0.10/commons/src/main/java/org/apache/oodt/commons/object/jndi/ObjectContext.java - oodt - Git at Google

 // Licensed to the Apache Software Foundation (ASF) under one or more contributor
 // license agreements.  See the NOTICE.txt file distributed with this work for
 // additional information regarding copyright ownership.  The ASF licenses this
 // file to you under the Apache License, Version 2.0 (the "License"); you may not
 // use this file except in compliance with the License.  You may obtain a copy of
 // the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 // License for the specific language governing permissions and limitations under
 // the License.

 package org.apache.oodt.commons.object.jndi;

 import java.io.FileInputStream;
 import java.io.IOException;
 import java.lang.reflect.Constructor;
 import java.net.URI;
 import java.util.ArrayList;
 import java.util.Hashtable;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Properties;
 import javax.naming.CompositeName;
 import javax.naming.Context;
 import javax.naming.InvalidNameException;
 import javax.naming.Name;
 import javax.naming.NameAlreadyBoundException;
 import javax.naming.NameClassPair;
 import javax.naming.NameNotFoundException;
 import javax.naming.NameParser;
 import javax.naming.NamingEnumeration;
 import javax.naming.NamingException;
 import javax.naming.OperationNotSupportedException;
 import org.apache.oodt.commons.util.Utility;

 /**
  * Context for binding and looking up distributed objects.
  *
  * @author Kelly
  * @version $Revision: 1.5 $
  */
 class ObjectContext implements Context {
 	/**
 	 * Construct the object context.
 	 *
 	 * @param environment Its environment, currently unused.
 	 */
 	ObjectContext(Hashtable environment) {
 		this.environment = environment != null? (Hashtable) environment.clone() : new Hashtable();

 		// Add the CORBA context, but by name so we don't get a compile-time
 		// coupling with the edm-corba component, and only if CORBA's available.
 		try {
 			Class clazz = Class.forName("org.apache.oodt.commons.object.jndi.CORBAContext");
 			Constructor ctor = clazz.getConstructor(new Class[]{Hashtable.class});
 			Object corbaContext = ctor.newInstance(new Object[]{this.environment});
 			contexts.add(corbaContext);
 		} catch (Throwable ex) {}

 		String registryList = (String) environment.get("rmiregistries");
 		if (registryList != null) for (Iterator i = Utility.parseCommaList(registryList); i.hasNext();) {
 			Hashtable rmiEnv = (Hashtable) this.environment.clone();
 			URI uri = URI.create((String) i.next());
 			rmiEnv.put("host", uri.getHost());
 			rmiEnv.put("port", new Integer(uri.getPort()));
 			contexts.add(new RMIContext(rmiEnv));
 		}

 		Hashtable httpEnv = (Hashtable) this.environment.clone();
 		contexts.add(new HTTPContext(httpEnv));

 		String className = null;
 		for (Iterator i = org.apache.oodt.commons.util.Utility.parseCommaList(System.getProperty("org.apache.oodt.commons.object.contexts", ""));
 		        i.hasNext();) try {
 			className = (String) i.next();
 			Class clazz = Class.forName(className);
 			contexts.add(clazz.newInstance());
 		} catch (ClassNotFoundException ex) {
 			System.err.println("Ignoring not-found context class `" + className + "': " + ex.getMessage());
 		} catch (InstantiationException ex) {
 			System.err.println("Ignoring non-instantiable context class `" + className + "': " + ex.getMessage());
 		} catch (IllegalAccessException ex) {
 			System.err.println("Ignoring context class `" + className + "' with non-accessible no-args c'tor: "
 				+ ex.getMessage());
 		}

 		installAliases();
 		System.err.println("Object context ready; delegating to: " + contexts);
 	}

 	/**
 	 * Creates a new <code>ObjectContext</code> instance.  This constructor takes a
 	 * list of delegate contexts instead of building them from a passed-in
 	 * environment.  Currently, it's used solely for this class's {@link
 	 * ObjectContextTest unit test}.
 	 *
 	 * @param contexts a <code>List</code> of {@link Context}s.
 	 */
 	ObjectContext(List contexts) {
 		this.contexts = contexts;
 		installAliases();
 	}

