Spring Framework example source code file (HandlerAdapter.java)

This example Spring Framework source code file (HandlerAdapter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

actionresponse, actionresponse, exception, exception, handleradapter, modelandview, object, object, renderresponse, renderresponse

The Spring Framework HandlerAdapter.java source code

/*
 * Copyright 2002-2006 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.portlet;

import javax.portlet.ActionRequest;
import javax.portlet.ActionResponse;
import javax.portlet.RenderRequest;
import javax.portlet.RenderResponse;

/**
 * Portlet MVC framework SPI interface, allowing parameterization of core MVC workflow.
 *
 * <p>Interface that must be implemented for each handler type to handle a request.
 * This interface is used to allow the DispatcherPortlet to be indefinitely
 * extensible. The DispatcherPortlet accesses all installed handlers through this
 * interface, meaning that it does not contain code specific to any handler type.
 *
 * <p>Note that a handler can be of type Object. This is to enable handlers from
 * other frameworks to be integrated with this framework without custom coding.
 *
 * <p>This interface is not intended for application developers. It is available
 * to handlers who want to develop their own web workflow.
 *
 * <p>Note: Implementations can implement the Ordered interface to be able to
 * specify a sorting order and thus a priority for getting applied by
 * DispatcherPortlet. Non-Ordered instances get treated as lowest priority.
 *
 * @author John A. Lewis
 * @since 2.0
 * @see org.springframework.web.portlet.mvc.SimpleControllerHandlerAdapter
 */
public interface HandlerAdapter {
	
	/**
	 * Given a handler instance, return whether or not this HandlerAdapter can
	 * support it. Typical HandlerAdapters will base the decision on the handler
	 * type. HandlerAdapters will usually only support one handler type each.
	 * <p>A typical implementation:
	 * <p>
	 * return (handler instanceof MyHandler);
	 * </code>
	 * @param handler handler object to check
	 * @return whether or not this object can use the given handler
	 */
	boolean supports(Object handler); 

	/**
	 * Use the given handler to handle this action request.
	 * The workflow that is required may vary widely.
	 * @param request current action request
	 * @param response current action response
	 * @param handler handler to use. This object must have previously been passed
	 * to the <code>supports method of this interface, which must have
	 * returned true.
	 * @throws Exception in case of errors
	 */
	void handleAction(ActionRequest request, ActionResponse response, Object handler) throws Exception;

	/**
	 * Use the given handler to handle this render request.
	 * The workflow that is required may vary widely.
	 * @param request current render request
	 * @param response current render response
	 * @param handler handler to use. This object must have previously been passed
	 * to the <code>supports method of this interface, which must have
	 * returned <code>true.
	 * @throws Exception in case of errors
	 * @return ModelAndView object with the name of the view and the required
	 * model data, or <code>null if the request has been handled directly
	 */
	ModelAndView handleRender(RenderRequest request, RenderResponse response, Object handler) throws Exception;

}