//----------------------------BEGIN LICENSE----------------------------
/* 
 * Willow : the Open Source WorkFlow Project
 * Distributable under GNU LGPL license by gun.org
 *
 * Copyright (C) 2004-2010  huihoo.org 
 * Copyright (C) 2004-2010  ZosaTapo <dertyang@hotmail.com> 
 * 
 * ====================================================================
 * Project Homepage : http://www.huihoo.org/willow
 * Source Forge     : http://sourceforge.net/projects/huihoo
 * Mailing list     : willow@lists.sourceforge.net 
 */
//----------------------------END  LICENSE-----------------------------
package org.huihoo.willow.naming.resources;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NameNotFoundException;
import javax.naming.NameParser;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.directory.ModificationItem;
import javax.naming.directory.SearchControls;

import org.huihoo.willow.util.StringManager;

public class ProxyDirContext implements DirContext
{

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

	public static final String CONTEXT = "context";
	public static final String SERVICE = "service";

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

	/**
	 * Builds a proxy directory context using the given environment.
	 */
	public ProxyDirContext(Hashtable env, DirContext dirContext)
	{
		this.env = env;
		this.dirContext = dirContext;
		if (dirContext instanceof BaseDirContext)
		{
			// Initialize parameters based on the associated dir context, like
			// the caching policy.
			BaseDirContext baseDirContext = (BaseDirContext) dirContext;
			if (baseDirContext.isCached())
			{
				try
				{
					cache = (ResourceCache) Class.forName(cacheClassName).newInstance();
				}
				catch (Exception e)
				{
					//FIXME
					e.printStackTrace();
				}
				cache.setCacheMaxSize(baseDirContext.getCacheMaxSize());
				cacheObjectMaxSize = baseDirContext.getCacheMaxSize() / 20;
			}
		}
		engineName = (String) env.get(SERVICE);
		contextName = (String) env.get(CONTEXT);
	}


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

	/**
	 * Proxy DirContext (either this or the real proxy).
	 */
	protected ProxyDirContext proxy = this;

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

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

	/**
	 * Associated DirContext.
	 */
	protected DirContext dirContext;

	/**
	 * Virtual path.
	 */
	protected String vPath = null;

	/**
	 * Host name.
	 */
	protected String engineName;

	/**
	 * Context name.
	 */
	protected String contextName;

	/**
	 * Cache class.
	 */
	protected String cacheClassName = "org.huihoo.willow.naming.resources.ResourceCache";

	/**
	 * Cache.
	 */
	protected ResourceCache cache = null;

	/**
	 * Cache TTL.
	 */
	protected int cacheTTL = 5000; // 5s

	/**
	 * Max size of resources which will have their content cached.
	 */
	protected int cacheObjectMaxSize = 512; // 512 KB

	/**
	 * Immutable name not found exception.
	 */
	protected NameNotFoundException notFoundException = new ImmutableNameNotFoundException();

	/**
	 * Non cacheable resources.
	 */
	protected String[] nonCacheable = { "/WEB-INF/lib/", "/WEB-INF/classes/" };

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

	/**
	 * Get the cache used for this context.
	 */
	public ResourceCache getCache()
	{
		return cache;
	}

	/**
	 * Return the actual directory context we are wrapping.
	 */
	public DirContext getDirContext()
	{
		return this.dirContext;
	}

	/**
	 * Return the document root for this component.
	 */
	public String getDocBase()
	{
		if (dirContext instanceof BaseDirContext)
			return ((BaseDirContext) dirContext).getDocBase();
		else
			return "";
	}

	/**
	 * Return the host name.
	 */
	public String getEngineName()
	{
		return this.engineName;
	}

	/**
	 * Return the context name.
	 */
	public String getContextName()
	{
		return this.contextName;
	}

	// -------------------------------------------------------- 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
	{
		CacheEntry entry = cacheLookup(name.toString());
		if (entry != null)
		{
			if (entry.resource != null)
			{
				// Check content caching.
				return entry.resource;
			}
			else
			{
				return entry.context;
			}
		}
		Object object = dirContext.lookup(parseName(name));
		if (object instanceof InputStream)
			return new Resource((InputStream) object);
		else
			return object;
	}