 	/**
 	 * Returns the object to which the given name is bound.  Because this context
 	 * delegates to multiple other contexts, the lookup returns the first successful
 	 * match.
 	 *
 	 * @param name a <code>String</code> value.
 	 * @return an <code>Object</code> value.
 	 * @throws NamingException if an error occurs.
 	 */
 	public Object lookup(String name) throws NamingException {
 		if (name == null) throw new IllegalArgumentException("Name required");
 		if (name.length() == 0) return this;

 		// Let alias redirection do its magic
 		String alias = aliases.getProperty(name);
 		if (alias != null) name = alias;

 		for (Iterator i = contexts.iterator(); i.hasNext();) {
 			Context c = (Context) i.next();
 			try {
 				return c.lookup(name);
 			} catch (InvalidNameException ignore) {
 			} catch (NameNotFoundException ignore) {
 			} catch (NamingException ignore){}
 		}
 		throw new NameNotFoundException(name + " not found in any managed subcontext");
 	}

 	public Object lookup(Name name) throws NamingException {
 		return lookup(name.toString());
 	}

 	public synchronized void bind(String name, Object obj) throws NamingException {
 		if (name == null) throw new IllegalArgumentException("Name required");
 		if (name.length() == 0) throw new InvalidNameException("Cannot bind object named after context");

 		// If it's an alias name, stop here.
 		if (aliases.containsKey(name))
 			throw new NameAlreadyBoundException("Name \"" + name + "\" already bound as an aliased name");

 		// Make sure it isn't bound anywhere
 		for (NamingEnumeration e = list(""); e.hasMore();) {
 			NameClassPair nameClassPair = (NameClassPair) e.next();
 			if (name.equals(nameClassPair.getName()))
 				throw new NameAlreadyBoundException("Name \"" + name + "\" already bound by a managed subcontext");
 		}
 		doRebind(name, obj);
 	}

 	public void bind(Name name, Object obj) throws NamingException {
 		bind(name.toString(), obj);
 	}

 	/** {@inheritDoc} */
 	public synchronized void rebind(String name, Object obj) throws NamingException {
 		if (name == null) throw new IllegalArgumentException("Name required");
 		if (name.length() == 0) throw new InvalidNameException("Cannot rebind object named after context");

 		// If it's an alias name, remove the alias
 		if (aliases.containsKey(name))
 			aliases.remove(name);

 		doRebind(name, obj);
 	}

 	/**
 	 * Rebind the given name to the given object.
 	 *
 	 * @param name Name to rebind
 	 * @param obj Object to which it's bound
 	 * @throws NamingException if an error occurs.
 	 */
 	private void doRebind(String name, Object obj) throws NamingException {
 		boolean bound = false;
 		for (Iterator i = contexts.iterator(); i.hasNext();) {
 			Context c = (Context) i.next();
 			try {
 				c.rebind(name, obj);
 				bound = true;
 			} catch (NamingException ex) {}
 		}
 		if (!bound) throw new InvalidNameException("Name \"" + name + "\" not compatible with any managed subcontext");
 	}

 	public void rebind(Name name, Object obj) throws NamingException {
 		rebind(name.toString(), obj);
 	}

 	public void unbind(String name) throws NamingException {
 		if (name == null) throw new IllegalArgumentException("Name required");
 		if (name.length() == 0) throw new InvalidNameException("Cannot unbind object named after context");

 		// See if it's an aliased name
 		if (aliases.containsKey(name)) {
 			aliases.remove(name);
 			return;
 		}

 		boolean unbound = false;
 		for (Iterator i = contexts.iterator(); i.hasNext();) {
 			Context c = (Context) i.next();
 			try {
 				c.unbind(name);
 				unbound = true;
 			} catch (NamingException ignore) {}
 		}
 		if (!unbound) throw new InvalidNameException("Name \"" + name + "\" not compatible with any managed subcontext");
 	}

 	public void unbind(Name name) throws NamingException {
 		unbind(name.toString());
 	}

 	public void rename(String oldName, String newName) throws NamingException {
 		if (oldName == null || newName == null)
 			throw new IllegalArgumentException("Name required");
 		if (oldName.length() == 0 || newName.length() == 0)
 			throw new InvalidNameException("Cannot rename object named after context");

