/*
 * $Header: /home/cvs/jakarta-tomcat-4.0/catalina/src/share/org/apache/naming/NamingContext.java,v 1.8 2001/11/08 21:02:04 remm Exp $
 * $Revision: 1.8 $
 * $Date: 2001/11/08 21:02:04 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written 
 *    permission, please contact [email protected]
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */ 


package org.apache.naming;

import java.util.Hashtable;
import java.util.Enumeration;
import javax.naming.Context;
import javax.naming.Name;
import javax.naming.LinkRef;
import javax.naming.CompositeName;
import javax.naming.NameParser;
import javax.naming.Referenceable;
import javax.naming.Reference;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.NameNotFoundException;
import javax.naming.NotContextException;
import javax.naming.InitialContext;
import javax.naming.OperationNotSupportedException;
import javax.naming.spi.NamingManager;

/**
 * Catalina JNDI Context implementation.
 *
 * @author Remy Maucherat
 * @version $Revision: 1.8 $ $Date: 2001/11/08 21:02:04 $
 */

public class NamingContext implements Context {


    // -------------------------------------------------------------- Constants


    /**
     * Name parser for this context.
     */
    protected static final NameParser nameParser = new NameParserImpl();


    // ----------------------------------------------------------- Constructors


    /**
     * Builds a naming context using the given environment.
     */
    public NamingContext(Hashtable env, String name) 
        throws NamingException {
        this.bindings = new Hashtable();
        this.env = new Hashtable();
        // FIXME ? Could be put in the environment ?
        this.name = name;
        // Populating the environment hashtable
        if (env != null ) {
            Enumeration envEntries = env.keys();
            while (envEntries.hasMoreElements()) {
                String entryName = (String) envEntries.nextElement();
                addToEnvironment(entryName, env.get(entryName));
            }
        }
    }


    /**
     * Builds a naming context using the given environment.
     */
    public NamingContext(Hashtable env, String name, Hashtable bindings) 
        throws NamingException {
        this(env, name);
        this.bindings = bindings;
    }


    // ----------------------------------------------------- Instance Variables


    /**
     * Environment.
     */
    protected Hashtable env;


    /**
     * The string manager for this package.
     */
    protected StringManager sm = StringManager.getManager(Constants.Package);


    /**
     * Bindings in this Context.
     */
    protected Hashtable bindings;


    /**
     * Name of the associated Catalina Context.
     */
    protected String name;


    // --------------------------------------------------------- Public Methods


    // -------------------------------------------------------- Context Methods


    /**
     * Retrieves the named object. If name is empty, returns a new instance 
     * of this context (which represents the same naming context as this 
     * context, but its environment may be modified independently and it may 
     * be accessed concurrently).
     * 
     * @param name the name of the object to look up
     * @return the object bound to name
     * @exception NamingException if a naming exception is encountered
     */
    public Object lookup(Name name)
        throws NamingException {
        return lookup(name, true);
    }


    /**
     * Retrieves the named object.
     * 
     * @param name the name of the object to look up
     * @return the object bound to name
     * @exception NamingException if a naming exception is encountered
     */
    public Object lookup(String name)
        throws NamingException {
        return lookup(new CompositeName(name), true);
    }


    /**
     * Binds a name to an object. All intermediate contexts and the target 
     * context (that named by all but terminal atomic component of the name) 
     * must already exist.
     * 
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if object did not supply all 
     * mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    public void bind(Name name, Object obj)
        throws NamingException {
        bind(name, obj, false);
    }


    /**
     * Binds a name to an object.
     * 
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if object did not supply all 
     * mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    public void bind(String name, Object obj)
        throws NamingException {
        bind(new CompositeName(name), obj);
    }


    /**
     * Binds a name to an object, overwriting any existing binding. All 
     * intermediate contexts and the target context (that named by all but 
     * terminal atomic component of the name) must already exist.
     * <p>
     * If the object is a DirContext, any existing attributes associated with 
     * the name are replaced with those of the object. Otherwise, any 
     * existing attributes associated with the name remain unchanged.
     * 
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @exception InvalidAttributesException if object did not supply all 
     * mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    public void rebind(Name name, Object obj)
        throws NamingException {
        bind(name, obj, true);
    }


