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1   /*
2    * $Id$
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  
22  package org.apache.struts.tiles2.actions;
23  
24  import jakarta.servlet.http.HttpServletRequest;
25  import jakarta.servlet.http.HttpServletResponse;
26  
27  import org.apache.struts.action.Action;
28  import org.apache.struts.action.ActionForm;
29  import org.apache.struts.action.ActionForward;
30  import org.apache.struts.action.ActionMapping;
31  import org.apache.tiles.TilesContainer;
32  import org.apache.tiles.access.TilesAccess;
33  import org.apache.tiles.request.ApplicationContext;
34  import org.apache.tiles.request.Request;
35  import org.apache.tiles.request.jakarta.servlet.ServletRequest;
36  import org.apache.tiles.request.jakarta.servlet.ServletUtil;
37  import org.slf4j.Logger;
38  import org.slf4j.LoggerFactory;
39  
40  /**
41   * <p>An <strong>Action</strong> that dispatches to a Tiles Definition
42   * that is named by the request parameter whose name is specified
43   * by the <code>parameter</code> property of the corresponding
44   * ActionMapping.
45   * This action is useful in following situations:
46   * <li>
47   * <ul>To associate an Url to a definition</ul>
48   * <ul>To use Struts &lt;html:link&gt; tag on a definition</ul>
49   * </li>
50   * <p>To configure the use of this action in your
51   * <code>struts-config.xml</code> file, create an entry like this:</p>
52   *
53   * <code>
54   *   &lt;action path="/saveSubscription"
55   *           type="org.apache.struts.tiles2.actions.DefinitionDispatcherAction"
56   *           parameter="def"/&gt;
57   *     &lt;forward name="success"   path="anything" //&gt;
58   *     &lt;forward name="error"     path="path.to.error.page" //&gt;
59   * </code>
60   *
61   * <p>which will use the value of the request parameter named "def"
62   * to pick the appropriate definition name.
63   * <p>  The value for success doesn't matter. The forward will forward to
64   * appropriate definition.
65   * <p> The value for error should denote a valid jsp path or definition name.
66   *
67   * @version $Rev$ $Date$
68   */
69  public class DefinitionDispatcherAction extends Action {
70      private static final long serialVersionUID = 9052008321390723214L;
71  
72      /**
73       * The {@code Log} instance for this class.
74       */
75      private transient final Logger log =
76          LoggerFactory.getLogger(DefinitionDispatcherAction.class);
77  
78      /**
79       * Process the specified HTTP request, and create the corresponding HTTP
80       * response (or forward to another web component that will create it),
81       * with provision for handling exceptions thrown by the business logic.
82       *
83       * @param mapping The ActionMapping used to select this instance
84       * @param form The optional ActionForm bean for this request (if any)
85       * @param req The HTTP request we are processing
86       * @param res The HTTP response we are creating
87       *
88       * @throws Exception if the application business logic throws
89       *  an exception
90       * @return The forward object..
91       * @since Struts 1.1
92       */
93      public ActionForward execute(
94          ActionMapping mapping,
95          ActionForm form,
96          HttpServletRequest req,
97          HttpServletResponse res)
98          throws Exception {
99  
100         // Identify the request parameter containing the method name
101         // If none defined, use "def"
102         String parameter = mapping.getParameter();
103         if (parameter == null) {
104             parameter = "def";
105         }
106 
107         // Identify the method name to be dispatched to
108         String name = req.getParameter(parameter);
109         if (name == null) {
110             log.error("Can't get parameter '{}'.", parameter);
111 
112             return mapping.findForward("error");
113         }
114 
115         // Try to dispatch to requested definition
116         // Read definition from factory, but we can create it here.
117         ApplicationContext applicationContext = ServletUtil
118                 .getApplicationContext(req.getSession().getServletContext());
119         Request request = new ServletRequest(applicationContext,
120                 req, res);
121         TilesContainer container = TilesAccess.getContainer(applicationContext);
122         if (container != null
123                 && container.isValidDefinition(name, request)) {
124             container.render(name, request);
125         } else {
126             log.error("Can't get definition '{}'.", name);
127             return mapping.findForward("error");
128         }
129 
130         return mapping.findForward("success");
131     }
132 }