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1   /*
2    * $Id: ServletContextSingleton.java 471756 2006-11-06 15:01:43Z husted $
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.config;
22  
23  import javax.servlet.ServletContext;
24  
25  /***
26   * This singleton holds an instance of the web servlet context.
27   * <p/>
28   * This is needed for running Struts on Weblogic Server 6.1
29   * because there is no provision to retrieve the servlet context
30   * from the web session object.
31   * <p/>
32   * This class is created to bet that this singleton can be set by
33   * {@link org.apache.struts2.dispatcher.FilterDispatcherCompatWeblogic61}
34   * before the servlet context is needed by
35   * {@link org.apache.struts2.lifecycle.SessionLifecycleListener}
36   * which will use this object to get it.
37   *
38   */
39  public class ServletContextSingleton {
40      /***
41       * The web servlet context.  Holding this is the
42       * purpose of this singleton.
43       */
44      private ServletContext servletContext;
45  
46      /***
47       * The sole instance of this class.
48       */
49      private static ServletContextSingleton singleton;
50  
51      /***
52       * Constructor which cannot be called
53       * publicly.
54       */
55      private ServletContextSingleton() {
56      }
57  
58      /***
59       * Answers the singleton.
60       * <p/>
61       * At some point, the caller must populate the web servlet
62       * context.
63       *
64       * @return Answers the singleton instance of this class
65       */
66      public static ServletContextSingleton getInstance() {
67          if (singleton == null) {
68              singleton = new ServletContextSingleton();
69          }
70          return singleton;
71      }
72  
73      /***
74       * Gets the servlet context
75       *
76       * @return The web servlet context
77       */
78      public ServletContext getServletContext() {
79          return servletContext;
80      }
81  
82      /***
83       * Sets the servlet context
84       *
85       * @param context The web servlet context
86       */
87      public void setServletContext(ServletContext context) {
88          servletContext = context;
89      }
90  
91  }