	/**
	 * 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
	{
		CacheEntry entry = cacheLookup(name);
		if (entry != null)
		{
			if (entry.resource != null)
			{
				return entry.resource;
			}
			else
			{
				return entry.context;
			}
		}
		Object object = dirContext.lookup(parseName(name));
		if (object instanceof InputStream)
		{
			return new Resource((InputStream) object);
		}
		else if (object instanceof DirContext)
		{
			return object;
		}
		else if (object instanceof Resource)
		{
			return object;
		}
		else
		{
			return new Resource(new ByteArrayInputStream(object.toString().getBytes()));
		}
	}

	/**
	 * 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
	{
		dirContext.bind(parseName(name), obj);
		cacheUnload(name.toString());
	}

	/**
	 * 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
	{
		dirContext.bind(parseName(name), obj);
		cacheUnload(name);
	}

	/**
	 * 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
	{
		dirContext.rebind(parseName(name), obj);
		cacheUnload(name.toString());
	}

	/**
	 * 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
	{
		dirContext.rebind(parseName(name), obj);
		cacheUnload(name);
	}

	/**
	 * 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
	{
		dirContext.unbind(parseName(name));
		cacheUnload(name.toString());
	}

	/**
	 * 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
	{
		dirContext.unbind(parseName(name));
		cacheUnload(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
	{
		dirContext.rename(parseName(oldName), parseName(newName));
		cacheUnload(oldName.toString());
	}

	/**
	 * 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
	{
		dirContext.rename(parseName(oldName), parseName(newName));
		cacheUnload(oldName);
	}

	/**
	 * 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
	{
		return dirContext.list(parseName(name));
	}

	/**
	 * 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 dirContext.list(parseName(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
	{
		return dirContext.listBindings(parseName(name));
	}

	/**
	 * 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 dirContext.listBindings(parseName(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
	{
		dirContext.destroySubcontext(parseName(name));
		cacheUnload(name.toString());
	}

	/**
	 * 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
	{
		dirContext.destroySubcontext(parseName(name));
		cacheUnload(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
	{
		Context context = dirContext.createSubcontext(parseName(name));
		cacheUnload(name.toString());
		return context;
	}

	/**
	 * 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
	{
		Context context = dirContext.createSubcontext(parseName(name));
		cacheUnload(name);
		return context;
	}

	/**
	 * 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 dirContext.lookupLink(parseName(name));
	}

	/**
	 * 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 dirContext.lookupLink(parseName(name));
	}

	/**
	 * 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
	{
		return dirContext.getNameParser(parseName(name));
	}

	/**
	 * 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 dirContext.getNameParser(parseName(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 dirContext.addToEnvironment(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 dirContext.removeFromEnvironment(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 dirContext.getEnvironment();
	}

	/**
	 * 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
	{
		dirContext.close();
	}

	/**
	 * 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
	{
		return dirContext.getNameInNamespace();
	}

