Spring Integration: Message Endpoint

[lihongjie0209]

Message Endpoints

A Message Endpoint represents the “filter” of a pipes-and-filters architecture. As mentioned earlier, the endpoint’s primary role is to connect application code to the messaging framework and to do so in a non-invasive manner. In other words, the application code should ideally have no awareness of the message objects or the message channels. This is similar to the role of a controller in the MVC paradigm. Just as a controller handles HTTP requests, the message endpoint handles messages. Just as controllers are mapped to URL patterns, message endpoints are mapped to message channels. The goal is the same in both cases: isolate application code from the infrastructure. These concepts and all of the patterns that follow are discussed at length in the Enterprise Integration Patterns book. Here, we provide only a high-level description of the main endpoint types supported by Spring Integration and the roles associated with those types. The chapters that follow elaborate and provide sample code as well as configuration examples.

[lihongjie0209]

javax.resource.spi.endpoint.MessageEndpoint

把消息映射到方法中

public interface MessageEndpoint {

    /**
     * This is called by a resource adapter before a message is delivered.
     *
     * @param method description of a target method. This information about
     * the intended target method allows an application server to decide 
     * whether to start a transaction during this method call, depending 
     * on the transaction preferences of the target method.
     * The processing (by the application server) of the actual message 
     * delivery method call on the endpoint must be independent of the 
     * class loader associated with this descriptive method object. 
     *
     * @throws NoSuchMethodException indicates that the specified method
     * does not exist on the target endpoint.
     *
     * @throws ResourceException generic exception.
     *
     * @throws ApplicationServerInternalException indicates an error 
     * condition in the application server.
     *
     * @throws IllegalStateException indicates that the endpoint is in an
     * illegal state for the method invocation. For example, this occurs when
     * <code>beforeDelivery</code> and <code>afterDelivery</code> 
     * method calls are not paired.
     *
     * @throws UnavailableException indicates that the endpoint is not 
     * available.
     */
    void beforeDelivery(java.lang.reflect.Method method)
    throws NoSuchMethodException, ResourceException;

    /**
     * This is called by a resource adapter after a message is delivered.
     *
     * @throws ResourceException generic exception.
     *
     * @throws ApplicationServerInternalException indicates an error 
     * condition in the application server.
     *
     * @throws IllegalStateException indicates that the endpoint is in an
     * illegal state for the method invocation. For example, this occurs when
     * beforeDelivery and afterDelivery method calls are not paired.
     *
     * @throws UnavailableException indicates that the endpoint is not 
     * available.
     */
    void afterDelivery() throws ResourceException;

    /**
     * This method may be called by the resource adapter to indicate that it
     * no longer needs a proxy endpoint instance. This hint may be used by
     * the application server for endpoint pooling decisions.
     */
    void release();
}