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


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.Iterator ;
22 import java.util.HashMap ;
23 import java.util.Map ;
24 import java.util.Set ;
25 import java.util.Collections ;
26 import javax.servlet.ServletConfig ;
27 import javax.servlet.http.HttpSession ;
28
29 import org.apache.turbine.services.TurbineBaseService;
30 import org.apache.turbine.services.InitializationException;
31 import org.apache.turbine.util.RunData;
32
33 import org.apache.jetspeed.services.logging.JetspeedLogFactoryService;
34 import org.apache.jetspeed.services.logging.JetspeedLogger;
35 import org.apache.jetspeed.services.statemanager.StateManagerService;
36 import org.apache.jetspeed.services.statemanager.SessionStateBindingListener;
37
38 /**
39 * <p>BaseStateManagerService is a Turbine Service implementation of the
40 * StateManagerService.</p>
41 * <p>Each SessionState is stored in a Map, storing the names and values
42 * of the state attributes.</p>
43 * <p>The set of states managed is stored in some specific way by extension classes.</p>
44 * <p>See the proposal: jakarta-jetspeed/proposals/StateManager.txt for more details.</p>
45 * @version $Revision: 1.5 $
46 * @see org.apache.jetspeed.services.statemanager.StateManagerService
47 * @see org.apache.jetspeed.services.statemanager.SessionState
48 * @author <a HREF="mailto:ggolden@apache.org">Glenn R. Golden</a>
49 */
50 public abstract class BaseStateManagerService
51     extends TurbineBaseService
52     implements StateManagerService
53 {
54     /**
55      * Static initialization of the logger for this class
56      */
57     private static final JetspeedLogger logger = JetspeedLogFactoryService.getLogger(BaseStateManagerService.class.getName());
58     
59     /** map of thread to http session for that thread. */
60     protected Map m_httpSessions = null;
61
62     /*******************************************************************************
63     * Abstract methods
64     *******************************************************************************/
65
66     /**
67     * Initialize the states storage.
68     */
69     protected abstract void initStates();
70
71     /**
72     * Cleanup the states storage.
73     */
74     protected abstract void shutdownStates();
75
76     /**
77     * Access the Map which is the set of attributes for a state.
78     * @param key The state key.
79     * @return The Map which is the set of attributes for a state.
80     */
81     protected abstract Map getState( String key );
82
83     /**
84     * Add a new state to the states we are managing.
85     * @param key The state key.
86     * @param state The Map which is the set of attributes for the state.
87     */
88     protected abstract void addState( String key, Map state );
89
90     /**
91     * Remove a state from the states we are managing.
92     * @param key The state key.
93     */
94     protected abstract void removeState( String key );
95
96     /**
97     * Access an array of the keys of all states managed, those that start with the parameter.
98     * @param start The starting string used to select the keys.
99     * @return an array of the keys of all states managed.
100     */
101     protected abstract String [] getStateKeys( String start );
102
103     /**
104     * retire the attributes of the state.
105     * @param key The state key.
106     * @param state The Map of attributes to retire.
107     */
108     protected void retireAttributes( String key, Map state )
109     {
110         if (state == null) return;
111
112         Set attributes = state.entrySet();
113         synchronized (state)
114         {
115             Iterator i = attributes.iterator();
116             while (i.hasNext())
117             {
118                 Map.Entry attribute = (Map.Entry ) i.next();
119                 unBindAttributeValue(key, (String )attribute.getKey(), attribute.getValue());
120             }
121         }
122
123         // remove all attributes
124 state.clear();
125
126     } // retireAttributes
127
128     /**
129     * If the object is a SessionStateBindingListener, unbind it
130     * @param stateKey The state key.
131     * @param attributeName The attribute name.
132     * @param attribute The attribute object
133     */
134     protected void unBindAttributeValue( String stateKey, String attributeName, Object attribute )
135     {
136         // if this object wants session binding notification
137 if ((attribute != null) && (attribute instanceof SessionStateBindingListener))
138         {
139             try
140             {
141                 ((SessionStateBindingListener)attribute)
142                     .valueUnbound(stateKey, attributeName);
143             }
144             catch (Throwable e)
145             {
146                 logger.warn("JetspeedStateManagerService.unBindAttributeValue: unbinding exception: ", e);
147             }
148         }
149
150     } // unBindAttributeValue
151
152     /**
153     * If the object is a SessionStateBindingListener, bind it
154     * @param stateKey The state key.
155     * @param attributeName The attribute name.
