1 /*
   2  * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.sql.rowset.spi;
  27 
  28 import java.util.logging.*;
  29 import java.util.*;
  30 
  31 import java.sql.*;
  32 import javax.sql.*;
  33 
  34 import java.io.FileInputStream;
  35 import java.io.InputStream;
  36 import java.io.IOException;
  37 import java.io.FileNotFoundException;
  38 import java.security.AccessController;
  39 import java.security.PrivilegedAction;
  40 import java.security.PrivilegedActionException;
  41 import java.security.PrivilegedExceptionAction;
  42 
  43 import javax.naming.*;
  44 import sun.reflect.misc.ReflectUtil;
  45 
  46 /**
  47  * The Service Provider Interface (SPI) mechanism that generates <code>SyncProvider</code>
  48  * instances to be used by disconnected <code>RowSet</code> objects.
  49  * The <code>SyncProvider</code> instances in turn provide the
  50  * <code>javax.sql.RowSetReader</code> object the <code>RowSet</code> object
  51  * needs to populate itself with data and the
  52  * <code>javax.sql.RowSetWriter</code> object it needs to
  53  * propagate changes to its
  54  * data back to the underlying data source.
  55  * <P>
  56  * Because the methods in the <code>SyncFactory</code> class are all static,
  57  * there is only one <code>SyncFactory</code> object
  58  * per Java VM at any one time. This ensures that there is a single source from which a
  59  * <code>RowSet</code> implementation can obtain its <code>SyncProvider</code>
  60  * implementation.
  61  *
  62  * <h3>1.0 Overview</h3>
  63  * The <code>SyncFactory</code> class provides an internal registry of available
  64  * synchronization provider implementations (<code>SyncProvider</code> objects).
  65  * This registry may be queried to determine which
  66  * synchronization providers are available.
  67  * The following line of code gets an enumeration of the providers currently registered.
  68  * <PRE>
  69  *     java.util.Enumeration e = SyncFactory.getRegisteredProviders();
  70  * </PRE>
  71  * All standard <code>RowSet</code> implementations must provide at least two providers:
  72  * <UL>
  73  *  <LI>an optimistic provider for use with a <code>CachedRowSet</code> implementation
  74  *     or an implementation derived from it
  75  *  <LI>an XML provider, which is used for reading and writing XML, such as with
  76  *       <code>WebRowSet</code> objects
  77  * </UL>
  78  * Note that the JDBC RowSet Implementations include the <code>SyncProvider</code>
  79  * implementations <code>RIOptimisticProvider</code> and <code>RIXmlProvider</code>,
  80  * which satisfy this requirement.
  81  * <P>
  82  * The <code>SyncFactory</code> class provides accessor methods to assist
  83  * applications in determining which synchronization providers are currently
  84  * registered with the <code>SyncFactory</code>.
  85  * <p>
  86  * Other methods let <code>RowSet</code> persistence providers be
  87  * registered or de-registered with the factory mechanism. This
  88  * allows additional synchronization provider implementations to be made
  89  * available to <code>RowSet</code> objects at run time.
  90  * <p>
  91  * Applications can apply a degree of filtering to determine the level of
  92  * synchronization that a <code>SyncProvider</code> implementation offers.
  93  * The following criteria determine whether a provider is
  94  * made available to a <code>RowSet</code> object:
  95  * <ol>
  96  * <li>If a particular provider is specified by a <code>RowSet</code> object, and
  97  * the <code>SyncFactory</code> does not contain a reference to this provider,
  98  * a <code>SyncFactoryException</code> is thrown stating that the synchronization
  99  * provider could not be found.
 100  *
 101  * <li>If a <code>RowSet</code> implementation is instantiated with a specified
 102  * provider and the specified provider has been properly registered, the
 103  * requested provider is supplied. Otherwise a <code>SyncFactoryException</code>
 104  * is thrown.
 105  *
 106  * <li>If a <code>RowSet</code> object does not specify a
 107  * <code>SyncProvider</code> implementation and no additional
 108  * <code>SyncProvider</code> implementations are available, the reference
 109  * implementation providers are supplied.
 110  * </ol>
 111  * <h3>2.0 Registering <code>SyncProvider</code> Implementations</h3>
 112  * <p>
 113  * Both vendors and developers can register <code>SyncProvider</code>
 114  * implementations using one of the following mechanisms.
 115  * <ul>
 116  * <LI><B>Using the command line</B><BR>
 117  * The name of the provider is supplied on the command line, which will add
 118  * the provider to the system properties.