 		// See if it's an aliased name
 		String oldValue = (String) aliases.remove(oldName);
 		if (oldValue != null) {
 			aliases.setProperty(newName, oldName);
 			return;
 		}

 		boolean renamed = false;
 		for (Iterator i = contexts.iterator(); i.hasNext();) {
 			Context c = (Context) i.next();
 			try {
 				c.rename(oldName, newName);
 				renamed = true;
 			} catch (NamingException ignore) {}
 		}
 		if (!renamed) throw new InvalidNameException("Names not compatible with any managed subcontext");
 	}

 	public void rename(Name oldName, Name newName) throws NamingException {
 		rename(oldName.toString(), newName.toString());
 	}

 	public NamingEnumeration list(final String name) throws NamingException {
 		final Iterator eachContext = contexts.iterator();
 		return new NamingEnumeration() {
 			private NamingEnumeration enumeration
 				= eachContext.hasNext()? ((Context) eachContext.next()).list(name) : null;
 			private boolean open = true;
 			public Object next() throws NamingException {
 				if (!open) throw new NamingException("closed");
 				if (enumeration != null && enumeration.hasMore())
 					return enumeration.next();
 				else if (eachContext.hasNext()) {
 					enumeration = ((Context) eachContext.next()).list(name);
 					if (enumeration.hasMore())
 						return enumeration.next();
 				}
 				throw new NoSuchElementException("No more objects in context");
 			}
 			public Object nextElement() {
 				Object rc = null;
 				try {
 					rc = next();
 				} catch (NamingException ignore) {}
 				return rc;
 			}
 			public boolean hasMore() throws NamingException {
 				if (!open) return false;
 				if (enumeration == null)
 					return false;
 				else if (enumeration.hasMore())
 					return true;
 				else if (eachContext.hasNext()) {
 					enumeration = ((Context) eachContext.next()).list(name);
 					return hasMore();
 				}
 				return false;
 			}
 			public boolean hasMoreElements() {
 				boolean h = false;
 				try {
 					h = hasMore();
 				} catch (NamingException ignore) {}
 				return h;
 			}
 			public void close() throws NamingException {
 				open = false;
 				if (enumeration != null)
 					enumeration.close();
 			}
 		};
 	}

 	public NamingEnumeration list(Name name) throws NamingException {
 		return list(name.toString());
 	}

 	public NamingEnumeration listBindings(final String name) throws NamingException {
 		final Iterator eachContext = contexts.iterator();
 		return new NamingEnumeration() {
 			private NamingEnumeration enumeration
 				= eachContext.hasNext()? ((Context) eachContext.next()).listBindings(name) : null;
 			private boolean open = true;
 			public Object next() throws NamingException {
 				if (!open) throw new NamingException("closed");
 				if (enumeration != null && enumeration.hasMore())
 					return enumeration.next();
 				else if (eachContext.hasNext()) {
 					enumeration = ((Context) eachContext.next()).listBindings(name);
 					if (enumeration.hasMore())
 						return enumeration.next();
 				}
 				throw new NoSuchElementException("No more objects in context");
 			}
 			public Object nextElement() {
 				Object rc = null;
 				try {
 					rc = next();
 				} catch (NamingException ignore) {}
 				return rc;
 			}
 			public boolean hasMore() throws NamingException {
 				if (!open) return false;
 				if (enumeration == null)
 					return false;
 				else if (enumeration.hasMore())
 					return true;
 				else if (eachContext.hasNext()) {
 					enumeration = ((Context) eachContext.next()).listBindings(name);
 					return hasMore();
 				}
 				return false;
 			}
 			public boolean hasMoreElements() {
 				boolean h = false;
 				try {
 					h = hasMore();
 				} catch (NamingException ignore) {}
 				return h;
 			}
 			public void close() throws NamingException {
 				open = false;
 				if (enumeration != null)
 					enumeration.close();
 			}
 		};
 	}

 	public NamingEnumeration listBindings(Name name) throws NamingException {
 		return listBindings(name.toString());
 	}

 	public void destroySubcontext(String name) throws NamingException {
 		throw new OperationNotSupportedException("Subcontexts not supported by ObjectContext");
 	}

 	public void destroySubcontext(Name name) throws NamingException {
 		destroySubcontext(name.toString());
 	}

