naming/impl/SerialContext.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2006-2011 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * GPL Classpath Exception:
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package com.sun.enterprise.naming.impl;

import com.sun.enterprise.naming.util.LogFacade;
import org.glassfish.api.naming.NamingObjectProxy;
import org.jvnet.hk2.component.Habitat;

import org.glassfish.api.admin.ProcessEnvironment;
import org.glassfish.api.admin.ProcessEnvironment.ProcessType;
import javax.naming.spi.ObjectFactory;
import java.rmi.RemoteException;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.Map;
import java.util.HashMap;
import javax.naming.Binding;
import javax.naming.CommunicationException;
import javax.naming.CompositeName;
import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NameClassPair;
import javax.naming.NameParser;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.NotContextException;
import javax.naming.Reference;
import javax.naming.Referenceable;
import org.omg.CORBA.ORBPackage.InvalidName;

import org.omg.CosNaming.NamingContext;
import org.omg.CosNaming.NameComponent;
import org.omg.CosNaming.NamingContextHelper;
import javax.rmi.PortableRemoteObject;
import org.glassfish.internal.api.Globals;
import org.glassfish.internal.api.ORBLocator;
import org.glassfish.internal.api.ServerContext;

import org.omg.CORBA.ORB;
import org.omg.CosNaming.NamingContextPackage.CannotProceed;
import org.omg.CosNaming.NamingContextPackage.NotFound;


/**
 * This context provides access to the app server naming service. This
 * is the default Context for GlassFish. Lookups of unqualified names (i.e.
 * names not starting with "java:", "corbaname:" etc) are serviced by
 * SerialContext. The namespace is implemented in the
 * SerialContextProviderImpl object,  which is accessed directly in the
 * case that the client is collocated with the naming service impl or
 * remotely via RMI-IIOP if not collocated.
 * <p/>
 * <b>NOT THREAD SAFE: mutable instance variables</b>
 */
public class SerialContext implements Context {
    // Maximum number of recursive calls to lookup on comm error
    // Maximum number of recursive calls to lookup on comm error
    private static final int MAX_LEVEL = 5 ;

    private static final String JAVA_URL = "java:";

    private static final String JAVA_GLOBAL_URL = "java:global/";

    // Sets unmanaged SerialContext in test mode to prevent attempts to contact server.
    static final String INITIAL_CONTEXT_TEST_MODE = "com.sun.enterprise.naming.TestMode";

    private static final Logger _logger = LogFacade.getLogger();

    private static final NameParser myParser = new SerialNameParser();

    private static final Map<ProviderCacheKey, SerialContextProvider> providerCache =
            new HashMap<ProviderCacheKey, SerialContextProvider>();

    private static final ThreadLocal<ThreadLocalIC> stickyContext =
        new ThreadLocal<ThreadLocalIC>() {
            @Override
            protected ThreadLocalIC initialValue() {
                return new ThreadLocalIC() ;
            }
        } ;

    private Hashtable myEnv = null; // THREAD UNSAFE

    private SerialContextProvider provider;

    private final String myName;

    private final JavaURLContext javaUrlContext;

    private Habitat habitat;

    private boolean testMode = false;

    private ProcessType processType = ProcessType.Server;

    private ORB orbFromEnv;

    private String targetHost;
    private String targetPort;

    private ORB orb = null ;

    // True if we're running in the server and no orb,host, or port
    // properties have been explicitly set in the properties
    // Allows special optimized intra-server naming service access
    private boolean intraServerLookups;

    // Common Class Loader. It is used as a fallback classloader to locate
    // GlassFish object factories.
    private ClassLoader commonCL;

