Source for javax.naming.spi.NamingManager

   1: /* NamingManager.java -- Creates contexts and objects
   2:    Copyright (C) 2000, 2001, 2002, 2003, 2004,
   3:    2006 Free Software Foundation, Inc.
   4: 
   5: This file is part of GNU Classpath.
   6: 
   7: GNU Classpath is free software; you can redistribute it and/or modify
   8: it under the terms of the GNU General Public License as published by
   9: the Free Software Foundation; either version 2, or (at your option)
  10: any later version.
  11: 
  12: GNU Classpath is distributed in the hope that it will be useful, but
  13: WITHOUT ANY WARRANTY; without even the implied warranty of
  14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15: General Public License for more details.
  16: 
  17: You should have received a copy of the GNU General Public License
  18: along with GNU Classpath; see the file COPYING.  If not, write to the
  19: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  20: 02110-1301 USA.
  21: 
  22: Linking this library statically or dynamically with other modules is
  23: making a combined work based on this library.  Thus, the terms and
  24: conditions of the GNU General Public License cover the whole
  25: combination.
  26: 
  27: As a special exception, the copyright holders of this library give you
  28: permission to link this library with independent modules to produce an
  29: executable, regardless of the license terms of these independent
  30: modules, and to copy and distribute the resulting executable under
  31: terms of your choice, provided that you also meet, for each linked
  32: independent module, the terms and conditions of the license of that
  33: module.  An independent module is a module which is not derived from
  34: or based on this library.  If you modify this library, you may extend
  35: this exception to your version of the library, but you are not
  36: obligated to do so.  If you do not wish to do so, delete this
  37: exception statement from your version. */
  38: 
  39: 
  40: package javax.naming.spi;
  41: 
  42: import gnu.classpath.VMStackWalker;
  43: 
  44: import java.util.Enumeration;
  45: import java.util.Hashtable;
  46: import java.util.StringTokenizer;
  47: 
  48: import javax.naming.CannotProceedException;
  49: import javax.naming.Context;
  50: import javax.naming.Name;
  51: import javax.naming.NamingException;
  52: import javax.naming.NoInitialContextException;
  53: import javax.naming.RefAddr;
  54: import javax.naming.Reference;
  55: import javax.naming.Referenceable;
  56: import javax.naming.StringRefAddr;
  57: 
  58: /**
  59:  * Contains methods for creating contexts and objects referred to by
  60:  * location information. The location is specified in the scope of the
  61:  * certain naming or directory service. This class only contais static
  62:  * methods and cannot be instantiated.
  63:  */
  64: public class NamingManager
  65: {
  66:   /**
  67:    * The environment property into which getContinuationContext() stores the
  68:    * value of the CannotProceedException parameter. The value of this field
  69:    * is <i>java.naming.spi.CannotProceedException<i>.
  70:    */
  71:   public static final String CPE = "java.naming.spi.CannotProceedException";
  72: 
  73:   private static InitialContextFactoryBuilder icfb;
  74: 
  75:   // Package private so DirectoryManager can access it.
  76:   static ObjectFactoryBuilder ofb;
  77: 
  78:   // This class cannot be instantiated.
  79:   NamingManager ()
  80:   {
  81:   }
  82:   
  83:   /**
  84:    * Checks if the initial context factory builder has been set.
  85:    * 
  86:    * @return true if the builder has been set
  87:    * 
  88:    * @see #setInitialContextFactoryBuilder(InitialContextFactoryBuilder)
  89:    */
  90:   public static boolean hasInitialContextFactoryBuilder ()
  91:   {
  92:     return icfb != null;
  93:   }
  94:   
  95:   /**
  96:    * Creates the initial context. If the initial object factory builder has
  97:    * been set with {@link #setObjectFactoryBuilder(ObjectFactoryBuilder)},
  98:    * the work is delegated to this builder. Otherwise, the method searches
  99:    * for the property Context.INITIAL_CONTEXT_FACTORY first in the passed
 100:    * table and then in the system properties. The value of this property is
 101:    * uses as a class name to install the context factory. The corresponding
 102:    * class must exist, be public and have the public parameterless constructor. 
 103:    * 
 104:    * @param environment the properties, used to create the context.
