Source for org.jfree.base.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 1.18 2006/06/20 18:43:15 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:             this.bootInProgress = true;
 169:         }
 170: 
 171:         // boot dependent libraries ...
 172:         final BootableProjectInfo info = getProjectInfo();
 173:         if (info != null) {
 174:             final BootableProjectInfo[] childs = info.getDependencies();
 175:             for (int i = 0; i < childs.length; i++) {
 176:                 final AbstractBoot boot = loadBooter(childs[i].getBootClass());
 177:                 if (boot != null) {
 178:                     // but we're waiting until the booting is complete ...
 179:                     synchronized(boot) {
 180:                       boot.start();
 181:                       while (boot.isBootDone() == false) {
 182:                         try {
 183:                           boot.wait();
 184:                         }
 185:                         catch (InterruptedException e) {
 186:                           // ignore it ..
 187:                         }
 188:                       }
 189:                     }
 190:                 }
 191:             }
 192:         }
 193: 
 194:         performBoot();
 195:         if (info != null)
 196:         {
 197:           Log.info (info.getName() + " " + info.getVersion() + " started.");
 198:         }
 199:         else
 200:         {
 201:           Log.info (getClass() + " started.");
 202:         }
 203: 
 204:         synchronized (this) {
 205:             this.bootInProgress = false;
 206:             this.bootDone = true;
 207:             notifyAll();
 208:         }
 209:     }
 210: 
 211:     /**
 212:      * Performs the boot.
 213:      */
 214:     protected abstract void performBoot();
 215: 
 216:     /**
 217:      * Returns the project info.
 218:      *
 219:      * @return The project info.
 220:      */
 221:     protected abstract BootableProjectInfo getProjectInfo();
 222: 
 223:     /**
 224:      * Loads the specified booter implementation.
 225:      * 
 226:      * @param classname  the class name.
 227:      * 
 228:      * @return The boot class.
 229:      */
 230:     protected AbstractBoot loadBooter(final String classname) {
 231:         if (classname == null) {
 232:             return null;
 233:         }
 234:         try {
 235:             final Class c = ObjectUtilities.getClassLoader(
 236:                     getClass()).loadClass(classname);
 237:             final Method m = c.getMethod("getInstance", (Class[]) null);
 238:             return (AbstractBoot) m.invoke(null, (Object[]) null);
 239:         }
 240:         catch (Exception e) {
 241:             Log.info ("Unable to boot dependent class: " + classname);
 242:             return null;
 243:         }
 244:     }
 245: 
 246:     /**
 247:      * Creates a default configuration setup, which loads its settings from
 248:      * the static configuration (defaults provided by the developers of the
 249:      * library) and the user configuration (settings provided by the deployer).
 250:      * The deployer's settings override the developer's settings.
 251:      *
 252:      * If the parameter <code>addSysProps</code> is set to true, the system
 253:      * properties will be added as third configuration layer. The system 
 254:      * properties configuration allows to override all other settings.
 255:      *
 256:      * @param staticConfig the resource name of the developers configuration
 257:      * @param userConfig the resource name of the deployers configuration
 258:      * @param addSysProps a flag defining whether to include the system 
 259:      *                    properties into the configuration.
 260:      * @return the configured Configuration instance.
 261:      */
 262:     protected Configuration createDefaultHierarchicalConfiguration
 263:         (final String staticConfig, final String userConfig, 
 264:                 final boolean addSysProps)
 265:     {
 266:         final HierarchicalConfiguration globalConfig 
 267:             = new HierarchicalConfiguration();
 268: 
 269:         if (staticConfig != null) {
 270:           final PropertyFileConfiguration rootProperty 
 271:               = new PropertyFileConfiguration();
 272:           rootProperty.load(staticConfig);
 273:           globalConfig.insertConfiguration(rootProperty);
 274:           globalConfig.insertConfiguration(
 275:                   getPackageManager().getPackageConfiguration());
 276:         }
 277:         if (userConfig != null) {
 278:           String userConfigStripped;
 279:           if (userConfig.startsWith("/")) {
 280:             userConfigStripped = userConfig.substring(1);
 281:           }
 282:           else {
 283:             userConfigStripped = userConfig;
 284:           }
 285:           try {
 286:             final Enumeration userConfigs = ObjectUtilities.getClassLoader
 287:                             (getClass()).getResources(userConfigStripped);
 288:             final ArrayList configs = new ArrayList();
 289:             while (userConfigs.hasMoreElements()) {
 290:               final URL url = (URL) userConfigs.nextElement();
 291:               try {
 292:                 final PropertyFileConfiguration baseProperty =
 293:                         new PropertyFileConfiguration();
 294:                 final InputStream in = url.openStream();
 295:                 baseProperty.load(in);
 296:                 in.close();
 297:                 configs.add(baseProperty);
 298:               }
 299:               catch(IOException ioe) {
 300:                 Log.warn ("Failed to load the user configuration at " + url, ioe);
 301:               }
 302:             }
 303: 
 304:             for (int i = configs.size() - 1; i >= 0; i--) {
 305:               final PropertyFileConfiguration baseProperty =
 306:                       (PropertyFileConfiguration) configs.get(i);
 307:               globalConfig.insertConfiguration(baseProperty);
 308:             }
 309:           }
 310:           catch (IOException e) {
 311:             Log.warn ("Failed to lookup the user configurations.", e);
 312:           }
 313:         }
 314:         final SystemPropertyConfiguration systemConfig 
 315:             = new SystemPropertyConfiguration();
 316:         globalConfig.insertConfiguration(systemConfig);
 317:         return globalConfig;
 318:     }
 319: 
 320:     /**
 321:      * Returns the global configuration as extended configuration.
 322:      *
 323:      * @return the extended configuration.
 324:      */
 325:     public synchronized ExtendedConfiguration getExtendedConfig ()
 326:     {
 327:       if (extWrapper == null) {
 328:           extWrapper = new ExtendedConfigurationWrapper(getGlobalConfig());
 329:       }
 330:       return extWrapper;
 331:     }
 332: }