    /** Methods for preserving stickiness. This is a
     * solution to store the sticky IC as a thread local variable. This sticky
     * IC will be used by all classes that require a context object to do lookup
     * (if LB is enabled) SerialContext.lookup() sets a value for the thread
     * local variable (stickyContext) before performing th lookup in case LB is
     * enabled. If not, the thread local variable is null. At the end of the
     * SerialContext.lookup() method, the thread local variable gets set to
     * null. So actually speaking, more than being a global variable for the
     * entire thread, its global only during the execution of the
     * SerialContext.lookup() method. bug 5050591
     *
     */
    static Context getStickyContext() {
        return stickyContext.get().getContext() ;
    }

    private void grabSticky() {
        stickyContext.get().grab( this ) ;
    }

    private void releaseSticky() {
        stickyContext.get().release() ;
    }

    static void clearSticky() {
        stickyContext.get().clear() ;
    }

    /** Store the sticky context as a threadlocal variable (bug 5050591).
    * Count is needed to know how many times the lookup method is being called
    * from within the user code's ic.lookup().
    * e.g. JMS resource lookups (via ConnectorObjectFactory)
    */
    private static class ThreadLocalIC {
        private Context ctx = null ;
        private int count = 0;

        Context getContext() {
            return ctx ;
        }

        void grab( Context context ) {
            if (ctx == null) {
                ctx = context ;
            }

            count++ ;
        }

        void release() {
            if (count > 0) {
                count-- ;
                if (count == 0) {
                    ctx = null ;
                }
            } else {
                if (_logger.isLoggable(Level.FINE))  {
                    _logger.log( Level.FINE,
                        "SerialContext: attempt to release StickyContext "
                        + " without grab") ;
                }
                ctx = null ;
            }
        }

        void clear() {
            ctx = null ;
            count = 0 ;
        }
    }


    /**
     * Constructor for the context. Initializes the object reference to the
     * remote provider object.
     */
    public SerialContext(String name, Hashtable environment, Habitat h)
            throws NamingException {

        habitat = h;

        myEnv = (environment != null) ? (Hashtable) (environment.clone())
                : null;

        // TODO REMOVE when property stuff is figured out
        myEnv.put("java.naming.factory.url.pkgs",
            "com.sun.enterprise.naming");
        myEnv.put("java.naming.factory.state",
            "com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl" );

        this.myName = name;
        if (_logger.isLoggable(Level.FINE))
            _logger.fine("SerialContext ==> SerialContext instance created : "
                    + this);

        if( myEnv.get(INITIAL_CONTEXT_TEST_MODE) != null ) {
            testMode = true;
            System.out.println("SerialContext in test mode");
        }

        if( (habitat == null) && !testMode ) {
            synchronized(SerialContext.class) {
                if( SerialInitContextFactory.getDefaultHabitat() == null ) {

                    // Bootstrap a hk2 environment.
                    // TODO This will need to be moved somewhere else.  Potentially any
                    // piece of glassfish code that can be an initial entry point from a
                    // Java SE client will need to make this happen.

                    habitat = Globals.getStaticHabitat();

                    SerialInitContextFactory.setDefaultHabitat(habitat);
                } else {
                    habitat = SerialInitContextFactory.getDefaultHabitat();
                }

            }
        }

        if( testMode ) {
            processType = ProcessType.Server;
        } else {
            ProcessEnvironment processEnv = habitat.getComponent(ProcessEnvironment.class);
            processType = processEnv.getProcessType();
            if (_logger.isLoggable(Level.FINE)) {
                _logger.log(Level.FINE,
                    "Serial Context initializing with process environment {0}",
                    processEnv);
            }
        }

        // using these two temp variables allows instance variables
        // to be 'final'.
        JavaURLContext urlContextTemp = null;

        if (myEnv.get(SerialInitContextFactory.IIOP_URL_PROPERTY) != null) {
            urlContextTemp = new JavaURLContext(myEnv, this);
        } else {
            urlContextTemp = new JavaURLContext(myEnv, null);
        }

        javaUrlContext = urlContextTemp;

        orbFromEnv  = (ORB) myEnv.get(ORBLocator.JNDI_CORBA_ORB_PROPERTY);
        String targetHostFromEnv = (String)myEnv.get(
            ORBLocator.OMG_ORB_INIT_HOST_PROPERTY);
        String targetPortFromEnv = (String)myEnv.get(
            ORBLocator.OMG_ORB_INIT_PORT_PROPERTY);

        intraServerLookups = (processType.isServer()) && (orbFromEnv == null) &&
            (targetHostFromEnv == null) && (targetPortFromEnv == null);