 	public Context createSubcontext(String name) throws NamingException {
 		throw new OperationNotSupportedException("Subcontexts not supported by ObjectContext");
 	}

 	public Context createSubcontext(Name name) throws NamingException {
 		return createSubcontext(name.toString());
 	}

 	public Object lookupLink(String name) throws NamingException {
 		return lookup(name);
 	}

 	public Object lookupLink(Name name) throws NamingException {
 		return lookupLink(name.toString());
 	}

 	public NameParser getNameParser(String name) throws NamingException {
 		return nameParser;
 	}

 	public NameParser getNameParser(Name name) throws NamingException {
 		return getNameParser(name.toString());
 	}

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

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

 	public Object addToEnvironment(String propName, Object propVal) throws NamingException {
 		if (environment == null) environment = new Hashtable();
 		return environment.put(propName, propVal);
 	}

 	public Object removeFromEnvironment(String propName) throws NamingException {
 		if (environment == null) return null;
 		return environment.remove(propName);
 	}

 	public Hashtable getEnvironment() throws NamingException {
 		if (environment == null) return new Hashtable();
 		return (Hashtable) environment.clone();
 	}

 	public String getNameInNamespace() throws NamingException {
 		return "";
 	}

 	public void close() throws NamingException {
 		environment = null;
 	}

 	/**
 	 * Install aliases specified in the properties file.  The properties file simply
 	 * maps a string object name to a new object name.  Use the system property
 	 * <code>org.apache.oodt.commons.object.jndi.aliases</code> (preferred) or simply
 	 * <code>aliases</code> to tell the location of the properties file.
 	 */
 	private void installAliases() {
 		String aliasFileName = System.getProperty("org.apache.oodt.commons.object.jndi.aliases", System.getProperty("aliases"));
 		if (aliasFileName != null && aliasFileName.length() > 0) {
 			FileInputStream in = null;
 			try {
 				in = new FileInputStream(aliasFileName);
 				aliases.load(in);
 			} catch (IOException ex) {
 				throw new IllegalStateException("Cannot handle I/O exception reading alias file " + aliasFileName
 					+ ": " + ex.getMessage());
 			} finally {
 				if (in != null) try {
 					in.close();
 				} catch (IOException ignore) {}
 			}
 		}
 	}

 	/** Context's environment; currently unused. */
 	private Hashtable environment;

 	/** Parser for object names. */
 	private static final NameParser nameParser = new ObjectNameParser();

 	/** List of {@link Context}s to which we "multiplex". */
 	private List contexts = new ArrayList();

 	/** Aliased names. */
 	private Properties aliases = new Properties();
 }
	// Licensed to the Apache Software Foundation (ASF) under one or more contributor
	// license agreements. See the NOTICE.txt file distributed with this work for
	// additional information regarding copyright ownership. The ASF licenses this
	// file to you under the Apache License, Version 2.0 (the "License"); you may not
	// use this file except in compliance with the License. You may obtain a copy of
	// the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
	// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
	// License for the specific language governing permissions and limitations under
	// the License.

	package org.apache.oodt.commons.object.jndi;

	import java.io.FileInputStream;
	import java.io.IOException;
	import java.lang.reflect.Constructor;
	import java.net.URI;
	import java.util.ArrayList;
	import java.util.Hashtable;
	import java.util.Iterator;
	import java.util.List;
	import java.util.NoSuchElementException;
	import java.util.Properties;
	import javax.naming.CompositeName;
	import javax.naming.Context;
	import javax.naming.InvalidNameException;
	import javax.naming.Name;
	import javax.naming.NameAlreadyBoundException;
	import javax.naming.NameClassPair;
	import javax.naming.NameNotFoundException;
	import javax.naming.NameParser;
	import javax.naming.NamingEnumeration;
	import javax.naming.NamingException;
	import javax.naming.OperationNotSupportedException;
	import org.apache.oodt.commons.util.Utility;

	/**
	* Context for binding and looking up distributed objects.
	*
	* @author Kelly
	* @version $Revision: 1.5 $
	*/
	class ObjectContext implements Context {
	/**
	* Construct the object context.
	*
	* @param environment Its environment, currently unused.
	*/
	ObjectContext(Hashtable environment) {
	this.environment = environment != null? (Hashtable) environment.clone() : new Hashtable();

