and the given additional interfaces.

When methods are invoked on the returned T object, messages will be put in the queue.

Writers are NOT thread-safe. Sharing a Writer across threads will lead to errors and unpredictable behaviour.

Specified by:

methodWriter in interface net.openhft.chronicle.wire.MarshallableOut

Type Parameters:

T - type parameter of the main interface

Parameters:

tClass - of the main interface to be implemented

additional - interfaces to be implemented

Returns:

a new proxy for the given interface tclass and the given additional interfaces

Throws:

NullPointerException - if any of the provided parameters are null.

methodWriterBuilder

@NotNull
default <T> net.openhft.chronicle.wire.VanillaMethodWriterBuilder<T> methodWriterBuilder(@NotNull
                                                                                                  Class<T> tClass)

Creates and returns a new writer proxy for the given interface tclass.

When methods are invoked on the returned T object, messages will be put in the queue.

Writers are NOT thread-safe. Sharing a Writer across threads will lead to errors and unpredictable behaviour.

Specified by:

methodWriterBuilder in interface net.openhft.chronicle.wire.MarshallableOut

Type Parameters:

T - type parameter of the main interface

Parameters:

tClass - of the main interface to be implemented

Returns:

a new proxy for the given interface tclass

Throws:

NullPointerException - if the provided parameter is null.

wire

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

Returns a raw wire for low level direct access.

Returns:

a raw wire for low level direct access

batchAppend

@Deprecated
long batchAppend(int timeoutMS,
                             BatchAppender batchAppender)

Deprecated. This method is not recommended unless you really know what you are doing. Misuse of this API could corrupt your data or even worst cause the JVM or your application to crash.

Appends a number of excerpts in a single batch operation.

Parameters:

timeoutMS - time out in miliseconds

batchAppender - to apply for the batch append

Returns:

the number of messages written in call the batches

See Also:

BatchAppender