Source code: org/objectstyle/cayenne/conf/ServletConfiguration.java
1 /* ====================================================================
2 *
3 * The ObjectStyle Group Software License, Version 1.0
4 *
5 * Copyright (c) 2002 The ObjectStyle Group
6 * and individual authors of the software. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
18 * distribution.
19 *
20 * 3. The end-user documentation included with the redistribution, if
21 * any, must include the following acknowlegement:
22 * "This product includes software developed by the
23 * ObjectStyle Group (http://objectstyle.org/)."
24 * Alternately, this acknowlegement may appear in the software itself,
25 * if and wherever such third-party acknowlegements normally appear.
26 *
27 * 4. The names "ObjectStyle Group" and "Cayenne"
28 * must not be used to endorse or promote products derived
29 * from this software without prior written permission. For written
30 * permission, please contact andrus@objectstyle.org.
31 *
32 * 5. Products derived from this software may not be called "ObjectStyle"
33 * nor may "ObjectStyle" appear in their names without prior written
34 * permission of the ObjectStyle Group.
35 *
36 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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48 * ====================================================================
49 *
50 * This software consists of voluntary contributions made by many
51 * individuals on behalf of the ObjectStyle Group. For more
52 * information on the ObjectStyle Group, please see
53 * <http://objectstyle.org/>.
54 *
55 */
56
57 package org.objectstyle.cayenne.conf;
58
59 import javax.servlet.ServletContext;
60 import javax.servlet.ServletContextEvent;
61 import javax.servlet.ServletContextListener;
62 import javax.servlet.http.HttpSession;
63 import javax.servlet.http.HttpSessionEvent;
64 import javax.servlet.http.HttpSessionListener;
65
66 import org.objectstyle.cayenne.access.DataContext;
67
68 /**
69 * ServletConfiguration is a Configuration that uses ServletContext to locate resources.
70 * This class can only be used in a context of a servlet/jsp container.
71 * It resolves configuration file paths relative to the web application
72 * "WEB-INF" directory.
73 *
74 * <p>It performs the following tasks:
75 * <ul>
76 * <li>Loads Cayenne configuration when the application is started within container.</li>
77 * <li>Assigns new DataContext to every new session created within the application.</li>
78 * </ul>
79 * </p>
80 *
81 * <p>ServletConfiguration must be configured in <code>web.xml</code> deployment
82 * descriptor as a listener of context and session events:</p>
83 *<pre><listener>
84 <listener-class>org.objectstyle.cayenne.conf.ServletConfiguration</listener-class>
85 </listener></pre>
86 *
87 * <p>Note that to set ServletConfiguration as a listener of web application events,
88 * you must use servlet containers
89 * compatible with Servlet Specification 2.3 (such as Tomcat 4.0). Listeners were only added
90 * to servlet specification in 2.3. If you are using an older container. You will need
91 * to configure Cayenne in you code.</p>
92 *
93 * @author Andrei Adamchik
94 */
95 public class ServletConfiguration
96 extends BasicServletConfiguration
97 implements HttpSessionListener, ServletContextListener {
98
99 public static final String DATA_CONTEXT_KEY = "cayenne.datacontext";
100
101 public ServletConfiguration() {}
102
103 public ServletConfiguration(ServletContext context) {}
104
105 /** Returns default Cayenne DataContext associated with session <code>s</code>. */
106 public static DataContext getDefaultContext(HttpSession s) {
107 return (DataContext) s.getAttribute(DATA_CONTEXT_KEY);
108 }
109
110 /** Sets itself as a Cayenne shared Configuration object that can later
111 * be obtained by calling <code>Configuration.getSharedConfig()</code>.
112 * This method is a part of ServletContextListener interface and is called
113 * on application startup. */
114 public void contextInitialized(ServletContextEvent sce) {
115 this.servletContext = sce.getServletContext();
116 servletContext.log("*************** app created");
117 Configuration.initSharedConfig(this);
118 }
119
120 /** Currently does nothing. <i>In the future it should close down
121 * any database connections if they wheren't obtained via JNDI.</i>
122 * This method is a part of ServletContextListener interface and is called
123 * on application shutdown. */
124 public void contextDestroyed(ServletContextEvent sce) {}
125
126 /** Creates and assigns a new data context based on default domain
127 * to the session object associated with this event. This method
128 * is a part of HttpSessionListener interface and is called every time
129 * when a new session is created. */
130 public void sessionCreated(HttpSessionEvent se) {
131 servletContext.log("*************** session created");
132 se.getSession().setAttribute(DATA_CONTEXT_KEY, getDomain().createDataContext());
133 }
134
135 /** Does nothing. This method
136 * is a part of HttpSessionListener interface and is called every time
137 * when a session is destroyed. */
138 public void sessionDestroyed(HttpSessionEvent se) {}
139 }