org.springframework.integration.handler
Class MessageHandlerChain

java.lang.Object
  org.springframework.integration.context.IntegrationObjectSupport
      org.springframework.integration.handler.MessageHandlerChain

All Implemented Interfaces:

org.springframework.beans.factory.BeanFactoryAware, org.springframework.beans.factory.BeanNameAware, org.springframework.core.Ordered, MessageHandler

public class MessageHandlerChain
extends IntegrationObjectSupport
implements MessageHandler, org.springframework.core.Ordered

A composite MessageHandler implementation that invokes a chain of MessageHandler instances in order.

Each of the handlers has to implement public void setOutputChannel(MessageChannel outputChannel);. An exception is made for the last handler in the case that the chain itself does not have an output channel. No other assumptions about the type of handler are made.

It is expected that each handler will produce reply messages and send them to its output channel, although this is not enforced. It is possible to filter messages in the middle of the chain, for example using a MessageFilter. A MessageHandler returning null will have the same effect, although this option is less expressive.

This component can be used from the namespace to improve the readability of the configuration by removing channels that can be created implicitly.

 <chain>
     <filter ref="someFilter"/>
     <bean class="SomeMessageHandlerImplementation"/>
     <transformer ref="someTransformer"/>
     <aggregator ... />
 </chain>
 

Author:

Mark Fisher, Iwein Fuld

Field Summary

Fields inherited from class org.springframework.integration.context.IntegrationObjectSupport

logger

Fields inherited from interface org.springframework.core.Ordered

HIGHEST_PRECEDENCE, LOWEST_PRECEDENCE

Constructor Summary

MessageHandlerChain()

Method Summary

void	afterPropertiesSet()
int	getOrder()
void	handleMessage(Message<?> message) Handles the message if possible.
void	setHandlers(java.util.List<MessageHandler> handlers)
void	setOrder(int order)
void	setOutputChannel(MessageChannel outputChannel)

Methods inherited from class org.springframework.integration.context.IntegrationObjectSupport

getBeanFactory, getBeanName, getChannelResolver, getTaskScheduler, setBeanFactory, setBeanName, setTaskScheduler, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageHandlerChain

public MessageHandlerChain()

Method Detail

setHandlers

public void setHandlers(java.util.List<MessageHandler> handlers)

setOutputChannel

public void setOutputChannel(MessageChannel outputChannel)

setOrder

public void setOrder(int order)

getOrder

public int getOrder()

Specified by:

getOrder in interface org.springframework.core.Ordered

afterPropertiesSet

public final void afterPropertiesSet()

handleMessage

public void handleMessage(Message<?> message)

Description copied from interface: MessageHandler

Handles the message if possible. If the handler cannot deal with the message this will result in a MessageRejectedException e.g. in case of a Selective Consumer. When a consumer tries to handle a message, but fails to do so, a MessageHandlingException is thrown. In the last case it is recommended to treat the message as tainted and go into an error scenario.

When the handling results in a message being sent failure to send that message will result in a MessageDeliveryException.

Specified by:

handleMessage in interface MessageHandler

Parameters:

message - the message to be handled