src/java.sql.rowset/share/classes/javax/sql/rowset/spi/SyncFactory.java
changeset 47216 71c04702a3d5
parent 37782 ad8fe7507ecc
child 54106 9a90236ab64c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.sql.rowset/share/classes/javax/sql/rowset/spi/SyncFactory.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,958 @@
+/*
+ * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package javax.sql.rowset.spi;
+
+import java.util.logging.*;
+import java.util.*;
+
+import java.sql.*;
+import javax.sql.*;
+
+import java.io.FileInputStream;
+import java.io.InputStream;
+import java.io.IOException;
+import java.io.FileNotFoundException;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+
+import javax.naming.*;
+import sun.reflect.misc.ReflectUtil;
+
+/**
+ * The Service Provider Interface (SPI) mechanism that generates <code>SyncProvider</code>
+ * instances to be used by disconnected <code>RowSet</code> objects.
+ * The <code>SyncProvider</code> instances in turn provide the
+ * <code>javax.sql.RowSetReader</code> object the <code>RowSet</code> object
+ * needs to populate itself with data and the
+ * <code>javax.sql.RowSetWriter</code> object it needs to
+ * propagate changes to its
+ * data back to the underlying data source.
+ * <P>
+ * Because the methods in the <code>SyncFactory</code> class are all static,
+ * there is only one <code>SyncFactory</code> object
+ * per Java VM at any one time. This ensures that there is a single source from which a
+ * <code>RowSet</code> implementation can obtain its <code>SyncProvider</code>
+ * implementation.
+ *
+ * <h3>1.0 Overview</h3>
+ * The <code>SyncFactory</code> class provides an internal registry of available
+ * synchronization provider implementations (<code>SyncProvider</code> objects).
+ * This registry may be queried to determine which
+ * synchronization providers are available.
+ * The following line of code gets an enumeration of the providers currently registered.
+ * <PRE>
+ *     java.util.Enumeration e = SyncFactory.getRegisteredProviders();
+ * </PRE>
+ * All standard <code>RowSet</code> implementations must provide at least two providers:
+ * <UL>
+ *  <LI>an optimistic provider for use with a <code>CachedRowSet</code> implementation
+ *     or an implementation derived from it
+ *  <LI>an XML provider, which is used for reading and writing XML, such as with
+ *       <code>WebRowSet</code> objects
+ * </UL>
+ * Note that the JDBC RowSet Implementations include the <code>SyncProvider</code>
+ * implementations <code>RIOptimisticProvider</code> and <code>RIXmlProvider</code>,
+ * which satisfy this requirement.
+ * <P>
+ * The <code>SyncFactory</code> class provides accessor methods to assist
+ * applications in determining which synchronization providers are currently
+ * registered with the <code>SyncFactory</code>.
+ * <p>
+ * Other methods let <code>RowSet</code> persistence providers be
+ * registered or de-registered with the factory mechanism. This
+ * allows additional synchronization provider implementations to be made
+ * available to <code>RowSet</code> objects at run time.
+ * <p>
+ * Applications can apply a degree of filtering to determine the level of
+ * synchronization that a <code>SyncProvider</code> implementation offers.
+ * The following criteria determine whether a provider is
+ * made available to a <code>RowSet</code> object:
+ * <ol>
+ * <li>If a particular provider is specified by a <code>RowSet</code> object, and
+ * the <code>SyncFactory</code> does not contain a reference to this provider,
+ * a <code>SyncFactoryException</code> is thrown stating that the synchronization
+ * provider could not be found.
+ *
+ * <li>If a <code>RowSet</code> implementation is instantiated with a specified
+ * provider and the specified provider has been properly registered, the
+ * requested provider is supplied. Otherwise a <code>SyncFactoryException</code>
+ * is thrown.
+ *
+ * <li>If a <code>RowSet</code> object does not specify a
+ * <code>SyncProvider</code> implementation and no additional
+ * <code>SyncProvider</code> implementations are available, the reference
+ * implementation providers are supplied.
+ * </ol>
+ * <h3>2.0 Registering <code>SyncProvider</code> Implementations</h3>
+ * <p>
+ * Both vendors and developers can register <code>SyncProvider</code>
+ * implementations using one of the following mechanisms.
