1   /**
2    * Copyright (c) 2000-2010 Liferay, Inc. All rights reserved.
3    *
4    * The contents of this file are subject to the terms of the Liferay Enterprise
5    * Subscription License ("License"). You may not use this file except in
6    * compliance with the License. You can obtain a copy of the License by
7    * contacting Liferay, Inc. See the License for the specific language governing
8    * permissions and limitations under the License, including but not limited to
9    * distribution rights of the Software.
10   *
11   *
12   *
13   */
14  
15  package com.liferay.portal.servlet;
16  
17  import com.liferay.portal.kernel.concurrent.ConcurrentHashSet;
18  import com.liferay.portal.kernel.servlet.ServletVersionDetector;
19  import com.liferay.portal.kernel.util.ArrayUtil;
20  import com.liferay.portal.util.PropsValues;
21  
22  import java.util.Set;
23  
24  import javax.servlet.http.HttpSession;
25  import javax.servlet.http.HttpSessionAttributeListener;
26  import javax.servlet.http.HttpSessionBindingEvent;
27  import javax.servlet.http.HttpSessionEvent;
28  import javax.servlet.http.HttpSessionListener;
29  
30  /**
31   * <a href="SharedSessionAttributeListener.java.html"><b><i>View Source</i></b>
32   * </a>
33   *
34   * <p>
35   * Listener used to help manage shared session attributes into a cache. This
36   * cache is more thread safe than the HttpSession and leads to fewer problems
37   * with shared session attributes being modified out of sequence.
38   * </p>
39   *
40   * @author Michael C. Han
41   */
42  public class SharedSessionAttributeListener
43      implements HttpSessionAttributeListener, HttpSessionListener {
44  
45      public SharedSessionAttributeListener() {
46          if (ServletVersionDetector.is2_5()) {
47              return;
48          }
49  
50          _sessionIds = new ConcurrentHashSet<String>();
51      }
52  
53      public void attributeAdded(HttpSessionBindingEvent event) {
54          if (PropsValues.SESSION_DISABLED || ServletVersionDetector.is2_5()) {
55              return;
56          }
57  
58          HttpSession session = event.getSession();
59  
60          if (!_sessionIds.contains(session.getId())) {
61              return;
62          }
63  
64          SharedSessionAttributeCache sharedSessionAttributeCache =
65              SharedSessionAttributeCache.getInstance(session);
66  
67          String name = event.getName();
68  
69          if (ArrayUtil.contains(
70                  PropsValues.SHARED_SESSION_ATTRIBUTES_EXCLUDES, name)) {
71  
72              return;
73          }
74  
75          for (String sharedName : PropsValues.SHARED_SESSION_ATTRIBUTES) {
76              if (!name.startsWith(sharedName)) {
77                  continue;
78              }
79  
80              sharedSessionAttributeCache.setAttribute(name, event.getValue());
81  
82              return;
83          }
84      }
85  
86      public void attributeRemoved(HttpSessionBindingEvent event) {
87          if (PropsValues.SESSION_DISABLED || ServletVersionDetector.is2_5()) {
88              return;
89          }
90  
91          HttpSession session = event.getSession();
92  
93          if (!_sessionIds.contains(session.getId())) {
94              return;
95          }
96  
97          SharedSessionAttributeCache sharedSessionAttributeCache =
98              SharedSessionAttributeCache.getInstance(session);
99  
100         sharedSessionAttributeCache.removeAttribute(event.getName());
101     }
102 
103     public void attributeReplaced(HttpSessionBindingEvent event) {
104         if (PropsValues.SESSION_DISABLED || ServletVersionDetector.is2_5()) {
105             return;
106         }
107 
108         HttpSession session = event.getSession();
109 
110         if (!_sessionIds.contains(session.getId())) {
111             return;
112         }
113 
114         SharedSessionAttributeCache sharedSessionAttributeCache =
115             SharedSessionAttributeCache.getInstance(session);
116 
117         if (sharedSessionAttributeCache.contains(event.getName())) {
118             Object value = session.getAttribute(event.getName());
119 
120             sharedSessionAttributeCache.setAttribute(event.getName(), value);
121         }
122     }
123 
124     public void sessionCreated(HttpSessionEvent event) {
125         if (PropsValues.SESSION_DISABLED || ServletVersionDetector.is2_5()) {
126             return;
127         }
128 
129         HttpSession session = event.getSession();
130 
131         SharedSessionAttributeCache.getInstance(session);
132 
133         _sessionIds.add(session.getId());
134     }
135 
136     public void sessionDestroyed(HttpSessionEvent event) {
137         if (PropsValues.SESSION_DISABLED || ServletVersionDetector.is2_5()) {
138             return;
139         }
140 
141         HttpSession session = event.getSession();
142 
143         _sessionIds.remove(session.getId());
144     }
145 
146     private Set<String> _sessionIds;
147 
148 }