 105:    * 
 106:    * @return the created context
 107:    * 
 108:    * @throws NoInitialContextException if the initial builder is not set,
 109:    *           the property Context.INITIAL_CONTEXT_FACTORY is missing of the
 110:    *           class, named by this property, cannot be instantiated. 
 111:    * @throws NamingException if throws by the context factory
 112:    */
 113:   public static Context getInitialContext (Hashtable environment)
 114:     throws NamingException
 115:   {
 116:     InitialContextFactory icf = null;
 117:     
 118:     if (icfb != null)
 119:       icf = icfb.createInitialContextFactory(environment);
 120:     else
 121:       {     
 122:     String java_naming_factory_initial = null;
 123:     if (environment != null)
 124:       java_naming_factory_initial
 125:         = (String) environment.get (Context.INITIAL_CONTEXT_FACTORY);
 126:     if (java_naming_factory_initial == null)
 127:       java_naming_factory_initial =
 128:         System.getProperty (Context.INITIAL_CONTEXT_FACTORY);
 129:     if (java_naming_factory_initial == null)
 130:       throw new
 131:         NoInitialContextException ("Can't find property: "
 132:                        + Context.INITIAL_CONTEXT_FACTORY);
 133: 
 134:     try
 135:       {
 136:         icf = (InitialContextFactory)Class.forName
 137:         (java_naming_factory_initial, true,
 138:          Thread.currentThread().getContextClassLoader())
 139:         .newInstance ();
 140:       }
 141:     catch (Exception exception)
 142:       {
 143:         NoInitialContextException e
 144:           = new NoInitialContextException
 145:           ("Can't load InitialContextFactory class: "
 146:            + java_naming_factory_initial);
 147:         e.setRootCause(exception);
 148:         throw e;
 149:       }
 150:       }
 151: 
 152:     return icf.getInitialContext (environment);
 153:   }
 154:   
 155:   /**
 156:    * <p>
 157:    * Creates the URL context for the given URL scheme id.
 158:    * </p>
 159:    * <p>
 160:    * The class name of the factory that creates the context has the naming
 161:    * pattern scheme-idURLContextFactory. For instance, the factory for the "ftp"
 162:    * sheme should be named "ftpURLContextFactory".
 163:    * </p>
 164:    * <p>
 165:    * The Context.URL_PKG_PREFIXES environment property contains the
 166:    * colon-separated list of the possible package prefixes. The package name is
 167:    * constructed concatenating the package prefix with the scheme id. This
 168:    * property is searched in the passed <i>environment</i> parameter and later
 169:    * in the system properties.
 170:    * </p>
 171:    * <p>
 172:    * If the factory class cannot be found in the specified packages, system will
 173:    * try to use the default internal factory for the given scheme.
 174:    * </p>
 175:    * <p>
 176:    * After the factory is instantiated, its method
 177:    * {@link ObjectFactory#getObjectInstance(Object, Name, Context, Hashtable)}
 178:    * is called to create and return the object instance.
 179:    * 
 180:    * @param refInfo passed to the factory
 181:    * @param name passed to the factory
 182:    * @param nameCtx passed to the factory
 183:    * @param scheme the url scheme that must be supported by the given context
 184:    * @param environment the properties for creating the factory and context (may
 185:    *          be null)
 186:    * @return the created context
 187:    * @throws NamingException if thrown by the factory when creating the context.
 188:    */
 189:   static Context getURLContext(Object refInfo, Name name, Context nameCtx,
 190:                                String scheme, Hashtable environment)
 191:       throws NamingException
 192:   {
 193:     // Specified as the default in the docs. Unclear if this is
 194:     // right for us.