+ * <ul>
+ * <LI><B>Using the command line</B><BR>
+ * The name of the provider is supplied on the command line, which will add
+ * the provider to the system properties.
+ * For example:
+ * <PRE>
+ *    -Drowset.provider.classname=com.fred.providers.HighAvailabilityProvider
+ * </PRE>
+ * <li><b>Using the Standard Properties File</b><BR>
+ * The reference implementation is targeted
+ * to ship with J2SE 1.5, which will include an additional resource file
+ * that may be edited by hand. Here is an example of the properties file
+ * included in the reference implementation:
+ * <PRE>
+ *   #Default JDBC RowSet sync providers listing
+ *   #
+ *
+ *   # Optimistic synchronization provider
+ *   rowset.provider.classname.0=com.sun.rowset.providers.RIOptimisticProvider
+ *   rowset.provider.vendor.0=Oracle Corporation
+ *   rowset.provider.version.0=1.0
+ *
+ *   # XML Provider using standard XML schema
+ *   rowset.provider.classname.1=com.sun.rowset.providers.RIXMLProvider
+ *   rowset.provider.vendor.1=Oracle Corporation
+ *   rowset.provider.version.1=1.0
+ * </PRE>
+ * The <code>SyncFactory</code> checks this file and registers the
+ * <code>SyncProvider</code> implementations that it contains. A
+ * developer or vendor can add other implementations to this file.
+ * For example, here is a possible addition:
+ * <PRE>
+ *     rowset.provider.classname.2=com.fred.providers.HighAvailabilityProvider
+ *     rowset.provider.vendor.2=Fred, Inc.
+ *     rowset.provider.version.2=1.0
+ * </PRE>
+ *
+ * <li><b>Using a JNDI Context</b><BR>
+ * Available providers can be registered on a JNDI
+ * context, and the <code>SyncFactory</code> will attempt to load
+ * <code>SyncProvider</code> implementations from that JNDI context.
+ * For example, the following code fragment registers a provider implementation
+ * on a JNDI context.  This is something a deployer would normally do. In this
+ * example, <code>MyProvider</code> is being registered on a CosNaming
+ * namespace, which is the namespace used by J2EE resources.
+ * <PRE>
+ *    import javax.naming.*;
+ *
+ *    Hashtable svrEnv = new  Hashtable();
+ *    srvEnv.put(Context.INITIAL_CONTEXT_FACTORY, "CosNaming");
+ *
+ *    Context ctx = new InitialContext(svrEnv);
+ *    com.fred.providers.MyProvider = new MyProvider();
+ *    ctx.rebind("providers/MyProvider", syncProvider);
+ * </PRE>
+ * </ul>
+ * Next, an application will register the JNDI context with the
+ * <code>SyncFactory</code> instance.  This allows the <code>SyncFactory</code>
+ * to browse within the JNDI context looking for <code>SyncProvider</code>
+ * implementations.
+ * <PRE>
+ *    Hashtable appEnv = new Hashtable();
+ *    appEnv.put(Context.INITIAL_CONTEXT_FACTORY, "CosNaming");
+ *    appEnv.put(Context.PROVIDER_URL, "iiop://hostname/providers");
+ *    Context ctx = new InitialContext(appEnv);
+ *
+ *    SyncFactory.registerJNDIContext(ctx);
+ * </PRE>
+ * If a <code>RowSet</code> object attempts to obtain a <code>MyProvider</code>
+ * object, the <code>SyncFactory</code> will try to locate it. First it searches
+ * for it in the system properties, then it looks in the resource files, and
+ * finally it checks the JNDI context that has been set. The <code>SyncFactory</code>
+ * instance verifies that the requested provider is a valid extension of the
+ * <code>SyncProvider</code> abstract class and then gives it to the
+ * <code>RowSet</code> object. In the following code fragment, a new
+ * <code>CachedRowSet</code> object is created and initialized with
+ * <i>env</i>, which contains the binding to <code>MyProvider</code>.