 119  * For example:
 120  * <PRE>
 121  *    -Drowset.provider.classname=com.fred.providers.HighAvailabilityProvider
 122  * </PRE>
 123  * <li><b>Using the Standard Properties File</b><BR>
 124  * The reference implementation is targeted
 125  * to ship with J2SE 1.5, which will include an additional resource file
 126  * that may be edited by hand. Here is an example of the properties file
 127  * included in the reference implementation:
 128  * <PRE>
 129  *   #Default JDBC RowSet sync providers listing
 130  *   #
 131  *
 132  *   # Optimistic synchronization provider
 133  *   rowset.provider.classname.0=com.sun.rowset.providers.RIOptimisticProvider
 134  *   rowset.provider.vendor.0=Oracle Corporation
 135  *   rowset.provider.version.0=1.0
 136  *
 137  *   # XML Provider using standard XML schema
 138  *   rowset.provider.classname.1=com.sun.rowset.providers.RIXMLProvider
 139  *   rowset.provider.vendor.1=Oracle Corporation
 140  *   rowset.provider.version.1=1.0
 141  * </PRE>
 142  * The <code>SyncFactory</code> checks this file and registers the
 143  * <code>SyncProvider</code> implementations that it contains. A
 144  * developer or vendor can add other implementations to this file.
 145  * For example, here is a possible addition:
 146  * <PRE>
 147  *     rowset.provider.classname.2=com.fred.providers.HighAvailabilityProvider
 148  *     rowset.provider.vendor.2=Fred, Inc.
 149  *     rowset.provider.version.2=1.0
 150  * </PRE>
 151  *
 152  * <li><b>Using a JNDI Context</b><BR>
 153  * Available providers can be registered on a JNDI
 154  * context, and the <code>SyncFactory</code> will attempt to load
 155  * <code>SyncProvider</code> implementations from that JNDI context.
 156  * For example, the following code fragment registers a provider implementation
 157  * on a JNDI context.  This is something a deployer would normally do. In this
 158  * example, <code>MyProvider</code> is being registered on a CosNaming
 159  * namespace, which is the namespace used by J2EE resources.
 160  * <PRE>
 161  *    import javax.naming.*;
 162  *
 163  *    Hashtable svrEnv = new  Hashtable();
 164  *    srvEnv.put(Context.INITIAL_CONTEXT_FACTORY, "CosNaming");
 165  *
 166  *    Context ctx = new InitialContext(svrEnv);
 167  *    com.fred.providers.MyProvider = new MyProvider();
 168  *    ctx.rebind("providers/MyProvider", syncProvider);
 169  * </PRE>
 170  * </ul>
 171  * Next, an application will register the JNDI context with the
 172  * <code>SyncFactory</code> instance.  This allows the <code>SyncFactory</code>
 173  * to browse within the JNDI context looking for <code>SyncProvider</code>
 174  * implementations.
 175  * <PRE>
 176  *    Hashtable appEnv = new Hashtable();
 177  *    appEnv.put(Context.INITIAL_CONTEXT_FACTORY, "CosNaming");
 178  *    appEnv.put(Context.PROVIDER_URL, "iiop://hostname/providers");
 179  *    Context ctx = new InitialContext(appEnv);
 180  *
 181  *    SyncFactory.registerJNDIContext(ctx);
 182  * </PRE>
 183  * If a <code>RowSet</code> object attempts to obtain a <code>MyProvider</code>
 184  * object, the <code>SyncFactory</code> will try to locate it. First it searches
 185  * for it in the system properties, then it looks in the resource files, and
 186  * finally it checks the JNDI context that has been set. The <code>SyncFactory</code>
 187  * instance verifies that the requested provider is a valid extension of the
 188  * <code>SyncProvider</code> abstract class and then gives it to the
 189  * <code>RowSet</code> object. In the following code fragment, a new
 190  * <code>CachedRowSet</code> object is created and initialized with
 191  * <i>env</i>, which contains the binding to <code>MyProvider</code>.
 192  * <PRE>
 193  *    Hashtable env = new Hashtable();
 194  *    env.put(SyncFactory.ROWSET_SYNC_PROVIDER, "com.fred.providers.MyProvider");
 195  *    CachedRowSet crs = new com.sun.rowset.CachedRowSetImpl(env);
 196  * </PRE>
 197  * Further details on these mechanisms are available in the
 198  * <code>javax.sql.rowset.spi</code> package specification.