	// ----------------------------------------------------- DirContext Methods

	/**
	 * Retrieves all of the attributes associated with a named object. 
	 * 
	 * @return the set of attributes associated with name. 
	 * Returns an empty attribute set if name has no attributes; never null.
	 * @param name the name of the object from which to retrieve attributes
	 * @exception NamingException if a naming exception is encountered
	 */
	public Attributes getAttributes(Name name) throws NamingException
	{
		CacheEntry entry = cacheLookup(name.toString());
		if (entry != null)
		{
			return entry.attributes;
		}
		Attributes attributes = dirContext.getAttributes(parseName(name));
		if (!(attributes instanceof ResourceAttributes))
		{
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Retrieves all of the attributes associated with a named object.
	 * 
	 * @return the set of attributes associated with name
	 * @param name the name of the object from which to retrieve attributes
	 * @exception NamingException if a naming exception is encountered
	 */
	public Attributes getAttributes(String name) throws NamingException
	{
		CacheEntry entry = cacheLookup(name);
		if (entry != null)
		{
			return entry.attributes;
		}
		Attributes attributes = dirContext.getAttributes(parseName(name));
		if (!(attributes instanceof ResourceAttributes))
		{
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Retrieves selected attributes associated with a named object. 
	 * See the class description regarding attribute templates, attribute type 
	 * names, and operational attributes.
	 * 
	 * @return the requested attributes; never null
	 * @param name the name of the object from which to retrieve attributes
	 * @param attrIds the identifiers of the attributes to retrieve. null 
	 * indicates that all attributes should be retrieved; an empty array 
	 * indicates that none should be retrieved
	 * @exception NamingException if a naming exception is encountered
	 */
	public Attributes getAttributes(Name name, String[] attrIds) throws NamingException
	{
		Attributes attributes = dirContext.getAttributes(parseName(name), attrIds);
		if (!(attributes instanceof ResourceAttributes))
		{
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Retrieves selected attributes associated with a named object.
	 * 
	 * @return the requested attributes; never null
	 * @param name the name of the object from which to retrieve attributes
	 * @param attrIds the identifiers of the attributes to retrieve. null 
	 * indicates that all attributes should be retrieved; an empty array 
	 * indicates that none should be retrieved
	 * @exception NamingException if a naming exception is encountered
	 */
	public Attributes getAttributes(String name, String[] attrIds) throws NamingException
	{
		Attributes attributes = dirContext.getAttributes(parseName(name), attrIds);
		if (!(attributes instanceof ResourceAttributes))
		{
			attributes = new ResourceAttributes(attributes);
		}
		return attributes;
	}

	/**
	 * Modifies the attributes associated with a named object. The order of 
	 * the modifications is not specified. Where possible, the modifications 
	 * are performed atomically.
	 * 
	 * @param name the name of the object whose attributes will be updated
	 * @param mod_op the modification operation, one of: ADD_ATTRIBUTE, 
	 * REPLACE_ATTRIBUTE, REMOVE_ATTRIBUTE
	 * @param attrs the attributes to be used for the modification; may not 
	 * be null
	 * @exception AttributeModificationException if the modification cannot be
	 * completed successfully
	 * @exception NamingException if a naming exception is encountered
	 */
	public void modifyAttributes(Name name, int mod_op, Attributes attrs) throws NamingException
	{
		dirContext.modifyAttributes(parseName(name), mod_op, attrs);
		cacheUnload(name.toString());
	}

	/**
	 * Modifies the attributes associated with a named object.
	 * 
	 * @param name the name of the object whose attributes will be updated
	 * @param mod_op the modification operation, one of: ADD_ATTRIBUTE, 
	 * REPLACE_ATTRIBUTE, REMOVE_ATTRIBUTE
	 * @param attrs the attributes to be used for the modification; may not 
	 * be null
	 * @exception AttributeModificationException if the modification cannot be
	 * completed successfully
	 * @exception NamingException if a naming exception is encountered
	 */
	public void modifyAttributes(String name, int mod_op, Attributes attrs) throws NamingException
	{
		dirContext.modifyAttributes(parseName(name), mod_op, attrs);
		cacheUnload(name);
	}

	/**
	 * Modifies the attributes associated with a named object using an an 
	 * ordered list of modifications. The modifications are performed in the 
	 * order specified. Each modification specifies a modification operation 
	 * code and an attribute on which to operate. Where possible, the 
	 * modifications are performed atomically.
	 * 
	 * @param name the name of the object whose attributes will be updated
	 * @param mods an ordered sequence of modifications to be performed; may 
	 * not be null
	 * @exception AttributeModificationException if the modification cannot be
	 * completed successfully
	 * @exception NamingException if a naming exception is encountered
	 */
	public void modifyAttributes(Name name, ModificationItem[] mods) throws NamingException
	{
		dirContext.modifyAttributes(parseName(name), mods);
		cacheUnload(name.toString());
	}