    /**
     * Binds a name to an object, overwriting any existing binding.
     * 
     * @param name the name to bind; may not be empty
     * @param obj the object to bind; possibly null
     * @exception InvalidAttributesException if object did not supply all 
     * mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    public void rebind(String name, Object obj)
        throws NamingException {
        rebind(new CompositeName(name), obj);
    }


    /**
     * Unbinds the named object. Removes the terminal atomic name in name 
     * from the target context--that named by all but the terminal atomic 
     * part of name.
     * <p>
     * This method is idempotent. It succeeds even if the terminal atomic 
     * name is not bound in the target context, but throws 
     * NameNotFoundException if any of the intermediate contexts do not exist. 
     * 
     * @param name the name to bind; may not be empty
     * @exception NameNotFoundException if an intermediate context does not 
     * exist
     * @exception NamingException if a naming exception is encountered
     */
    public void unbind(Name name)
        throws NamingException {
        checkWritable();
        
	while ((!name.isEmpty()) && (name.get(0).length() == 0))
	    name = name.getSuffix(1);
        if (name.isEmpty())
            throw new NamingException
                (sm.getString("namingContext.invalidName"));
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (entry == null) {
            throw new NameNotFoundException
                (sm.getString("namingContext.nameNotBound", name.get(0)));
        }
        
        if (name.size() > 1) {
            if (entry.type == NamingEntry.CONTEXT) {
                ((Context) entry.value).unbind(name.getSuffix(1));
            } else {
                throw new NamingException
                    (sm.getString("namingContext.contextExpected"));
            }
        } else {
            bindings.remove(name.get(0));
        }
        
    }


    /**
     * Unbinds the named object.
     * 
     * @param name the name to bind; may not be empty
     * @exception NameNotFoundException if an intermediate context does not 
     * exist
     * @exception NamingException if a naming exception is encountered
     */
    public void unbind(String name)
        throws NamingException {
        unbind(new CompositeName(name));
    }


    /**
     * Binds a new name to the object bound to an old name, and unbinds the 
     * old name. Both names are relative to this context. Any attributes 
     * associated with the old name become associated with the new name. 
     * Intermediate contexts of the old name are not changed.
     * 
     * @param oldName the name of the existing binding; may not be empty
     * @param newName the name of the new binding; may not be empty
     * @exception NameAlreadyBoundException if newName is already bound
     * @exception NamingException if a naming exception is encountered
     */
    public void rename(Name oldName, Name newName)
        throws NamingException {
        Object value = lookup(oldName);
        bind(newName, value);
        unbind(oldName);
    }


    /**
     * Binds a new name to the object bound to an old name, and unbinds the 
     * old name.
     * 
     * @param oldName the name of the existing binding; may not be empty
     * @param newName the name of the new binding; may not be empty
     * @exception NameAlreadyBoundException if newName is already bound
     * @exception NamingException if a naming exception is encountered
     */
    public void rename(String oldName, String newName)
        throws NamingException {
        rename(new CompositeName(oldName), new CompositeName(newName));
    }


    /**
     * Enumerates the names bound in the named context, along with the class 
     * names of objects bound to them. The contents of any subcontexts are 
     * not included.
     * <p>
     * If a binding is added to or removed from this context, its effect on 
     * an enumeration previously returned is undefined.
     * 
     * @param name the name of the context to list
     * @return an enumeration of the names and class names of the bindings in 
     * this context. Each element of the enumeration is of type NameClassPair.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration list(Name name)
        throws NamingException {
        // Removing empty parts
        while ((!name.isEmpty()) && (name.get(0).length() == 0))
            name = name.getSuffix(1);
        if (name.isEmpty()) {
            return new NamingContextEnumeration(bindings.elements());
        }
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (entry == null) {
            throw new NameNotFoundException
                (sm.getString("namingContext.nameNotBound", name.get(0)));
        }
        
        if (entry.type != NamingEntry.CONTEXT) {
            throw new NamingException
                (sm.getString("namingContext.contextExpected"));
        }
        return ((Context) entry.value).list(name.getSuffix(1));
    }