 199  *
 200  * @author  Jonathan Bruce
 201  * @see javax.sql.rowset.spi.SyncProvider
 202  * @see javax.sql.rowset.spi.SyncFactoryException
 203  * @since 1.5
 204  */
 205 public class SyncFactory {
 206 
 207     /**
 208      * Creates a new <code>SyncFactory</code> object, which is the singleton
 209      * instance.
 210      * Having a private constructor guarantees that no more than
 211      * one <code>SyncProvider</code> object can exist at a time.
 212      */
 213     private SyncFactory() {
 214     }
 215 
 216     /**
 217      * The standard property-id for a synchronization provider implementation
 218      * name.
 219      */
 220     public static final String ROWSET_SYNC_PROVIDER =
 221             "rowset.provider.classname";
 222     /**
 223      * The standard property-id for a synchronization provider implementation
 224      * vendor name.
 225      */
 226     public static final String ROWSET_SYNC_VENDOR =
 227             "rowset.provider.vendor";
 228     /**
 229      * The standard property-id for a synchronization provider implementation
 230      * version tag.
 231      */
 232     public static final String ROWSET_SYNC_PROVIDER_VERSION =
 233             "rowset.provider.version";
 234     /**
 235      * The standard resource file name.
 236      */
 237     private static String ROWSET_PROPERTIES = "rowset.properties";
 238 
 239     /**
 240      *  Permission required to invoke setJNDIContext and setLogger
 241      */
 242     private static final SQLPermission SET_SYNCFACTORY_PERMISSION =
 243             new SQLPermission("setSyncFactory");
 244     /**
 245      * The initial JNDI context where <code>SyncProvider</code> implementations can
 246      * be stored and from which they can be invoked.
 247      */
 248     private static Context ic;
 249     /**
 250      * The <code>Logger</code> object to be used by the <code>SyncFactory</code>.
 251      */
 252     private static volatile Logger rsLogger;
 253 
 254     /**
 255      * The registry of available <code>SyncProvider</code> implementations.
 256      * See section 2.0 of the class comment for <code>SyncFactory</code> for an
 257      * explanation of how a provider can be added to this registry.
 258      */
 259     private static Hashtable<String, SyncProvider> implementations;
 260 
 261     /**
 262      * Adds the given synchronization provider to the factory register. Guidelines
 263      * are provided in the <code>SyncProvider</code> specification for the
 264      * required naming conventions for <code>SyncProvider</code>
 265      * implementations.
 266      * <p>
 267      * Synchronization providers bound to a JNDI context can be
 268      * registered by binding a SyncProvider instance to a JNDI namespace.
 269      *
 270      * <pre>
 271      * {@code
 272      * SyncProvider p = new MySyncProvider();
 273      * InitialContext ic = new InitialContext();
 274      * ic.bind ("jdbc/rowset/MySyncProvider", p);
 275      * } </pre>
 276      *
 277      * Furthermore, an initial JNDI context should be set with the
 278      * <code>SyncFactory</code> using the <code>setJNDIContext</code> method.
 279      * The <code>SyncFactory</code> leverages this context to search for
 280      * available <code>SyncProvider</code> objects bound to the JNDI
 281      * context and its child nodes.
 282      *
 283      * @param providerID A <code>String</code> object with the unique ID of the
 284      *             synchronization provider being registered
 285      * @throws SyncFactoryException if an attempt is made to supply an empty
 286      *         or null provider name
 287      * @see #setJNDIContext
 288      */
 289     public static synchronized void registerProvider(String providerID)
 290             throws SyncFactoryException {
 291 
 292         ProviderImpl impl = new ProviderImpl();
 293         impl.setClassname(providerID);
 294         initMapIfNecessary();
 295         implementations.put(providerID, impl);
 296 
 297     }
 298 
 299     /**
 300      * Returns the <code>SyncFactory</code> singleton.
 301      *
 302      * @return the <code>SyncFactory</code> instance
 303      */
 304     public static SyncFactory getSyncFactory() {
 305         /*
 306          * Using Initialization on Demand Holder idiom as
 307          * Effective Java 2nd Edition,ITEM 71, indicates it is more performant
 308          * than the Double-Check Locking idiom.
 309          */
 310         return SyncFactoryHolder.factory;
 311     }
 312 
 313     /**
 314      * Removes the designated currently registered synchronization provider from the
 315      * Factory SPI register.
 316      *
 317      * @param providerID The unique-id of the synchronization provider
 318      * @throws SyncFactoryException If an attempt is made to
 319      * unregister a SyncProvider implementation that was not registered.
