UserInstance


1   /* 
2    * This file is part of the Echo Web Application Framework (hereinafter "Echo").
3    * Copyright (C) 2002-2005 NextApp, Inc.
4    *
5    * Version: MPL 1.1/GPL 2.0/LGPL 2.1
6    *
7    * The contents of this file are subject to the Mozilla Public License Version
8    * 1.1 (the "License"); you may not use this file except in compliance with
9    * the License. You may obtain a copy of the License at
10   * http://www.mozilla.org/MPL/
11   *
12   * Software distributed under the License is distributed on an "AS IS" basis,
13   * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
14   * for the specific language governing rights and limitations under the
15   * License.
16   *
17   * Alternatively, the contents of this file may be used under the terms of
18   * either the GNU General Public License Version 2 or later (the "GPL"), or
19   * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
20   * in which case the provisions of the GPL or the LGPL are applicable instead
21   * of those above. If you wish to allow use of your version of this file only
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23   * use your version of this file under the terms of the MPL, indicate your
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27   * the terms of any one of the MPL, the GPL or the LGPL.
28   */
29  
30  package nextapp.echo2.webrender;
31  
32  import java.io.Serializable  ;
33  
34  import javax.servlet.http.HttpSession  ;
35  import javax.servlet.http.HttpSessionActivationListener  ;
36  import javax.servlet.http.HttpSessionBindingEvent  ;
37  import javax.servlet.http.HttpSessionBindingListener  ;
38  import javax.servlet.http.HttpSessionEvent  ;
39  
40  /**
41   * An abstract base class representing a single user-instance of an application
42   * hosted in an application container.
43   */
44  public abstract class UserInstance 
45  implements HttpSessionActivationListener  , HttpSessionBindingListener  , Serializable   {
46      
47      public static final String   PROPERTY_CLIENT_CONFIGURATION = "clientConfiguration";
48      public static final String   PROPERTY_SERVER_DELAY_MESSAGE = "serverDelayMessage";
49  
50      /**
51       * The default character encoding in which responses should be rendered.
52       */
53      private String   characterEncoding = "UTF-8";
54      
55      /**
56       * <code>ClientConfiguration</code> information containing 
57       * application-specific client behavior settings.
58       */
59      private ClientConfiguration clientConfiguration;
60  
61      /**
62       * The <code>ServerDelayMessage</code> displayed during 
63       * client/server-interactions.
64       */
65      private ServerDelayMessage serverDelayMessage;
66      
67      /**
68       * A <code>ClientProperties</code> object describing the web browser
69       * client.
70       */
71      private ClientProperties clientProperties;
72      
73      /**
74       * The URI of the servlet.
75       */
76      private String   servletUri;
77      
78      /**
79       * Reference to the <code>HttpSession</code> in which this
80       * <code>UserInstance</code> is stored.
81       */
82      private transient HttpSession   session;
83      
84      /**
85       * Provides information about updated <code>UserInstance</code> properties.
86       */
87      private UserInstanceUpdateManager updateManager;
88  
89      /**
90       * The current transactionId.  Used to ensure incoming ClientMessages reflect
91       * changes made by user against current server-side state of user interface.
92       * This is used to eliminate issues that could be encountered with two
93       * browser windows pointing at the same application instance.
94       */
95      private long transactionId = 0;
96      
97      /**
98       * Creates a new <code>UserInstance</code>.
99       * 
100      * @param conn the client/server <code>Connection</code> for which the
101      *        instance is being instantiated
102      */
103     public UserInstance(Connection conn) {
104         super();
105         updateManager = new UserInstanceUpdateManager();
106         conn.initUserInstance(this);
107     }
108 
109     /**
110      * Returns the default character encoding in which responses should be
111      * rendered.
112      * 
113      * @return the default character encoding in which responses should be
114      *         rendered
115      */
116     public String   getCharacterEncoding() {
117         return characterEncoding;
118     }
119     
120     /**the <code>ServerDelayMessage</code> displayed during 
121      * client/server-interactions.
122      * Retrieves the <code>ClientConfiguration</code> information containing
123      * application-specific client behavior settings.
124      * 
125      * @return the relevant <code>ClientProperties</code>
126      */
127     public ClientConfiguration getClientConfiguration() {
128         return clientConfiguration;
129     }
130     
131     /**
132      * Retrieves the <code>ClientProperties</code> object providing
133      * information about the client of this instance.
134      * 
135      * @return the relevant <code>ClientProperties</code>
136      */
137     public ClientProperties getClientProperties() {
138         return clientProperties;
139     }
140     
141     /**
142      * Returns the current transaction id.
143      * 
144      * @return the current transaction id
145      */
146     public long getCurrentTransactionId() {
147         return transactionId;
148     }
149     
150     /**
151      * Increments the current transaction id and returns it.
152      * 
153      * @return the current transaction id, after an increment
154      */
155     public long getNextTransactionId() {
156         ++transactionId;
157         return transactionId;
158     }
159 
160     /**
161      * Retrieves the <code>ServerDelayMessage</code> displayed during 
162      * client/server-interactions.
