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Java > Open Source Codes > org > apache > struts > actions > RedeployableActionServlet


1 package org.apache.struts.actions;
2
3 import javax.servlet.ServletException JavaDoc;
4
5 import org.apache.struts.Globals;
6 import org.apache.struts.action.ActionServlet;
7 import org.apache.struts.action.RequestProcessor;
8 import org.apache.struts.config.ModuleConfig;
9 import org.apache.struts.tiles.DefinitionsFactory;
10 import org.apache.struts.tiles.DefinitionsFactoryException;
11 import org.apache.struts.tiles.TilesRequestProcessor;
12
13
14 /**
15  * <p>
16  * WebLogic (at least v6 and v7) attempts to serialize the TilesRequestProcessor
17  * when re-deploying the Webapp in development mode. The TilesRequestProcessor
18  * is not serializable, and loses the Tiles definitions. This results in
19  * NullPointerException and/or NotSerializableException when using the app after
20  * automatic redeploy.
21  * </p>
22  * <p>
23  * This bug report proposes a workaround for this problem, in the hope it will
24  * help others and maybe motivate an actual fix.
25  * </p>
26  * <p>
27  * The attached class extends the Struts Action servlet and fixes the problem by
28  * reloading the Tiles definitions when they have disappeared.
29  * </p>
30  * <p>
31  * For background discussion see
32  * http://issues.apache.org/bugzilla/show_bug.cgi?id=26322
33  * </p>
34  * @version $Rev: 54954 $ $Date: 2004-10-17 07:40:12 +0100 (Sun, 17 Oct 2004) $
35  * @since 1.2.1
36  */
37 public class RedeployableActionServlet extends ActionServlet {
38     private TilesRequestProcessor tileProcessor;
39
40     protected synchronized RequestProcessor
41             getRequestProcessor(ModuleConfig config) throws ServletException JavaDoc {
42
43         if (tileProcessor != null) {
44             TilesRequestProcessor processor = (TilesRequestProcessor) super.getRequestProcessor(config);
45             return processor;
46         }
47
48         // reset the request processor
49 String JavaDoc requestProcessorKey = Globals.REQUEST_PROCESSOR_KEY +
50                 config.getPrefix();
51         getServletContext().removeAttribute(requestProcessorKey);
52
53         // create a new request processor instance
54 TilesRequestProcessor processor = (TilesRequestProcessor) super.getRequestProcessor(config);
55
56         tileProcessor = processor;
57
58         try {
59             // reload Tiles defs
60 DefinitionsFactory factory = processor.getDefinitionsFactory();
61             factory.init(factory.getConfig(), getServletContext());
62             // System.out.println("reloaded tiles-definitions");
63 } catch (DefinitionsFactoryException e) {
64             e.printStackTrace();
65         }
66
67         return processor;
68     }
69 }
70
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