requestprocessor.java

来自「这是一个轻便的j2ee的web应用框架,是一个在多个项目中运用的实际框架,采用s」· Java 代码 · 共 1,168 行 · 第 1/3 页

/*
 * $Header: /sfroot/cvs/esimple/src/core/org/apache/struts/action/RequestProcessor.java,v 1.1.1.1 2004/09/08 06:38:31 lava Exp $
 * $Revision: 1.1.1.1 $
 * $Date: 2004/09/08 06:38:31 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Struts", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */


package org.apache.struts.action;


import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Locale;

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

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.Globals;
import org.apache.struts.config.ActionConfig;
import org.apache.struts.config.ExceptionConfig;
import org.apache.struts.config.ForwardConfig;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.taglib.html.Constants;
import org.apache.struts.upload.MultipartRequestWrapper;
import org.apache.struts.util.MessageResources;
import org.apache.struts.util.RequestUtils;


/**
 * <p><strong>RequestProcessor</strong> contains the processing logic that
 * the Struts controller servlet performs as it receives each servlet request
 * from the container.  You can customize the request processing behavior by
 * subclassing this class and overriding the method(s) whose behavior you are
 * interested in changing.</p>
 *
 * @author Craig R. McClanahan
 * @author Cedric Dumoulin
 * @version $Revision: 1.1.1.1 $ $Date: 2004/09/08 06:38:31 $
 * @since Struts 1.1
 */

public class RequestProcessor {


    // ----------------------------------------------------- Manifest Constants


    /**
     * The request attribute under which the path information is stored for
     * processing during a RequestDispatcher.include() call.
     */
    public static final String INCLUDE_PATH_INFO =
        "javax.servlet.include.path_info";


    /**
     * The request attribute under which the servlet path information is stored
     * for processing during a RequestDispatcher.include() call.
     */
    public static final String INCLUDE_SERVLET_PATH =
        "javax.servlet.include.servlet_path";


    // ----------------------------------------------------- Instance Variables


    /**
     * The set of Action instances that have been created and initialized,
     * keyed by the fully qualified Java class name of the Action class.
     */
    protected HashMap actions = new HashMap();


    /**
     * The ModuleConfiguration we are associated with.
     * @deprecated use moduleConfig instead.
     */
    protected ModuleConfig appConfig = null;

    /**
     * The ModuleConfiguration we are associated with.
     */
    protected ModuleConfig moduleConfig = null;


    /**
     * Commons Logging instance.
     */
    protected static Log log = LogFactory.getLog(RequestProcessor.class);


    /**
     * The controller servlet we are associated with.
     */
    protected ActionServlet servlet = null;


    // --------------------------------------------------------- Public Methods


    /**
     * Clean up in preparation for a shutdown of this application.
     */
    public void destroy() {

        synchronized (this.actions) {
            Iterator actions = this.actions.values().iterator();
            while (actions.hasNext()) {
                Action action = (Action) actions.next();
                action.setServlet(null);
            }
            this.actions.clear();
        }
        this.servlet = null;

    }


    /**
     * Initialize this request processor instance.
     *
     * @param servlet The ActionServlet we are associated with
     * @param moduleConfig The ModuleConfig we are associated with.
     * @throws ServletException If an error occor during initialization
     */
    public void init(ActionServlet servlet,
                     ModuleConfig moduleConfig)
           throws ServletException {

        synchronized (actions) {
            actions.clear();
        }
        this.servlet = servlet;
        this.appConfig = moduleConfig;
        this.moduleConfig = moduleConfig;

    }


    /**
     * <p>Process an <code>HttpServletRequest</code> and create the
     * corresponding <code>HttpServletResponse</code>.</p>
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     *
     * @exception IOException if an input/output error occurs
     * @exception ServletException if a processing exception occurs
     */
    public void process(HttpServletRequest request,
                        HttpServletResponse response)
        throws IOException, ServletException {

        // Wrap multipart requests with a special wrapper
        request = processMultipart(request);

        // Identify the path component we will use to select a mapping
        String path = processPath(request, response);
        if (path == null) {
            return;
        }
        if (log.isDebugEnabled()) {
            log.debug("Processing a '" + request.getMethod() +
                      "' for path '" + path + "'");
        }

