diff --git a/spring-integration-reference/src/message-publishing.xml b/spring-integration-reference/src/message-publishing.xml new file mode 100644 index 0000000000..26889fc3bc --- /dev/null +++ b/spring-integration-reference/src/message-publishing.xml @@ -0,0 +1,153 @@ + + + + Message Publishing + + Message Publishing feature will allow you to send a message as a result of method invocation. For example; Imagine you + have a component and every time the state of this components changes you would like to get notified. The easiest + way to send notification would be to send a message to a dedicated channel, but how would you connect the method invocation that + changes the state of the object to a message sending process and what should be the structure of the + message? Message Publishing feature will allow you to do just that. + +
+ Message Publishing Configuration + + Spring Integration provides two approaches - XML and Annotation. + +
+ Annotation-based approach via @Publisher annotation + + Annotation bassed approach allows you to annotate any method with @Publisher annotation and + provide configuration attributes which will dictate the structure of a Message. Invocation of such + method will be proxied through PublisherAnnotationAdvisor which will + construct a Message and send it to a channel. + + + Internally PublisherAnnotationAdvisor uses Spring 3.0 Expression Language support giving you + the flexibility and control over the structure of a Message it will build. + + + PublisherAnnotationAdvisor defines and binds the following variables: + + + #return - will bind to a return value allowing you to reference it or its + attributes (e.g., #return.foo where 'foo' is an attribute of the object bound to + #return) + + + #exception - will bind to an exception if one is thrown. + + + #[parameName] - will be dynamically constructed pointing to the method parameter + names (e.g., #fname as in the above method) + + + + +@Publisher(value="#return", channel="testChannel", headers="bar='123',fname=#fname") +public String setName(String fname, String lname){ + return fname + " " + lname; +} + + + In the above example the Message will be constructed and its structure will be as follows: + + + Message payload - will be of type String and contain the value returned by the method. + + + Message headers will be 'bar' with value of "123" and 'fname' with value of 'fname' parameter of the method. + + + + + As with any other annotation you will need to register PublisherAnnotationBeanPostProcessor + <bean class="org.springframework.integration.aop.PublisherAnnotationBeanPostProcessor"/> + +
+
+ XML-based approach via MessagePublishingInterceptor + + XML-based approach allows you to configure Message Publishing via AOP-based configuration and although + configuration itself is a bit more extensive it has certain benefits over annotation based approach since it + allows you to use pointcut expressions, thus possibly intercepting multiple methods at once. + + + To configure Message Publishing via XML you need to provide two things: + + + Register MessagePublishingInterceptor + + + Provide AOP configuration to apply MessagePublishingInterceptor + + + + +<bean id="testBean" + class="org.springframework.integration.aop.MessagePublishingInterceptorUsageTest$TestBean" /> + + <si:channel id="testChannel"> + <si:queue /> + </si:channel> + + <aop:config> + <aop:advisor advice-ref="publishingInterceptor" pointcut="bean(testBean)" /> + </aop:config> + + <bean id="publishingInterceptor" + class="org.springframework.integration.aop.MessagePublishingInterceptor"> + <constructor-arg> + <bean + class="org.springframework.integration.aop.MethodNameMappingExpressionSource"> + <constructor-arg> + <map> + <entry key="*" value="#return" /> + </map> + </constructor-arg> + <property name="headerExpressionMap"> + <map> + <entry key="*" value="foo='bar'" /> + </map> + </property> + <property name="channelMap"> + <map> + <entry key="setName" value="channel" /> + </map> + </property> + </bean> + </constructor-arg> + <property name="channelResolver"> + <bean + class="org.springframework.integration.channel.MapBasedChannelResolver"> + <property name="channelMap"> + <map> + <entry key="channel" value-ref="testChannel" /> + </map> + </property> + </bean> + </property> + </bean> + + + As you can see MessagePublishingInterceptor defines and binds the same variables as + PublisherAnnotationAdvisor to utilize the power of Spring 3.0 Expression Langage. + + + In this example after execution of any public method of a testBean a Message + will be constructed with the following structure: + + + Message payload - will be of type and value returned by an executed method. + + + Message headers will be 'foo' with value of "bar". + + + + +In future versions namespace support will be available to simplify XML-based configuration. + +
+
+ \ No newline at end of file diff --git a/spring-integration-reference/src/spring-integration-reference.xml b/spring-integration-reference/src/spring-integration-reference.xml index a706cae16a..d67ea13ef8 100644 --- a/spring-integration-reference/src/spring-integration-reference.xml +++ b/spring-integration-reference/src/spring-integration-reference.xml @@ -62,6 +62,7 @@ +