	/**
	 * Modifies the attributes associated with a named object using an an 
	 * ordered list of modifications.
	 * 
	 * @param name the name of the object whose attributes will be updated
	 * @param mods an ordered sequence of modifications to be performed; may 
	 * not be null
	 * @exception AttributeModificationException if the modification cannot be
	 * completed successfully
	 * @exception NamingException if a naming exception is encountered
	 */
	public void modifyAttributes(String name, ModificationItem[] mods) throws NamingException
	{
		dirContext.modifyAttributes(parseName(name), mods);
		cacheUnload(name);
	}

	/**
	 * Binds a name to an object, along with associated attributes. If attrs 
	 * is null, the resulting binding will have the attributes associated 
	 * with obj if obj is a DirContext, and no attributes otherwise. If attrs 
	 * is non-null, the resulting binding will have attrs as its attributes; 
	 * any attributes associated with obj are ignored.
	 * 
	 * @param name the name to bind; may not be empty
	 * @param obj the object to bind; possibly null
	 * @param attrs the attributes to associate with the binding
	 * @exception NameAlreadyBoundException if name is already bound
	 * @exception InvalidAttributesException if some "mandatory" attributes 
	 * of the binding are not supplied
	 * @exception NamingException if a naming exception is encountered
	 */
	public void bind(Name name, Object obj, Attributes attrs) throws NamingException
	{
		dirContext.bind(parseName(name), obj, attrs);
		cacheUnload(name.toString());
	}

	/**
	 * Binds a name to an object, along with associated attributes.
	 * 
	 * @param name the name to bind; may not be empty
	 * @param obj the object to bind; possibly null
	 * @param attrs the attributes to associate with the binding
	 * @exception NameAlreadyBoundException if name is already bound
	 * @exception InvalidAttributesException if some "mandatory" attributes 
	 * of the binding are not supplied
	 * @exception NamingException if a naming exception is encountered
	 */
	public void bind(String name, Object obj, Attributes attrs) throws NamingException
	{
		dirContext.bind(parseName(name), obj, attrs);
		cacheUnload(name);
	}

	/**
	 * Binds a name to an object, along with associated attributes, 
	 * overwriting any existing binding. If attrs is null and obj is a 
	 * DirContext, the attributes from obj are used. If attrs is null and obj 
	 * is not a DirContext, any existing attributes associated with the object
	 * already bound in the directory remain unchanged. If attrs is non-null, 
	 * any existing attributes associated with the object already bound in 
	 * the directory are removed and attrs is associated with the named 
	 * object. If obj is a DirContext and attrs is non-null, the attributes 
	 * of obj are ignored.
	 * 
	 * @param name the name to bind; may not be empty
	 * @param obj the object to bind; possibly null
	 * @param attrs the attributes to associate with the binding
	 * @exception InvalidAttributesException if some "mandatory" attributes 
	 * of the binding are not supplied
	 * @exception NamingException if a naming exception is encountered
	 */
	public void rebind(Name name, Object obj, Attributes attrs) throws NamingException
	{
		dirContext.rebind(parseName(name), obj, attrs);
		cacheUnload(name.toString());
	}

	/**
	 * Binds a name to an object, along with associated attributes, 
	 * overwriting any existing binding.
	 * 
	 * @param name the name to bind; may not be empty
	 * @param obj the object to bind; possibly null
	 * @param attrs the attributes to associate with the binding
	 * @exception InvalidAttributesException if some "mandatory" attributes 
	 * of the binding are not supplied
	 * @exception NamingException if a naming exception is encountered
	 */
	public void rebind(String name, Object obj, Attributes attrs) throws NamingException
	{
		dirContext.rebind(parseName(name), obj, attrs);
		cacheUnload(name);
	}