        // Select a Locale for the current user if requested
        processLocale(request, response);

        // Set the content type and no-caching headers if requested
        processContent(request, response);
        processNoCache(request, response);

        // General purpose preprocessing hook
        if (!processPreprocess(request, response)) {
            return;
        }

        // Identify the mapping for this request
        ActionMapping mapping = processMapping(request, response, path);
        if (mapping == null) {
            return;
        }

        // Check for any role required to perform this action
        if (!processRoles(request, response, mapping)) {
            return;
        }

        // Process any ActionForm bean related to this request
        ActionForm form = processActionForm(request, response, mapping);
        processPopulate(request, response, form, mapping);
        if (!processValidate(request, response, form, mapping)) {
            return;
        }

        // Process a forward or include specified by this mapping
        if (!processForward(request, response, mapping)) {
            return;
        }
        if (!processInclude(request, response, mapping)) {
            return;
        }

        // Create or acquire the Action instance to process this request
        Action action = processActionCreate(request, response, mapping);
        if (action == null) {
            return;
        }

        // Call the Action instance itself
        ActionForward forward =
            processActionPerform(request, response,
                                 action, form, mapping);

        // Process the returned ActionForward instance
        processForwardConfig(request, response, forward);

    }


    // ----------------------------------------------------- Processing Methods


    /**
     * Return an <code>Action</code> instance that will be used to process
     * the current request, creating a new one if necessary.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param mapping The mapping we are using
     *
     * @exception IOException if an input/output error occurs
     */
    protected Action processActionCreate(HttpServletRequest request,
                                         HttpServletResponse response,
                                         ActionMapping mapping)
        throws IOException {

        // Acquire the Action instance we will be using (if there is one)
        String className = mapping.getType();
        if (log.isDebugEnabled()) {
            log.debug(" Looking for Action instance for class " + className);
        }
        
        Action instance = null;
        synchronized (actions) {

            // Return any existing Action instance of this class
            instance = (Action) actions.get(className);
            if (instance != null) {
                if (log.isTraceEnabled()) {
                    log.trace("  Returning existing Action instance");
                }
                return (instance);
            }

            // Create and return a new Action instance
            if (log.isTraceEnabled()) {
                log.trace("  Creating new Action instance");
            }
            
            try {
                instance = (Action) RequestUtils.applicationInstance(className);
                // TODO Maybe we should propagate this exception instead of returning
                // null.
            } catch (Exception e) {
                log.error(
                    getInternal().getMessage("actionCreate", mapping.getPath()),
                    e);
                    
                response.sendError(
                    HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
                    getInternal().getMessage("actionCreate", mapping.getPath()));
                    
                return (null);
            }
            
            instance.setServlet(this.servlet);
            actions.put(className, instance);
        }

        return (instance);

    }


    /**
     * Retrieve and return the <code>ActionForm</code> bean associated with
     * this mapping, creating and stashing one if necessary.  If there is no
     * form bean associated with this mapping, return <code>null</code>.
     *
     * @param request The servlet request we are processing
     * @param response The servlet response we are creating
     * @param mapping The mapping we are using
     */
    protected ActionForm processActionForm(HttpServletRequest request,
                                           HttpServletResponse response,
                                           ActionMapping mapping) {

        // Create (if necessary a form bean to use
        ActionForm instance = RequestUtils.createActionForm
            (request, mapping, moduleConfig, servlet);
        if (instance == null) {
            return (null);
        }

        // Store the new instance in the appropriate scope
        if (log.isDebugEnabled()) {
            log.debug(" Storing ActionForm bean instance in scope '" +
                mapping.getScope() + "' under attribute key '" +
                mapping.getAttribute() + "'");
        }
        if ("request".equals(mapping.getScope())) {
            request.setAttribute(mapping.getAttribute(), instance);
        } else {
            HttpSession session = request.getSession();
            session.setAttribute(mapping.getAttribute(), instance);
        }
        return (instance);

    }



    /**
     * Forward or redirect to the specified destination, by the specified
     * mechanism.