        // Set target host / port from env.  If only one of the two is set, fill in the
        // other with the default.
        if( targetHostFromEnv != null ) {
            targetHost = targetHostFromEnv;
            if( targetPortFromEnv == null ) {
                targetPort = ORBLocator.DEFAULT_ORB_INIT_PORT;
            }
        }

        if( targetPortFromEnv != null ) {
            targetPort = targetPortFromEnv;
            if( targetHostFromEnv == null ) {
                targetHost = ORBLocator.DEFAULT_ORB_INIT_HOST;
            }
        }

        orb = orbFromEnv;
        if (habitat != null) { // can happen in test mode
            ServerContext sc = habitat.getByContract(ServerContext.class);
            if (sc != null) {
                commonCL = sc.getCommonClassLoader();
            }
        }
    }

    /**
     * This constructor takes the component id as an argument. All name
     * arguments to operations are prepended by the component id.
     */
    public SerialContext(Hashtable env, Habitat habitat) throws NamingException {
        this("", env, habitat);
    }

    private SerialContextProvider getProvider() throws NamingException {
        SerialContextProvider returnValue = provider;

        if (provider == null) {
            try {
                if (intraServerLookups) {
                    returnValue =
                        ProviderManager.getProviderManager().getLocalProvider();
                }  else {
                    returnValue = getRemoteProvider();
                }
            } catch(Exception e) {
                clearSticky() ;
                e.printStackTrace();
                NamingException ne = new NamingException(
                    "Unable to acquire SerialContextProvider for " + this);
                ne.initCause(e);
                throw ne;
            }
        }

        return returnValue;
    }

    private ORB getORB() {
        ORBLocator orbHelper = habitat.getComponent(ORBLocator.class);
        if (orb == null) {
            orb = orbHelper.getORB() ;
        }

        return orb ;
    }

    private ProviderCacheKey getProviderCacheKey() {
        final ORB myORB = getORB();
        ProviderCacheKey key;

        String eplist = null ;
        if (myEnv != null) {
            eplist = (String)myEnv.get(
                SerialInitContextFactory.IIOP_URL_PROPERTY) ;
        }

        if (eplist != null) {
            key = new ProviderCacheKey(eplist) ;
        } else if (targetHost == null) {
            key = new ProviderCacheKey(myORB) ;
        }  else {
            key = new ProviderCacheKey(targetHost, targetPort);
        }

        return key ;
    }

    private void clearProvider() {
        ProviderCacheKey key = getProviderCacheKey() ;
        synchronized(SerialContext.class) {
            providerCache.remove( key ) ;
        }
        provider = null ;
    }

    private SerialContextProvider getRemoteProvider() throws Exception {
        if (provider == null) {
            ProviderCacheKey key = getProviderCacheKey() ;

            SerialContextProvider cachedProvider;
            synchronized(SerialContext.class) {
                cachedProvider = providerCache.get(key);
            }

            if (cachedProvider == null) {
                // Don't hold lock during this call: remote invocation
                SerialContextProvider newProvider = key.getNameService() ;

                synchronized(SerialContext.class) {
                    cachedProvider = providerCache.get(key);
                    if (cachedProvider == null)  {
                        providerCache.put(key, newProvider);
                        provider = newProvider;
                    } else {
                        provider = cachedProvider;
                    }
                }
            } else {
                provider = cachedProvider;
            }

        }

        return provider;
    }

    /**
     * The getNameInNamespace API is not supported in this context.
     *
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public String getNameInNamespace() throws NamingException {
        return myName;
    }