    /**
     * Enumerates the names bound in the named context, along with the class 
     * names of objects bound to them.
     * 
     * @param name the name of the context to list
     * @return an enumeration of the names and class names of the bindings in 
     * this context. Each element of the enumeration is of type NameClassPair.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration list(String name)
        throws NamingException {
        return list(new CompositeName(name));
    }


    /**
     * Enumerates the names bound in the named context, along with the 
     * objects bound to them. The contents of any subcontexts are not 
     * included.
     * <p>
     * If a binding is added to or removed from this context, its effect on 
     * an enumeration previously returned is undefined.
     * 
     * @param name the name of the context to list
     * @return an enumeration of the bindings in this context. 
     * Each element of the enumeration is of type Binding.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration listBindings(Name name)
        throws NamingException {
        // Removing empty parts
        while ((!name.isEmpty()) && (name.get(0).length() == 0))
            name = name.getSuffix(1);
        if (name.isEmpty()) {
            return new NamingContextBindingsEnumeration(bindings.elements());
        }
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (entry == null) {
            throw new NameNotFoundException
                (sm.getString("namingContext.nameNotBound", name.get(0)));
        }
        
        if (entry.type != NamingEntry.CONTEXT) {
            throw new NamingException
                (sm.getString("namingContext.contextExpected"));
        }
        return ((Context) entry.value).listBindings(name.getSuffix(1));
    }


    /**
     * Enumerates the names bound in the named context, along with the 
     * objects bound to them.
     * 
     * @param name the name of the context to list
     * @return an enumeration of the bindings in this context. 
     * Each element of the enumeration is of type Binding.
     * @exception NamingException if a naming exception is encountered
     */
    public NamingEnumeration listBindings(String name)
        throws NamingException {
        return listBindings(new CompositeName(name));
    }


    /**
     * Destroys the named context and removes it from the namespace. Any 
     * attributes associated with the name are also removed. Intermediate 
     * contexts are not destroyed.
     * <p>
     * This method is idempotent. It succeeds even if the terminal atomic 
     * name is not bound in the target context, but throws 
     * NameNotFoundException if any of the intermediate contexts do not exist. 
     * 
     * In a federated naming system, a context from one naming system may be 
     * bound to a name in another. One can subsequently look up and perform 
     * operations on the foreign context using a composite name. However, an 
     * attempt destroy the context using this composite name will fail with 
     * NotContextException, because the foreign context is not a "subcontext" 
     * of the context in which it is bound. Instead, use unbind() to remove 
     * the binding of the foreign context. Destroying the foreign context 
     * requires that the destroySubcontext() be performed on a context from 
     * the foreign context's "native" naming system.
     * 
     * @param name the name of the context to be destroyed; may not be empty
     * @exception NameNotFoundException if an intermediate context does not 
     * exist
     * @exception NotContextException if the name is bound but does not name 
     * a context, or does not name a context of the appropriate type
     */
    public void destroySubcontext(Name name)
        throws NamingException {
        
        checkWritable();
        
	while ((!name.isEmpty()) && (name.get(0).length() == 0))
	    name = name.getSuffix(1);
        if (name.isEmpty())
            throw new NamingException
                (sm.getString("namingContext.invalidName"));
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (entry == null) {
            throw new NameNotFoundException
                (sm.getString("namingContext.nameNotBound", name.get(0)));
        }
        
        if (name.size() > 1) {
            if (entry.type == NamingEntry.CONTEXT) {
                ((Context) entry.value).unbind(name.getSuffix(1));
            } else {
                throw new NamingException
                    (sm.getString("namingContext.contextExpected"));
            }
        } else {
            if (entry.type == NamingEntry.CONTEXT) {
                ((Context) entry.value).close();
                bindings.remove(name.get(0));
            } else {
                throw new NotContextException
                    (sm.getString("namingContext.contextExpected"));
            }
        }
        
