AbstractBoot


1   /* ========================================================================
2    * JCommon : a free general purpose class library for the Java(tm) platform
3    * ========================================================================
4    *
5    * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6    *
7    * Project Info:  http://www.jfree.org/jcommon/index.html
8    *
9    * This library is free software; you can redistribute it and/or modify it
10   * under the terms of the GNU Lesser General Public License as published by
11   * the Free Software Foundation; either version 2.1 of the License, or
12   * (at your option) any later version.
13   *
14   * This library is distributed in the hope that it will be useful, but
15   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17   * License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this library; if not, write to the Free Software
21   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
22   * USA.
23   *
24   * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25   * in the United States and other countries.]
26   *
27   * -----------------
28   * AbstractBoot.java
29   * -----------------
30   * (C)opyright 2004, 2005, by Thomas Morgner and Contributors.
31   *
32   * Original Author:  Thomas Morgner;
33   * Contributor(s):   David Gilbert (for Object Refinery Limited);
34   *
35   * $Id: AbstractBoot.java,v 1.19 2006/12/11 12:02:27 taqua Exp $
36   *
37   * Changes
38   * -------
39   * 07-Jun-2004 : Added source headers (DG);
40   * 18-Aug-2005 : Added casts to suppress compiler warnings, as suggested in
41   *               patch 1260622 (DG);
42   *
43   */
44  
45  package org.jfree.base;
46  
47  import java.io.IOException  ;
48  import java.io.InputStream  ;
49  import java.lang.reflect.Method  ;
50  import java.net.URL  ;
51  import java.util.ArrayList  ;
52  import java.util.Enumeration  ;
53  
54  import org.jfree.base.config.HierarchicalConfiguration;
55  import org.jfree.base.config.PropertyFileConfiguration;
56  import org.jfree.base.config.SystemPropertyConfiguration;
57  import org.jfree.base.modules.PackageManager;
58  import org.jfree.base.modules.SubSystem;
59  import org.jfree.util.Configuration;
60  import org.jfree.util.ExtendedConfiguration;
61  import org.jfree.util.ExtendedConfigurationWrapper;
62  import org.jfree.util.Log;
63  import org.jfree.util.ObjectUtilities;
64  
65  /**
66   * The common base for all Boot classes.
67   * <p>
68   * This initializes the subsystem and all dependent subsystems.
69   * Implementors of this class have to provide a public static
70   * getInstance() method which returns a singleton instance of the
71   * booter implementation.
72   * <p>
73   * Further creation of Boot object should be prevented using
74   * protected or private constructors in that class, or proper
75   * initialzation cannot be guaranteed.
76   *
77   * @author Thomas Morgner
78   */
79  public abstract class AbstractBoot implements SubSystem {
80  
81      /** The configuration wrapper around the plain configuration. */
82      private ExtendedConfigurationWrapper extWrapper;
83  
84      /** A packageManager instance of the package manager. */
85      private PackageManager packageManager;
86  
87      /** Global configuration. */
88      private Configuration globalConfig;
89  
90      /** A flag indicating whether the booting is currenly in progress. */
91      private boolean bootInProgress;
92  
93      /** A flag indicating whether the booting is complete. */
94      private boolean bootDone;
95  
96      /**
97       * Default constructor.
98       */
99      protected AbstractBoot() {
100     }
101 
102     /**
103      * Returns the packageManager instance of the package manager.
104      *
105      * @return The package manager.
106      */
107     public synchronized PackageManager getPackageManager() {
108         if (this.packageManager == null) {
109             this.packageManager = PackageManager.createInstance(this);
110         }
111         return this.packageManager;
112     }
113 
114     /**
115      * Returns the global configuration.
116      *
117      * @return The global configuration.
118      */
119     public synchronized Configuration getGlobalConfig() {
120         if (this.globalConfig == null) {
121             this.globalConfig = loadConfiguration();
122         }
123         return this.globalConfig;
124     }
125 
126     /**
127      * Checks, whether the booting is in progress.
128      *
129      * @return true, if the booting is in progress, false otherwise.
130      */
131     public final synchronized boolean isBootInProgress() {
132         return this.bootInProgress;
133     }
134 
135     /**
136      * Checks, whether the booting is complete.
137      *
138      * @return true, if the booting is complete, false otherwise.
139      */
140     public final synchronized boolean isBootDone() {
141         return this.bootDone;
142     }
143 
144     /**
145      * Loads the configuration. This will be called exactly once.
146      *
147      * @return The configuration.
148      */
149     protected abstract Configuration loadConfiguration();
150 
151     /**
152      * Starts the boot process.
153      */
154     public final void start() {
155 
156         synchronized (this) {
157             if (isBootDone()) {
158                 return;
159             }
160             while (isBootInProgress()) {
161               try {
162                 wait();
163               }
164               catch (InterruptedException   e) {
165                 // ignore ..
166               }
167             }
168             if (isBootDone()) {
169                 return;
170             }
171             this.bootInProgress = true;
172         }
173 
174         // boot dependent libraries ...
