Spring Framework example source code file (AbstractCommandController.java)

This example Spring Framework source code file (AbstractCommandController.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

abstractcommandcontroller, abstractcommandcontroller, actionresponse, bindexception, bindexception, exception, modelandview, object, object, render, renderresponse, string, string, true

The Spring Framework AbstractCommandController.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.mvc;

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

import org.springframework.validation.BindException;
import org.springframework.web.portlet.ModelAndView;
import org.springframework.web.portlet.bind.PortletRequestDataBinder;

/**
 * <p>Abstract base class for custom command controllers. Autopopulates a
 * command bean from the request. For command validation, a validator
 * (property inherited from BaseCommandController) can be used.</p>
 *
 * <p>This command controller should preferrable not be used to handle form
 * submission, because functionality for forms is more offered in more
 * detail by the {@link org.springframework.web.portlet.mvc.AbstractFormController
 * AbstractFormController} and its corresponding implementations.</p>
 *
 * <p>Exposed configuration properties
 * (<a href="BaseCommandController.html#config">and those defined by superclass):

 * <i>none (so only those available in superclass).

 *
 * <p>Workflow
 * (<a name="BaseCommandController.html#workflow">and that defined by superclass):

 *
 * @author John A. Lewis
 * @author Juergen Hoeller
 * @since 2.0
 * @see #setCommandClass
 * @see #setCommandName
 * @see #setValidator
 */
public abstract class AbstractCommandController extends BaseCommandController {

	/**
	 * This render parameter is used to indicate forward to the render phase
	 * that a valid command (and errors) object is in the session.
	 */
	private static final String COMMAND_IN_SESSION_PARAMETER = "command-in-session";

	private static final String TRUE = Boolean.TRUE.toString();


	/**
	 * Create a new AbstractCommandController.
	 */
	public AbstractCommandController() {
	}

	/**
	 * Create a new AbstractCommandController.
	 * @param commandClass class of the command bean
	 */
	public AbstractCommandController(Class commandClass) {
		setCommandClass(commandClass);
	}

	/**
	 * Create a new AbstractCommandController.
	 * @param commandClass class of the command bean
	 * @param commandName name of the command bean
	 */
	public AbstractCommandController(Class commandClass, String commandName) {
		setCommandClass(commandClass);
		setCommandName(commandName);
	}


	protected final void handleActionRequestInternal(ActionRequest request, ActionResponse response)
			throws Exception {

		// Create the command object.
		Object command = getCommand(request);

		// Compute the errors object.
		PortletRequestDataBinder binder = bindAndValidate(request, command);
		BindException errors = new BindException(binder.getBindingResult());

		// Actually handle the action.
		handleAction(request, response, command, errors);

		// Pass the command and errors forward to the render phase.
		setRenderCommandAndErrors(request, command, errors);
		setCommandInSession(response);
	}

	protected final ModelAndView handleRenderRequestInternal(
			RenderRequest request, RenderResponse response) throws Exception {

		Object command = null;
		BindException errors = null;

		// get the command and errors objects from the session, if they exist
		if (isCommandInSession(request)) {
			logger.debug("Render phase obtaining command and errors objects from session");
			command = getRenderCommand(request);
			errors = getRenderErrors(request);
		}
		else {
			logger.debug("Render phase creating new command and errors objects");
		}

		// If no command object was in the session, create a new one.
		if (command == null) {
			command = getCommand(request);
		}

		// If no errors object was in the session, compute a new one.
		if (errors == null) {
			PortletRequestDataBinder binder = bindAndValidate(request, command);
			errors = new BindException(binder.getBindingResult());
		}

		return handleRender(request, response, command, errors);
	}


	/**
	 * Template method for request handling, providing a populated and validated instance
	 * of the command class, and an Errors object containing binding and validation errors.
	 * <p>Call errors.getModel() to populate the ModelAndView model
	 * with the command and the Errors instance, under the specified command name,
	 * as expected by the "spring:bind" tag.
	 * @param request current action request
	 * @param response current action response
	 * @param command the populated command object
	 * @param errors validation errors holder
	 * @see org.springframework.validation.Errors
	 * @see org.springframework.validation.BindException#getModel
	 */
	protected abstract void handleAction(
			ActionRequest request, ActionResponse response, Object command, BindException errors)
			throws Exception;

	/**
	 * Template method for render request handling, providing a populated and validated instance
	 * of the command class, and an Errors object containing binding and validation errors.
	 * <p>Call errors.getModel() to populate the ModelAndView model
	 * with the command and the Errors instance, under the specified command name,
	 * as expected by the "spring:bind" tag.
	 * @param request current render request
	 * @param response current render response
	 * @param command the populated command object
	 * @param errors validation errors holder
	 * @return a ModelAndView to render, or null if handled directly
	 * @see org.springframework.validation.Errors
	 * @see org.springframework.validation.BindException#getModel
	 */
	protected abstract ModelAndView handleRender(
			RenderRequest request, RenderResponse response, Object command, BindException errors)
			throws Exception;


	/**
	 * Return the name of the render parameter that indicates there
	 * is a valid command (and errors) object in the session.
	 * @return the name of the render parameter
	 * @see javax.portlet.RenderRequest#getParameter
	 */
	protected String getCommandInSessionParameterName() {
		return COMMAND_IN_SESSION_PARAMETER;
	}

	/**
	 * Set the action response parameter that indicates there is a
	 * command (and errors) object in the session for the render phase.
	 * @param response the current action response
	 * @see #getCommandInSessionParameterName
	 * @see #isCommandInSession
	 */
	protected final void setCommandInSession(ActionResponse response) {
		if (logger.isDebugEnabled()) {
			logger.debug("Setting render parameter [" + getCommandInSessionParameterName() +
					"] to indicate a valid command (and errors) object are in the session");
		}
		try {
			response.setRenderParameter(getCommandInSessionParameterName(), TRUE);
		}
		catch (IllegalStateException ex) {
			// Ignore in case sendRedirect was already set.
		}
	}

	/**
	 * Determine if there is a valid command (and errors) object in the
	 * session for this render request.
	 * @param request current render request
	 * @return if there is a valid command object in the session
	 * @see #getCommandInSessionParameterName
	 * @see #setCommandInSession
	 */
	protected final boolean isCommandInSession(RenderRequest request) {
		return TRUE.equals(request.getParameter(getCommandInSessionParameterName()));
	}

}