    }


    /**
     * Destroys the named context and removes it from the namespace.
     * 
     * @param name the name of the context to be destroyed; may not be empty
     * @exception NameNotFoundException if an intermediate context does not 
     * exist
     * @exception NotContextException if the name is bound but does not name 
     * a context, or does not name a context of the appropriate type
     */
    public void destroySubcontext(String name)
        throws NamingException {
        destroySubcontext(new CompositeName(name));
    }


    /**
     * Creates and binds a new context. Creates a new context with the given 
     * name and binds it in the target context (that named by all but 
     * terminal atomic component of the name). All intermediate contexts and 
     * the target context must already exist.
     * 
     * @param name the name of the context to create; may not be empty
     * @return the newly created context
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if creation of the subcontext 
     * requires specification of mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    public Context createSubcontext(Name name)
        throws NamingException {
        checkWritable();
        
        Context newContext = new NamingContext(env, this.name);
        bind(name, newContext);
        
        return newContext;
    }


    /**
     * Creates and binds a new context.
     * 
     * @param name the name of the context to create; may not be empty
     * @return the newly created context
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if creation of the subcontext 
     * requires specification of mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    public Context createSubcontext(String name)
        throws NamingException {
        return createSubcontext(new CompositeName(name));
    }


    /**
     * Retrieves the named object, following links except for the terminal 
     * atomic component of the name. If the object bound to name is not a 
     * link, returns the object itself.
     * 
     * @param name the name of the object to look up
     * @return the object bound to name, not following the terminal link 
     * (if any).
     * @exception NamingException if a naming exception is encountered
     */
    public Object lookupLink(Name name)
        throws NamingException {
        return lookup(name, false);
    }


    /**
     * Retrieves the named object, following links except for the terminal 
     * atomic component of the name.
     * 
     * @param name the name of the object to look up
     * @return the object bound to name, not following the terminal link 
     * (if any).
     * @exception NamingException if a naming exception is encountered
     */
    public Object lookupLink(String name)
        throws NamingException {
        return lookup(new CompositeName(name), false);
    }


    /**
     * Retrieves the parser associated with the named context. In a 
     * federation of namespaces, different naming systems will parse names 
     * differently. This method allows an application to get a parser for 
     * parsing names into their atomic components using the naming convention 
     * of a particular naming system. Within any single naming system, 
     * NameParser objects returned by this method must be equal (using the 
     * equals() test).
     * 
     * @param name the name of the context from which to get the parser
     * @return a name parser that can parse compound names into their atomic 
     * components
     * @exception NamingException if a naming exception is encountered
     */
    public NameParser getNameParser(Name name)
        throws NamingException {

	while ((!name.isEmpty()) && (name.get(0).length() == 0))
	    name = name.getSuffix(1);
        if (name.isEmpty())
            return nameParser;

        if (name.size() > 1) {
            Object obj = bindings.get(name.get(0));
            if (obj instanceof Context) {
                return ((Context) obj).getNameParser(name.getSuffix(1));
            } else {
                throw new NotContextException
                    (sm.getString("namingContext.contextExpected"));
            }
        }

        return nameParser;

    }


    /**
     * Retrieves the parser associated with the named context.
     * 
     * @param name the name of the context from which to get the parser
     * @return a name parser that can parse compound names into their atomic 
     * components
     * @exception NamingException if a naming exception is encountered
     */
    public NameParser getNameParser(String name)
        throws NamingException {
        return getNameParser(new CompositeName(name));
    }