    /**
     * method to check if the name to look up starts with "java:"
     */
    private boolean isjavaURL(String name) {
        return name.startsWith(JAVA_URL) && !name.startsWith(JAVA_GLOBAL_URL) ;
    }

    /**
     * Lookup the specified name in the context. Returns the resolved object.
     *
     * @return the resolved object.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Object lookup(String name) throws NamingException {
        return lookup( name, 0 ) ;
    }

    private Object lookup(String name, int level ) throws NamingException {
        // Before any lookup bind any NamedNamingObjectProxy
        // Skip if in plain Java SE client
        // TODO this should really be moved somewhere else
        NamedNamingObjectManager.checkAndLoadProxies(habitat);

        if (_logger.isLoggable(Level.FINE)) {
            _logger.log(Level.FINE, "SerialContext ==> lookup( {0})", name);
        }

        /**
         * In case a user is creating an IC with env passed in constructor; env
         * specifies endpoints in some form in that case, the sticky IC should
         * be stored as a thread local variable.
         *
         */
        final boolean useSticky = myEnv.get(
            SerialInitContextFactory.IIOP_URL_PROPERTY) != null ;

        if (useSticky) {
            grabSticky() ;
        }

        try {
            if (name.isEmpty()) {
                // Asking to look up this context itself. Create and return
                // a new instance with its own independent environment.
                return (new SerialContext(myName, myEnv, habitat));
            }

            name = getRelativeName(name);

            if (_logger.isLoggable(Level.FINE)) {
                _logger.log(Level.FINE,
                    "SerialContext ==> lookup relative name : {0}", name);
            }

            if (isjavaURL(name)) {
                //it is possible that the object bound in a java url ("java:") is
                //reference object.
                Object o = javaUrlContext.lookup(name);
                if(o instanceof Reference){
                    o = getObjectInstance(name, o);
                }
                return o;
            } else {
                SerialContextProvider prvdr = getProvider() ;
                Object obj = prvdr.lookup(name);
                if (obj instanceof NamingObjectProxy) {
                    return ((NamingObjectProxy) obj).create(this);
                }

                if (obj instanceof Context) {
                    return new SerialContext(name, myEnv, habitat);
                }

                Object retObj = getObjectInstance(name, obj);
                return retObj;
            }
        } catch (NamingException nnfe) {
            NamingException ne = new NamingException
                    ("Lookup failed for '" + name + "' in " + this);
            ne.initCause(nnfe);
            throw ne;
        } catch (Exception ex) {
            // Issue 14732: make this FINE, as a cluster configuration change
            // can send us here in a normal retry scenario.
            _logger.log(Level.FINE,
                    "enterprise_naming.serialctx_communication_exception", name);
            _logger.log(Level.FINE, "", ex);

            final int nextLevel = level + 1 ;

            // temp fix for 6320008
            // this should be removed once we change the transient NS
            // implementation to persistent
            if (ex instanceof java.rmi.MarshalException
                    && ex.getCause() instanceof org.omg.CORBA.COMM_FAILURE
                    && nextLevel < MAX_LEVEL) {
                clearProvider();
                _logger.fine("Resetting provider to NULL. Will get new obj ref " +
                             "for provider since previous obj ref was stale...");
                return lookup(name, nextLevel );
            } else {
                CommunicationException ce = new CommunicationException(
                    "Communication exception for " + this);
                ce.initCause(ex);
                throw ce;
            }
        } finally {
            if (useSticky) {
                releaseSticky();
            }
        }
    }

    private Object getObjectInstance(String name, Object obj) throws Exception
    {
        Object retObj = javax.naming.spi.NamingManager.getObjectInstance(
            obj, new CompositeName(name), null, myEnv);

        if (retObj == obj) {
            // NamingManager.getObjectInstance() returns the same object
            // when it can't find the factory class. Since NamingManager
            // uses Thread's context class loader to locate factory classes,
            // it may not be able to locate the various GlassFish factories
            // when lookup is performed outside of a Java EE context like
            // inside an OSGi bundle's activator.
            // So, let's see if using CommonClassLoader helps or not.
            // We will only try with CommonClassLoader when the passed object
            // reference has a factory class name set.

