ForwardAction xref

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    1   /*
    2    * $Id: ForwardAction.java 471754 2006-11-06 14:55:09Z husted $
    3    *
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *  http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21  package org.apache.struts.actions;
    22
    23  import org.apache.struts.action.ActionForm;
    24  import org.apache.struts.action.ActionForward;
    25  import org.apache.struts.action.ActionMapping;
    26
    27  import javax.servlet.ServletException;
    28  import javax.servlet.http.HttpServletRequest;
    29  import javax.servlet.http.HttpServletResponse;
    30
    31  /**
    32   * <p>An <strong>Action</strong> that forwards to the context-relative URI
    33   * specified by the <code>parameter</code> property of our associated
    34   * <code>ActionMapping</code>.  This can be used to integrate Struts with
    35   * other business logic components that are implemented as servlets (or JSP
    36   * pages), but still take advantage of the Struts controller servlet's
    37   * functionality (such as processing of form beans).</p>
    38   *
    39   * <p>To configure the use of this Action in your <code>struts-config.xml</code>
    40   * file, create an entry like this:</p>
    41   *
    42   * <code> &lt;action path="/saveSubscription" type="org.apache.struts.actions.ForwardAction"
    43   * name="subscriptionForm" scope="request" input="/subscription.jsp"
    44   * parameter="/path/to/processing/servlet"/&gt; </code>
    45   *
    46   * <p>which will forward control to the context-relative URI specified by the
    47   * <code>parameter</code> attribute.</p>
    48   *
    49   * @version $Rev: 471754 $ $Date: 2005-08-14 17:24:39 -0400 (Sun, 14 Aug 2005)
    50   *          $
    51   */
    52  public class ForwardAction extends BaseAction {
    53      // ----------------------------------------------------- Instance Variables
    54
    55      /**
    56       * Process the specified HTTP request, and create the corresponding HTTP
    57       * response (or forward to another web component that will create it).
    58       * Return an <code>ActionForward</code> instance describing where and how
    59       * control should be forwarded, or <code>null</code> if the response has
    60       * already been completed.
    61       *
    62       * @param mapping  The ActionMapping used to select this instance
    63       * @param form     The optional ActionForm bean for this request (if any)
    64       * @param request  The HTTP request we are processing
    65       * @param response The HTTP response we are creating
    66       * @return The forward to which control should be transferred, or
    67       *         <code>null</code> if the response has been completed.
    68       * @throws Exception if an error occurs
    69       */
    70      public ActionForward execute(ActionMapping mapping, ActionForm form,
    71          HttpServletRequest request, HttpServletResponse response)
    72          throws Exception {
    73          // Create a RequestDispatcher the corresponding resource
    74          String path = mapping.getParameter();
    75
    76          if (path == null) {
    77              throw new ServletException(messages.getMessage("forward.path"));
    78          }
    79
    80          // Let the controller handle the request
    81          ActionForward retVal = new ActionForward(path);
    82
    83          return retVal;
    84      }
    85  }