net.openhft.chronicle.queue

Interface ExcerptAppender

All Superinterfaces:

AutoCloseable, Closeable, net.openhft.chronicle.wire.DocumentWritten, ExcerptCommon<ExcerptAppender>, net.openhft.chronicle.wire.MarshallableOut, net.openhft.chronicle.core.io.QueryCloseable

All Known Subinterfaces:

InternalAppender

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.

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
int	cycle() Returns the cycle this appender is on.
long	lastIndexAppended() Returns the index last written.
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.
default <T> @NotNull net.openhft.chronicle.wire.VanillaMethodWriterBuilder<T>	methodWriterBuilder(@NotNull Class<T> tClass) Creates and returns a new writer proxy for the given interface tclass.
default void	normaliseEOFs() Ensure all already-rolled cq4 files are correctly ended with EOF Used by replication sinks on startup to cover off any edge cases where the replicated EOF was not received/applied Can also be used on any appender, but this is not currently done automatically
default void	pretouch() Pre-touches storage resources for the current queue so that appenders may exhibit more predictable latencies.
@Nullable net.openhft.chronicle.wire.Wire	wire() Returns a raw wire for low level direct access.
default void	writeBytes(@NotNull net.openhft.chronicle.bytes.Bytes bytes) Writes (i.e.
void	writeBytes(@NotNull net.openhft.chronicle.bytes.BytesStore bytes) Writes (i.e.

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

currentFile, disableThreadSafetyCheck, queue, sourceId

Methods inherited from interface net.openhft.chronicle.core.io.Closeable

close, closeQuietly, closeQuietly, notifyClosing, warnAndCloseIfNotClosed

Methods inherited from interface net.openhft.chronicle.core.io.QueryCloseable

isClosed, isClosing, throwExceptionIfClosed

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

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

Method Detail

writeBytes

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

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

Parameters:

bytes - to write to excerpt.

Throws:

net.openhft.chronicle.wire.UnrecoverableTimeoutException - if the operation times out.

writeBytes

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

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

Parameters:

bytes - to write to excerpt.

Throws:

net.openhft.chronicle.wire.UnrecoverableTimeoutException - if the operation times out.

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);

methodWriter

@NotNull
default <T> T methodWriter(@NotNull
                                    @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> @NotNull net.openhft.chronicle.wire.VanillaMethodWriterBuilder<T> methodWriterBuilder(@NotNull
                                                                                                           @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

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

Returns a raw wire for low level direct access.

Returns:

a raw wire for low level direct access

normaliseEOFs

default void normaliseEOFs()

Ensure all already-rolled cq4 files are correctly ended with EOF Used by replication sinks on startup to cover off any edge cases where the replicated EOF was not received/applied Can also be used on any appender, but this is not currently done automatically