            ClassLoader tccl = Thread.currentThread().getContextClassLoader();
            if (tccl != commonCL) {
                Reference ref = getReference(obj);
                if (ref != null) {
                    _logger.logp(Level.FINE, "SerialContext",
                            "getObjectInstance",
                            "Trying with CommonClassLoader for name {0} ",
                            new Object[]{name});
                    ObjectFactory factory = getObjectFactory(ref, commonCL);
                    if (factory != null) {
                        retObj = factory.getObjectInstance(
                                ref, new CompositeName(name), null, myEnv);
                    }
                    if (retObj != obj) {
                        _logger.logp(Level.FINE, "SerialContext",
                                "getObjectInstance",
                                "Found with CommonClassLoader");
                    }
                }
            }
        }
        return retObj;
    }

    /**
     * This method tries to check if the passed object is a Reference or
     * Refenciable. If it is a Reference, it just casts it to a Reference and
     * returns, else if it is a Referenceable, it tries to get a Reference from
     * the Referenceable and returns that, otherwise, it returns null.
     *
     * @param obj
     * @return
     * @throws NamingException
     */
    private Reference getReference(Object obj) throws NamingException
    {
        Reference ref = null;
        if (obj instanceof Reference) {
            ref = (Reference) obj;
        } else if (obj instanceof Referenceable) {
            ref = ((Referenceable)(obj)).getReference();
        }

        return ref;
    }

    /**
     * It tries to load the factory class for the given reference using the
     * given class loader and return an instance of the same. Returns null
     * if it can't load the class.
     *
     * @param ref
     * @param cl
     * @return
     * @throws IllegalAccessException
     * @throws InstantiationException
     */
    private ObjectFactory getObjectFactory(Reference ref, ClassLoader cl)
            throws IllegalAccessException, InstantiationException
    {
        String factoryName = ref.getFactoryClassName();
        if (factoryName != null) {
            try
            {
                Class c = Class.forName(factoryName, false, cl);
                return (ObjectFactory)c.newInstance();
            }
            catch (ClassNotFoundException e)
            {
                // ignore only CNFE, all other exceptions are considered errors
            }
        }
        return null;
    }

    /**
     * Lookup the specifed name in the context. Returns the resolved object.
     *
     * @return the resolved object.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Object lookup(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        return lookup(name.toString());
    }

    /**
     * Bind the object to the specified name.
     *
     * @param name name that the object is being bound to.
     * @param obj object that is being bound.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void bind(String name, Object obj) throws NamingException {

        name = getRelativeName(name);
        if (isjavaURL(name)) {
            javaUrlContext.bind(name, obj);
        } else {
            try {
                getProvider().bind(name, obj);
            } catch (RemoteException ex) {
                throw new CommunicationException(ex.toString());
            }
        }
    }

    /**
     * Bind the object to the specified name.
     *
     * @param name name that the object is being bound to.
     * @param obj  object that is being bound.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void bind(Name name, Object obj) throws NamingException {
        // Flat namespace; no federation; just call string version
        bind(name.toString(), obj);
    }

    /**
     * Rebind the object to the specified name.
     *
     * @param name name that the object is being bound to.
     * @param obj  object that is being bound.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void rebind(String name, Object obj) throws NamingException {

        name = getRelativeName(name);
        if (isjavaURL(name)) {
            javaUrlContext.rebind(name, obj);
        } else {
            try {
                getProvider().rebind(name, obj);
            } catch (RemoteException ex) {
                throw new CommunicationException(ex.toString());
            }
        }
    }

    /**
     * Rebind the object to the specified name.
     *
     * @param name name that the object is being bound to.
     * @param obj  object that is being bound.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void rebind(Name name, Object obj) throws NamingException {
        // Flat namespace; no federation; just call string version
        rebind(name.toString(), obj);
    }