	/**
	 * Creates and binds a new context, along with associated attributes. 
	 * This method creates a new subcontext with the given name, binds it in 
	 * the target context (that named by all but terminal atomic component of 
	 * the name), and associates the supplied attributes with the newly 
	 * created object. All intermediate and target contexts must already 
	 * exist. If attrs is null, this method is equivalent to 
	 * Context.createSubcontext().
	 * 
	 * @param name the name of the context to create; may not be empty
	 * @param attrs the attributes to associate with the newly created context
	 * @return the newly created context
	 * @exception NameAlreadyBoundException if the name is already bound
	 * @exception InvalidAttributesException if attrs does not contain all 
	 * the mandatory attributes required for creation
	 * @exception NamingException if a naming exception is encountered
	 */
	public DirContext createSubcontext(Name name, Attributes attrs) throws NamingException
	{
		DirContext context = dirContext.createSubcontext(parseName(name), attrs);
		cacheUnload(name.toString());
		return context;
	}

	/**
	 * Creates and binds a new context, along with associated attributes.
	 * 
	 * @param name the name of the context to create; may not be empty
	 * @param attrs the attributes to associate with the newly created context
	 * @return the newly created context
	 * @exception NameAlreadyBoundException if the name is already bound
	 * @exception InvalidAttributesException if attrs does not contain all 
	 * the mandatory attributes required for creation
	 * @exception NamingException if a naming exception is encountered
	 */
	public DirContext createSubcontext(String name, Attributes attrs) throws NamingException
	{
		DirContext context = dirContext.createSubcontext(parseName(name), attrs);
		cacheUnload(name);
		return context;
	}

	/**
	 * Retrieves the schema associated with the named object. The schema 
	 * describes rules regarding the structure of the namespace and the 
	 * attributes stored within it. The schema specifies what types of 
	 * objects can be added to the directory and where they can be added; 
	 * what mandatory and optional attributes an object can have. The range 
	 * of support for schemas is directory-specific.
	 * 
	 * @param name the name of the object whose schema is to be retrieved
	 * @return the schema associated with the context; never null
	 * @exception OperationNotSupportedException if schema not supported
	 * @exception NamingException if a naming exception is encountered
	 */
	public DirContext getSchema(Name name) throws NamingException
	{
		return dirContext.getSchema(parseName(name));
	}

	/**
	 * Retrieves the schema associated with the named object.
	 * 
	 * @param name the name of the object whose schema is to be retrieved
	 * @return the schema associated with the context; never null
	 * @exception OperationNotSupportedException if schema not supported
	 * @exception NamingException if a naming exception is encountered
	 */
	public DirContext getSchema(String name) throws NamingException
	{
		return dirContext.getSchema(parseName(name));
	}

	/**
	 * Retrieves a context containing the schema objects of the named 
	 * object's class definitions.
	 * 
	 * @param name the name of the object whose object class definition is to 
	 * be retrieved
	 * @return the DirContext containing the named object's class 
	 * definitions; never null
	 * @exception OperationNotSupportedException if schema not supported
	 * @exception NamingException if a naming exception is encountered
	 */
	public DirContext getSchemaClassDefinition(Name name) throws NamingException
	{
		return dirContext.getSchemaClassDefinition(parseName(name));
	}

	/**
	 * Retrieves a context containing the schema objects of the named 
	 * object's class definitions.
	 * 
	 * @param name the name of the object whose object class definition is to 
	 * be retrieved
	 * @return the DirContext containing the named object's class 
	 * definitions; never null
	 * @exception OperationNotSupportedException if schema not supported
	 * @exception NamingException if a naming exception is encountered
	 */
	public DirContext getSchemaClassDefinition(String name) throws NamingException
	{
		return dirContext.getSchemaClassDefinition(parseName(name));
	}

	/**
	 * Searches in a single context for objects that contain a specified set 
	 * of attributes, and retrieves selected attributes. The search is 
	 * performed using the default SearchControls settings.
	 * 
	 * @param name the name of the context to search
	 * @param matchingAttributes the attributes to search for. If empty or 
	 * null, all objects in the target context are returned.
	 * @param attributesToReturn the attributes to return. null indicates 
	 * that all attributes are to be returned; an empty array indicates that 
	 * none are to be returned.
	 * @return a non-null enumeration of SearchResult objects. Each 
	 * SearchResult contains the attributes identified by attributesToReturn 
	 * and the name of the corresponding object, named relative to the 
	 * context named by name.
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, Attributes matchingAttributes, String[] attributesToReturn)
		throws NamingException
	{
		return dirContext.search(parseName(name), matchingAttributes, attributesToReturn);
	}