+ * <PRE>
+ *    Hashtable env = new Hashtable();
+ *    env.put(SyncFactory.ROWSET_SYNC_PROVIDER, "com.fred.providers.MyProvider");
+ *    CachedRowSet crs = new com.sun.rowset.CachedRowSetImpl(env);
+ * </PRE>
+ * Further details on these mechanisms are available in the
+ * <code>javax.sql.rowset.spi</code> package specification.
+ *
+ * @author  Jonathan Bruce
+ * @see javax.sql.rowset.spi.SyncProvider
+ * @see javax.sql.rowset.spi.SyncFactoryException
+ * @since 1.5
+ */
+public class SyncFactory {
+
+    /**
+     * Creates a new <code>SyncFactory</code> object, which is the singleton
+     * instance.
+     * Having a private constructor guarantees that no more than
+     * one <code>SyncProvider</code> object can exist at a time.
+     */
+    private SyncFactory() {
+    }
+
+    /**
+     * The standard property-id for a synchronization provider implementation
+     * name.
+     */
+    public static final String ROWSET_SYNC_PROVIDER =
+            "rowset.provider.classname";
+    /**
+     * The standard property-id for a synchronization provider implementation
+     * vendor name.
+     */
+    public static final String ROWSET_SYNC_VENDOR =
+            "rowset.provider.vendor";
+    /**
+     * The standard property-id for a synchronization provider implementation
+     * version tag.
+     */
+    public static final String ROWSET_SYNC_PROVIDER_VERSION =
+            "rowset.provider.version";
+    /**
+     * The standard resource file name.
+     */
+    private static String ROWSET_PROPERTIES = "rowset.properties";
+
+    /**
+     *  Permission required to invoke setJNDIContext and setLogger
+     */
+    private static final SQLPermission SET_SYNCFACTORY_PERMISSION =
+            new SQLPermission("setSyncFactory");
+    /**
+     * The initial JNDI context where <code>SyncProvider</code> implementations can
+     * be stored and from which they can be invoked.
+     */
+    private static Context ic;
+    /**
+     * The <code>Logger</code> object to be used by the <code>SyncFactory</code>.
+     */
+    private static volatile Logger rsLogger;
+
+    /**
+     * The registry of available <code>SyncProvider</code> implementations.
+     * See section 2.0 of the class comment for <code>SyncFactory</code> for an
+     * explanation of how a provider can be added to this registry.
+     */
+    private static Hashtable<String, SyncProvider> implementations;
+
+    /**
+     * Adds the given synchronization provider to the factory register. Guidelines
+     * are provided in the <code>SyncProvider</code> specification for the
+     * required naming conventions for <code>SyncProvider</code>
+     * implementations.
+     * <p>
+     * Synchronization providers bound to a JNDI context can be
+     * registered by binding a SyncProvider instance to a JNDI namespace.
+     *
+     * <pre>
+     * {@code
+     * SyncProvider p = new MySyncProvider();
+     * InitialContext ic = new InitialContext();
+     * ic.bind ("jdbc/rowset/MySyncProvider", p);
+     * } </pre>
+     *
+     * Furthermore, an initial JNDI context should be set with the
+     * <code>SyncFactory</code> using the <code>setJNDIContext</code> method.
+     * The <code>SyncFactory</code> leverages this context to search for
+     * available <code>SyncProvider</code> objects bound to the JNDI
+     * context and its child nodes.
+     *
+     * @param providerID A <code>String</code> object with the unique ID of the
+     *             synchronization provider being registered
+     * @throws SyncFactoryException if an attempt is made to supply an empty
+     *         or null provider name
+     * @see #setJNDIContext
+     */
+    public static synchronized void registerProvider(String providerID)
+            throws SyncFactoryException {
+
+        ProviderImpl impl = new ProviderImpl();
+        impl.setClassname(providerID);
+        initMapIfNecessary();
+        implementations.put(providerID, impl);
+
+    }
+
+    /**
+     * Returns the <code>SyncFactory</code> singleton.
+     *
+     * @return the <code>SyncFactory</code> instance
+     */
+    public static SyncFactory getSyncFactory() {
+        /*
+         * Using Initialization on Demand Holder idiom as
+         * Effective Java 2nd Edition,ITEM 71, indicates it is more performant
+         * than the Double-Check Locking idiom.
