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1   /*
2    * $Id: RedeployableActionServlet.java 481833 2006-12-03 17:32:52Z niallp $
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.tiles;
22  
23  import javax.servlet.ServletException;
24  
25  import org.apache.struts.Globals;
26  import org.apache.struts.action.ActionServlet;
27  import org.apache.struts.action.RequestProcessor;
28  import org.apache.struts.config.ModuleConfig;
29  import org.apache.struts.tiles.DefinitionsFactory;
30  import org.apache.struts.tiles.DefinitionsFactoryException;
31  import org.apache.struts.tiles.TilesRequestProcessor;
32  
33  
34  /**
35   * <p>
36   * WebLogic (at least v6 and v7) attempts to serialize the TilesRequestProcessor
37   * when re-deploying the Webapp in development mode. The TilesRequestProcessor
38   * is not serializable, and loses the Tiles definitions. This results in
39   * NullPointerException and/or NotSerializableException when using the app after
40   * automatic redeploy.
41   * </p>
42   * <p>
43   * This bug report proposes a workaround for this problem, in the hope it will
44   * help others and maybe motivate an actual fix.
45   * </p>
46   * <p>
47   * The attached class extends the Struts Action servlet and fixes the problem by
48   * reloading the Tiles definitions when they have disappeared.
49   * </p>
50   * <p>
51   * For background discussion see
52   * http://issues.apache.org/bugzilla/show_bug.cgi?id=26322
53   * </p>
54   * @version $Rev: 481833 $ $Date: 2006-12-03 11:32:52 -0600 (Sun, 03 Dec 2006) $
55   * @since 1.2.1
56   */
57  public class RedeployableActionServlet extends ActionServlet {
58      private TilesRequestProcessor tileProcessor;
59  
60      protected synchronized RequestProcessor
61              getRequestProcessor(ModuleConfig config) throws ServletException {
62  
63          if (tileProcessor != null) {
64              TilesRequestProcessor processor = (TilesRequestProcessor) super.getRequestProcessor(config);
65              return processor;
66          }
67  
68          // reset the request processor
69          String requestProcessorKey = Globals.REQUEST_PROCESSOR_KEY +
70                  config.getPrefix();
71          getServletContext().removeAttribute(requestProcessorKey);
72  
73          // create a new request processor instance
74          TilesRequestProcessor processor = (TilesRequestProcessor) super.getRequestProcessor(config);
75  
76          tileProcessor = processor;
77  
78          try {
79              // reload Tiles defs
80              DefinitionsFactory factory = processor.getDefinitionsFactory();
81              factory.init(factory.getConfig(), getServletContext());
82              // System.out.println("reloaded tiles-definitions");
83          } catch (DefinitionsFactoryException e) {
84              e.printStackTrace();
85          }
86  
87          return processor;
88      }
89  }