bundles/org.eclipse.equinox.http/src/org/eclipse/equinox/http/HttpListener.java - equinox/rt.equinox.bundles - Git at Google

 /*******************************************************************************
  * Copyright (c) 1999, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.equinox.http;

 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.Socket;
 import java.util.*;

 import javax.servlet.Servlet;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletResponse;

 import org.eclipse.equinox.http.servlet.*;
 import org.eclipse.equinox.socket.ServerSocketInterface;
 import org.eclipse.equinox.socket.SocketInterface;
 import org.eclipse.osgi.util.NLS;
 import org.osgi.framework.*;
 import org.osgi.service.http.HttpContext;
 import org.osgi.service.http.NamespaceException;

 public class HttpListener extends Thread implements ServiceFactory {
 	protected Http http;
 	/** ServerSocket upon which this listener operates */
 	protected volatile ServerSocketInterface serverSocket;
 	/** Controlling HttpConfiguration object */
 	protected HttpConfiguration configuration;
 	/** if true this thread must terminate */
 	protected volatile boolean running;
 	protected ServiceRegistration service;
 	private String httpsvcClass = "org.osgi.service.http.HttpService"; //$NON-NLS-1$
 	protected Hashtable registrations;
 	/** Mapping of HttpContext => ServletContextImpl */
 	protected Hashtable servletContexts;
 	protected int socketTimeout;
 	protected Object lock = new Object();

 	/**
 	 * Constructor.
 	 *
 	 */
 	protected HttpListener(Http http, HttpConfiguration configuration, Dictionary properties) throws IOException {
 		this.http = http;
 		this.configuration = configuration;
 		registrations = new Hashtable(51);
 		//initialize servletContext Hashtable
 		servletContexts = new Hashtable(15);
 		setProperties(properties);
 		start();
 	}

 	/**
 	 * Returns true if this thread has been closed.
 	 * @return boolean
 	 */
 	public boolean isClosed() {
 		return (!running);
 	}

 	/**
 	 * Close this thread.
 	 */
 	public void close() {
 		running = false;
 		try {
 			setProperties(null);
 		} catch (IOException e) {
 			/* this will not occur when calling with null */
 		}

 		servletContexts = null;
 	}

 	/*
 	 * ----------------------------------------------------------------------
 	 *      ServiceFactory Interface implementation
 	 * ----------------------------------------------------------------------
 	 */
 	public Object getService(Bundle bundle, ServiceRegistration reg) {
 		return (new HttpService(this, bundle));
 	}

 	public void ungetService(Bundle bundle, ServiceRegistration reg, Object httpService) {
 		((HttpService) httpService).destroy();
 	}

 	public synchronized void setProperties(Dictionary properties) throws IOException {
 		ServerSocketInterface oldServerSocket = serverSocket;

 		if (properties != null) {
 			String address = (String) properties.get(HttpConfiguration.keyHttpAddress);
 			int port = ((Integer) (properties.get(HttpConfiguration.keyHttpPort))).intValue();
 			String scheme = (String) properties.get(HttpConfiguration.keyHttpScheme);
 			socketTimeout = ((Integer) (properties.get(HttpConfiguration.keyHttpTimeout))).intValue() * 1000;

 			if ("ALL".equalsIgnoreCase(address)) { //$NON-NLS-1$
 				address = null;
 			}

 			if ((serverSocket == null) || (port != serverSocket.getLocalPort()) || !scheme.equals(serverSocket.getScheme())) {
 				serverSocket = configuration.createServerSocket(address, port, scheme);
 				closeServerSocket(oldServerSocket);
 			} else if ((serverSocket.getAddress() != null && !serverSocket.getAddress().equals(address)) || (serverSocket.getAddress() == null && address != null)) {
 				serverSocket = null;
 				closeServerSocket(oldServerSocket);
 				serverSocket = configuration.createServerSocket(address, port, scheme);
 				synchronized (lock) {
 					lock.notify();
 				}
 			}

 			properties.put(HttpConfiguration.keyHttpPort, new Integer(serverSocket.getLocalPort()));
 			if (service == null) {
 				service = http.context.registerService(httpsvcClass, this, properties);
 			} else {
 				service.setProperties(properties);
 			}
 		} else {
 			serverSocket = null;
 			closeServerSocket(oldServerSocket);
 			service.unregister();
 			service = null;
 		}
 	}

 	protected Object getProperty(String key) {
 		return service.getReference().getProperty(key);
 	}