 320      */
 321     public static synchronized void unregisterProvider(String providerID)
 322             throws SyncFactoryException {
 323         initMapIfNecessary();
 324         if (implementations.containsKey(providerID)) {
 325             implementations.remove(providerID);
 326         }
 327     }
 328     private static String colon = ":";
 329     private static String strFileSep = "/";
 330 
 331     private static synchronized void initMapIfNecessary() throws SyncFactoryException {
 332 
 333         // Local implementation class names and keys from Properties
 334         // file, translate names into Class objects using Class.forName
 335         // and store mappings
 336         final Properties properties = new Properties();
 337 
 338         if (implementations == null) {
 339             implementations = new Hashtable<>();
 340 
 341             try {
 342 
 343                 // check if user is supplying his Synchronisation Provider
 344                 // Implementation if not using Oracle's implementation.
 345                 // properties.load(new FileInputStream(ROWSET_PROPERTIES));
 346 
 347                 // The rowset.properties needs to be in jdk/jre/lib when
 348                 // integrated with jdk.
 349                 // else it should be picked from -D option from command line.
 350 
 351                 // -Drowset.properties will add to standard properties. Similar
 352                 // keys will over-write
 353 
 354                 /*
 355                  * Dependent on application
 356                  */
 357                 String strRowsetProperties;
 358                 try {
 359                     strRowsetProperties = AccessController.doPrivileged(new PrivilegedAction<String>() {
 360                         public String run() {
 361                             return System.getProperty("rowset.properties");
 362                         }
 363                     }, null, new PropertyPermission("rowset.properties", "read"));
 364                 } catch (Exception ex) {
 365                     System.out.println("errorget rowset.properties: " + ex);
 366                     strRowsetProperties = null;
 367                 };
 368 
 369                 if (strRowsetProperties != null) {
 370                     // Load user's implementation of SyncProvider
 371                     // here. -Drowset.properties=/abc/def/pqr.txt
 372                     ROWSET_PROPERTIES = strRowsetProperties;
 373                     try (FileInputStream fis = new FileInputStream(ROWSET_PROPERTIES)) {
 374                         properties.load(fis);
 375                     }
 376                     parseProperties(properties);
 377                 }
 378 
 379                 /*
 380                  * Always available
 381                  */
 382                 ROWSET_PROPERTIES = "javax" + strFileSep + "sql" +
 383                         strFileSep + "rowset" + strFileSep +
 384                         "rowset.properties";
 385 
 386                 try {
 387                     AccessController.doPrivileged((PrivilegedExceptionAction<Void>) () -> {
 388                         InputStream in = SyncFactory.class.getModule().getResourceAsStream(ROWSET_PROPERTIES);
 389                         if (in == null) {
 390                             throw new SyncFactoryException("Resource " + ROWSET_PROPERTIES + " not found");
 391                         }
 392                         try (in) {
 393                             properties.load(in);
 394                         }
 395                         return null;
 396                     });
 397                 } catch (PrivilegedActionException ex) {
 398                     Throwable e = ex.getException();
 399                     if (e instanceof SyncFactoryException) {
 400                       throw (SyncFactoryException) e;
 401                     } else {
 402                         SyncFactoryException sfe = new SyncFactoryException();
 403                         sfe.initCause(ex.getException());
 404                         throw sfe;
 405                     }
 406                 }
 407 
 408                 parseProperties(properties);
 409 
 410             // removed else, has properties should sum together
 411 
 412             } catch (FileNotFoundException e) {
 413                 throw new SyncFactoryException("Cannot locate properties file: " + e);
 414             } catch (IOException e) {
 415                 throw new SyncFactoryException("IOException: " + e);
 416             }
 417 
 418             /*
 419              * Now deal with -Drowset.provider.classname
 420              * load additional properties from -D command line
 421              */
 422             properties.clear();
 423             String providerImpls;
 424             try {
 425                 providerImpls = AccessController.doPrivileged(new PrivilegedAction<String>() {
 426                     public String run() {
 427                         return System.getProperty(ROWSET_SYNC_PROVIDER);
 428                     }
 429                 }, null, new PropertyPermission(ROWSET_SYNC_PROVIDER, "read"));
 430             } catch (Exception ex) {
 431                 providerImpls = null;
 432             }
 433 
 434             if (providerImpls != null) {
 435                 int i = 0;
 436                 if (providerImpls.indexOf(colon) > 0) {
 437                     StringTokenizer tokenizer = new StringTokenizer(providerImpls, colon);
 438                     while (tokenizer.hasMoreElements()) {
 439                         properties.put(ROWSET_SYNC_PROVIDER + "." + i, tokenizer.nextToken());
 440                         i++;
 441                     }
 442                 } else {
 443                     properties.put(ROWSET_SYNC_PROVIDER, providerImpls);
 444                 }
 445                 parseProperties(properties);
 446             }
 447         }
 448     }
 449 
 450     /**
 451      * The internal debug switch.