	// Add the CORBA context, but by name so we don't get a compile-time
	// coupling with the edm-corba component, and only if CORBA's available.
	try {
	Class clazz = Class.forName("org.apache.oodt.commons.object.jndi.CORBAContext");
	Constructor ctor = clazz.getConstructor(new Class[]{Hashtable.class});
	Object corbaContext = ctor.newInstance(new Object[]{this.environment});
	contexts.add(corbaContext);
	} catch (Throwable ex) {}

	String registryList = (String) environment.get("rmiregistries");
	if (registryList != null) for (Iterator i = Utility.parseCommaList(registryList); i.hasNext();) {
	Hashtable rmiEnv = (Hashtable) this.environment.clone();
	URI uri = URI.create((String) i.next());
	rmiEnv.put("host", uri.getHost());
	rmiEnv.put("port", new Integer(uri.getPort()));
	contexts.add(new RMIContext(rmiEnv));
	}

	Hashtable httpEnv = (Hashtable) this.environment.clone();
	contexts.add(new HTTPContext(httpEnv));

	String className = null;
	for (Iterator i = org.apache.oodt.commons.util.Utility.parseCommaList(System.getProperty("org.apache.oodt.commons.object.contexts", ""));
	i.hasNext();) try {
	className = (String) i.next();
	Class clazz = Class.forName(className);
	contexts.add(clazz.newInstance());
	} catch (ClassNotFoundException ex) {
	System.err.println("Ignoring not-found context class `" + className + "': " + ex.getMessage());
	} catch (InstantiationException ex) {
	System.err.println("Ignoring non-instantiable context class `" + className + "': " + ex.getMessage());
	} catch (IllegalAccessException ex) {
	System.err.println("Ignoring context class `" + className + "' with non-accessible no-args c'tor: "
	+ ex.getMessage());
	}

	installAliases();
	System.err.println("Object context ready; delegating to: " + contexts);
	}

	/**
	* Creates a new <code>ObjectContext</code> instance. This constructor takes a
	* list of delegate contexts instead of building them from a passed-in
	* environment. Currently, it's used solely for this class's {@link
	* ObjectContextTest unit test}.
	*
	* @param contexts a <code>List</code> of {@link Context}s.
	*/
	ObjectContext(List contexts) {
	this.contexts = contexts;
	installAliases();
	}

	/**
	* Returns the object to which the given name is bound. Because this context
	* delegates to multiple other contexts, the lookup returns the first successful
	* match.
	*
	* @param name a <code>String</code> value.
	* @return an <code>Object</code> value.
	* @throws NamingException if an error occurs.
	*/
	public Object lookup(String name) throws NamingException {
	if (name == null) throw new IllegalArgumentException("Name required");
	if (name.length() == 0) return this;

	// Let alias redirection do its magic
	String alias = aliases.getProperty(name);
	if (alias != null) name = alias;

	for (Iterator i = contexts.iterator(); i.hasNext();) {
	Context c = (Context) i.next();
	try {
	return c.lookup(name);
	} catch (InvalidNameException ignore) {
	} catch (NameNotFoundException ignore) {
	} catch (NamingException ignore){}
	}
	throw new NameNotFoundException(name + " not found in any managed subcontext");
	}

	public Object lookup(Name name) throws NamingException {
	return lookup(name.toString());
	}

	public synchronized void bind(String name, Object obj) throws NamingException {
	if (name == null) throw new IllegalArgumentException("Name required");
	if (name.length() == 0) throw new InvalidNameException("Cannot bind object named after context");

	// If it's an alias name, stop here.
	if (aliases.containsKey(name))
	throw new NameAlreadyBoundException("Name \"" + name + "\" already bound as an aliased name");

	// Make sure it isn't bound anywhere
	for (NamingEnumeration e = list(""); e.hasMore();) {
	NameClassPair nameClassPair = (NameClassPair) e.next();
	if (name.equals(nameClassPair.getName()))
	throw new NameAlreadyBoundException("Name \"" + name + "\" already bound by a managed subcontext");
	}
	doRebind(name, obj);
	}

	public void bind(Name name, Object obj) throws NamingException {
	bind(name.toString(), obj);
	}