    /**
     * Unbind the object with the specified name.
     *
     * @param name that is being unbound.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void unbind(String name) throws NamingException {
        name = getRelativeName(name);
        if (isjavaURL(name)) {
            javaUrlContext.unbind(name);
        } else {
            try {
                getProvider().unbind(name);
            } catch (RemoteException ex) {
                throw new CommunicationException(ex.toString());
            }
        }
    }

    /**
     * Unbind the object with the specified name.
     *
     * @param name name that is being unbound.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void unbind(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        unbind(name.toString());
    }

    /**
     * Rename the bound object.
     *
     * @param oldname old name that the object is bound as.
     * @param newname new name that the object will be bound as.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void rename(String oldname, String newname) throws NamingException {
        oldname = getRelativeName(oldname);
        newname = getRelativeName(newname);
        if (isjavaURL(oldname)) {
            javaUrlContext.rename(oldname, newname);
        } else {
            try {
                getProvider().rename(oldname, newname);
            } catch (RemoteException ex) {
                throw new CommunicationException(ex.toString());
            }
        }
    }

    /**
     * Rename the bound object.
     *
     * @param oldname old name that the object is bound as.
     * @param newname new name that the object will be bound as.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void rename(Name oldname, Name newname) throws NamingException {
        // Flat namespace; no federation; just call string version
        rename(oldname.toString(), newname.toString());
    }

    /**
     * List the contents of the specified context.
     *
     * @param name context name.
     * @return an enumeration of the contents.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public NamingEnumeration<NameClassPair> list(String name) throws NamingException {
        if (name.isEmpty()) {
            // listing this context
            try {
                Hashtable bindings = getProvider().list(myName);
                return new RepNames<NameClassPair>(bindings);
            } catch (RemoteException ex) {
                throw new CommunicationException(ex.toString());
            }
        }

        name = getRelativeName(name);
        if (isjavaURL(name)) {
            return javaUrlContext.list(name);
        } else {
            // Perhaps 'name' names a context
            Object target = lookup(name);
            if (target instanceof Context) {
                return ((Context) target).list("");
            }
            throw new NotContextException(name + " cannot be listed");
        }
    }

    /**
     * List the contents of the specified context.
     *
     * @param name context name.
     * @return an enumeration of the contents.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public NamingEnumeration<NameClassPair> list(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        return list(name.toString());
    }

    /**
     * List the bindings in the specified context.
     *
     * @param name context name.
     * @return an enumeration of the bindings.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public NamingEnumeration<Binding> listBindings(String name) throws NamingException {
        if (name.isEmpty()) {
            // listing this context
            try {
                Hashtable bindings = getProvider().list(myName);
                return new RepBindings<Binding>(bindings);
            } catch (RemoteException ex) {
                CommunicationException ce = new CommunicationException(ex
                        .toString());
                ce.initCause(ex);
                throw ce;
            }
        }

        name = getRelativeName(name);
        if (isjavaURL(name)) {
            return javaUrlContext.listBindings(name);
        } else {
            // Perhaps 'name' names a context
            Object target = lookup(name);
            if (target instanceof Context) {
                return ((Context) target).listBindings("");
            }
            throw new NotContextException(name + " cannot be listed");
        }
    }

    /**
     * List the bindings in the specified context.
     *
     * @param name context name.
     * @return an enumeration of the bindings.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public NamingEnumeration<Binding> listBindings(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        return listBindings(name.toString());
    }

    /**
     * Destroy the specified subcontext.
     *
     * @param name name of the subcontext.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void destroySubcontext(String name) throws NamingException {
        name = getRelativeName(name);
        if (isjavaURL(name)) {
            javaUrlContext.destroySubcontext(name);
        } else {
            try {
                getProvider().destroySubcontext(name);
            } catch (RemoteException e) {
                CommunicationException ce = new CommunicationException(e
                        .toString());
                ce.initCause(e);
                throw ce;
            }
        }
    }

