IncludeAction xref

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    1   /*
    2    * $Id: IncludeAction.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.RequestDispatcher;
    28  import javax.servlet.ServletException;
    29  import javax.servlet.http.HttpServletRequest;
    30  import javax.servlet.http.HttpServletResponse;
    31
    32  /**
    33   * <p>An <strong>Action</strong> that includes the context-relative URI
    34   * specified by the <code>parameter</code> property of our associated
    35   * <code>ActionMapping</code>.  This can be used to integrate Struts with
    36   * other business logic components that are implemented as servlets (or JSP
    37   * pages), but still take advantage of the Struts controller servlet's
    38   * functionality (such as processing of form beans).</p>
    39   *
    40   * <p>To configure the use of this Action in your <code>struts-config.xml</code>
    41   * file, create an entry like this:</p>
    42   *
    43   * <code> &lt;action path="/saveSubscription"
    44   * type="org.apache.struts.actions.IncludeAction"
    45   * name="subscriptionForm" scope="request" input="/subscription.jsp"
    46   * parameter="/path/to/processing/servlet"&gt; </code>
    47   *
    48   * <p>which will include the context-relative URI specified by the
    49   * <code>parameter</code> attribute.</p>
    50   *
    51   * @version $Rev: 471754 $ $Date: 2005-11-09 00:11:45 -0500 (Wed, 09 Nov 2005)
    52   *          $
    53   */
    54  public class IncludeAction extends BaseAction {
    55      // ----------------------------------------------------- Instance Variables
    56
    57      /**
    58       * Process the specified HTTP request, and create the corresponding HTTP
    59       * response (or forward to another web component that will create it).
    60       * Return an <code>ActionForward</code> instance describing where and how
    61       * control should be forwarded, or <code>null</code> if the response has
    62       * already been completed.
    63       *
    64       * @param mapping  The ActionMapping used to select this instance
    65       * @param form     The optional ActionForm bean for this request (if any)
    66       * @param request  The HTTP request we are processing
    67       * @param response The HTTP response we are creating
    68       * @return The forward to which control should be transferred, or
    69       *         <code>null</code> if the response has been completed.
    70       * @throws Exception if an error occurs
    71       */
    72      public ActionForward execute(ActionMapping mapping, ActionForm form,
    73          HttpServletRequest request, HttpServletResponse response)
    74          throws Exception {
    75          // Create a RequestDispatcher the corresponding resource
    76          String path = mapping.getParameter();
    77
    78          if (path == null) {
    79              throw new ServletException(messages.getMessage("include.path"));
    80          }
    81
    82          RequestDispatcher rd =
    83              servlet.getServletContext().getRequestDispatcher(path);
    84
    85          if (rd == null) {
    86              throw new ServletException(messages.getMessage("include.rd", path));
    87          }
    88
    89          // Forward control to the specified resource
    90          rd.include(request, response);
    91
    92          // Tell the controller servlet that the response has been created
    93          return (null);
    94      }
    95  }