	/**
	 * Searches in a single context for objects that contain a specified set 
	 * of attributes, and retrieves selected attributes.
	 * 
	 * @param name the name of the context to search
	 * @param matchingAttributes the attributes to search for. If empty or 
	 * null, all objects in the target context are returned.
	 * @param attributesToReturn the attributes to return. null indicates 
	 * that all attributes are to be returned; an empty array indicates that 
	 * none are to be returned.
	 * @return a non-null enumeration of SearchResult objects. Each 
	 * SearchResult contains the attributes identified by attributesToReturn 
	 * and the name of the corresponding object, named relative to the 
	 * context named by name.
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, Attributes matchingAttributes, String[] attributesToReturn)
		throws NamingException
	{
		return dirContext.search(parseName(name), matchingAttributes, attributesToReturn);
	}

	/**
	 * Searches in a single context for objects that contain a specified set 
	 * of attributes. This method returns all the attributes of such objects. 
	 * It is equivalent to supplying null as the atributesToReturn parameter 
	 * to the method search(Name, Attributes, String[]).
	 * 
	 * @param name the name of the context to search
	 * @param matchingAttributes the attributes to search for. If empty or 
	 * null, all objects in the target context are returned.
	 * @return a non-null enumeration of SearchResult objects. Each 
	 * SearchResult contains the attributes identified by attributesToReturn 
	 * and the name of the corresponding object, named relative to the 
	 * context named by name.
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, Attributes matchingAttributes) throws NamingException
	{
		return dirContext.search(parseName(name), matchingAttributes);
	}

	/**
	 * Searches in a single context for objects that contain a specified set 
	 * of attributes.
	 * 
	 * @param name the name of the context to search
	 * @param matchingAttributes the attributes to search for. If empty or 
	 * null, all objects in the target context are returned.
	 * @return a non-null enumeration of SearchResult objects. Each 
	 * SearchResult contains the attributes identified by attributesToReturn 
	 * and the name of the corresponding object, named relative to the 
	 * context named by name.
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, Attributes matchingAttributes) throws NamingException
	{
		return dirContext.search(parseName(name), matchingAttributes);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the 
	 * given search filter. Performs the search as specified by the search 
	 * controls.
	 * 
	 * @param name the name of the context or object to search
	 * @param filter the filter expression to use for the search; may not be 
	 * null
	 * @param cons the search controls that control the search. If null, 
	 * the default search controls are used (equivalent to 
	 * (new SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisfy 
	 * the filter; never null
	 * @exception InvalidSearchFilterException if the search filter specified 
	 * is not supported or understood by the underlying directory
	 * @exception InvalidSearchControlsException if the search controls 
	 * contain invalid settings
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, String filter, SearchControls cons) throws NamingException
	{
		return dirContext.search(parseName(name), filter, cons);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the 
	 * given search filter. Performs the search as specified by the search 
	 * controls.
	 * 
	 * @param name the name of the context or object to search
	 * @param filter the filter expression to use for the search; may not be 
	 * null
	 * @param cons the search controls that control the search. If null, 
	 * the default search controls are used (equivalent to 
	 * (new SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisfy 
	 * the filter; never null
	 * @exception InvalidSearchFilterException if the search filter 
	 * specified is not supported or understood by the underlying directory
	 * @exception InvalidSearchControlsException if the search controls 
	 * contain invalid settings
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, String filter, SearchControls cons) throws NamingException
	{
		return dirContext.search(parseName(name), filter, cons);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the 
	 * given search filter. Performs the search as specified by the search 
	 * controls.
	 * 
	 * @param name the name of the context or object to search
	 * @param filterExpr the filter expression to use for the search. 
	 * The expression may contain variables of the form "{i}" where i is a 
	 * nonnegative integer. May not be null.
	 * @param filterArgs the array of arguments to substitute for the 
	 * variables in filterExpr. The value of filterArgs[i] will replace each 
	 * occurrence of "{i}". If null, equivalent to an empty array.
	 * @param cons the search controls that control the search. If null, the 
	 * default search controls are used (equivalent to (new SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisy the 
	 * filter; never null
	 * @exception ArrayIndexOutOfBoundsException if filterExpr contains {i} 
	 * expressions where i is outside the bounds of the array filterArgs
	 * @exception InvalidSearchControlsException if cons contains invalid 
	 * settings
	 * @exception InvalidSearchFilterException if filterExpr with filterArgs 
	 * represents an invalid search filter
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(Name name, String filterExpr, Object[] filterArgs, SearchControls cons)
		throws NamingException
	{
		return dirContext.search(parseName(name), filterExpr, filterArgs, cons);
	}

