Package com.lmax.disruptor

Class AggregateEventHandler<T>

java.lang.Object

com.lmax.disruptor.AggregateEventHandler<T>

Type Parameters:

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

All Implemented Interfaces:

EventHandler<T>, EventHandlerBase<T>, EventHandlerIdentity

public final class AggregateEventHandler<T>
extends Object
implements EventHandler<T>

An aggregate collection of EventHandlers that get called in sequence for each event.

Field Summary

Fields

Modifier and Type	Field	Description
private final EventHandler<T>[]	eventHandlers

Constructor Summary

Constructors

Constructor	Description
AggregateEventHandler(EventHandler<T>... eventHandlers)	Construct an aggregate collection of EventHandlers to be called in sequence.

Method Summary

Modifier and Type	Method	Description
void	onEvent(T event, long sequence, boolean endOfBatch)	Called when a publisher has published an event to the RingBuffer.
void	onShutdown()	Called once just before the event processing thread is shutdown.
void	onStart()	Called once on thread start before first event is available.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.lmax.disruptor.EventHandler

setSequenceCallback

Methods inherited from interface com.lmax.disruptor.EventHandlerBase

onBatchStart, onTimeout

Field Details

eventHandlers

private final EventHandler<T>[] eventHandlers

Constructor Details

AggregateEventHandler

@SafeVarargs
public AggregateEventHandler(EventHandler<T>... eventHandlers)

Construct an aggregate collection of EventHandlers to be called in sequence.

Parameters:

eventHandlers - to be called in sequence.

Method Details

onEvent

public void onEvent(T event,
 long sequence,
 boolean endOfBatch)
             throws Exception

Description copied from interface: EventHandler

Called when a publisher has published an event to the RingBuffer. The BatchEventProcessor will read messages from the RingBuffer in batches, where a batch is all of the events available to be processed without having to wait for any new event to arrive. This can be useful for event handlers that need to do slower operations like I/O as they can group together the data from multiple events into a single operation. Implementations should ensure that the operation is always performed when endOfBatch is true as the time between that message and the next one is indeterminate.

Specified by:

onEvent in interface EventHandler<T>

Specified by:

onEvent in interface EventHandlerBase<T>

Parameters:

event - published to the RingBuffer

sequence - of the event being processed

endOfBatch - flag to indicate if this is the last event in a batch from the RingBuffer

Throws:

Exception - if the EventHandler would like the exception handled further up the chain.

onStart

public void onStart()

Description copied from interface: EventHandlerBase

Called once on thread start before first event is available.

Specified by:

onStart in interface EventHandlerBase<T>

onShutdown

public void onShutdown()

Description copied from interface: EventHandlerBase

Called once just before the event processing thread is shutdown.

Sequence event processing will already have stopped before this method is called. No events will be processed after this message.

Specified by:

onShutdown in interface EventHandlerBase<T>