	/** {@inheritDoc} */
	public synchronized void rebind(String name, Object obj) throws NamingException {
	if (name == null) throw new IllegalArgumentException("Name required");
	if (name.length() == 0) throw new InvalidNameException("Cannot rebind object named after context");

	// If it's an alias name, remove the alias
	if (aliases.containsKey(name))
	aliases.remove(name);

	doRebind(name, obj);
	}

	/**
	* Rebind the given name to the given object.
	*
	* @param name Name to rebind
	* @param obj Object to which it's bound
	* @throws NamingException if an error occurs.
	*/
	private void doRebind(String name, Object obj) throws NamingException {
	boolean bound = false;
	for (Iterator i = contexts.iterator(); i.hasNext();) {
	Context c = (Context) i.next();
	try {
	c.rebind(name, obj);
	bound = true;
	} catch (NamingException ex) {}
	}
	if (!bound) throw new InvalidNameException("Name \"" + name + "\" not compatible with any managed subcontext");
	}

	public void rebind(Name name, Object obj) throws NamingException {
	rebind(name.toString(), obj);
	}

	public void unbind(String name) throws NamingException {
	if (name == null) throw new IllegalArgumentException("Name required");
	if (name.length() == 0) throw new InvalidNameException("Cannot unbind object named after context");

	// See if it's an aliased name
	if (aliases.containsKey(name)) {
	aliases.remove(name);
	return;
	}

	boolean unbound = false;
	for (Iterator i = contexts.iterator(); i.hasNext();) {
	Context c = (Context) i.next();
	try {
	c.unbind(name);
	unbound = true;
	} catch (NamingException ignore) {}
	}
	if (!unbound) throw new InvalidNameException("Name \"" + name + "\" not compatible with any managed subcontext");
	}

	public void unbind(Name name) throws NamingException {
	unbind(name.toString());
	}

	public void rename(String oldName, String newName) throws NamingException {
	if (oldName == null \|\| newName == null)
	throw new IllegalArgumentException("Name required");
	if (oldName.length() == 0 \|\| newName.length() == 0)
	throw new InvalidNameException("Cannot rename object named after context");

	// See if it's an aliased name
	String oldValue = (String) aliases.remove(oldName);
	if (oldValue != null) {
	aliases.setProperty(newName, oldName);
	return;
	}

	boolean renamed = false;
	for (Iterator i = contexts.iterator(); i.hasNext();) {
	Context c = (Context) i.next();
	try {
	c.rename(oldName, newName);
	renamed = true;
	} catch (NamingException ignore) {}
	}
	if (!renamed) throw new InvalidNameException("Names not compatible with any managed subcontext");
	}

	public void rename(Name oldName, Name newName) throws NamingException {
	rename(oldName.toString(), newName.toString());
	}

	public NamingEnumeration list(final String name) throws NamingException {
	final Iterator eachContext = contexts.iterator();
	return new NamingEnumeration() {
	private NamingEnumeration enumeration
	= eachContext.hasNext()? ((Context) eachContext.next()).list(name) : null;
	private boolean open = true;
	public Object next() throws NamingException {
	if (!open) throw new NamingException("closed");
	if (enumeration != null && enumeration.hasMore())
	return enumeration.next();
	else if (eachContext.hasNext()) {
	enumeration = ((Context) eachContext.next()).list(name);
	if (enumeration.hasMore())
	return enumeration.next();
	}
	throw new NoSuchElementException("No more objects in context");
	}
	public Object nextElement() {
	Object rc = null;
	try {
	rc = next();
	} catch (NamingException ignore) {}
	return rc;
	}
	public boolean hasMore() throws NamingException {
	if (!open) return false;
	if (enumeration == null)
	return false;
	else if (enumeration.hasMore())
	return true;
	else if (eachContext.hasNext()) {
	enumeration = ((Context) eachContext.next()).list(name);
	return hasMore();
	}
	return false;
	}
	public boolean hasMoreElements() {
	boolean h = false;
	try {
	h = hasMore();
	} catch (NamingException ignore) {}
	return h;
	}
	public void close() throws NamingException {
	open = false;
	if (enumeration != null)
	enumeration.close();
	}
	};
	}

	public NamingEnumeration list(Name name) throws NamingException {
	return list(name.toString());
	}

