Spring Framework example source code file (ViewRendererServlet.java)

This example Spring Framework source code file (ViewRendererServlet.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

exception, http, httpservletresponse, httpservletresponse, io, ioexception, ioexception, map, model, nestedservletexception, request, response, servlet, servletexception, servletexception, string, util, view, view, view_attribute

The Spring Framework ViewRendererServlet.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.servlet;

import java.io.IOException;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.util.NestedServletException;

/**
 * ViewRendererServlet is a bridge servlet, mainly for the Portlet MVC support.
 *
 * <p>For usage with Portlets, this Servlet is necessary to force the portlet container
 * to convert the PortletRequest to a ServletRequest, which it has to do when
 * including a resource via the PortletRequestDispatcher. This allows for reuse
 * of the entire Servlet-based View support even in a Portlet environment.
 *
 * <p>The actual mapping of the bridge servlet is configurable in the DispatcherPortlet,
 * via a "viewRendererUrl" property. The default is "/WEB-INF/servlet/view", which is
 * just available for internal resource dispatching.
 *
 * @author William G. Thompson, Jr.
 * @author John A. Lewis
 * @author Juergen Hoeller
 * @since 2.0
 */
public class ViewRendererServlet extends HttpServlet {

	/**
	 * Request attribute to hold current web application context.
	 * Otherwise only the global web app context is obtainable by tags etc.
	 * @see org.springframework.web.servlet.support.RequestContextUtils#getWebApplicationContext
	 */
	public static final String WEB_APPLICATION_CONTEXT_ATTRIBUTE = DispatcherServlet.WEB_APPLICATION_CONTEXT_ATTRIBUTE;

	/** Name of request attribute that holds the View object */
	public static final String VIEW_ATTRIBUTE = ViewRendererServlet.class.getName() + ".VIEW";

	/** Name of request attribute that holds the model Map */
	public static final String MODEL_ATTRIBUTE = ViewRendererServlet.class.getName() + ".MODEL";


	protected final void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		processRequest(request, response);
	}

	protected final void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		processRequest(request, response);
	}

	/**
	 * Process this request, handling exceptions.
	 * The actually event handling is performed by the abstract
	 * <code>renderView() template method.
	 * @see #renderView
	 */
	protected final void processRequest(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		try {
			renderView(request, response);
		}
		catch (ServletException ex) {
			throw ex;
		}
		catch (IOException ex) {
			throw ex;
		}
		catch (Exception ex) {
			throw new NestedServletException("View rendering failed", ex);
		}
	}

	/**
	 * Retrieve the View instance and model Map to render
	 * and trigger actual rendering.
	 * @param request current HTTP request
	 * @param response current HTTP response
	 * @throws Exception in case of any kind of processing failure
	 * @see org.springframework.web.servlet.View#render
	 */
	protected void renderView(HttpServletRequest request, HttpServletResponse response) throws Exception {
		View view = (View) request.getAttribute(VIEW_ATTRIBUTE);
		if (view == null) {
			throw new ServletException("Could not complete render request: View is null");
		}
		Map model = (Map) request.getAttribute(MODEL_ATTRIBUTE);
		view.render(model, request, response);
	}

}