    /**
     * Destroy the specified subcontext.
     *
     * @param name name of the subcontext.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void destroySubcontext(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        destroySubcontext(name.toString());
    }

    /**
     * Create the specified subcontext.
     *
     * @param name name of the subcontext.
     * @return the created subcontext.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Context createSubcontext(String name) throws NamingException {
        Context c = null;
        name = getRelativeName(name);
        if (isjavaURL(name)) {
            return javaUrlContext.createSubcontext(name);
        } else {
            try {
                c = getProvider().createSubcontext(name);
                /*
                 * this simulates the transient context structure on the client
                 * side. Have to do this - as reference to Transient Context is
                 * not resolved properly due to rmi
                 */
                if (c instanceof Context) {
                    c = new SerialContext(name, myEnv, habitat);
                }
            } catch (RemoteException e) {
                CommunicationException ce = new CommunicationException(e
                        .toString());
                ce.initCause(e);
                throw ce;
            }
            return c;
        }
    }

    /**
     * Create the specified subcontext.
     *
     * @param name name of the subcontext.
     * @return the created subcontext.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Context createSubcontext(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        return createSubcontext(name.toString());
    }

    /**
     * Links are not treated specially.
     *
     * @param name name of the link.
     * @return the resolved object.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Object lookupLink(String name) throws NamingException {
        name = getRelativeName(name);
        if (isjavaURL(name)) {
            return javaUrlContext.lookupLink(name);
        } else {
            // This flat context does not treat links specially
            return lookup(name);
        }
    }

    /**
     * Links are not treated specially.
     *
     * @param name name of the link.
     * @return the resolved object.
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Object lookupLink(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        return lookupLink(name.toString());
    }

    /**
     * Allow access to the name parser object.
     *
     * @param name JNDI name, is ignored since there is only one Name Parser
     *             object.
     * @return NameParser object
     * @throws NamingException
     */
    @Override
    public NameParser getNameParser(String name) throws NamingException {
        return myParser;
    }

    /**
     * Allow access to the name parser object.
     *
     * @param name JNDI name, is ignored since there is only one Name Parser
     *             object.
     * @return NameParser object
     * @throws NamingException
     */
    @Override
    public NameParser getNameParser(Name name) throws NamingException {
        // Flat namespace; no federation; just call string version
        return getNameParser(name.toString());
    }

    @Override
    public String composeName(String name, String prefix)
            throws NamingException {
        Name result = composeName(new CompositeName(name), new CompositeName(
                prefix));
        return result.toString();
    }

    @Override
    public Name composeName(Name name, Name prefix) throws NamingException {
        Name result = (Name) (prefix.clone());
        result.addAll(name);
        return result;
    }

    /**
     * Add to the environment for the current context.
     *
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Object addToEnvironment(String propName, Object propVal)
            throws NamingException {
        if (myEnv == null) {
            myEnv = new Hashtable(5, 0.75f);
        }
        return myEnv.put(propName, propVal);
    }

    /**
     * Remove from the environment for the current context.
     *
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Object removeFromEnvironment(String propName) throws NamingException {
        if (myEnv == null) {
            return null;
        }
        return myEnv.remove(propName);
    }

    /**
     * Return the environment for the current context.
     *
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public Hashtable getEnvironment() throws NamingException {
        if (myEnv == null) {
            // Must return non-null
            myEnv = new Hashtable(3, 0.75f);
        }
        return myEnv;
    }

    /**
     * Set the environment for the current context to null when close is called.
     *
     * @throws NamingException if there is a naming exception.
     */
    @Override
    public void close() throws NamingException {
        myEnv = null;
    }

    private String getRelativeName(String name) {
        if (!myName.equals("")) {
            name = myName + "/" + name;
        }
        return name;
    }

    // Class for enumerating name/class pairs
    static class RepNames<T> implements NamingEnumeration<T> {
        Hashtable bindings;