156     * @param attribute The attribute object
157     */
158     protected void bindAttributeValue( String stateKey, String attributeName, Object attribute )
159     {
160         // if this object wants session binding notification
161 if ((attribute != null) && (attribute instanceof SessionStateBindingListener))
162         {
163             try
164             {
165                 ((SessionStateBindingListener)attribute)
166                     .valueBound(stateKey, attributeName);
167             }
168             catch (Throwable e)
169             {
170                 logger.warn("JetspeedStateManagerService.bindAttributeValue: unbinding exception: ", e);
171             }
172         }
173
174     } // bindAttributeValue
175
176     /*******************************************************************************
177     * Service implementation
178     *******************************************************************************/
179
180     /**
181     * Performs early initialization.
182     *
183     * @param config A ServletConfing to use for initialization
184     * activities.
185     * @exception InitializationException, if initialization of this
186     * class was not successful.
187     */
188     public void init( ServletConfig config )
189         throws InitializationException
190     {
191         super.init(config);
192
193     } // init
194
195     /**
196     * Performs early initialization.
197     *
198     * @param data An RunData to use for initialization activities.
199     * @exception InitializationException, if initialization of this
200     * class was not successful.
201     */
202     public void init( RunData data )
203         throws InitializationException
204     {
205         super.init(data);
206
207     } // init
208
209     /**
210     * Performs late initialization.
211     *
212     * If your class relies on early initialization, and the object it
213     * expects was not received, you can use late initialization to
214     * throw an exception and complain.
215     *
216     * @exception InitializationException, if initialization of this
217     * class was not successful.
218     */
219     public void init()
220         throws InitializationException
221     {
222         super.init();
223
224         // allocate a thread-safe map to store the "current" http session for each thread
225 m_httpSessions = Collections.synchronizedMap(new HashMap ());
226
227         // create our states storage
228 initStates();
229
230     } // init
231
232     /**
233     * Returns to uninitialized state.
234     *
235     * You can use this method to release resources thet your Service
236     * allocated when Turbine shuts down.
237     */
238     public void shutdown()
239     {
240         m_httpSessions.clear();
241         m_httpSessions = null;
242         shutdownStates();
243         super.shutdown();
244
245     } // shutdown
246
247     /*******************************************************************************
248     * StateManagerService implementation
249     *******************************************************************************/
250
251     /**
252     * Access the named attribute of the keyed state.
253     * @param key The state key.
254     * @param name The attribute name.
255     * @return The named attribute value of the keyed state.
256     */
257     public Object getAttribute ( String key, String name )
258     {
259         Map state = getState(key);
260         if (state == null) return null;
261         return state.get(name);
262
263     } // getAttribute
264
265     /**
266     * Set the named state attribute of the keyed state with the provided object.
267     * @param key The state key.
268     * @param name The attribute name.
269     * @param value The new value of the attribute (any object type).
270     */
271     public void setAttribute( String key, String name, Object value )
272     {
273         Map state = getState(key);
274         if (state == null)
275         {
276             // create a synchronized map to store the state attributes
277 state = Collections.synchronizedMap(new HashMap ());
278             addState(key, state);
279         }
280
281         // get the old, if any
282 Object old = getAttribute(key, name);
283         
284         // store the new
285 state.put(name, value);
286
287         // if there was an old value, unbind it
288 if (old != null)
289         {
290             unBindAttributeValue(key, name, old);
291         }
292
293         // bind the new
294 bindAttributeValue(key, name, value);
295
296     } // setAttribute
297
298     /**
299     * Remove the named state attribute of the keyed state, if it exists.
300     * @param key The state key.
301     * @param name The attribute name.
302     */
303     public void removeAttribute( String key, String name )
304     {
305         Map state = getState(key);
306         if (state == null) return;
307
308         // get the old, if any
309 Object old = getAttribute(key, name);
310
311         // remove
312 state.remove(name);
313         
314         // if the state is now empty, remove it
315 if (state.isEmpty())
316         {
317             removeState(key);
318         }
319
320         // if there was an old value, unbind it
321 if (old != null)
322         {
323             unBindAttributeValue(key, name, old);
324         }
325
326     } // removeAttribute
327
328     /**
329     * Remove all state attribute of the keyed state.
330     * @param key The state key.
331     */
332     public void clear( String key )
333     {
334         Map state = getState(key);
335         if (state == null) return;
336
337         // notify all attribute and clear the state
338 retireAttributes(key, state);
339         
340         // and forget about it
341 removeState(key);
342
343     } // clear
344
345     /**
346     * Access an array of all names of attributes stored in the keyed state.
347     * @param key The state key.
348     * @return An array of all names of attributes stored in the keyed state.
349     */
350     public String [] getAttributeNames( String key )
351     {
352         Map state = (Map ) getState(key);
353         if (state == null) return null;
354         if (state.size() == 0) return null;
355
356         // put the names into an array for return
357 return (String []) state.keySet().toArray(new String [state.size()]);
358
359     } // getAttributeNames
360
361     /**
362     * Access an SessionState object with the given key.
363     * @param key The SessionState key.
364     * @return an SessionState object with the given key.