+         */
+        return SyncFactoryHolder.factory;
+    }
+
+    /**
+     * Removes the designated currently registered synchronization provider from the
+     * Factory SPI register.
+     *
+     * @param providerID The unique-id of the synchronization provider
+     * @throws SyncFactoryException If an attempt is made to
+     * unregister a SyncProvider implementation that was not registered.
+     */
+    public static synchronized void unregisterProvider(String providerID)
+            throws SyncFactoryException {
+        initMapIfNecessary();
+        if (implementations.containsKey(providerID)) {
+            implementations.remove(providerID);
+        }
+    }
+    private static String colon = ":";
+    private static String strFileSep = "/";
+
+    private static synchronized void initMapIfNecessary() throws SyncFactoryException {
+
+        // Local implementation class names and keys from Properties
+        // file, translate names into Class objects using Class.forName
+        // and store mappings
+        final Properties properties = new Properties();
+
+        if (implementations == null) {
+            implementations = new Hashtable<>();
+
+            try {
+
+                // check if user is supplying his Synchronisation Provider
+                // Implementation if not using Oracle's implementation.
+                // properties.load(new FileInputStream(ROWSET_PROPERTIES));
+
+                // The rowset.properties needs to be in jdk/jre/lib when
+                // integrated with jdk.
+                // else it should be picked from -D option from command line.
+
+                // -Drowset.properties will add to standard properties. Similar
+                // keys will over-write
+
+                /*
+                 * Dependent on application
+                 */
+                String strRowsetProperties;
+                try {
+                    strRowsetProperties = AccessController.doPrivileged(new PrivilegedAction<String>() {
+                        public String run() {
+                            return System.getProperty("rowset.properties");
+                        }
+                    }, null, new PropertyPermission("rowset.properties", "read"));
+                } catch (Exception ex) {
+                    System.out.println("errorget rowset.properties: " + ex);
+                    strRowsetProperties = null;
+                };
+
+                if (strRowsetProperties != null) {
+                    // Load user's implementation of SyncProvider
+                    // here. -Drowset.properties=/abc/def/pqr.txt
+                    ROWSET_PROPERTIES = strRowsetProperties;
+                    try (FileInputStream fis = new FileInputStream(ROWSET_PROPERTIES)) {
+                        properties.load(fis);
+                    }
+                    parseProperties(properties);
+                }
+
+                /*
+                 * Always available
+                 */
+                ROWSET_PROPERTIES = "javax" + strFileSep + "sql" +
+                        strFileSep + "rowset" + strFileSep +
+                        "rowset.properties";
+
+                try {
+                    AccessController.doPrivileged((PrivilegedExceptionAction<Void>) () -> {
+                        InputStream in = SyncFactory.class.getModule().getResourceAsStream(ROWSET_PROPERTIES);
+                        if (in == null) {
+                            throw new SyncFactoryException("Resource " + ROWSET_PROPERTIES + " not found");
+                        }
+                        try (in) {
+                            properties.load(in);
+                        }
+                        return null;
+                    });
+                } catch (PrivilegedActionException ex) {
+                    Throwable e = ex.getException();
+                    if (e instanceof SyncFactoryException) {
+                      throw (SyncFactoryException) e;
+                    } else {
+                        SyncFactoryException sfe = new SyncFactoryException();
+                        sfe.initCause(ex.getException());
+                        throw sfe;
+                    }
+                }
+
+                parseProperties(properties);
+
+            // removed else, has properties should sum together
+
+            } catch (FileNotFoundException e) {
+                throw new SyncFactoryException("Cannot locate properties file: " + e);
+            } catch (IOException e) {
+                throw new SyncFactoryException("IOException: " + e);
+            }
+
+            /*
+             * Now deal with -Drowset.provider.classname
+             * load additional properties from -D command line
+             */
+            properties.clear();
+            String providerImpls;
+            try {
+                providerImpls = AccessController.doPrivileged(new PrivilegedAction<String>() {
+                    public String run() {
+                        return System.getProperty(ROWSET_SYNC_PROVIDER);
+                    }
+                }, null, new PropertyPermission(ROWSET_SYNC_PROVIDER, "read"));
+            } catch (Exception ex) {
+                providerImpls = null;
+            }
+
+            if (providerImpls != null) {
+                int i = 0;
+                if (providerImpls.indexOf(colon) > 0) {
+                    StringTokenizer tokenizer = new StringTokenizer(providerImpls, colon);
+                    while (tokenizer.hasMoreElements()) {
+                        properties.put(ROWSET_SYNC_PROVIDER + "." + i, tokenizer.nextToken());
+                        i++;
+                    }
+                } else {
+                    properties.put(ROWSET_SYNC_PROVIDER, providerImpls);
+                }
+                parseProperties(properties);
+            }
+        }
+    }
+
+    /**
+     * The internal debug switch.