 452      */
 453     private static boolean debug = false;
 454     /**
 455      * Internal registry count for the number of providers contained in the
 456      * registry.
 457      */
 458     private static int providerImplIndex = 0;
 459 
 460     /**
 461      * Internal handler for all standard property parsing. Parses standard
 462      * ROWSET properties and stores lazy references into the internal registry.
 463      */
 464     private static void parseProperties(Properties p) {
 465 
 466         ProviderImpl impl = null;
 467         String key = null;
 468         String[] propertyNames = null;
 469 
 470         for (Enumeration<?> e = p.propertyNames(); e.hasMoreElements();) {
 471 
 472             String str = (String) e.nextElement();
 473 
 474             int w = str.length();
 475 
 476             if (str.startsWith(SyncFactory.ROWSET_SYNC_PROVIDER)) {
 477 
 478                 impl = new ProviderImpl();
 479                 impl.setIndex(providerImplIndex++);
 480 
 481                 if (w == (SyncFactory.ROWSET_SYNC_PROVIDER).length()) {
 482                     // no property index has been set.
 483                     propertyNames = getPropertyNames(false);
 484                 } else {
 485                     // property index has been set.
 486                     propertyNames = getPropertyNames(true, str.substring(w - 1));
 487                 }
 488 
 489                 key = p.getProperty(propertyNames[0]);
 490                 impl.setClassname(key);
 491                 impl.setVendor(p.getProperty(propertyNames[1]));
 492                 impl.setVersion(p.getProperty(propertyNames[2]));
 493                 implementations.put(key, impl);
 494             }
 495         }
 496     }
 497 
 498     /**
 499      * Used by the parseProperties methods to disassemble each property tuple.
 500      */
 501     private static String[] getPropertyNames(boolean append) {
 502         return getPropertyNames(append, null);
 503     }
 504 
 505     /**
 506      * Disassembles each property and its associated value. Also handles
 507      * overloaded property names that contain indexes.
 508      */
 509     private static String[] getPropertyNames(boolean append,
 510             String propertyIndex) {
 511         String dot = ".";
 512         String[] propertyNames =
 513                 new String[]{SyncFactory.ROWSET_SYNC_PROVIDER,
 514             SyncFactory.ROWSET_SYNC_VENDOR,
 515             SyncFactory.ROWSET_SYNC_PROVIDER_VERSION};
 516         if (append) {
 517             for (int i = 0; i < propertyNames.length; i++) {
 518                 propertyNames[i] = propertyNames[i] +
 519                         dot +
 520                         propertyIndex;
 521             }
 522             return propertyNames;
 523         } else {
 524             return propertyNames;
 525         }
 526     }
 527 
 528     /**
 529      * Internal debug method that outputs the registry contents.
 530      */
 531     private static void showImpl(ProviderImpl impl) {
 532         System.out.println("Provider implementation:");
 533         System.out.println("Classname: " + impl.getClassname());
 534         System.out.println("Vendor: " + impl.getVendor());
 535         System.out.println("Version: " + impl.getVersion());
 536         System.out.println("Impl index: " + impl.getIndex());
 537     }
 538 
 539     /**
 540      * Returns the <code>SyncProvider</code> instance identified by <i>providerID</i>.
 541      *
 542      * @param providerID the unique identifier of the provider
 543      * @return a <code>SyncProvider</code> implementation
 544      * @throws SyncFactoryException If the SyncProvider cannot be found,
 545      * the providerID is {@code null}, or
 546      * some error was encountered when trying to invoke this provider.
 547      */
 548     public static SyncProvider getInstance(String providerID)
 549             throws SyncFactoryException {
 550 
 551         if(providerID == null) {
 552             throw new SyncFactoryException("The providerID cannot be null");
 553         }
 554 
 555         initMapIfNecessary(); // populate HashTable
 556         initJNDIContext();    // check JNDI context for any additional bindings
 557 
 558         ProviderImpl impl = (ProviderImpl) implementations.get(providerID);
 559 
 560         if (impl == null) {
 561             // Requested SyncProvider is unavailable. Return default provider.
