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1   /*
2    * $Id: FilterDispatcherCompatWeblogic61.java 476075 2006-11-17 08:28:30Z mrdon $
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.struts2.dispatcher;
22  
23  import javax.servlet.Filter;
24  import javax.servlet.FilterConfig;
25  import javax.servlet.ServletContext;
26  import javax.servlet.ServletException;
27  import javax.servlet.http.HttpSession;
28  
29  import org.apache.commons.logging.Log;
30  import org.apache.commons.logging.LogFactory;
31  import org.apache.struts2.config.ServletContextSingleton;
32  
33  
34  /***
35   * When running Weblogic Server 6.1, this class should be
36   * specified in web.xml instead of {@link FilterDispatcher}.
37   * <p/>
38   * This class properly handles the weblogic.jar handling
39   * of servlet filters.  There is one serious incompatibility, and
40   * that is that while {@link FilterDispatcher#init(FilterConfig)}
41   * throws a {@link ServletException}, this class's method
42   * {@link #setFilterConfig(FilterConfig)} does not throw
43   * the exception.  Since {@link #setFilterConfig(FilterConfig)}
44   * invokes {@link FilterDispatcher#init(FilterConfig)}, the setter
45   * must "swallow" the exception.  This it does by logging the
46   * exception as an error.
47   *
48   */
49  public class FilterDispatcherCompatWeblogic61 extends FilterDispatcher {
50  
51      private static Log log =
52              LogFactory.getLog(FilterDispatcherCompatWeblogic61.class);
53  
54      /***
55       * dummy setter for {@link #filterConfig}; this method
56       * sets up the {@link org.apache.struts2.config.ServletContextSingleton} with
57       * the servlet context from the filter configuration.
58       * <p/>
59       * This is needed by Weblogic Server 6.1 because it
60       * uses a slightly obsolete Servlet 2.3-minus spec
61       * whose {@link Filter} interface requires this method.
62       * <p/>
63       *
64       * @param filterConfig the filter configuration.
65       */
66      public void setFilterConfig(FilterConfig filterConfig) {
67          try {
68              init(filterConfig);
69          } catch (ServletException se) {
70              log.error("Couldn't set the filter configuration in this filter", se);
71          }
72  
73          ServletContextSingleton singleton = ServletContextSingleton.getInstance();
74          singleton.setServletContext(filterConfig.getServletContext());
75      }
76  
77      /***
78       * answers the servlet context.
79       * <p/>
80       * Servlet 2.3 specifies that this can be retrieved from
81       * the session.  Unfortunately, weblogic.jar can only retrieve
82       * the servlet context from the filter config.  Hence, this
83       * returns the servlet context from the singleton that was
84       * setup by {@link #setFilterConfig(FilterConfig)}.
85       *
86       * @param session the HTTP session.  Not used
87       * @return the servlet context.
88       */
89      protected ServletContext getServletContext(HttpSession session) {
90          ServletContextSingleton singleton =
91                  ServletContextSingleton.getInstance();
92          return singleton.getServletContext();
93      }
94  
95      /***
96       * This method is required by Weblogic 6.1 SP4 because
97       * they defined this as a required method just before
98       * the Servlet 2.3 specification was finalized.
99       *
100      * @return the filter's filter configuration
101      */
102     public FilterConfig getFilterConfig() {
103         return super.getFilterConfig();
104     }
105 }