	/**
	 * Searches in the named context or object for entries that satisfy the 
	 * given search filter. Performs the search as specified by the search 
	 * controls.
	 * 
	 * @param name the name of the context or object to search
	 * @param filterExpr the filter expression to use for the search. 
	 * The expression may contain variables of the form "{i}" where i is a 
	 * nonnegative integer. May not be null.
	 * @param filterArgs the array of arguments to substitute for the 
	 * variables in filterExpr. The value of filterArgs[i] will replace each 
	 * occurrence of "{i}". If null, equivalent to an empty array.
	 * @param cons the search controls that control the search. If null, the 
	 * default search controls are used (equivalent to (new SearchControls())).
	 * @return an enumeration of SearchResults of the objects that satisy the 
	 * filter; never null
	 * @exception ArrayIndexOutOfBoundsException if filterExpr contains {i} 
	 * expressions where i is outside the bounds of the array filterArgs
	 * @exception InvalidSearchControlsException if cons contains invalid 
	 * settings
	 * @exception InvalidSearchFilterException if filterExpr with filterArgs 
	 * represents an invalid search filter
	 * @exception NamingException if a naming exception is encountered
	 */
	public NamingEnumeration search(String name, String filterExpr, Object[] filterArgs, SearchControls cons)
		throws NamingException
	{
		return dirContext.search(parseName(name), filterExpr, filterArgs, cons);
	}

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

	/**
	 * Parses a name.
	 * 
	 * @return the parsed name
	 */
	protected String parseName(String name) throws NamingException
	{
		return name;
	}

	/**
	 * Parses a name.
	 * 
	 * @return the parsed name
	 */
	protected Name parseName(Name name) throws NamingException
	{
		return name;
	}

	/**
	 * Lookup in cache.
	 */
	protected CacheEntry cacheLookup(String name) throws NamingException
	{
		if (cache == null)
			return (null);
		if (name == null)
			name = "";
		for (int i = 0; i < nonCacheable.length; i++)
		{
			if (name.startsWith(nonCacheable[i]))
			{
				return (null);
			}
		}
		CacheEntry cacheEntry = cache.lookup(name);
		if (cacheEntry == null)
		{
			cacheEntry = new CacheEntry();
			cacheEntry.name = name;
			// Load entry
			cacheLoad(cacheEntry);
		}
		else
		{
			if (!validate(cacheEntry))
			{
				if (!revalidate(cacheEntry))
				{
					cacheUnload(cacheEntry.name);
					return (null);
				}
				else
				{
					cacheEntry.timestamp = System.currentTimeMillis() + cacheTTL;
				}
			}
			cacheEntry.accessCount++;
		}
		if (!cacheEntry.exists)
		{
			throw notFoundException;
		}
		return (cacheEntry);
	}