 562             return new com.sun.rowset.providers.RIOptimisticProvider();
 563         }
 564 
 565         try {
 566             ReflectUtil.checkPackageAccess(providerID);
 567         } catch (java.security.AccessControlException e) {
 568             SyncFactoryException sfe = new SyncFactoryException();
 569             sfe.initCause(e);
 570             throw sfe;
 571         }
 572 
 573         // Attempt to invoke classname from registered SyncProvider list
 574         Class<?> c = null;
 575         try {
 576             ClassLoader cl = Thread.currentThread().getContextClassLoader();
 577 
 578             /**
 579              * The SyncProvider implementation of the user will be in
 580              * the classpath. We need to find the ClassLoader which loads
 581              * this SyncFactory and try to load the SyncProvider class from
 582              * there.
 583              **/
 584             c = Class.forName(providerID, true, cl);
 585             @SuppressWarnings("deprecation")
 586             Object result =  c.newInstance();
 587             return (SyncProvider)result;
 588 
 589         } catch (IllegalAccessException | InstantiationException | ClassNotFoundException e) {
 590             throw new SyncFactoryException("IllegalAccessException: " + e.getMessage());
 591         }
 592     }
 593 
 594     /**
 595      * Returns an Enumeration of currently registered synchronization
 596      * providers.  A <code>RowSet</code> implementation may use any provider in
 597      * the enumeration as its <code>SyncProvider</code> object.
 598      * <p>
 599      * At a minimum, the reference synchronization provider allowing
 600      * RowSet content data to be stored using a JDBC driver should be
 601      * possible.
 602      *
 603      * @return Enumeration  A enumeration of available synchronization
 604      * providers that are registered with this Factory
 605      * @throws SyncFactoryException If an error occurs obtaining the registered
 606      * providers
 607      */
 608     public static Enumeration<SyncProvider> getRegisteredProviders()
 609             throws SyncFactoryException {
 610         initMapIfNecessary();
 611         // return a collection of classnames
 612         // of type SyncProvider
 613         return implementations.elements();
 614     }
 615 
 616     /**
 617      * Sets the logging object to be used by the <code>SyncProvider</code>
 618      * implementation provided by the <code>SyncFactory</code>. All
 619      * <code>SyncProvider</code> implementations can log their events to
 620      * this object and the application can retrieve a handle to this
 621      * object using the <code>getLogger</code> method.
 622      * <p>
 623      * This method checks to see that there is an {@code SQLPermission}
 624      * object  which grants the permission {@code setSyncFactory}
 625      * before allowing the method to succeed.  If a
 626      * {@code SecurityManager} exists and its
 627      * {@code checkPermission} method denies calling {@code setLogger},
 628      * this method throws a
 629      * {@code java.lang.SecurityException}.
 630      *
 631      * @param logger A Logger object instance
 632      * @throws java.lang.SecurityException if a security manager exists and its
 633      *   {@code checkPermission} method denies calling {@code setLogger}
 634      * @throws NullPointerException if the logger is null
 635      * @see SecurityManager#checkPermission
 636      */
 637     public static void setLogger(Logger logger) {
 638 
 639         SecurityManager sec = System.getSecurityManager();
 640         if (sec != null) {
 641             sec.checkPermission(SET_SYNCFACTORY_PERMISSION);
 642         }
 643 
 644         if(logger == null){
 645             throw new NullPointerException("You must provide a Logger");
 646         }
 647         rsLogger = logger;
 648     }
 649 
 650     /**
 651      * Sets the logging object that is used by <code>SyncProvider</code>
 652      * implementations provided by the <code>SyncFactory</code> SPI. All
 653      * <code>SyncProvider</code> implementations can log their events
 654      * to this object and the application can retrieve a handle to this
 655      * object using the <code>getLogger</code> method.
 656      * <p>
 657      * This method checks to see that there is an {@code SQLPermission}
 658      * object  which grants the permission {@code setSyncFactory}
 659      * before allowing the method to succeed.  If a
 660      * {@code SecurityManager} exists and its
 661      * {@code checkPermission} method denies calling {@code setLogger},
 662      * this method throws a
 663      * {@code java.lang.SecurityException}.
