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1   /**
2    * Logback: the reliable, generic, fast and flexible logging framework.
3    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
4    *
5    * This program and the accompanying materials are dual-licensed under
6    * either the terms of the Eclipse Public License v1.0 as published by
7    * the Eclipse Foundation
8    *
9    *   or (per the licensee's choosing)
10   *
11   * under the terms of the GNU Lesser General Public License version 2.1
12   * as published by the Free Software Foundation.
13   */
14  package ch.qos.logback.classic.selector.servlet;
15  
16  import java.io.IOException;
17  
18  import javax.servlet.Filter;
19  import javax.servlet.FilterChain;
20  import javax.servlet.FilterConfig;
21  import javax.servlet.ServletException;
22  import javax.servlet.ServletRequest;
23  import javax.servlet.ServletResponse;
24  
25  import org.slf4j.LoggerFactory;
26  
27  import ch.qos.logback.classic.LoggerContext;
28  import ch.qos.logback.classic.selector.ContextJNDISelector;
29  import ch.qos.logback.classic.selector.ContextSelector;
30  import ch.qos.logback.classic.util.ContextSelectorStaticBinder;
31  
32  /**
33   * A servlet filter that puts the environment dependent LoggerContext in a
34   * ThreadLocal variable, removing it after the request is processed.
35   * 
36   * <p>
37   * To use it, add the following lines to a web.xml file
38   * 
39   * <filter> <filter-name>LoggerContextFilter</filter-name> <filter-class>
40   * ch.qos.logback.classic.selector.servlet.LoggerContextFilter </filter-class>
41   * </filter> <filter-mapping> <filter-name>LoggerContextFilter</filter-name>
42   * <url-pattern>/*</url-pattern> </filter-mapping>
43   * 
44   * @author S&eacute;bastien Pennec
45   */
46  public class LoggerContextFilter implements Filter {
47  
48      public void destroy() {
49          // do nothing
50      }
51  
52      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
53              throws IOException, ServletException {
54  
55          LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
56          ContextSelector selector = ContextSelectorStaticBinder.getSingleton().getContextSelector();
57          ContextJNDISelector sel = null;
58  
59          if (selector instanceof ContextJNDISelector) {
60              sel = (ContextJNDISelector) selector;
61              sel.setLocalContext(lc);
62          }
63  
64          try {
65              chain.doFilter(request, response);
66          } finally {
67              if (sel != null) {
68                  sel.removeLocalContext();
69              }
70          }
71      }
72  
73      public void init(FilterConfig arg0) throws ServletException {
74          // do nothing
75      }
76  }