+     */
+    private static boolean debug = false;
+    /**
+     * Internal registry count for the number of providers contained in the
+     * registry.
+     */
+    private static int providerImplIndex = 0;
+
+    /**
+     * Internal handler for all standard property parsing. Parses standard
+     * ROWSET properties and stores lazy references into the internal registry.
+     */
+    private static void parseProperties(Properties p) {
+
+        ProviderImpl impl = null;
+        String key = null;
+        String[] propertyNames = null;
+
+        for (Enumeration<?> e = p.propertyNames(); e.hasMoreElements();) {
+
+            String str = (String) e.nextElement();
+
+            int w = str.length();
+
+            if (str.startsWith(SyncFactory.ROWSET_SYNC_PROVIDER)) {
+
+                impl = new ProviderImpl();
+                impl.setIndex(providerImplIndex++);
+
+                if (w == (SyncFactory.ROWSET_SYNC_PROVIDER).length()) {
+                    // no property index has been set.
+                    propertyNames = getPropertyNames(false);
+                } else {
+                    // property index has been set.
+                    propertyNames = getPropertyNames(true, str.substring(w - 1));
+                }
+
+                key = p.getProperty(propertyNames[0]);
+                impl.setClassname(key);
+                impl.setVendor(p.getProperty(propertyNames[1]));
+                impl.setVersion(p.getProperty(propertyNames[2]));
+                implementations.put(key, impl);
+            }
+        }
+    }
+
+    /**
+     * Used by the parseProperties methods to disassemble each property tuple.
+     */
+    private static String[] getPropertyNames(boolean append) {
+        return getPropertyNames(append, null);
+    }
+
+    /**
+     * Disassembles each property and its associated value. Also handles
+     * overloaded property names that contain indexes.
+     */
+    private static String[] getPropertyNames(boolean append,
+            String propertyIndex) {
+        String dot = ".";
+        String[] propertyNames =
+                new String[]{SyncFactory.ROWSET_SYNC_PROVIDER,
+            SyncFactory.ROWSET_SYNC_VENDOR,
+            SyncFactory.ROWSET_SYNC_PROVIDER_VERSION};
+        if (append) {
+            for (int i = 0; i < propertyNames.length; i++) {
+                propertyNames[i] = propertyNames[i] +
+                        dot +
+                        propertyIndex;
+            }
+            return propertyNames;
+        } else {
+            return propertyNames;
+        }
+    }
+
+    /**
+     * Internal debug method that outputs the registry contents.
+     */
+    private static void showImpl(ProviderImpl impl) {
+        System.out.println("Provider implementation:");
+        System.out.println("Classname: " + impl.getClassname());
+        System.out.println("Vendor: " + impl.getVendor());
+        System.out.println("Version: " + impl.getVersion());
+        System.out.println("Impl index: " + impl.getIndex());
+    }
+
+    /**
+     * Returns the <code>SyncProvider</code> instance identified by <i>providerID</i>.
+     *
+     * @param providerID the unique identifier of the provider
+     * @return a <code>SyncProvider</code> implementation
+     * @throws SyncFactoryException If the SyncProvider cannot be found,
+     * the providerID is {@code null}, or
+     * some error was encountered when trying to invoke this provider.
+     */
+    public static SyncProvider getInstance(String providerID)
+            throws SyncFactoryException {
+
+        if(providerID == null) {
+            throw new SyncFactoryException("The providerID cannot be null");
+        }
+
+        initMapIfNecessary(); // populate HashTable
+        initJNDIContext();    // check JNDI context for any additional bindings
+
+        ProviderImpl impl = (ProviderImpl) implementations.get(providerID);
+
+        if (impl == null) {
+            // Requested SyncProvider is unavailable. Return default provider.