163      * 
164      * @return the <code>ServerDelayMessage</code>
165      */
166     public ServerDelayMessage getServerDelayMessage() {
167         return serverDelayMessage;
168     }
169     
170     /**
171      * Determines the URI to invoke the specified <code>Service</code>.
172      * 
173      * @param service the <code>Service</code>
174      * @return the URI
175      */
176     public String   getServiceUri(Service service) {
177         return servletUri + "?serviceId=" + service.getId();
178     }
179 
180     /**
181      * Determines the URI to invoke the specified <code>Service</code> with
182      * additional request parameters. The additional parameters are provided by
183      * way of the <code>parameterNames</code> and <code>parameterValues</code>
184      * arrays. The value of a parameter at a specific index in the
185      * <code>parameterNames</code> array is provided in the
186      * <code>parameterValues</code> array at the same index. The arrays must
187      * thus be of equal length. Null values are allowed in the
188      * <code>parameterValues</code> array, and in such cases only the parameter
189      * name will be rendered in the returned URI.
190      * 
191      * @param service the <code>Service</code>
192      * @param parameterNames the names of the additional URI parameters
193      * @param parameterValues the values of the additional URI parameters
194      * @return the URI
195      */
196     public String   getServiceUri(Service service, String  [] parameterNames, String  [] parameterValues) {
197         StringBuffer   out = new StringBuffer  (servletUri);
198         out.append("?serviceId=");
199         out.append(service.getId());
200         for (int i = 0; i < parameterNames.length; ++i) {
201             out.append("&");
202             out.append(parameterNames[i]);
203             if (parameterValues[i] != null) {
204                 out.append("=");
205                 out.append(parameterValues[i]);
206             }
207         }
208         return out.toString();
209     }
210 
211     /**
212      * Returns the URI of the servlet managing this <code>UserInstance</code>.
213      * 
214      * @return the URI
215      */
216     public String   getServletUri() {
217         return servletUri;
218     }
219 
220     /**
221      * Returns the <code>UserInstanceUpdateManager</code> providing information
222      * about updated <code>UserInstance</code> properties.
223      * 
224      * @return the <code>UserInstanceUpdateManager</code>
225      */
226     public UserInstanceUpdateManager getUserInstanceUpdateManager() {
227         return updateManager;
228     }
229     
230     /**
231      * Returns the <code>HttpSession</code> containing this
232      * <code>UserInstance</code>.
233      * 
234      * @return the <code>HttpSession</code>
235      */
236     public HttpSession   getSession() {
237         return session;
238     }
239     
240     /**
241      * @see javax.servlet.http.HttpSessionActivationListener#sessionDidActivate(javax.servlet.http.HttpSessionEvent)
242      */
243     public void sessionDidActivate(HttpSessionEvent   e) {
244         session = e.getSession();
245     }
246 
247     /**
248      * @see javax.servlet.http.HttpSessionActivationListener#sessionWillPassivate(javax.servlet.http.HttpSessionEvent)
249      */
250     public void sessionWillPassivate(HttpSessionEvent   e) {
251         session = null;
252     }
253 
254     /**
255      * Sets the <code>ClientConfiguration</code> information containing
256      * application-specific client behavior settings.
257      * 
258      * @param clientConfiguration the new <code>ClientConfiguration</code>
259      */
260     public void setClientConfiguration(ClientConfiguration clientConfiguration) {
261         this.clientConfiguration = clientConfiguration;
262         updateManager.processPropertyUpdate(PROPERTY_CLIENT_CONFIGURATION);
263     }
264     
265    /**
266      * Stores the <code>ClientProperties</code> object that provides
267      * information about the client of this instance.
268      * 
269      * @param clientProperties the relevant <code>ClientProperties</code>
270      */
271     void setClientProperties(ClientProperties clientProperties) {
272         this.clientProperties = clientProperties;
273     }
274     
275     /**
276      * Sets the <code>ServerDelayMessage</code> displayed during 
277      * client/server-interactions.
278      * 
279      * @param serverDelayMessage the new <code>ServerDelayMessage</code>
280      */
281     public void setServerDelayMessage(ServerDelayMessage serverDelayMessage) {
282         this.serverDelayMessage = serverDelayMessage;
283         updateManager.processPropertyUpdate(PROPERTY_SERVER_DELAY_MESSAGE);
284     }
285 
286     /**
287      * Sets the URI of the servlet managing this <code>UserInstance</code>.
288      * 
289      * @param servletUri the URI
290      */
291     void setServletUri(String   servletUri) {
292         this.servletUri = servletUri;
293     }
294 
295     /**
296      * Listener implementation of <code>HttpSessionBindingListener</code>.
297      * Stores reference to session when invoked.
298      * 
299      * @see javax.servlet.http.HttpSessionBindingListener#valueBound(HttpSessionBindingEvent)
300      */
301     public void valueBound(HttpSessionBindingEvent   e) {
302         session = e.getSession();
303     }
304 
305     /**
306      * Listener implementation of <code>HttpSessionBindingListener</code>.
307      * Removes reference to session when invoked.
308      * 
309      * @see javax.servlet.http.HttpSessionBindingListener#valueUnbound(HttpSessionBindingEvent)
310      */
311     public void valueUnbound(HttpSessionBindingEvent   e) {
312         session = null;
313     }
314 }
315
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