    /**
     * Composes the name of this context with a name relative to this context.
     * <p>
     * Given a name (name) relative to this context, and the name (prefix) 
     * of this context relative to one of its ancestors, this method returns 
     * the composition of the two names using the syntax appropriate for the 
     * naming system(s) involved. That is, if name names an object relative 
     * to this context, the result is the name of the same object, but 
     * relative to the ancestor context. None of the names may be null.
     * 
     * @param name a name relative to this context
     * @param prefix the name of this context relative to one of its ancestors
     * @return the composition of prefix and name
     * @exception NamingException if a naming exception is encountered
     */
    public Name composeName(Name name, Name prefix)
        throws NamingException {
	prefix = (Name) name.clone();
	return prefix.addAll(name);
    }


    /**
     * Composes the name of this context with a name relative to this context.
     * 
     * @param name a name relative to this context
     * @param prefix the name of this context relative to one of its ancestors
     * @return the composition of prefix and name
     * @exception NamingException if a naming exception is encountered
     */
    public String composeName(String name, String prefix)
        throws NamingException {
        return prefix + "/" + name;
    }


    /**
     * Adds a new environment property to the environment of this context. If 
     * the property already exists, its value is overwritten.
     * 
     * @param propName the name of the environment property to add; may not 
     * be null
     * @param propVal the value of the property to add; may not be null
     * @exception NamingException if a naming exception is encountered
     */
    public Object addToEnvironment(String propName, Object propVal)
        throws NamingException {
        return env.put(propName, propVal);
    }


    /**
     * Removes an environment property from the environment of this context. 
     * 
     * @param propName the name of the environment property to remove; 
     * may not be null
     * @exception NamingException if a naming exception is encountered
     */
    public Object removeFromEnvironment(String propName)
        throws NamingException {
        return env.remove(propName);
    }


    /**
     * Retrieves the environment in effect for this context. See class 
     * description for more details on environment properties. 
     * The caller should not make any changes to the object returned: their 
     * effect on the context is undefined. The environment of this context 
     * may be changed using addToEnvironment() and removeFromEnvironment().
     * 
     * @return the environment of this context; never null
     * @exception NamingException if a naming exception is encountered
     */
    public Hashtable getEnvironment()
        throws NamingException {
        return env;
    }


    /**
     * Closes this context. This method releases this context's resources 
     * immediately, instead of waiting for them to be released automatically 
     * by the garbage collector.
     * This method is idempotent: invoking it on a context that has already 
     * been closed has no effect. Invoking any other method on a closed 
     * context is not allowed, and results in undefined behaviour.
     * 
     * @exception NamingException if a naming exception is encountered
     */
    public void close()
        throws NamingException {
        env.clear();
    }


    /**
     * Retrieves the full name of this context within its own namespace.
     * <p>
     * Many naming services have a notion of a "full name" for objects in 
     * their respective namespaces. For example, an LDAP entry has a 
     * distinguished name, and a DNS record has a fully qualified name. This 
     * method allows the client application to retrieve this name. The string 
     * returned by this method is not a JNDI composite name and should not be 
     * passed directly to context methods. In naming systems for which the 
     * notion of full name does not make sense, 
     * OperationNotSupportedException is thrown.
     * 
     * @return this context's name in its own namespace; never null
     * @exception OperationNotSupportedException if the naming system does 
     * not have the notion of a full name
     * @exception NamingException if a naming exception is encountered
     */
    public String getNameInNamespace()
        throws NamingException {
        throw  new OperationNotSupportedException
            (sm.getString("namingContext.noAbsoluteName"));
        //FIXME ?
    }


    // ------------------------------------------------------ Protected Methods


    /**
     * Retrieves the named object.
     * 
     * @param name the name of the object to look up
     * @param resolveLinks If true, the links will be resolved
     * @return the object bound to name
     * @exception NamingException if a naming exception is encountered
     */
    protected Object lookup(Name name, boolean resolveLinks)
        throws NamingException {

