1 /*
2 * $Id: ForwardAction.java 54929 2004-10-16 16:38:42Z germuska $
3 *
4 * Copyright 2001-2004 The Apache Software Foundation.
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package org.apache.struts.actions;
20
21 import javax.servlet.ServletException;
22 import javax.servlet.http.HttpServletRequest;
23 import javax.servlet.http.HttpServletResponse;
24
25 import org.apache.struts.action.Action;
26 import org.apache.struts.action.ActionForm;
27 import org.apache.struts.action.ActionForward;
28 import org.apache.struts.action.ActionMapping;
29 import org.apache.struts.util.MessageResources;
30
31 /**
32 * <p>An <strong>Action</strong> that forwards to the context-relative
33 * URI 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
40 * <code>struts-config.xml</code> file, create an entry like this:</p>
41 *
42 * <code>
43 * <action path="/saveSubscription"
44 * type="org.apache.struts.actions.ForwardAction"
45 * name="subscriptionForm"
46 * scope="request"
47 * input="/subscription.jsp"
48 * parameter="/path/to/processing/servlet"/>
49 * </code>
50 *
51 * <p>which will forward control to the context-relative URI specified by the
52 * <code>parameter</code> attribute.</p>
53 *
54 * @version $Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $
55 */
56 public class ForwardAction extends Action {
57
58
59 // ----------------------------------------------------- Instance Variables
60
61
62 /**
63 * The message resources for this package.
64 */
65 protected static MessageResources messages =
66 MessageResources.getMessageResources
67 ("org.apache.struts.actions.LocalStrings");
68
69
70 // --------------------------------------------------------- Public Methods
71
72
73 /**
74 * Process the specified HTTP request, and create the corresponding HTTP
75 * response (or forward to another web component that will create it).
76 * Return an <code>ActionForward</code> instance describing where and how
77 * control should be forwarded, or <code>null</code> if the response has
78 * already been completed.
79 *
80 * @param mapping The ActionMapping used to select this instance
81 * @param form The optional ActionForm bean for this request (if any)
82 * @param request The HTTP request we are processing
83 * @param response The HTTP response we are creating
84 *
85 * @exception Exception if an error occurs
86 */
87 public ActionForward execute(
88 ActionMapping mapping,
89 ActionForm form,
90 HttpServletRequest request,
91 HttpServletResponse response)
92 throws Exception {
93
94 // Create a RequestDispatcher the corresponding resource
95 String path = mapping.getParameter();
96
97 if (path == null) {
98 throw new ServletException(messages.getMessage("forward.path"));
99 }
100
101 // Let the controller handle the request
102 ActionForward retVal = new ActionForward(path);
103 retVal.setContextRelative(true);
104
105 return retVal;
106 }
107
108
109 }
110
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