175         final BootableProjectInfo info = getProjectInfo();
176         if (info != null) {
177             final BootableProjectInfo[] childs = info.getDependencies();
178             for (int i = 0; i < childs.length; i++) {
179                 final AbstractBoot boot = loadBooter(childs[i].getBootClass());
180                 if (boot != null) {
181                     // but we're waiting until the booting is complete ...
182                     synchronized(boot) {
183                       boot.start();
184                       while (boot.isBootDone() == false) {
185                         try {
186                           boot.wait();
187                         }
188                         catch (InterruptedException   e) {
189                           // ignore it ..
190                         }
191                       }
192                     }
193                 }
194             }
195         }
196 
197         performBoot();
198         if (info != null)
199         {
200           Log.info (info.getName() + " " + info.getVersion() + " started.");
201         }
202         else
203         {
204           Log.info (getClass() + " started.");
205         }
206 
207         synchronized (this) {
208             this.bootInProgress = false;
209             this.bootDone = true;
210             notifyAll();
211         }
212     }
213 
214     /**
215      * Performs the boot.
216      */
217     protected abstract void performBoot();
218 
219     /**
220      * Returns the project info.
221      *
222      * @return The project info.
223      */
224     protected abstract BootableProjectInfo getProjectInfo();
225 
226     /**
227      * Loads the specified booter implementation.
228      *
229      * @param classname  the class name.
230      *
231      * @return The boot class.
232      */
233     protected AbstractBoot loadBooter(final String   classname) {
234         if (classname == null) {
235             return null;
236         }
237         try {
238             final Class   c = ObjectUtilities.getClassLoader(
239                     getClass()).loadClass(classname);
240             final Method   m = c.getMethod("getInstance", (Class  []) null);
241             return (AbstractBoot) m.invoke(null, (Object  []) null);
242         }
243         catch (Exception   e) {
244             Log.info ("Unable to boot dependent class: " + classname);
245             return null;
246         }
247     }
248 
249     /**
250      * Creates a default configuration setup, which loads its settings from
251      * the static configuration (defaults provided by the developers of the
252      * library) and the user configuration (settings provided by the deployer).
253      * The deployer's settings override the developer's settings.
254      *
255      * If the parameter <code>addSysProps</code> is set to true, the system
256      * properties will be added as third configuration layer. The system
257      * properties configuration allows to override all other settings.
258      *
259      * @param staticConfig the resource name of the developers configuration
260      * @param userConfig the resource name of the deployers configuration
261      * @param addSysProps a flag defining whether to include the system
262      *                    properties into the configuration.
263      * @return the configured Configuration instance.
264      */
265     protected Configuration createDefaultHierarchicalConfiguration
266         (final String   staticConfig, final String   userConfig,
267                 final boolean addSysProps)
268     {
269         final HierarchicalConfiguration globalConfig
270             = new HierarchicalConfiguration();
271 
272         if (staticConfig != null) {
273           final PropertyFileConfiguration rootProperty
274               = new PropertyFileConfiguration();
275           rootProperty.load(staticConfig);
276           globalConfig.insertConfiguration(rootProperty);
277           globalConfig.insertConfiguration(
278                   getPackageManager().getPackageConfiguration());
279         }
280         if (userConfig != null) {
281           String   userConfigStripped;
282           if (userConfig.startsWith("/")) {
283             userConfigStripped = userConfig.substring(1);
284           }
285           else {
286             userConfigStripped = userConfig;
287           }
288           try {
289             final Enumeration   userConfigs = ObjectUtilities.getClassLoader
290                             (getClass()).getResources(userConfigStripped);
291             final ArrayList   configs = new ArrayList  ();
292             while (userConfigs.hasMoreElements()) {
293               final URL   url = (URL  ) userConfigs.nextElement();
294               try {
295                 final PropertyFileConfiguration baseProperty =
296                         new PropertyFileConfiguration();
297                 final InputStream   in = url.openStream();
298                 baseProperty.load(in);
299                 in.close();
300                 configs.add(baseProperty);
301               }
302               catch(IOException   ioe) {
303                 Log.warn ("Failed to load the user configuration at " + url, ioe);
304               }
305             }
306 
307             for (int i = configs.size() - 1; i >= 0; i--) {
308               final PropertyFileConfiguration baseProperty =
309                       (PropertyFileConfiguration) configs.get(i);
310               globalConfig.insertConfiguration(baseProperty);
311             }
312           }
313           catch (IOException   e) {
314             Log.warn ("Failed to lookup the user configurations.", e);
315           }
316         }
317         final SystemPropertyConfiguration systemConfig
318             = new SystemPropertyConfiguration();
319         globalConfig.insertConfiguration(systemConfig);
320         return globalConfig;
321     }
322 
323     /**
324      * Returns the global configuration as extended configuration.
325      *
326      * @return the extended configuration.
327      */
328     public synchronized ExtendedConfiguration getExtendedConfig ()
329     {
330       if (extWrapper == null) {
331           extWrapper = new ExtendedConfigurationWrapper(getGlobalConfig());
332       }
333       return extWrapper;
334     }
335 }
336
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