        // Removing empty parts
        while ((!name.isEmpty()) && (name.get(0).length() == 0))
            name = name.getSuffix(1);
        if (name.isEmpty()) {
            // If name is empty, a newly allocated naming context is returned
            return new NamingContext(env, this.name, bindings);
        }
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (entry == null) {
            throw new NameNotFoundException
                (sm.getString("namingContext.nameNotBound", name.get(0)));
        }
        
        if (name.size() > 1) {
            // If the size of the name is greater that 1, then we go through a
            // number of subcontexts.
            if (entry.type != NamingEntry.CONTEXT) {
                throw new NamingException
                    (sm.getString("namingContext.contextExpected"));
            }
            return ((Context) entry.value).lookup(name.getSuffix(1));
        } else {
            if ((resolveLinks) && (entry.type == NamingEntry.LINK_REF)) {
                String link = ((LinkRef) entry.value).getLinkName();
                if (link.startsWith(".")) {
                    // Link relative to this context
                    return lookup(link.substring(1));
                } else {
                    return (new InitialContext(env)).lookup(link);
                }
            } else if (entry.type == NamingEntry.REFERENCE) {
                try {
                    Object obj = NamingManager.getObjectInstance
                        (entry.value, name, this, env);
                    if (obj != null) {
                        entry.value = obj;
                        entry.type = NamingEntry.ENTRY;
                    }
                    return obj;
                } catch (NamingException e) {
                    throw e;
                } catch (Exception e) {
                    throw new NamingException(e.getMessage());
                }
            } else {
                return entry.value;
            }
        }
        
    }


    /**
     * Binds a name to an object. All intermediate contexts and the target 
     * context (that named by all but terminal atomic component of the name) 
     * must already exist.
     * 
     * @param name the name to bind; may not be empty
     * @param object the object to bind; possibly null
     * @param rebind if true, then perform a rebind (ie, overwrite)
     * @exception NameAlreadyBoundException if name is already bound
     * @exception InvalidAttributesException if object did not supply all 
     * mandatory attributes
     * @exception NamingException if a naming exception is encountered
     */
    protected void bind(Name name, Object obj, boolean rebind)
        throws NamingException {
        
        checkWritable();
        
	while ((!name.isEmpty()) && (name.get(0).length() == 0))
	    name = name.getSuffix(1);
        if (name.isEmpty())
            throw new NamingException
                (sm.getString("namingContext.invalidName"));
        
        NamingEntry entry = (NamingEntry) bindings.get(name.get(0));
        
        if (name.size() > 1) {
            if (entry == null) {
                throw new NameNotFoundException
                    (sm.getString("namingContext.nameNotBound", name.get(0)));
            }
            if (entry.type == NamingEntry.CONTEXT) {
                if (rebind) {
                    ((Context) entry.value).rebind(name.getSuffix(1), obj);
                } else {
                    ((Context) entry.value).bind(name.getSuffix(1), obj);
                }
            } else {
                throw new NamingException
                    (sm.getString("namingContext.contextExpected"));
            }
        } else {
            if ((!rebind) && (entry != null)) {
                throw new NamingException
                    (sm.getString("namingContext.alreadyBound", name.get(0)));
            } else {
                // Getting the type of the object and wrapping it within a new
                // NamingEntry
                Object toBind = 
                    NamingManager.getStateToBind(obj, name, this, env);
                if (toBind instanceof Context) {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.CONTEXT);
                } else if (toBind instanceof LinkRef) {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.LINK_REF);
                } else if (toBind instanceof Reference) {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.REFERENCE);
                } else if (toBind instanceof Referenceable) {
                    toBind = ((Referenceable) toBind).getReference();
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.REFERENCE);
                } else {
                    entry = new NamingEntry(name.get(0), toBind, 
                                            NamingEntry.ENTRY);
                }
                bindings.put(name.get(0), entry);
            }
        }
        
    }


    /**
     * Returns true if writing is allowed on this context.
     */
    protected boolean isWritable() {
        return ContextAccessController.isWritable(name);
    }


    /**
     * Throws a naming exception is Context is not writable.
     */
    protected void checkWritable() 
        throws NamingException {
        if (!isWritable())
            throw new NamingException(sm.getString("namingContext.readOnly"));
    }


}