Spring Framework example source code file (ComponentControllerSupport.java)

This example Spring Framework source code file (ComponentControllerSupport.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

componentcontext, componentcontext, exception, file, http, httpservletrequest, httpservletrequest, httpservletresponse, httpservletresponse, io, ioexception, messagesourceaccessor, request, response, servlet, servletcontext, servletcontext, servletexception, webapplicationcontext

The Spring Framework ComponentControllerSupport.java source code

/*
 * Copyright 2002-2008 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.view.tiles;

import java.io.File;
import java.io.IOException;

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

import org.apache.struts.tiles.ComponentContext;
import org.apache.struts.tiles.ControllerSupport;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.MessageSourceAccessor;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.servlet.support.RequestContextUtils;
import org.springframework.web.util.NestedServletException;
import org.springframework.web.util.WebUtils;

/**
 * Convenience class for Spring-aware Tiles component controllers.
 * Provides a reference to the current Spring application context,
 * e.g. for bean lookup or resource loading.
 *
 * <p>Derives from the Tiles {@link ControllerSupport} class rather than
 * implementing the Tiles {@link org.apache.struts.tiles.Controller} interface
 * in order to be compatible with Struts 1.1 and 1.2. Implements both Struts 1.1's
 * <code>perform and Struts 1.2's execute method accordingly.
 *
 * @author Juergen Hoeller
 * @author Alef Arendsen
 * @since 22.08.2003
 * @see org.springframework.web.context.support.WebApplicationObjectSupport
 */
public abstract class ComponentControllerSupport extends ControllerSupport {

	private WebApplicationContext webApplicationContext;

	private MessageSourceAccessor messageSourceAccessor;


	/**
	 * This implementation delegates to <code>execute,
	 * converting non-Servlet/IO Exceptions to ServletException.
	 * <p>This is the only execution method available in Struts 1.1.
	 * @see #execute
	 */
	public final void perform(
			ComponentContext componentContext, HttpServletRequest request,
			HttpServletResponse response, ServletContext servletContext)
	    throws ServletException, IOException {

		try {
			execute(componentContext, request, response, servletContext);
		}
		catch (ServletException ex) {
			throw ex;
		}
		catch (IOException ex) {
			throw ex;
		}
		catch (Throwable ex) {
			throw new NestedServletException("Execution of component controller failed", ex);
		}
	}

	/**
	 * This implementation delegates to <code>doPerform,
	 * lazy-initializing the application context reference if necessary.
	 * <p>This is the preferred execution method in Struts 1.2.
	 * When running with Struts 1.1, it will be called by <code>perform.
	 * @see #perform
	 * @see #doPerform
	 */
	public final void execute(
			ComponentContext componentContext, HttpServletRequest request,
			HttpServletResponse response, ServletContext servletContext)
	    throws Exception {

		synchronized (this) {
			if (this.webApplicationContext == null) {
				this.webApplicationContext = RequestContextUtils.getWebApplicationContext(request, servletContext);
				this.messageSourceAccessor = new MessageSourceAccessor(this.webApplicationContext);
			}
		}
		doPerform(componentContext, request, response);
	}


	/**
	 * Subclasses can override this for custom initialization behavior.
	 * Gets called on initialization of the context for this controller.
	 * @throws org.springframework.context.ApplicationContextException in case of initialization errors
	 * @throws org.springframework.beans.BeansException if thrown by application context methods
	 */
	protected void initApplicationContext() throws BeansException {
	}

	/**
	 * Return the current Spring ApplicationContext.
	 */
	protected final ApplicationContext getApplicationContext() {
		return this.webApplicationContext;
	}

	/**
	 * Return the current Spring WebApplicationContext.
	 */
	protected final WebApplicationContext getWebApplicationContext() {
		return this.webApplicationContext;
	}

	/**
	 * Return a MessageSourceAccessor for the application context
	 * used by this object, for easy message access.
	 */
	protected final MessageSourceAccessor getMessageSourceAccessor() {
		return this.messageSourceAccessor;
	}

	/**
	 * Return the current ServletContext.
	 */
	protected final ServletContext getServletContext() {
		return this.webApplicationContext.getServletContext();
	}

	/**
	 * Return the temporary directory for the current web application,
	 * as provided by the servlet container.
	 * @return the File representing the temporary directory
	 */
	protected final File getTempDir() {
		return WebUtils.getTempDir(getServletContext());
	}


	/**
	 * Perform the preparation for the component, allowing for any Exception to be thrown.
	 * The ServletContext can be retrieved via getServletContext, if necessary.
	 * The Spring WebApplicationContext can be accessed via getWebApplicationContext.
	 * <p>This method will be called both in the Struts 1.1 and Struts 1.2 case,
	 * by <code>perform or execute, respectively.
	 * @param componentContext current Tiles component context
	 * @param request current HTTP request
	 * @param response current HTTP response
	 * @throws Exception in case of errors
	 * @see org.apache.struts.tiles.Controller#perform
	 * @see #getServletContext
	 * @see #getWebApplicationContext
	 * @see #perform
	 * @see #execute
	 */
	protected abstract void doPerform(
			ComponentContext componentContext, HttpServletRequest request, HttpServletResponse response)
			throws Exception;

}