Package com.lmax.disruptor

Class BatchEventProcessor<T>

java.lang.Object

com.lmax.disruptor.BatchEventProcessor<T>

Type Parameters:

T - event implementation storing the data for sharing during exchange or parallel coordination of an event.

All Implemented Interfaces:

EventProcessor, Runnable

public final class BatchEventProcessor<T>
extends Object
implements EventProcessor

Convenience class for handling the batching semantics of consuming entries from a RingBuffer and delegating the available events to an EventHandler.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	BatchEventProcessor.NoRewindHandler
private class	BatchEventProcessor.TryRewindHandler

Field Summary

Fields

Modifier and Type	Field	Description
private final int	batchLimitOffset
private final DataProvider<T>	dataProvider
private final EventHandlerBase<? super T>	eventHandler
private ExceptionHandler<? super T>	exceptionHandler
private static final int	HALTED
private static final int	IDLE
private int	retriesAttempted
private final RewindHandler	rewindHandler
private final AtomicInteger	running
private static final int	RUNNING
private final Sequence	sequence
private final SequenceBarrier	sequenceBarrier

Constructor Summary

Constructors

Constructor	Description
BatchEventProcessor(DataProvider<T> dataProvider, SequenceBarrier sequenceBarrier, EventHandlerBase<? super T> eventHandler, int maxBatchSize, BatchRewindStrategy batchRewindStrategy)

Method Summary

Modifier and Type	Method	Description
private void	earlyExit()
private ExceptionHandler<? super T>	getExceptionHandler()
Sequence	getSequence()	Get a reference to the Sequence being used by this EventProcessor.
void	halt()	Signal that this EventProcessor should stop when it has finished consuming at the next clean break.
private void	handleEventException(Throwable ex, long sequence, T event)	Delegate to ExceptionHandler.handleEventException(Throwable, long, Object) on the delegate or the default ExceptionHandler if one has not been configured.
private void	handleOnShutdownException(Throwable ex)	Delegate to ExceptionHandler.handleOnShutdownException(Throwable) on the delegate or the default ExceptionHandler if one has not been configured.
private void	handleOnStartException(Throwable ex)	Delegate to ExceptionHandler.handleOnStartException(Throwable) on the delegate or the default ExceptionHandler if one has not been configured.
boolean	isRunning()
private void	notifyShutdown()	Notifies the EventHandler immediately prior to this processor shutting down.
private void	notifyStart()	Notifies the EventHandler when this processor is starting up.
private void	notifyTimeout(long availableSequence)
private void	processEvents()
void	run()	It is ok to have another thread rerun this method after a halt().
void	setExceptionHandler(ExceptionHandler<? super T> exceptionHandler)	Set a new ExceptionHandler for handling exceptions propagated out of the BatchEventProcessor.

Methods inherited from class java.lang.Object

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

Field Details

IDLE

private static final int IDLE

See Also:

• Constant Field Values

HALTED

private static final int HALTED

See Also:

• Constant Field Values

RUNNING

private static final int RUNNING

See Also:

• Constant Field Values

running

private final AtomicInteger running

exceptionHandler

private ExceptionHandler<? super T> exceptionHandler

dataProvider

private final DataProvider<T> dataProvider

sequenceBarrier

private final SequenceBarrier sequenceBarrier

eventHandler

private final EventHandlerBase<? super T> eventHandler

batchLimitOffset

private final int batchLimitOffset

sequence

private final Sequence sequence

rewindHandler

private final RewindHandler rewindHandler

retriesAttempted

private int retriesAttempted

Constructor Details

BatchEventProcessor

BatchEventProcessor(DataProvider<T> dataProvider,
 SequenceBarrier sequenceBarrier,
 EventHandlerBase<? super T> eventHandler,
 int maxBatchSize,
 BatchRewindStrategy batchRewindStrategy)

Method Details

getSequence

public Sequence getSequence()

Description copied from interface: EventProcessor

Get a reference to the Sequence being used by this EventProcessor.

Specified by:

getSequence in interface EventProcessor

Returns:

reference to the Sequence for this EventProcessor

halt

public void halt()

Description copied from interface: EventProcessor

Signal that this EventProcessor should stop when it has finished consuming at the next clean break. It will call SequenceBarrier.alert() to notify the thread to check status.

Specified by:

halt in interface EventProcessor

isRunning

public boolean isRunning()

Specified by:

isRunning in interface EventProcessor

Returns:

whether this event processor is running or not Implementations should ideally return false only when the associated thread is idle.

setExceptionHandler

public void setExceptionHandler(ExceptionHandler<? super T> exceptionHandler)

Set a new ExceptionHandler for handling exceptions propagated out of the BatchEventProcessor.

Parameters:

exceptionHandler - to replace the existing exceptionHandler.

run

public void run()

It is ok to have another thread rerun this method after a halt().

Specified by:

run in interface Runnable

Throws:

IllegalStateException - if this object instance is already running in a thread

processEvents

private void processEvents()

earlyExit

private void earlyExit()

notifyTimeout

private void notifyTimeout(long availableSequence)

notifyStart

private void notifyStart()

Notifies the EventHandler when this processor is starting up.

notifyShutdown

private void notifyShutdown()

Notifies the EventHandler immediately prior to this processor shutting down.

handleEventException

private void handleEventException(Throwable ex,
 long sequence,
 T event)

Delegate to ExceptionHandler.handleEventException(Throwable, long, Object) on the delegate or the default ExceptionHandler if one has not been configured.

handleOnStartException

private void handleOnStartException(Throwable ex)

Delegate to ExceptionHandler.handleOnStartException(Throwable) on the delegate or the default ExceptionHandler if one has not been configured.

handleOnShutdownException

private void handleOnShutdownException(Throwable ex)

Delegate to ExceptionHandler.handleOnShutdownException(Throwable) on the delegate or the default ExceptionHandler if one has not been configured.

getExceptionHandler

private ExceptionHandler<? super T> getExceptionHandler()