+            return new com.sun.rowset.providers.RIOptimisticProvider();
+        }
+
+        try {
+            ReflectUtil.checkPackageAccess(providerID);
+        } catch (java.security.AccessControlException e) {
+            SyncFactoryException sfe = new SyncFactoryException();
+            sfe.initCause(e);
+            throw sfe;
+        }
+
+        // Attempt to invoke classname from registered SyncProvider list
+        Class<?> c = null;
+        try {
+            ClassLoader cl = Thread.currentThread().getContextClassLoader();
+
+            /**
+             * The SyncProvider implementation of the user will be in
+             * the classpath. We need to find the ClassLoader which loads
+             * this SyncFactory and try to load the SyncProvider class from
+             * there.
+             **/
+            c = Class.forName(providerID, true, cl);
+            @SuppressWarnings("deprecation")
+            Object result =  c.newInstance();
+            return (SyncProvider)result;
+
+        } catch (IllegalAccessException | InstantiationException | ClassNotFoundException e) {
+            throw new SyncFactoryException("IllegalAccessException: " + e.getMessage());
+        }
+    }
+
+    /**
+     * Returns an Enumeration of currently registered synchronization
+     * providers.  A <code>RowSet</code> implementation may use any provider in
+     * the enumeration as its <code>SyncProvider</code> object.
+     * <p>
+     * At a minimum, the reference synchronization provider allowing
+     * RowSet content data to be stored using a JDBC driver should be
+     * possible.
+     *
+     * @return Enumeration  A enumeration of available synchronization
+     * providers that are registered with this Factory
+     * @throws SyncFactoryException If an error occurs obtaining the registered
+     * providers
+     */
+    public static Enumeration<SyncProvider> getRegisteredProviders()
+            throws SyncFactoryException {
+        initMapIfNecessary();
+        // return a collection of classnames
+        // of type SyncProvider
+        return implementations.elements();
+    }
+
+    /**
+     * Sets the logging object to be used by the <code>SyncProvider</code>
+     * implementation provided by the <code>SyncFactory</code>. All
+     * <code>SyncProvider</code> implementations can log their events to
+     * this object and the application can retrieve a handle to this
+     * object using the <code>getLogger</code> method.
+     * <p>
+     * This method checks to see that there is an {@code SQLPermission}
+     * object  which grants the permission {@code setSyncFactory}
+     * before allowing the method to succeed.  If a
+     * {@code SecurityManager} exists and its
+     * {@code checkPermission} method denies calling {@code setLogger},
+     * this method throws a
+     * {@code java.lang.SecurityException}.
+     *
+     * @param logger A Logger object instance
+     * @throws java.lang.SecurityException if a security manager exists and its
+     *   {@code checkPermission} method denies calling {@code setLogger}
+     * @throws NullPointerException if the logger is null
+     * @see SecurityManager#checkPermission
+     */
+    public static void setLogger(Logger logger) {
+
+        SecurityManager sec = System.getSecurityManager();
+        if (sec != null) {
+            sec.checkPermission(SET_SYNCFACTORY_PERMISSION);
+        }
+
+        if(logger == null){
+            throw new NullPointerException("You must provide a Logger");
+        }
+        rsLogger = logger;
+    }
+
+    /**
+     * Sets the logging object that is used by <code>SyncProvider</code>
+     * implementations provided by the <code>SyncFactory</code> SPI. All
+     * <code>SyncProvider</code> implementations can log their events
+     * to this object and the application can retrieve a handle to this
+     * object using the <code>getLogger</code> method.
+     * <p>
+     * This method checks to see that there is an {@code SQLPermission}
+     * object  which grants the permission {@code setSyncFactory}
+     * before allowing the method to succeed.  If a
+     * {@code SecurityManager} exists and its
+     * {@code checkPermission} method denies calling {@code setLogger},
+     * this method throws a
+     * {@code java.lang.SecurityException}.