365     */
366     public SessionState getSessionState( String key )
367     {
368         return new MySessionState(key, this);
369
370     } // getSessionState
371
372     /**
373     * Access the SessionState object associated with the current request's http session.
374     * The session id is used as the key.
375     * @return an SessionState object associated with the current request's http session.
376     */
377     public SessionState getCurrentSessionState()
378     {
379         HttpSession session = (HttpSession ) m_httpSessions.get(Thread.currentThread());
380         if (session == null) return null;
381
382         return getSessionState(session.getId());
383
384     } // getCurrentSessionState
385
386     /**
387     * Access the SessionState object associated with the current request's http session with the given key.
388     * @param key The string to add to the session id to form the SessionState key.
389     * @return an SessionState object associated with the current request's http session with the given key.
390     */
391     public SessionState getCurrentSessionState( String key )
392     {
393         HttpSession session = (HttpSession ) m_httpSessions.get(Thread.currentThread());
394         if (session == null) return null;
395
396         return getSessionState(session.getId() + key);
397
398     } // getCurrentSessionState
399
400     /**
401     * Retire, forget about and clean up all states that start with the given key.
402     * @param keyStart The beginning of the key of the states to clean up.
403     */
404     public synchronized void retireState( String keyStart )
405     {
406         // get the current state keys into an array
407 String keys[] = getStateKeys(keyStart);
408         if (keys == null) return;
409         
410         // clear them
411 for (int i = 0; i < keys.length; i++)
412         {
413             clear(keys[i]);
414         }
415
416     } // retireState
417
418     /**
419     * Set the "current" context for this thread -
420     * Call this at the start of each request, and call %%% at the end.
421     * getCurrentSession() uses this for the session state key.
422     * @param session the HttpSession of the current request.
423     */
424     public void setCurrentContext( HttpSession session )
425     {
426         // store the session associated with this thread
427 m_httpSessions.put(Thread.currentThread(), session);
428
429     } // setCurrentContext
430
431     /**
432     * Clear the "current context for this thread -
433     * Call at the end of each request, balanced with calls to setCurrentContext()
434     */
435     public void clearCurrentContext()
436     {
437         // clear the session associated with this thread
438 m_httpSessions.remove(Thread.currentThread());
439
440     } // clearCurrentContext
441
442     /*******************************************************************************
443     * SessionState implementation
444     *******************************************************************************/
445
446     /**
447     * A SessionState implementation, as covers to this service, storing the key.
448     */
449     private class MySessionState
450         implements SessionState
451     {
452         /** The state key. */
453         private String m_key = null;
454
455         /** The StateManagerService object. */
456         private BaseStateManagerService m_service = null;
457
458         /**
459         * Construct.
460         * @param key The state key.
461         * @param service The JetspeedStateManagerService instance.
462         */
463         public MySessionState( String key,
464                                 BaseStateManagerService service)
465         {
466             m_key = key;
467             m_service = service;
468
469         } // MySessionState
470
471         /**
472         * Access the named attribute.
473         * @param name The attribute name.
474         * @return The named attribute value.
475         */
476         public Object getAttribute( String name )
477         {
478             return m_service.getAttribute(m_key, name);
479
480         } // getAttribute
481
482         /**
483         * Set the named attribute value to the provided object.
484         * @param name The attribute name.
485         * @param value The value of the attribute (any object type).
486         */
487         public void setAttribute( String name, Object value )
488         {
489             m_service.setAttribute(m_key, name, value);
490
491         } // setAttribute
492
493         /**
494         * Remove the named attribute, if it exists.
495         * @param name The attribute name.
496         */
497         public void removeAttribute( String name )
498         {
499             m_service.removeAttribute(m_key, name);
500
501         } // removeAttribute
502
503         /**
504         * Remove all attributes.
505         */
506         public void clear()
507         {
508             m_service.clear(m_key);
509
510         } // clear
511
512         /**
513         * Access an array of all names of attributes stored in the SessionState.
514         * @return An array of all names of attribute stored in the SessionState.
515         */
516         public String [] getAttributeNames()
517         {
518             return m_service.getAttributeNames(m_key);
519
520         } // getAttributeNames
521
522         /**
523         * Access the full unique StateManager key for the SessionState.
524         * @return the full unique StateManager key for the SessionState.
525         */
526         public String getKey()
527         {
528             return m_key;
529
530         } // getKey
531
532         /**
533         * Retire, forget about and clean up this state.
534         */
535         public void retire()
536         {
537             m_service.retireState(m_key);
538
539         } // retire
540
541     } // class MySessionState
542
543 } // BaseStateManagerService
544
545 /**********************************************************************************
546 *
547 * $Header: /home/cvs/jakarta-jetspeed/src/java/org/apache/jetspeed/services/statemanager/BaseStateManagerService.java,v 1.5 2004/02/23 03:38:28 jford Exp $
548 *
549 **********************************************************************************/
550
551

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