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Java > Open Source Codes > org > apache > jetspeed > services > statemanager > JetspeedHttpStateManagerService


1 /*
2  * Copyright 2000-2002,2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 // package
18 package org.apache.jetspeed.services.statemanager;
19
20 // imports
21 import java.util.Map JavaDoc;
22 import java.util.Vector JavaDoc;
23 import java.util.Enumeration JavaDoc;
24
25 import javax.servlet.http.HttpSession JavaDoc;
26 import javax.servlet.http.HttpSessionBindingListener JavaDoc;
27 import javax.servlet.http.HttpSessionBindingEvent JavaDoc;
28
29 import org.apache.jetspeed.services.statemanager.BaseStateManagerService;
30
31 /**
32 * <p>JetspeedHttpStateManagerService is an implementation of the BaseStateManagerService
33 * which manages the states stored in the "current" HttpSession.</p>
34 * <p>Note: This implementation of the StateManagerService takes advantage of the
35 * Servlet container's management of the HttpSession.
36 * When the session is invalidated, the states we manage will be automatically cleaned up.
37 * When this happens, the objects placed into our states will have their
38 * SessionStateBindingListener mechanism invoked.</p>
39 * <p>Note: This implementation segments the states by session. States created in one session will NOT BE AVAILABLE
40 * from other sessions.</p>
41 * @version $Revision: 1.4 $
42 * @see org.apache.jetspeed.services.statemanager.BaseStateManagerService
43 * @see org.apache.jetspeed.services.statemanager.StateManagerService
44 * @see org.apache.jetspeed.services.statemanager.SessionState
45 * @author <a HREF="mailto:ggolden@apache.org">Glenn R. Golden</a>
46 */
47 public class JetspeedHttpStateManagerService
48     extends BaseStateManagerService
49 {
50     /**
51     * Initialize the states storage.
52     */
53     protected void initStates()
54     {
55     } // initStates
56
57     /**
58     * Cleanup the states storage.
59     */
60     protected void shutdownStates()
61     {
62     } // shutdownStates
63
64     /**
65     * Access the current HttpSession.
66     */
67     private HttpSession JavaDoc getSession()
68     {
69         // get the current session that was installed for this thread
70 HttpSession JavaDoc session = (HttpSession JavaDoc) m_httpSessions.get(Thread.currentThread());
71         if (session == null) return null;
72
73         // call isNew just to see if the session has been invalidated already
74 try
75         {
76             session.isNew();
77         }
78         catch (IllegalStateException JavaDoc e)
79         {
80             return null;
81         }
82
83         return session;
84
85     } // getSession
86
87     /**
88     * Convert the key to a name safe to store directly in the session.
89     * @param key The state key.
90     * @return a name safe to store directly in the session based on key.
91     */
92     private String JavaDoc getSessionKey( String JavaDoc key )
93     {
94         // we want our keys not to conflict with any other session usage...
95 return JetspeedHttpStateManagerService.class.getName() + "." + key;
96
97     } // getSessionKey
98
99     /**
100     * Access the Map which is the set of attributes for a state.
101     * @param key The state key.
102     * @return The Map which is the set of attributes for a state.
103     */
104     protected Map JavaDoc getState( String JavaDoc key )
105     {
106         // get the session
107 HttpSession JavaDoc session = getSession();
108         if (session == null) return null;
109
110         // get this state from our entry in the session
111 StateEntry stateEntry = (StateEntry) session.getAttribute(getSessionKey(key));
112         if (stateEntry == null) return null;
113
114         return stateEntry.getMap();
115
116     } // getState
117
118     /**
119     * Add a new state to the states we are managing.
120     * @param key The state key.
121     * @param state The Map which is the set of attributes for the state.
122     */
123     protected void addState( String JavaDoc key, Map JavaDoc state )
124     {
125         // get the session
126 HttpSession JavaDoc session = getSession();
127         if (session == null) return;
128
129         // create a stateEntry to hold our state Map
130 StateEntry stateEntry = new StateEntry(key, state);
131
132         // put it in the session
133 session.setAttribute(getSessionKey(key), stateEntry);
134
135     } // addState
136
137     /**
138     * Remove a state from the states we are managing.
139     * @param key The state key.
140     */
141     protected void removeState( String JavaDoc key )
142     {
143         // get the session
144 HttpSession JavaDoc session = getSession();
145         if (session == null) return;
146
147         // remove the key from the session - the StateEntry will be notified
148 session.removeAttribute(getSessionKey(key));
149
150     } // removeState
151
152     /**
153     * Access an array of the keys of all states managed, those that start with the parameter.
154     * @param start The starting string used to select the keys.
155     * @return an array of the keys of all states managed.
156     */
157     protected String JavaDoc[] getStateKeys( String JavaDoc start )
158     {
159         // get the session
160 HttpSession JavaDoc session = getSession();
161         if (session == null) return null;
162
163         // use this as the test pattern
164 String JavaDoc pattern = getSessionKey(start);
165
166         // for those that match, this starts the session key
167 int subStart = getSessionKey("").length();
168
169         // collect for return
170 Vector JavaDoc rv = new Vector JavaDoc();
171
172         // get the session names
173 Enumeration JavaDoc names = session.getAttributeNames();
174         while (names.hasMoreElements())
175         {
176             String JavaDoc sessionName = (String JavaDoc) names.nextElement();
177             
178             // pick our states, and those whose key starts with the pattern
179 if (sessionName.startsWith(pattern))
180             {
181                 rv.add(sessionName.substring(subStart));
182             }
183         }
184
185         if (rv.size() == 0) return null;
186
187         return (String JavaDoc[]) rv.toArray(new String JavaDoc[rv.size()]);
188
189     } // getStateKeys
190
191     /**
192     * Store the Map for the state, and listen for HttpSessionBinding events
193     */
194     private class StateEntry
195         implements HttpSessionBindingListener JavaDoc
196     {
197         /** Store the map. */
198         private Map JavaDoc m_map = null;
199         
200         /** The state key. */
201         private String JavaDoc m_key = null;
202
203         /**
204         * Construct.
205         * @param key The state key.
206         * @param map The map to hold.
207         */
208         public StateEntry( String JavaDoc key, Map JavaDoc map )
209         {
210             m_key = key;
211             m_map = map;
212
213         } // StateEntry
214
215         /**
216         * Access the map we are holding.
217         * @return the Map we are holding.
218         */
219         public Map JavaDoc getMap()
220         {
221             return m_map;
222
223         } // getMap
224
225         /**
226         * We don't care about when we are bound...
227         */
228         public void valueBound( HttpSessionBindingEvent JavaDoc event ) {}
229
230         /**
231         * When we are unbound, unbind our state's (map's) attributes
232         */
233         public void valueUnbound( HttpSessionBindingEvent JavaDoc event )
234         {
235             // notify all attribute and clear the state
236 retireAttributes(m_key, m_map);
237             m_map = null;
238             m_key = null;
239         }
240
241     } // class StateEntry
242
243 } // JetspeedHttpStateManagerService
244
245 /**********************************************************************************
246 *
247 * $Header: /home/cvs/jakarta-jetspeed/src/java/org/apache/jetspeed/services/statemanager/JetspeedHttpStateManagerService.java,v 1.4 2004/02/23 03:38:28 jford Exp $
248 *
249 **********************************************************************************/
250
251
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