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1   /*
2    * $Id: PlexusFilter.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.plexus;
22  
23  import java.io.IOException;
24  import java.util.Collections;
25  
26  import javax.servlet.Filter;
27  import javax.servlet.FilterChain;
28  import javax.servlet.FilterConfig;
29  import javax.servlet.ServletContext;
30  import javax.servlet.ServletException;
31  import javax.servlet.ServletRequest;
32  import javax.servlet.ServletResponse;
33  import javax.servlet.http.HttpServletRequest;
34  import javax.servlet.http.HttpSession;
35  
36  import org.apache.commons.logging.Log;
37  import org.apache.commons.logging.LogFactory;
38  import org.codehaus.plexus.PlexusContainer;
39  
40  /***
41   * Creates a plexus container for the application, session, and request
42   */
43  public class PlexusFilter implements Filter {
44      private static final Log log = LogFactory.getLog(PlexusObjectFactory.class);
45      private static final String CHILD_CONTAINER_NAME = "request";
46  
47      private static boolean loaded = false;
48  
49      private ServletContext ctx;
50  
51      /***
52       * @return Returns if the container is loaded.
53       */
54      public static boolean isLoaded() {
55          return loaded;
56      }
57  
58      /* (non-Javadoc)
59       * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
60       */
61      public void init(FilterConfig filterConfig) throws ServletException {
62          ctx = filterConfig.getServletContext();
63          loaded = true;
64      }
65  
66      /* (non-Javadoc)
67       * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
68       */
69      public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
70          PlexusContainer child = null;
71          try {
72              try {
73                  HttpServletRequest request = (HttpServletRequest) req;
74                  HttpSession session = request.getSession(false);
75                  PlexusContainer parent;
76                  if (session != null) {
77                      parent = (PlexusContainer) session.getAttribute(PlexusLifecycleListener.KEY);
78                  } else {
79                      parent = (PlexusContainer) ctx.getAttribute(PlexusLifecycleListener.KEY);
80                  }
81  
82                  if (parent.hasChildContainer(CHILD_CONTAINER_NAME)) {
83                      log.warn("Plexus container (scope: request) alredy exist.");
84                      child = parent.getChildContainer(CHILD_CONTAINER_NAME);
85                  } else {
86                      child = parent.createChildContainer(CHILD_CONTAINER_NAME, Collections.EMPTY_LIST, Collections.EMPTY_MAP);
87                      PlexusUtils.configure(child, "plexus-request.xml");
88                      child.initialize();
89                      child.start();
90                  }
91                  PlexusThreadLocal.setPlexusContainer(child);
92              } catch (Exception e) {
93                  log.error("Error initializing plexus container (scope: request)", e);
94              }
95  
96              chain.doFilter(req, res);
97          }
98          finally {
99              try {
100                 if (child != null) {
101                     child.dispose();
102                 }
103                 PlexusThreadLocal.setPlexusContainer(null);
104             } catch (Exception e) {
105                 log.error("Error disposing plexus container (scope: request)", e);
106             }
107         }
108     }
109 
110     /* (non-Javadoc)
111      * @see javax.servlet.Filter#destroy()
112      */
113     public void destroy() {
114     }
115 }