2009/05/20 - Apache Shale has been retired.

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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to you under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.shale.dialog.scxml;
19  
20  import java.net.URL;
21  import java.util.Enumeration;
22  import java.util.HashMap;
23  import java.util.Map;
24  
25  import javax.faces.FacesException;
26  import javax.servlet.ServletContextEvent;
27  import javax.servlet.ServletContextListener;
28  
29  import org.apache.commons.beanutils.PropertyUtils;
30  import org.apache.commons.logging.Log;
31  import org.apache.commons.logging.LogFactory;
32  import org.apache.shale.dialog.scxml.config.ConfigurationParser;
33  
34  /***
35   * <p>ServletContextListener that loads dialog configuration resources
36   * at application startup, and cleans up the libraries we depend on at
37   * application shutdown.</p>
38   *
39   * $Id: SCXMLLifecycleListener.java 476713 2006-11-19 05:10:57Z rahul $
40   *
41   * @since 1.0.4
42   */
43  public class SCXMLLifecycleListener implements ServletContextListener {
44  
45  
46      // -------------------------------------------------------- Static Variables
47  
48  
49      /***
50       * <p>The default configuration resource we will process (if present),
51       * even if it is not explicitly configured.</p>
52       */
53      private static final String DEFAULT_CONFIGURATION_RESOURCE =
54              "/WEB-INF/dialog-config.xml";
55  
56  
57      /***
58       * <p>Resource name for dialog configuration resource(s) embedded in
59       * JAR files inside the application.</p>
60       */
61      private static final String EMBEDDED_CONFIGURATION_RESOURCE =
62              "META-INF/dialog-config.xml";
63  
64  
65      // ------------------------------------------------------ Instance Variables
66  
67  
68      /***
69       * <p>The <code>Log</code> instance we will use for this listener.</p>
70       */
71      private Log log = LogFactory.getLog(SCXMLLifecycleListener.class);
72  
73  
74      // ------------------------------------------ ServletContextListener Methods
75  
76  
77      /***
78       * <p>Process the application shutdown event, cleanup resources.</p>
79       *
80       * @param event Shutdown event to be processed
81       */
82      public void contextDestroyed(ServletContextEvent event) {
83  
84          if (log.isInfoEnabled()) {
85              log.info("Finalizing Dialog SCXML Implementation");
86          }
87  
88          // Clean up our cache of dialog configuration information
89          event.getServletContext().removeAttribute(Globals.DIALOGS);
90  
91          // Clean up dependency libraries we have used
92          PropertyUtils.clearDescriptors();
93          LogFactory.release(Thread.currentThread().getContextClassLoader());
94          log = null;
95  
96      }
97  
98  
99      /***
100      * <p>Process the application startup event, parse dialog
101      * configurations.</p>
102      *
103      * @param event Startup event to be processed
104      */
105     public void contextInitialized(ServletContextEvent event) {
106 
107         if (log.isInfoEnabled()) {
108             log.info("Initializing Dialog SCXML Implementation");
109         }
110 
111         // Set up to parse our specified configuration resources and cache the results
112         boolean didDefault = false;
113         ConfigurationParser parser = new ConfigurationParser();
114         parser.setDialogs(new HashMap());
115 
116         // Parse implicitly specified resources embedded in JAR files
117         ClassLoader loader = Thread.currentThread().getContextClassLoader();
118         if (loader == null) {
119             loader = this.getClass().getClassLoader();
120         }
121         try {
122             Enumeration resources = loader.getResources(EMBEDDED_CONFIGURATION_RESOURCE);
123             while (resources.hasMoreElements()) {
124                 URL resource = (URL) resources.nextElement();
125                 if (log.isDebugEnabled()) {
126                     log.debug("Parsing configuration resource '"
127                             + resource + "'");
128                 }
129                 parser.setResource(resource);
130                 parser.parse();
131             }
132         } catch (RuntimeException e) {
133             throw e;
134         } catch (Exception e) {
135             throw new FacesException(e);
136         }
137 
138         // Parse explicitly specified resources
139         String resources =
140           event.getServletContext().getInitParameter(Globals.CONFIGURATION);
141         if (resources == null) {
142             resources = "";
143         }
144         int comma = 0;
145         String path = null;
146         try {
147             while (true) {
148                 comma = resources.indexOf(",");
149                 if (comma < 0) {
150                     path = resources.trim();
151                     resources = "";
152                 } else {
153                     path = resources.substring(0, comma).trim();
154                     resources = resources.substring(comma + 1);
155                 }
156                 if (path.length() < 1) {
157                     break;
158                 }
159                 URL resource = event.getServletContext().getResource(path);
160                 if (log.isDebugEnabled()) {
161                     log.debug("Parsing configuration resource '"
162                             + resource + "'");
163                 }
164                 parser.setResource(resource);
165                 parser.parse();
166                 if (DEFAULT_CONFIGURATION_RESOURCE.equals(path)) {
167                     didDefault = true;
168                 }
169             }
170         } catch (RuntimeException e) {
171             throw e;
172         } catch (Exception e) {
173             throw new FacesException(e);
174         }
175 
176         // Parse the default configuration resource if it exists and has not
177         // already been parsed
178         if (!didDefault) {
179             try {
180                 URL resource =
181                   event.getServletContext().getResource(DEFAULT_CONFIGURATION_RESOURCE);
182                 if (resource != null) {
183                     if (log.isDebugEnabled()) {
184                         log.debug("Parsing configuration resource '"
185                                 + resource + "'");
186                     }
187                     parser.setResource(resource);
188                     parser.parse();
189                 }
190             } catch (RuntimeException e) {
191                 throw e;
192             } catch (Exception e) {
193                 throw new FacesException(e);
194             }
195         }
196 
197         // Cache the results in application scope
198         Map dialogs = parser.getDialogs();
199 
200         if (dialogs.size() == 0) {
201             if (log.isWarnEnabled()) {
202                 log.warn("No dialog configuration information present.  No default configuration found at: "
203                     + DEFAULT_CONFIGURATION_RESOURCE + ".  No embedded configuration found at: "
204                     + EMBEDDED_CONFIGURATION_RESOURCE);
205             }
206         }
207         event.getServletContext().setAttribute(Globals.DIALOGS, dialogs);
208 
209     }
210 
211 
212 }