 664      *
 665      * @param logger a Logger object instance
 666      * @param level a Level object instance indicating the degree of logging
 667      * required
 668      * @throws java.lang.SecurityException if a security manager exists and its
 669      *   {@code checkPermission} method denies calling {@code setLogger}
 670      * @throws NullPointerException if the logger is null
 671      * @see SecurityManager#checkPermission
 672      * @see LoggingPermission
 673      */
 674     public static void setLogger(Logger logger, Level level) {
 675         // singleton
 676         SecurityManager sec = System.getSecurityManager();
 677         if (sec != null) {
 678             sec.checkPermission(SET_SYNCFACTORY_PERMISSION);
 679         }
 680 
 681         if(logger == null){
 682             throw new NullPointerException("You must provide a Logger");
 683         }
 684         logger.setLevel(level);
 685         rsLogger = logger;
 686     }
 687 
 688     /**
 689      * Returns the logging object for applications to retrieve
 690      * synchronization events posted by SyncProvider implementations.
 691      * @return The {@code Logger} that has been specified for use by
 692      * {@code SyncProvider} implementations
 693      * @throws SyncFactoryException if no logging object has been set.
 694      */
 695     public static Logger getLogger() throws SyncFactoryException {
 696 
 697         Logger result = rsLogger;
 698         // only one logger per session
 699         if (result == null) {
 700             throw new SyncFactoryException("(SyncFactory) : No logger has been set");
 701         }
 702 
 703         return result;
 704     }
 705 
 706     /**
 707      * Sets the initial JNDI context from which SyncProvider implementations
 708      * can be retrieved from a JNDI namespace
 709      * <p>
 710      *  This method checks to see that there is an {@code SQLPermission}
 711      * object  which grants the permission {@code setSyncFactory}
 712      * before allowing the method to succeed.  If a
 713      * {@code SecurityManager} exists and its
 714      * {@code checkPermission} method denies calling {@code setJNDIContext},
 715      * this method throws a
 716      * {@code java.lang.SecurityException}.
 717      *
 718      * @param ctx a valid JNDI context
 719      * @throws SyncFactoryException if the supplied JNDI context is null
 720      * @throws java.lang.SecurityException if a security manager exists and its
 721      *  {@code checkPermission} method denies calling {@code setJNDIContext}
 722      * @see SecurityManager#checkPermission
 723      */
 724     public static synchronized void setJNDIContext(javax.naming.Context ctx)
 725             throws SyncFactoryException {
 726         SecurityManager sec = System.getSecurityManager();
 727         if (sec != null) {
 728             sec.checkPermission(SET_SYNCFACTORY_PERMISSION);
 729         }
 730         if (ctx == null) {
 731             throw new SyncFactoryException("Invalid JNDI context supplied");
 732         }
 733         ic = ctx;
 734     }
 735 
 736     /**
 737      * Controls JNDI context initialization.
 738      *
 739      * @throws SyncFactoryException if an error occurs parsing the JNDI context
 740      */
 741     private static synchronized void initJNDIContext() throws SyncFactoryException {
 742 
 743         if ((ic != null) && (lazyJNDICtxRefresh == false)) {
 744             try {
 745                 parseProperties(parseJNDIContext());
 746                 lazyJNDICtxRefresh = true; // touch JNDI namespace once.
 747             } catch (NamingException e) {
 748                 e.printStackTrace();
 749                 throw new SyncFactoryException("SPI: NamingException: " + e.getExplanation());
 750             } catch (Exception e) {
 751                 e.printStackTrace();
 752                 throw new SyncFactoryException("SPI: Exception: " + e.getMessage());
 753             }
 754         }
 755     }
 756     /**
 757      * Internal switch indicating whether the JNDI namespace should be re-read.
 758      */
 759     private static boolean lazyJNDICtxRefresh = false;
 760 
 761     /**
 762      * Parses the set JNDI Context and passes bindings to the enumerateBindings
 763      * method when complete.
 764      */
 765     private static Properties parseJNDIContext() throws NamingException {
 766 
 767         NamingEnumeration<?> bindings = ic.listBindings("");
 768         Properties properties = new Properties();
 769 
 770         // Hunt one level below context for available SyncProvider objects
 771         enumerateBindings(bindings, properties);
 772 
 773         return properties;
 774     }
 775 
 776     /**
 777      * Scans each binding on JNDI context and determines if any binding is an
 778      * instance of SyncProvider, if so, add this to the registry and continue to
 779      * scan the current context using a re-entrant call to this method until all
 780      * bindings have been enumerated.
 781      */
 782     private static void enumerateBindings(NamingEnumeration<?> bindings,
 783             Properties properties) throws NamingException {
 784 
 785         boolean syncProviderObj = false; // move to parameters ?