+     *
+     * @param logger a Logger object instance
+     * @param level a Level object instance indicating the degree of logging
+     * required
+     * @throws java.lang.SecurityException if a security manager exists and its
+     *   {@code checkPermission} method denies calling {@code setLogger}
+     * @throws NullPointerException if the logger is null
+     * @see SecurityManager#checkPermission
+     * @see LoggingPermission
+     */
+    public static void setLogger(Logger logger, Level level) {
+        // singleton
+        SecurityManager sec = System.getSecurityManager();
+        if (sec != null) {
+            sec.checkPermission(SET_SYNCFACTORY_PERMISSION);
+        }
+
+        if(logger == null){
+            throw new NullPointerException("You must provide a Logger");
+        }
+        logger.setLevel(level);
+        rsLogger = logger;
+    }
+
+    /**
+     * Returns the logging object for applications to retrieve
+     * synchronization events posted by SyncProvider implementations.
+     * @return The {@code Logger} that has been specified for use by
+     * {@code SyncProvider} implementations
+     * @throws SyncFactoryException if no logging object has been set.
+     */
+    public static Logger getLogger() throws SyncFactoryException {
+
+        Logger result = rsLogger;
+        // only one logger per session
+        if (result == null) {
+            throw new SyncFactoryException("(SyncFactory) : No logger has been set");
+        }
+
+        return result;
+    }
+
+    /**
+     * Sets the initial JNDI context from which SyncProvider implementations
+     * can be retrieved from a JNDI namespace
+     * <p>
+     *  This method checks to see that there is an {@code SQLPermission}
+     * object  which grants the permission {@code setSyncFactory}
+     * before allowing the method to succeed.  If a
+     * {@code SecurityManager} exists and its
+     * {@code checkPermission} method denies calling {@code setJNDIContext},
+     * this method throws a
+     * {@code java.lang.SecurityException}.
+     *
+     * @param ctx a valid JNDI context
+     * @throws SyncFactoryException if the supplied JNDI context is null
+     * @throws java.lang.SecurityException if a security manager exists and its
+     *  {@code checkPermission} method denies calling {@code setJNDIContext}
+     * @see SecurityManager#checkPermission
+     */
+    public static synchronized void setJNDIContext(javax.naming.Context ctx)
+            throws SyncFactoryException {
+        SecurityManager sec = System.getSecurityManager();
+        if (sec != null) {
+            sec.checkPermission(SET_SYNCFACTORY_PERMISSION);
+        }
+        if (ctx == null) {
+            throw new SyncFactoryException("Invalid JNDI context supplied");
+        }
+        ic = ctx;
+    }
+
+    /**
+     * Controls JNDI context initialization.
+     *
+     * @throws SyncFactoryException if an error occurs parsing the JNDI context
+     */
+    private static synchronized void initJNDIContext() throws SyncFactoryException {
+
+        if ((ic != null) && (lazyJNDICtxRefresh == false)) {
+            try {
+                parseProperties(parseJNDIContext());
+                lazyJNDICtxRefresh = true; // touch JNDI namespace once.
+            } catch (NamingException e) {
+                e.printStackTrace();
+                throw new SyncFactoryException("SPI: NamingException: " + e.getExplanation());
+            } catch (Exception e) {
+                e.printStackTrace();
+                throw new SyncFactoryException("SPI: Exception: " + e.getMessage());
+            }
+        }
+    }
+    /**
+     * Internal switch indicating whether the JNDI namespace should be re-read.
+     */
+    private static boolean lazyJNDICtxRefresh = false;
+
+    /**
+     * Parses the set JNDI Context and passes bindings to the enumerateBindings
+     * method when complete.
+     */
+    private static Properties parseJNDIContext() throws NamingException {
+
+        NamingEnumeration<?> bindings = ic.listBindings("");
+        Properties properties = new Properties();
+
+        // Hunt one level below context for available SyncProvider objects
+        enumerateBindings(bindings, properties);
+
+        return properties;
+    }
+
+    /**
+     * Scans each binding on JNDI context and determines if any binding is an
+     * instance of SyncProvider, if so, add this to the registry and continue to
+     * scan the current context using a re-entrant call to this method until all
+     * bindings have been enumerated.
+     */
+    private static void enumerateBindings(NamingEnumeration<?> bindings,
+            Properties properties) throws NamingException {
+
+        boolean syncProviderObj = false; // move to parameters ?