 195:     String defaultPrefix = "com.sun.jndi.url";
 196: 
 197:     StringBuffer allPrefixes = new StringBuffer();
 198: 
 199:     String prefixes;
 200:     if (environment != null)
 201:       {
 202:         prefixes = (String) environment.get(Context.URL_PKG_PREFIXES);
 203:         if (prefixes != null)
 204:           allPrefixes.append(prefixes);
 205:       }
 206: 
 207:     prefixes = System.getProperty(Context.URL_PKG_PREFIXES);
 208:     if (prefixes != null)
 209:       {
 210:         if (allPrefixes.length() > 0)
 211:           allPrefixes.append(':');
 212:         allPrefixes.append(prefixes);
 213:       }
 214: 
 215:     if (allPrefixes.length() > 0)
 216:       allPrefixes.append(':');
 217:     allPrefixes.append(defaultPrefix);
 218: 
 219:     scheme = scheme + "." + scheme + "URLContextFactory";
 220: 
 221:     StringTokenizer tokens = new StringTokenizer(allPrefixes.toString(), ":");
 222:     while (tokens.hasMoreTokens())
 223:       {
 224:         String aTry = tokens.nextToken();
 225:         try
 226:           {
 227:             String tryClass = aTry + "." + scheme;
 228:             Class factoryClass = forName(tryClass);
 229:             if (factoryClass != null)
 230:               {
 231:                 ObjectFactory factory = (ObjectFactory) factoryClass.newInstance();
 232:                 Object obj = factory.getObjectInstance(refInfo, name, nameCtx,
 233:                                                        environment);
 234:                 Context ctx = (Context) obj;
 235:                 if (ctx != null)
 236:                   return ctx;
 237:               }
 238:           }
 239:         catch (ClassNotFoundException _1)
 240:           {
 241:             // Ignore it.
 242:           }
 243:         catch (ClassCastException _2)
 244:           {
 245:             // This means that the class we found was not an
 246:             // ObjectFactory or that the factory returned something
 247:             // which was not a Context.
 248:           }
 249:         catch (InstantiationException _3)
 250:           {
 251:             // If we couldn't instantiate the factory we might get
 252:             // this.
 253:           }
 254:         catch (IllegalAccessException _4)
 255:           {
 256:             // Another possibility when instantiating.
 257:           }
 258:         catch (NamingException _5)
 259:           {
 260:             throw _5;
 261:           }
 262:         catch (Exception _6)
 263:           {
 264:             // Anything from getObjectInstance.
 265:           }
 266:       }
 267: 
 268:     return null;
 269:   }
 270:   
 271:   /**
 272:    * Load the class with the given name. This method tries to use the context
 273:    * class loader first. If this fails, it searches for the suitable class
 274:    * loader in the caller stack trace. This method is a central point where all
 275:    * requests to find a class by name are delegated.
 276:    */
 277:   static Class forName(String className)
 278:   {
 279:     try
 280:       {
 281:         return Class.forName(className, true,
 282:                              Thread.currentThread().getContextClassLoader());
 283:       }
 284:     catch (ClassNotFoundException nex)
 285:       {
 286:         /**
 287:          * Returns the first user defined class loader on the call stack, or
 288:          * null when no non-null class loader was found.
 289:          */
 290:         Class[] ctx = VMStackWalker.getClassContext();
 291:         for (int i = 0; i < ctx.length; i++)
 292:           {
 293:             // Since we live in a class loaded by the bootstrap
 294:             // class loader, getClassLoader is safe to call without
 295:             // needing to be wrapped in a privileged action.
 296:             ClassLoader cl = ctx[i].getClassLoader();
 297:             try
 298:               {
 299:                 if (cl != null)
 300:                   return Class.forName(className, true, cl);
 301:               }
 302:             catch (ClassNotFoundException nex2)
 303:               {
 304:                 // Try next.
 305:               }
 306:           }
 307:       }
 308:     return null;
 309:   }  
 310:   
 311:   
 312:   /**
 313:    * <p>
 314:    * Creates the URL context for the given URL scheme id.
 315:    * </p>
 316:    * <p>
 317:    * The class name of the factory that creates the context has the naming
 318:    * pattern scheme-idURLContextFactory. For instance, the factory for the "ftp"
 319:    * sheme should be named "ftpURLContextFactory". The Context.URL_PKG_PREFIXES
 320:    * environment property contains the colon-separated list of the possible
 321:    * package prefixes. The package name is constructed concatenating the package
 322:    * prefix with the scheme id.
 323:    * </p>
 324:    * <p>
 325:    * If the factory class cannot be found in the specified packages, system will
 326:    * try to use the default internal factory for the given scheme.