        Enumeration names;

        RepNames(Hashtable bindings) {
            this.bindings = bindings;
            this.names = bindings.keys();
        }

        @Override
        public boolean hasMoreElements() {
            return names.hasMoreElements();
        }

        @Override
        public boolean hasMore() throws NamingException {
            return hasMoreElements();
        }

        @Override
        public T nextElement() {
            if (names.hasMoreElements()) {
                String name = (String) names.nextElement();
                String className = bindings.get(name).getClass().getName();
                return (T) (new NameClassPair(name, className));
            } else {
                return null;
            }
        }

        @Override
        public T next() throws NamingException {
            return nextElement();
        }

        @Override
        public void close() {
            //no-op since no steps needed to free up resources
        }
    }

    // Class for enumerating bindings
    static class RepBindings<T> implements NamingEnumeration<T> {
        Enumeration names;

        Hashtable bindings;

        RepBindings(Hashtable bindings) {
            this.bindings = bindings;
            this.names = bindings.keys();
        }

        @Override
        public boolean hasMoreElements() {
            return names.hasMoreElements();
        }

        @Override
        public boolean hasMore() throws NamingException {
            return hasMoreElements();
        }

        @Override
        public T nextElement() {
            if (hasMoreElements()) {
                String name = (String) names.nextElement();
                return (T) (new Binding(name, bindings.get(name)));
            } else {
                return null;
            }
        }

        @Override
        public T next() throws NamingException {
            return nextElement();
        }

        @Override
        public void close() {
            //no-op since no steps needed to free up resources
        }
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("SerialContext[");
        if(testMode) {
            sb.append("( IN TEST MODE ) ");
        }

        sb.append( "myEnv=" ) ;
        sb.append( myEnv ) ;

        return sb.toString();

    }

    private class ProviderCacheKey {
        // Key is either orb OR host/port combo.
        private ORB localORB = null ;
        private String endpoints = null ;

        ProviderCacheKey(ORB orb) {
            this.localORB  = orb;
        }

        // Host and Port must both be non-null
        ProviderCacheKey(String host, String port) {
            endpoints = "corbaloc:iiop:1.2@" + host + ":" + port
                + "/NameService" ;
        }

        ProviderCacheKey( String endpoints ) {
            this.endpoints = endpoints ;
        }

        @Override
        public String toString() {
            if (localORB == null) {
                return "ProviderCacheKey[" + endpoints + "]" ;
            } else {
                return "ProviderCacheKey[" + localORB + "]" ;
            }
        }

        public SerialContextProvider getNameService() throws InvalidName,
            NotFound, CannotProceed,
            org.omg.CosNaming.NamingContextPackage.InvalidName {

            org.omg.CORBA.Object objref = null;
            if (endpoints == null) {
                objref = orb.resolve_initial_references( "NameService");
            } else {
                objref = orb.string_to_object(endpoints) ;
            }

            final NamingContext nctx = NamingContextHelper.narrow(objref);
            final NameComponent[] path =
                { new NameComponent("SerialContextProvider", "") };
            final org.omg.CORBA.Object obj = nctx.resolve(path) ;

            SerialContextProvider result =
                (SerialContextProvider)PortableRemoteObject.narrow( obj,
                    SerialContextProvider.class );

            return result ;
        }

        @Override
        public int hashCode() {
            return (orb != null) ? orb.hashCode() : endpoints.hashCode();
        }

        @Override
        public boolean equals(Object other) {
            if (other == null) {
                return false ;
            }

            if (!(other instanceof ProviderCacheKey)) {
                return false ;
            }

            ProviderCacheKey otherKey = (ProviderCacheKey) other;

            if (localORB != null) {
                return localORB == otherKey.localORB ;
            } else {
                if (endpoints == null) {
                    return otherKey.endpoints == null ;
                }

                return endpoints.equals(otherKey.endpoints) ;
            }
        }
    }
}