	public NamingEnumeration listBindings(final String name) throws NamingException {
	final Iterator eachContext = contexts.iterator();
	return new NamingEnumeration() {
	private NamingEnumeration enumeration
	= eachContext.hasNext()? ((Context) eachContext.next()).listBindings(name) : null;
	private boolean open = true;
	public Object next() throws NamingException {
	if (!open) throw new NamingException("closed");
	if (enumeration != null && enumeration.hasMore())
	return enumeration.next();
	else if (eachContext.hasNext()) {
	enumeration = ((Context) eachContext.next()).listBindings(name);
	if (enumeration.hasMore())
	return enumeration.next();
	}
	throw new NoSuchElementException("No more objects in context");
	}
	public Object nextElement() {
	Object rc = null;
	try {
	rc = next();
	} catch (NamingException ignore) {}
	return rc;
	}
	public boolean hasMore() throws NamingException {
	if (!open) return false;
	if (enumeration == null)
	return false;
	else if (enumeration.hasMore())
	return true;
	else if (eachContext.hasNext()) {
	enumeration = ((Context) eachContext.next()).listBindings(name);
	return hasMore();
	}
	return false;
	}
	public boolean hasMoreElements() {
	boolean h = false;
	try {
	h = hasMore();
	} catch (NamingException ignore) {}
	return h;
	}
	public void close() throws NamingException {
	open = false;
	if (enumeration != null)
	enumeration.close();
	}
	};
	}

	public NamingEnumeration listBindings(Name name) throws NamingException {
	return listBindings(name.toString());
	}

	public void destroySubcontext(String name) throws NamingException {
	throw new OperationNotSupportedException("Subcontexts not supported by ObjectContext");
	}

	public void destroySubcontext(Name name) throws NamingException {
	destroySubcontext(name.toString());
	}

	public Context createSubcontext(String name) throws NamingException {
	throw new OperationNotSupportedException("Subcontexts not supported by ObjectContext");
	}

	public Context createSubcontext(Name name) throws NamingException {
	return createSubcontext(name.toString());
	}

	public Object lookupLink(String name) throws NamingException {
	return lookup(name);
	}

	public Object lookupLink(Name name) throws NamingException {
	return lookupLink(name.toString());
	}

	public NameParser getNameParser(String name) throws NamingException {
	return nameParser;
	}

	public NameParser getNameParser(Name name) throws NamingException {
	return getNameParser(name.toString());
	}

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

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

	public Object addToEnvironment(String propName, Object propVal) throws NamingException {
	if (environment == null) environment = new Hashtable();
	return environment.put(propName, propVal);
	}

	public Object removeFromEnvironment(String propName) throws NamingException {
	if (environment == null) return null;
	return environment.remove(propName);
	}

	public Hashtable getEnvironment() throws NamingException {
	if (environment == null) return new Hashtable();
	return (Hashtable) environment.clone();
	}

	public String getNameInNamespace() throws NamingException {
	return "";
	}

	public void close() throws NamingException {
	environment = null;
	}

	/**
	* Install aliases specified in the properties file. The properties file simply
	* maps a string object name to a new object name. Use the system property
	* <code>org.apache.oodt.commons.object.jndi.aliases</code> (preferred) or simply
	* <code>aliases</code> to tell the location of the properties file.
	*/
	private void installAliases() {
	String aliasFileName = System.getProperty("org.apache.oodt.commons.object.jndi.aliases", System.getProperty("aliases"));
	if (aliasFileName != null && aliasFileName.length() > 0) {
	FileInputStream in = null;
	try {
	in = new FileInputStream(aliasFileName);
	aliases.load(in);
	} catch (IOException ex) {
	throw new IllegalStateException("Cannot handle I/O exception reading alias file " + aliasFileName
	+ ": " + ex.getMessage());
	} finally {
	if (in != null) try {
	in.close();
	} catch (IOException ignore) {}
	}
	}
	}

	/** Context's environment; currently unused. */
	private Hashtable environment;

	/** Parser for object names. */
	private static final NameParser nameParser = new ObjectNameParser();

	/** List of {@link Context}s to which we "multiplex". */
	private List contexts = new ArrayList();

	/** Aliased names. */
	private Properties aliases = new Properties();
	}