 327:    * </p>
 328:    * <p>
 329:    * After the factory is instantiated, its method
 330:    * {@link ObjectFactory#getObjectInstance(Object, Name, Context, Hashtable)}
 331:    * is called to create and return the object instance.
 332:    * 
 333:    * @param scheme the url scheme that must be supported by the given context
 334:    * @param environment the properties for creating the factory and context (may
 335:    *          be null)
 336:    * @return the created context
 337:    * @throws NamingException if thrown by the factory when creating the context.
 338:    */
 339:   public static Context getURLContext (String scheme,
 340:                        Hashtable environment) 
 341:        throws NamingException
 342:   {
 343:     return getURLContext (null, null, null, scheme, environment);
 344:   }
 345: 
 346:   /**
 347:    * Sets the initial object factory builder.
 348:    * 
 349:    * @param builder the builder to set
 350:    * 
 351:    * @throws SecurityException if the builder cannot be installed due
 352:    *           security restrictions.
 353:    * @throws NamingException if the builder cannot be installed due other 
 354:    *           reasons
 355:    * @throws IllegalStateException if setting the builder repeatedly
 356:    */
 357:   public static void setObjectFactoryBuilder (ObjectFactoryBuilder builder)
 358:     throws NamingException
 359:   {
 360:     SecurityManager sm = System.getSecurityManager ();
 361:     if (sm != null)
 362:       sm.checkSetFactory ();
 363:     // Once the builder is installed it cannot be replaced.
 364:     if (ofb != null)
 365:       throw new IllegalStateException ("object factory builder already installed");
 366:     if (builder != null)
 367:       ofb = builder;
 368:   }
 369: 
 370:   static StringTokenizer getPlusPath (String property, Hashtable env,
 371:                       Context nameCtx)
 372:     throws NamingException
 373:   {
 374:     String path = (String) env.get (property);
 375:     if (nameCtx == null)
 376:       nameCtx = getInitialContext (env);
 377:     String path2 = (String) nameCtx.getEnvironment ().get (property);
 378:     if (path == null)
 379:       path = path2;
 380:     else if (path2 != null)
 381:       path += ":" + path2;
 382:     return new StringTokenizer (path != null ? path : "", ":");
 383:   }
 384:   
 385:   /**
 386:    * <p>Creates an object for the specified name context, environment and
 387:    * referencing context object.</p>
 388:    * <p>
 389:    * If the builder factory is set by 
 390:    * {@link #setObjectFactoryBuilder(ObjectFactoryBuilder)}, the call is
 391:    * delegated to that factory. Otherwise, the object is created using the
 392:    * following rules:
 393:    * <ul>
 394:    * <li>If the referencing object (refInfo) contains the factory class name,
 395:    *       the object is created by this factory. If the creation fails,
 396:    *       the parameter refInfo is returned as the method return value.</li>
 397:    * <li>If the referencing object has no factory class name, and the addresses
 398:    *       are StringRefAddrs having the address type "URL", the object is
 399:    *       created by the URL context factory. The used factory corresponds the
 400:    *       the naming schema of the each URL. If the attempt to create
 401:    *       the object this way is not successful, the subsequent rule is 
 402:    *       tried.</li>
 403:    * <li>  If the refInfo is not an instance of Reference or Referencable
 404:    *       (for example, null), the object is created by the factories,
 405:    *       specified in the Context.OBJECT_FACTORIES property of the 
 406:    *       environment and the provider resource file, associated with the
 407:    *       nameCtx. The value of this property is the colon separated list
 408:    *       of the possible factories. If none of the factories can be
 409:    *       loaded, the refInfo is returned.            
 410:    * </ul>
 411:    * </p>
 412:    * <p>The object factory must be public and have the public parameterless
 413:    * constructor.</p>
 414:    *  
 415:    * @param refInfo the referencing object, for which the new object must be
 416:    *          created (can be null). If not null, it is usually an instance of
 417:    *          the {@link Reference} or {@link Referenceable}.
 418:    * @param name the name of the object. The name is relative to
 419:    *          the nameCtx naming context. The value of this parameter can be
 420:    *          null if the name is not specified.
 421:    * @param nameCtx the naming context, in which scope the name of the new
 422:    *          object is specified. If this parameter is null, the name is
 423:    *          specified in the scope of the initial context.
