org.springframework.integration.handler
Class ArgumentArrayMessageMapper

java.lang.Object
  org.springframework.integration.handler.ArgumentArrayMessageMapper

All Implemented Interfaces:

BeanFactoryAware, InboundMessageMapper<Object[]>

public class ArgumentArrayMessageMapper
extends Object
implements InboundMessageMapper<Object[]>, BeanFactoryAware

A Message Mapper implementation that supports mapping from a Message to an argument array when invoking handler methods, and mapping to a Message from an argument array when invoking gateway methods.

When mapping from a Message, the method parameters are matched against the Message, its payload as well as its headers. A message or payload parameter must not be annotated, and there can be at most one of these. In certain special cases, more than one non-annotated parameter can be used (more on this later), but there should always be at most one parameter that is expecting the message or its payload.

If a method parameter is annotated with @Header, the annotation's value will be used as a header name. If such an annotation contains no value, then the parameter name will be used as long as the information is available in the class file (requires compilation with debug settings for parameter names).

In addition a Map or Properties parameter can receive multiple message headers. In the case of a Map argument, all headers will be passed, but in the case of a Properties argument, only the headers with String-typed values will be passed. These parameters can be labeled explicitly with the @Headers annotation, or matched implicitly by using a non- ambiguous method signature. There can be as many parameters annotated with @Header as necessary, but typically there should be only one parameter expecting multiple headers (with or without the @Headers annotation).

If a Map or Properties object is expected, and the payload is not itself assignable to that type or capable of being converted to that type, then the MessageHeaders' values will be passed in the case of a Map-typed parameter, or the MessageHeaders' String-based values will be passed in the case of a Properties-typed parameter. In these cases multiple unannotated parameters are legal. If, however, the actual payload type is a Map or Properties instance, then this ambiguity cannot be resolved. For that reason, it is highly recommended to use the explicit Headers @Headers annotation whenever possible.

Some examples of legal method signatures:
public void dealWith(Object payload);
public void dealWith(Message message);
public void dealWith(@Header String myHeader, Object payload);
public void dealWith(@Header String myHeader, @Header String anotherHeader);
public void dealWith(@Headers Map headers, Object payload);
public void dealWith(@Headers Properties headers, Map payload);
public void dealWith(Properties headers, Object payload);

Some examples of illegal method signatures:
public void dealWith(Object payload, String payload);
public void dealWith(Message message, Object payload);
public void dealWith(Properties headers, Map payload);

Since:

2.0

Author:

Mark Fisher, Iwein Fuld, Oleg Zhurakousky

Constructor Summary

ArgumentArrayMessageMapper(Method method)

ArgumentArrayMessageMapper(Method method, Map<String,Object> staticHeaders)

Method Summary

void	setBeanFactory(BeanFactory beanFactory)
void	setPayloadExpression(String expressionString)
Message<?>	toMessage(Object[] arguments)

Methods inherited from class java.lang.Object

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

Constructor Detail

ArgumentArrayMessageMapper

public ArgumentArrayMessageMapper(Method method)

ArgumentArrayMessageMapper

public ArgumentArrayMessageMapper(Method method,
                                  Map<String,Object> staticHeaders)

Method Detail

setPayloadExpression

public void setPayloadExpression(String expressionString)

setBeanFactory

public void setBeanFactory(BeanFactory beanFactory)

Specified by:

setBeanFactory in interface BeanFactoryAware

toMessage

public Message<?> toMessage(Object[] arguments)

Specified by:

toMessage in interface InboundMessageMapper<Object[]>