org.springframework.integration.handler
Class MessageHandlerChain

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

All Implemented Interfaces:

BeanFactoryAware, BeanNameAware, InitializingBean, Ordered, MessageHandler, MessageProducer, NamedComponent

public class MessageHandlerChain
extends IntegrationObjectSupport
implements MessageHandler, MessageProducer, Ordered

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

Each of the handlers except for the last one must implement the MessageProducer interface. The last handler must also if the chain itself has an output channel configured. No other assumptions are made about the type of handler.

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

String	getComponentType() Subclasses may implement this method to provide component type information.
int	getOrder()
void	handleMessage(Message<?> message) Handles the message if possible.
void	setHandlers(List<MessageHandler> handlers)
void	setOrder(int order)
void	setOutputChannel(MessageChannel outputChannel) Specify the MessageChannel to which produced Messages should be sent.
void	setSendTimeout(long sendTimeout)

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

afterPropertiesSet, getBeanFactory, getChannelResolver, getComponentName, getConversionService, getTaskScheduler, onInit, setBeanFactory, setBeanName, setChannelResolver, setComponentName, setConversionService, setTaskScheduler, toString, writeMessageHistory

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(List<MessageHandler> handlers)

setOutputChannel

public void setOutputChannel(MessageChannel outputChannel)

Description copied from interface: MessageProducer

Specify the MessageChannel to which produced Messages should be sent.

Specified by:

setOutputChannel in interface MessageProducer

setSendTimeout

public void setSendTimeout(long sendTimeout)

setOrder

public void setOrder(int order)

getOrder

public int getOrder()

Specified by:

getOrder in interface Ordered

getComponentType

public String getComponentType()

Description copied from class: IntegrationObjectSupport

Subclasses may implement this method to provide component type information.

Specified by:

getComponentType in interface NamedComponent

Overrides:

getComponentType in class IntegrationObjectSupport

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