org.springframework.integration.aggregator
Class AbstractMessageAggregator

java.lang.Object
  org.springframework.integration.handler.AbstractMessageHandler
      org.springframework.integration.aggregator.AbstractMessageBarrierHandler
          org.springframework.integration.aggregator.AbstractMessageAggregator

All Implemented Interfaces:

org.springframework.beans.factory.InitializingBean, MessageHandler, TaskSchedulerAware

Direct Known Subclasses:

MethodInvokingAggregator

public abstract class AbstractMessageAggregator
extends AbstractMessageBarrierHandler

A base class for aggregating a group of Messages into a single Message. Extends AbstractMessageBarrierHandler and waits for a complete group of Messages to arrive. Subclasses must provide the implementation of the aggregateMessages(List) method to combine the group of Messages into a single Message.

The default strategy for determining whether a group is complete is based on the 'sequenceSize' property of the header. Alternatively, a custom implementation of the CompletionStrategy may be provided.

All considerations regarding timeout and grouping by correlationId from AbstractMessageBarrierHandler apply here as well.

Author:

Mark Fisher, Marius Bogoevici

Field Summary

Fields inherited from class org.springframework.integration.aggregator.AbstractMessageBarrierHandler

barriers, DEFAULT_REAPER_INTERVAL, DEFAULT_SEND_TIMEOUT, DEFAULT_TIMEOUT, DEFAULT_TRACKED_CORRRELATION_ID_CAPACITY, logger, trackedCorrelationIds

Constructor Summary

AbstractMessageAggregator()

Method Summary

protected abstract Message<?>	aggregateMessages(java.util.List<Message<?>> messages)
protected MessageBarrier	createMessageBarrier() Factory method for creating a suitable MessageBarrier implementation.
protected boolean	isBarrierRemovable(java.lang.Object correlationId, java.util.List<Message<?>> releasedMessages) Implements the logic for deciding whether, based on what the MessageBarrier has released so far, work for the correlationId can be considered complete and the barrier can be released.
protected Message<?>[]	processReleasedMessages(java.lang.Object correlationId, java.util.List<Message<?>> messages) Implements the logic for transforming the released Messages.
void	setCompletionStrategy(CompletionStrategy completionStrategy) Strategy to determine whether the group of messages is complete.

Methods inherited from class org.springframework.integration.aggregator.AbstractMessageBarrierHandler

afterPropertiesSet, handleMessageInternal, isRunning, resolveReplyChannelFromMessage, setDiscardChannel, setOutputChannel, setReaperInterval, setSendPartialResultOnTimeout, setSendTimeout, setTaskScheduler, setTimeout, setTrackedCorrelationIdCapacity, start, stop

Methods inherited from class org.springframework.integration.handler.AbstractMessageHandler

handleMessage

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractMessageAggregator

public AbstractMessageAggregator()

Method Detail

setCompletionStrategy

public void setCompletionStrategy(CompletionStrategy completionStrategy)

Strategy to determine whether the group of messages is complete.

createMessageBarrier

protected MessageBarrier createMessageBarrier()

Description copied from class: AbstractMessageBarrierHandler

Factory method for creating a suitable MessageBarrier implementation.

Specified by:

createMessageBarrier in class AbstractMessageBarrierHandler

isBarrierRemovable

protected boolean isBarrierRemovable(java.lang.Object correlationId,
                                     java.util.List<Message<?>> releasedMessages)

Description copied from class: AbstractMessageBarrierHandler

Implements the logic for deciding whether, based on what the MessageBarrier has released so far, work for the correlationId can be considered complete and the barrier can be released.

Specified by:

isBarrierRemovable in class AbstractMessageBarrierHandler

processReleasedMessages

protected Message<?>[] processReleasedMessages(java.lang.Object correlationId,
                                               java.util.List<Message<?>> messages)

Description copied from class: AbstractMessageBarrierHandler

Implements the logic for transforming the released Messages.

Specified by:

processReleasedMessages in class AbstractMessageBarrierHandler

aggregateMessages

protected abstract Message<?> aggregateMessages(java.util.List<Message<?>> messages)