+
+        try {
+            Binding bd = null;
+            Object elementObj = null;
+            String element = null;
+            while (bindings.hasMore()) {
+                bd = (Binding) bindings.next();
+                element = bd.getName();
+                elementObj = bd.getObject();
+
+                if (!(ic.lookup(element) instanceof Context)) {
+                    // skip directories/sub-contexts
+                    if (ic.lookup(element) instanceof SyncProvider) {
+                        syncProviderObj = true;
+                    }
+                }
+
+                if (syncProviderObj) {
+                    SyncProvider sync = (SyncProvider) elementObj;
+                    properties.put(SyncFactory.ROWSET_SYNC_PROVIDER,
+                            sync.getProviderID());
+                    syncProviderObj = false; // reset
+                }
+
+            }
+        } catch (javax.naming.NotContextException e) {
+            bindings.next();
+            // Re-entrant call into method
+            enumerateBindings(bindings, properties);
+        }
+    }
+
+    /**
+     * Lazy initialization Holder class used by {@code getSyncFactory}
+     */
+    private static class SyncFactoryHolder {
+        static final SyncFactory factory = new SyncFactory();
+    }
+}
+
+/**
+ * Internal class that defines the lazy reference construct for each registered
+ * SyncProvider implementation.
+ */
+class ProviderImpl extends SyncProvider {
+
+    private String className = null;
+    private String vendorName = null;
+    private String ver = null;
+    private int index;
+
+    public void setClassname(String classname) {
+        className = classname;
+    }
+
+    public String getClassname() {
+        return className;
+    }
+
+    public void setVendor(String vendor) {
+        vendorName = vendor;
+    }
+
+    public String getVendor() {
+        return vendorName;
+    }
+
+    public void setVersion(String providerVer) {
+        ver = providerVer;
+    }
+
+    public String getVersion() {
+        return ver;
+    }
+
+    public void setIndex(int i) {
+        index = i;
+    }
+
+    public int getIndex() {
+        return index;
+    }
+
+    public int getDataSourceLock() throws SyncProviderException {
+
+        int dsLock = 0;
+        try {
+            dsLock = SyncFactory.getInstance(className).getDataSourceLock();
+        } catch (SyncFactoryException sfEx) {
+
+            throw new SyncProviderException(sfEx.getMessage());
+        }
+
+        return dsLock;
+    }
+
+    public int getProviderGrade() {
+
+        int grade = 0;
+
+        try {
+            grade = SyncFactory.getInstance(className).getProviderGrade();
+        } catch (SyncFactoryException sfEx) {
+            //
+        }
+
+        return grade;
+    }
+
+    public String getProviderID() {
+        return className;
+    }
+
+    /*
+    public javax.sql.RowSetInternal getRowSetInternal() {
+    try
+    {
+    return SyncFactory.getInstance(className).getRowSetInternal();
+    } catch(SyncFactoryException sfEx) {
+    //
+    }
+    }
+     */
+    public javax.sql.RowSetReader getRowSetReader() {
+
+        RowSetReader rsReader = null;
+
+        try {
+            rsReader = SyncFactory.getInstance(className).getRowSetReader();
+        } catch (SyncFactoryException sfEx) {
+            //
+        }
+
+        return rsReader;
+
+    }
+
+    public javax.sql.RowSetWriter getRowSetWriter() {
+
+        RowSetWriter rsWriter = null;
+        try {
+            rsWriter = SyncFactory.getInstance(className).getRowSetWriter();
+        } catch (SyncFactoryException sfEx) {
+            //
+        }
+
+        return rsWriter;
+    }
+
+    public void setDataSourceLock(int param)
+            throws SyncProviderException {
+
+        try {
+            SyncFactory.getInstance(className).setDataSourceLock(param);
+        } catch (SyncFactoryException sfEx) {
+
+            throw new SyncProviderException(sfEx.getMessage());
+        }
+    }
+
+    public int supportsUpdatableView() {
+
+        int view = 0;
+
+        try {
+            view = SyncFactory.getInstance(className).supportsUpdatableView();
+        } catch (SyncFactoryException sfEx) {
+            //
+        }
+
+        return view;
+    }
+}