 786 
 787         try {
 788             Binding bd = null;
 789             Object elementObj = null;
 790             String element = null;
 791             while (bindings.hasMore()) {
 792                 bd = (Binding) bindings.next();
 793                 element = bd.getName();
 794                 elementObj = bd.getObject();
 795 
 796                 if (!(ic.lookup(element) instanceof Context)) {
 797                     // skip directories/sub-contexts
 798                     if (ic.lookup(element) instanceof SyncProvider) {
 799                         syncProviderObj = true;
 800                     }
 801                 }
 802 
 803                 if (syncProviderObj) {
 804                     SyncProvider sync = (SyncProvider) elementObj;
 805                     properties.put(SyncFactory.ROWSET_SYNC_PROVIDER,
 806                             sync.getProviderID());
 807                     syncProviderObj = false; // reset
 808                 }
 809 
 810             }
 811         } catch (javax.naming.NotContextException e) {
 812             bindings.next();
 813             // Re-entrant call into method
 814             enumerateBindings(bindings, properties);
 815         }
 816     }
 817 
 818     /**
 819      * Lazy initialization Holder class used by {@code getSyncFactory}
 820      */
 821     private static class SyncFactoryHolder {
 822         static final SyncFactory factory = new SyncFactory();
 823     }
 824 }
 825 
 826 /**
 827  * Internal class that defines the lazy reference construct for each registered
 828  * SyncProvider implementation.
 829  */
 830 class ProviderImpl extends SyncProvider {
 831 
 832     private String className = null;
 833     private String vendorName = null;
 834     private String ver = null;
 835     private int index;
 836 
 837     public void setClassname(String classname) {
 838         className = classname;
 839     }
 840 
 841     public String getClassname() {
 842         return className;
 843     }
 844 
 845     public void setVendor(String vendor) {
 846         vendorName = vendor;
 847     }
 848 
 849     public String getVendor() {
 850         return vendorName;
 851     }
 852 
 853     public void setVersion(String providerVer) {
 854         ver = providerVer;
 855     }
 856 
 857     public String getVersion() {
 858         return ver;
 859     }
 860 
 861     public void setIndex(int i) {
 862         index = i;
 863     }
 864 
 865     public int getIndex() {
 866         return index;
 867     }
 868 
 869     public int getDataSourceLock() throws SyncProviderException {
 870 
 871         int dsLock = 0;
 872         try {
 873             dsLock = SyncFactory.getInstance(className).getDataSourceLock();
 874         } catch (SyncFactoryException sfEx) {
 875 
 876             throw new SyncProviderException(sfEx.getMessage());
 877         }
 878 
 879         return dsLock;
 880     }
 881 
 882     public int getProviderGrade() {
 883 
 884         int grade = 0;
 885 
 886         try {
 887             grade = SyncFactory.getInstance(className).getProviderGrade();
 888         } catch (SyncFactoryException sfEx) {
 889             //
 890         }
 891 
 892         return grade;
 893     }
 894 
 895     public String getProviderID() {
 896         return className;
 897     }
 898 
 899     /*
 900     public javax.sql.RowSetInternal getRowSetInternal() {
 901     try
 902     {
 903     return SyncFactory.getInstance(className).getRowSetInternal();
 904     } catch(SyncFactoryException sfEx) {
 905     //
 906     }
 907     }
 908      */
 909     public javax.sql.RowSetReader getRowSetReader() {
 910 
 911         RowSetReader rsReader = null;
 912 
 913         try {
 914             rsReader = SyncFactory.getInstance(className).getRowSetReader();
 915         } catch (SyncFactoryException sfEx) {
 916             //
 917         }
 918 
 919         return rsReader;
 920 
 921     }
 922 
 923     public javax.sql.RowSetWriter getRowSetWriter() {
 924 
 925         RowSetWriter rsWriter = null;
 926         try {
 927             rsWriter = SyncFactory.getInstance(className).getRowSetWriter();
 928         } catch (SyncFactoryException sfEx) {
 929             //
 930         }
 931 
 932         return rsWriter;
 933     }
 934 
 935     public void setDataSourceLock(int param)
 936             throws SyncProviderException {
 937 
 938         try {
 939             SyncFactory.getInstance(className).setDataSourceLock(param);
 940         } catch (SyncFactoryException sfEx) {
 941 
 942             throw new SyncProviderException(sfEx.getMessage());
 943         }
 944     }
 945 
 946     public int supportsUpdatableView() {
 947 
 948         int view = 0;
 949 
 950         try {
 951             view = SyncFactory.getInstance(className).supportsUpdatableView();
 952         } catch (SyncFactoryException sfEx) {
 953             //
 954         }
 955 
 956         return view;
 957     }
 958 }