 424:    * @param environment contains additional information for creating the object.
 425:    *          This paramter can be null if there is no need to provide any
 426:    *          additional information.
 427:    *        
 428:    * @return  the created object. If the creation fails, in some cases
 429:    *          the parameter refInfo may be returned.
 430:    * 
 431:    * @throws NamingException if the attempt to name the new object has failed
 432:    * @throws Exception if the object factory throws it. The object factory
 433:    *           only throws an exception if it does not want other factories
 434:    *           to be used to create the object.
 435:    */
 436:   public static Object getObjectInstance (Object refInfo,
 437:                       Name name,
 438:                       Context nameCtx,
 439:                       Hashtable environment)
 440:     throws Exception
 441:   {
 442:     ObjectFactory factory = null;
 443: 
 444:     if (ofb != null)
 445:       factory = ofb.createObjectFactory (refInfo, environment);
 446:     else
 447:       {
 448:     // First see if we have a Reference or a Referenceable.  If so
 449:     // we do some special processing.
 450:     Object ref2 = refInfo;
 451:     if (refInfo instanceof Referenceable)
 452:       ref2 = ((Referenceable) refInfo).getReference ();
 453:     if (ref2 instanceof Reference)
 454:       {
 455:         Reference ref = (Reference) ref2;
 456: 
 457:         // If we have a factory class name then we use that.
 458:         String fClass = ref.getFactoryClassName ();
 459:         if (fClass != null)
 460:           {
 461:         // Exceptions here are passed to the caller.
 462:         Class k = Class.forName (fClass,
 463:                      true,
 464:                      Thread.currentThread().getContextClassLoader());
 465:         factory = (ObjectFactory) k.newInstance ();
 466:           }
 467:         else
 468:           {
 469:         // There's no factory class name.  If the address is a
 470:         // StringRefAddr with address type `URL', then we try
 471:         // the URL's context factory.
 472:         Enumeration e = ref.getAll ();
 473:         while (e.hasMoreElements ())
 474:           {
 475:             RefAddr ra = (RefAddr) e.nextElement ();
 476:             if (ra instanceof StringRefAddr
 477:             && "URL".equals (ra.getType ()))
 478:               {
 479:             factory
 480:               = (ObjectFactory) getURLContext (refInfo,
 481:                                name,
 482:                                nameCtx,
 483:                                (String) ra.getContent (),
 484:                                environment);
 485:             Object obj = factory.getObjectInstance (refInfo,
 486:                                 name,
 487:                                 nameCtx,
 488:                                 environment);
 489:             if (obj != null)
 490:               return obj;
 491:               }
 492:           }
 493: 
 494:         // Have to try the next step.
 495:         factory = null;
 496:           }
 497:       }
 498: 
 499:     // Now look at OBJECT_FACTORIES to find the factory.
 500:     if (factory == null)
 501:       {
 502:         StringTokenizer tokens = getPlusPath (Context.OBJECT_FACTORIES,
 503:                           environment, nameCtx);
 504: 
 505:         while (tokens.hasMoreTokens ())
 506:           {
 507:         String klassName = tokens.nextToken ();
 508:         Class k = Class.forName (klassName,
 509:                      true,
 510:                      Thread.currentThread().getContextClassLoader());
 511:         factory = (ObjectFactory) k.newInstance ();
 512:         Object obj = factory.getObjectInstance (refInfo, name,
 513:                             nameCtx, environment);
 514:         if (obj != null)
 515:           return obj;
 516:           }
 517: 
 518:         // Failure.
 519:         return refInfo;
 520:       }
 521:       }
 522: 
 523:     if (factory == null)
 524:       return refInfo;
 525:     Object obj = factory.getObjectInstance (refInfo, name,
 526:                         nameCtx, environment);
 527:     return obj == null ? refInfo : obj;
 528:   }
 529: 
 530:   /**
 531:    * Sets the initial context factory builder.
 532:    * 
 533:    * @param builder the builder to set
 534:    * 
 535:    * @throws SecurityException if the builder cannot be installed due
 536:    *           security restrictions.