	/**
	 * Validate entry.
	 */
	protected boolean validate(CacheEntry entry)
	{
		if (((!entry.exists)
			|| (entry.context != null)
			|| ((entry.resource != null) && (entry.resource.getContent() != null)))
			&& (System.currentTimeMillis() < entry.timestamp))
		{
			return true;
		}
		return false;
	}

	/**
	 * Revalidate entry.
	 */
	protected boolean revalidate(CacheEntry entry)
	{
		// Get the attributes at the given path, and check the last 
		// modification date
		if (!entry.exists)
			return false;
		if (entry.attributes == null)
			return false;
		long lastModified = entry.attributes.getLastModified();
		long contentLength = entry.attributes.getContentLength();
		if (lastModified <= 0)
			return false;
		try
		{
			Attributes tempAttributes = dirContext.getAttributes(entry.name);
			ResourceAttributes attributes = null;
			if (!(tempAttributes instanceof ResourceAttributes))
			{
				attributes = new ResourceAttributes(tempAttributes);
			}
			else
			{
				attributes = (ResourceAttributes) tempAttributes;
			}
			long lastModified2 = attributes.getLastModified();
			long contentLength2 = attributes.getContentLength();
			return (lastModified == lastModified2) && (contentLength == contentLength2);
		}
		catch (NamingException e)
		{
			return false;
		}
	}

	/**
	 * Load entry into cache.
	 */
	protected void cacheLoad(CacheEntry entry)
	{

		String name = entry.name;

		// Retrieve missing info
		boolean exists = true;

		// Retrieving attributes
		if (entry.attributes == null)
		{
			try
			{
				Attributes attributes = dirContext.getAttributes(entry.name);
				if (!(attributes instanceof ResourceAttributes))
				{
					entry.attributes = new ResourceAttributes(attributes);
				}
				else
				{
					entry.attributes = (ResourceAttributes) attributes;
				}
			}
			catch (NamingException e)
			{
				exists = false;
			}
		}

		// Retriving object
		if ((exists) && (entry.resource == null) && (entry.context == null))
		{
			try
			{
				Object object = dirContext.lookup(name);
				if (object instanceof InputStream)
				{
					entry.resource = new Resource((InputStream) object);
				}
				else if (object instanceof DirContext)
				{
					entry.context = (DirContext) object;
				}
				else if (object instanceof Resource)
				{
					entry.resource = (Resource) object;
				}
				else
				{
					entry.resource = new Resource(new ByteArrayInputStream(object.toString().getBytes()));
				}
			}
			catch (NamingException e)
			{
				exists = false;
			}
		}

		// Load object content
		if ((exists)
			&& (entry.resource != null)
			&& (entry.resource.getContent() == null)
			&& (entry.attributes.getContentLength() >= 0)
			&& (entry.attributes.getContentLength() < (cacheObjectMaxSize * 1024)))
		{
			int length = (int) entry.attributes.getContentLength();
			// The entry size is 1 + the resource size in KB, if it will be 
			// cached
			entry.size += (entry.attributes.getContentLength() / 1024);
			InputStream is = null;
			try
			{
				is = entry.resource.streamContent();
				int pos = 0;
				byte[] b = new byte[length];
				while (pos < length)
				{
					int n = is.read(b, pos, length - pos);
					if (n < 0)
						break;
					pos = pos + n;
				}
				entry.resource.setContent(b);
			}
			catch (IOException e)
			{
				; // Ignore
			}
			finally
			{
				try
				{
					if (is != null)
						is.close();
				}
				catch (IOException e)
				{
					; // Ignore
				}
			}
		}

		// Set existence flag
		entry.exists = exists;

		// Set timestamp
		entry.timestamp = System.currentTimeMillis() + cacheTTL;

		// Add new entry to cache
		synchronized (cache)
		{
			// Check cache size, and remove elements if too big
			if (cache.allocate(entry.size))
			{
				cache.load(entry);
			}
		}

	}

	/**
	 * Remove entry from cache.
	 */
	protected boolean cacheUnload(String name)
	{
		if (cache == null)
			return false;
		synchronized (cache)
		{
			return cache.unload(name);
		}
	}

}
