JivanFactory


1   /*
2    * Enhydra Java Application Server Project
3    *
4    * The contents of this file are subject to the Enhydra Public License
5    * Version 1.1 (the "License"); you may not use this file except in
6    * compliance with the License. You may obtain a copy of the License on
7    * the Enhydra web site ( http://www.enhydra.org/ ).
8    *
9    * Software distributed under the License is distributed on an "AS IS"
10   * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
11   * the License for the specific terms governing rights and limitations
12   * under the License.
13   *
14   * The Developer of the Enhydra Application Server is Together Austria.
15   * All Rights Reserved.
16   *
17   */
18  package org.enhydra.util.jivan;
19  
20  import java.io.File  ;
21  import java.net.URL  ;
22  import java.util.HashMap  ;
23  
24  import org.jivan.apache.xerces.xni.parser.XMLInputSource;
25  import org.jivan.html.document.DocumentFactory;
26  import org.jivan.html.document.DocumentManager;
27  
28  import com.lutris.logging.LogChannel;
29  import com.lutris.logging.Logger;
30  
31  /**
32   * <p>Title: JivanFactory</p>
33   * <p>Description: JivanFactory extends the capabilities of DocumentFactory
34   * class which is originaly supplied by Jivan project. The enhacements are the
35   * possibilites of logging and autoreloading. To invoke autoreloading, in the
36   * application configuration file, the parameter 'Server.Jivan.AutoReload'
37   * should be set to 'true'. Autoreloading parameter force Jivan DocumentFactory
38   * object to read neededy resource again from its source. Note that
39   * autoreloading slows down the performance, and it should be used in testing
40   * purpose. The default value for autoreloading is false.</p>
41   * <p>Copyright: Copyright (c) 2004</p>
42   * <p>Company: Together</p>
43   * @author Vladimir Radisic
44   * @version 1.0
45   */
46  public class JivanFactory extends DocumentFactory {
47  
48    /**
49     * Indicates autoreloading status (true = on, false = off)
50     */
51    private boolean isReload = false;
52  
53    /**
54     * Logging object
55     */
56    private LogChannel logChan;
57  
58    /**
59     * Storage for resource timestamps. The timestamps is used only in autoreload
60     * mode of Jivanfactory work.
61     */
62    private HashMap   resourceTimestamps = null;
63  
64    /**
65     * Constructs JivanFactory with autoreloading indicator, and given Log4j
66     * logging object. This constructor initialise DocumentManager singleton
67     * object if it is not initialised yet.
68     * @param reload autoreloading status indicator (true = on, false = off).
69     * @param logChan logging object
70     */
71    public JivanFactory(boolean reload, LogChannel logChan) {
72      super();
73      this.isReload = reload;
74      this.logChan = logChan;
75      if(reload)
76        this.resourceTimestamps = new HashMap  ();
77  
78      logChan.write(Logger.DEBUG,"JivanFactory is initialised with AutoReload status: " + reload);
79    }
80  
81    /**
82     * Returns logging object which can be used in applications.
83     * @return logging object
84     */
85      public LogChannel getLogger() {
86          return this.logChan;
87      }
88  
89  
90    /**
91     * Overrides DocumentFactory method in order to implement autoreloading
92     * possibility. It retrieves a DocumentManager for the specific 'resourceId'.
93     * Also, if DocumentManager for the corresponding 'resourceId' does not
94     * exists, it reads given XMLInputSource object and creates DocumentManager.<BR>
95     * <BR>
96     * Other docManFor() methods also call this method. docManFor() with single
97     * argument of String type, calls this method with self created XMLInputSource
98     * object by using its 'systemId' argument, which represents the location of
99     * the resource.<BR>
100    * <BR>
101    * For example the systemId can look like:<BR>
102    * <BR>
103    * file:///C:/projects/testjivan/Welcome.html<BR>
104    * <BR>
105    * @param resourceId unique resource identifier which is used as key for
106    * retrieving corresponding DocumentManager.
107    * @param inp XMLInputSource object which is taken as resource in case when
108    * there is no corresponding DocumentManager for given 'resourceId'.
109    * @return DocumentManager which corresponds to given 'resourceId'.
110    */
111   public DocumentManager docManFor(String   resourceId, XMLInputSource inp) {
112     this.logChan.write(Logger.DEBUG, "-------------------------------------------------------");
113     this.logChan.write(Logger.DEBUG, "resourceId:                    " + resourceId);
114     this.logChan.write(Logger.DEBUG, "XMLInputSource - BaseSystemId: " + inp.getBaseSystemId());
115     this.logChan.write(Logger.DEBUG, "XMLInputSource - Encoding:     " + inp.getEncoding());
116     this.logChan.write(Logger.DEBUG, "XMLInputSource - PublicId:     " + inp.getPublicId());
117     this.logChan.write(Logger.DEBUG, "XMLInputSource - SystemId:     " + inp.getSystemId());
118     resourceId = resourceId.intern();
119     synchronized (resourceId) {
120       if (isReload) {
121 // Object will be removed from HashMaps only if its timestamp is larger than
122 // timestamp for particular resource
123         if (reloadChecking(resourceId, inp)) {
124           super.mapMasterDoc.remove(resourceId);
125           super.mapSysemtId2Thread.remove(resourceId);
126         }
127 
128       }
129     }
130     return super.docManFor(resourceId, inp);
131   }
132 
133 
134   /**
135    * Checks is the resource autoreloading necessery or not. Checking is
136    * performed according to stored resource timestamp.
137    * @param resourceId resourceId unique resource identification
138    * @param inp XMLInputSource object which corresponds to given 'resourceId'.
139    * @return true if stored timestamp is older 'then' resource timestamp, or
140    * 'false' otherwise.
141    */
142   private boolean reloadChecking(String   resourceId, XMLInputSource inp) {
143 
144     if(inp.getCharacterStream() != null)
145       return true;
146     else if(inp.getByteStream() != null)
147       return true;
148 
149     String   systemId = inp.getSystemId();
150     if (systemId != null) {
151       try {
152         // try with URL if systemId is something like: file:///C:/projects/Welcome.html
153         URL   url = new URL  (systemId);
154         File   fResource = new File  (url.getFile());
155         if (fResource.exists())
156           return timestampCheck(resourceId, fResource);
157         else {
158           // try withFile if systemId is something like: C:/projects/Welcome.html
159           fResource = new File  (systemId);
160           if (fResource.exists())
161             return timestampCheck(resourceId, fResource);
162           else
163             return true;
164         }
165       }
166       catch (Exception   ex) {
167         return true;
168       }
169     }
170     else
171       return true;
172 
173   }
174 
175   /**
176    * Check the timestamp for given File resource. If corresponding timestamp
177    * does not exist it will be added to timestamp storage for later use.
178    * @param resourceId unique resource identification
179    * @param f file resource
180    * @return true if stored timestamp is older 'then' resource timestamp, or
181    * 'false' otherwise.
182    */
183   private boolean timestampCheck(String   resourceId, File   f) {
184     Long   oldTime = (Long  )this.resourceTimestamps.get(resourceId);
185     if (oldTime == null) {
186       resourceTimestamps.put(resourceId, new Long  (f.lastModified()));
187       return true;
188     }
189     else if (oldTime.longValue() < f.lastModified()) {
190       resourceTimestamps.put(resourceId, new Long  (f.lastModified()));
191       return true;
192     }
193     else
194       return false;
195 
196   }
197 
198 }
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