 537:    * @throws NamingException if the builder cannot be installed due other 
 538:    *           reasons
 539:    * @throws IllegalStateException if setting the builder repeatedly
 540:    * 
 541:    * @see #hasInitialContextFactoryBuilder()
 542:    */
 543:   public static void setInitialContextFactoryBuilder 
 544:     (InitialContextFactoryBuilder builder)
 545:     throws NamingException
 546:   {
 547:     SecurityManager sm = System.getSecurityManager ();
 548:     if (sm != null)
 549:       sm.checkSetFactory ();
 550:     // Once the builder is installed it cannot be replaced.
 551:     if (icfb != null)
 552:       throw new IllegalStateException ("ctx factory builder already installed");
 553:     if (builder != null)
 554:       icfb = builder;
 555:   }
 556:   
 557:   /**
 558:    * Creates a context in which the context operation must be continued.
 559:    * This method is used by operations on names that span multiple namespaces.
 560:    * 
 561:    * @param cpe the exception that triggered this continuation. This method
 562:    * obtains the environment ({@link CannotProceedException#getEnvironment()}
 563:    * and sets the environment property {@link #CPE} = cpe.
 564:    * 
 565:    * @return a non null context for continuing the operation
 566:    * 
 567:    * @throws NamingException if the naming problems have occured
 568:    */
 569:   public static Context getContinuationContext (CannotProceedException cpe)
 570:     throws NamingException
 571:   {
 572:     Hashtable env = cpe.getEnvironment ();
 573:     if (env != null)
 574:       env.put (CPE, cpe);
 575: 
 576:     // TODO: Check if this implementation matches the API specification
 577:     try
 578:       {
 579:     Object obj = getObjectInstance (cpe.getResolvedObj(),
 580:                     cpe.getAltName (),
 581:                     cpe.getAltNameCtx (), 
 582:                     env);
 583:     if (obj != null)
 584:       return (Context) obj;
 585:       }
 586:     catch (Exception _)
 587:       {
 588:       }
 589: 
 590:     // fix stack trace for re-thrown exception (message confusing otherwise)
 591:     cpe.fillInStackTrace();
 592: 
 593:     throw cpe;
 594:   }
 595:   
 596:   /**
 597:    * Get the object state for binding.
 598:    * 
 599:    * @param obj the object, for that the binding state must be retrieved. Cannot
 600:    *          be null.
 601:    * @param name the name of this object, related to the nameCtx. Can be null if
 602:    *          not specified.
 603:    * @param nameCtx the naming context, to that the object name is related. Can
 604:    *          be null if the name is related to the initial default context.
 605:    * @param environment the properties for creating the object state. Can be
 606:    *          null if no properties are provided.
 607:    * @return the object state for binding, may be null if no changes are
 608:    *         returned by the factory
 609:    * @throws NamingException
 610:    */ 
 611:   public static Object getStateToBind (Object obj, Name name,
 612:                        Context nameCtx, Hashtable environment)
 613:     throws NamingException
 614:   {
 615:     StringTokenizer tokens = getPlusPath (Context.STATE_FACTORIES,
 616:                       environment, nameCtx);
 617:     while (tokens.hasMoreTokens ())
 618:       {
 619:     String klassName = tokens.nextToken ();
 620:     try
 621:       {
 622:         Class k = Class.forName (klassName,
 623:                      true,
 624:                      Thread.currentThread().getContextClassLoader());
 625:         StateFactory factory = (StateFactory) k.newInstance ();
 626:         Object o = factory.getStateToBind (obj, name, nameCtx,
 627:                            environment);
 628:         if (o != null)
 629:           return o;
 630:       }
 631:     catch (ClassNotFoundException _1)
 632:       {
 633:         // Ignore it.
 634:       }
 635:     catch (ClassCastException _2)
 636:       {
 637:         // This means that the class we found was not an
 638:         // ObjectFactory or that the factory returned something
 639:         // which was not a Context.
 640:       }
 641:     catch (InstantiationException _3)
 642:       {
 643:         // If we couldn't instantiate the factory we might get
 644:         // this.
 645:       }
 646:     catch (IllegalAccessException _4)
 647:       {
 648:         // Another possibility when instantiating.
 649:       }
 650:       }
 651: 
 652:     return obj;
 653:   }
 654: }