 	private void closeServerSocket(ServerSocketInterface oldServerSocket) {
 		if (oldServerSocket != null) {
 			try {
 				try {
 					Socket phonyClient = new Socket(InetAddress.getByName(oldServerSocket.getAddress()), oldServerSocket.getLocalPort());
 					phonyClient.close();
 				} catch (IOException e) {
 					http.logWarning(HttpMsg.HTTP_UNEXPECTED_IOEXCEPTION, e);
 				}
 			} finally {
 				try {
 					oldServerSocket.close();
 				} catch (IOException e) {
 					http.logWarning(HttpMsg.HTTP_UNEXPECTED_IOEXCEPTION, e);
 				}
 			}

 			configuration.pool.recallThreads();
 		}
 	}

 	public void run() {
 		running = true;

 		while (running) {
 			SocketInterface socket = null;

 			try {
 				if (serverSocket == null) {
 					if (running) {
 						try {
 							synchronized (lock) {
 								lock.wait(5000);
 							}
 						} catch (InterruptedException e) {
 							// ignore and check exit condition
 						}
 						if (serverSocket == null) {
 							running = false;
 							continue;
 						}
 					} else {
 						continue;
 					}
 				}
 				ServerSocketInterface tempServerSocket = this.serverSocket;
 				socket = tempServerSocket.acceptSock();

 				if (tempServerSocket != this.serverSocket) /* socket changed while we were waiting */
 				{
 					try {
 						socket.close();
 					} catch (IOException e) {
 						// TODO: consider logging
 					}

 					socket = null;
 				}
 			} catch (IOException e) {
 				if (serverSocket != null) {
 					http.logError(NLS.bind(HttpMsg.HTTP_ACCEPT_SOCKET_EXCEPTION, new Integer(serverSocket.getLocalPort())), e);
 				}
 			}

 			if (socket != null) {
 				HttpThread thread = configuration.pool.getThread();

 				if (thread != null) {
 					thread.handleConnection(new HttpConnection(http, this, socket, socketTimeout));
 				} else {
 					try {
 						socket.close();
 					} catch (Exception e) {
 						// TODO: consider logging
 					}
 				}
 			}
 		}
 	}

 	protected void handleConnection(SocketInterface socket) throws IOException, ServletException {
 		/* Create the servlet request and response objects */
 		HttpServletResponseImpl response = new HttpServletResponseImpl(socket, http);

 		HttpServletRequestImpl request = new HttpServletRequestImpl(socket, http, response);

 		/* After the request and response objects are successfully created,
 		 * we enter a try/finally block to ensure that the response is
 		 * always closed.
 		 */
 		try {
 			//Get the URI from socket
 			String uri = request.getRequestURI();
 			//Get Registration object associated with the request
 			Registration registration = getRegistration(uri);

 			while (registration != null) {
 				try {
 					if (registration.getHttpContext().handleSecurity(request, response)) {
 						//Service Request
 						registration.service(request, response);
 					}

 					return;
 				} catch (ResourceUnavailableException e) {
 					uri = reduceURI(uri);

 					if (uri == null) {
 						registration = null;
 					} else {
 						registration = getRegistration(uri);
 					}
 				}
 			}

 			if (registration == null) {
 				if (Http.DEBUG) {
 					http.logDebug("File " + request.getRequestURI() + //$NON-NLS-1$
 							" not found -- No Registration object"); //$NON-NLS-1$
 				}

 				response.sendError(HttpServletResponse.SC_NOT_FOUND);
 			}
 		} finally {
 			response.close(); /* close (and flush) the response output */
 		}
 	}

 	protected ResourceRegistration registerResources(Bundle bundle, String alias, String name, HttpContext httpContext) throws NamespaceException {
 		synchronized (registrations) {
 			if (Http.DEBUG) {
 				http.logDebug("HttpService -- Registering Resource --  Alias = " + //$NON-NLS-1$
 						alias + " Name = " + name); //$NON-NLS-1$
 			}

 			checkAlias(alias);

 			//check to see if name is valid
 			if (name == null)
 				throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_RESOURCE_NAME_INVALID_EXCEPTION, name));
 			int length = name.length();
 			if (length > 1) { //we need to allow "/" and ""
 				if (name.endsWith("/")) //$NON-NLS-1$
 				{
 					throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_RESOURCE_NAME_INVALID_EXCEPTION, name));
 				}
 			}

 			checkNamespace(alias);

 			ResourceRegistration registration = new ResourceRegistration(bundle, alias, name, httpContext, http);

 			registrations.put(alias, registration);

 			return (registration);
 		}
 	}

 	private void checkAlias(String alias) {
 		if (alias == null)
 			throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_ALIAS_INVALID_EXCEPTION, alias));
 		//check to see if the alias is valid
 		if (!alias.equals("/")) //$NON-NLS-1$
 		{ //so one can register at "/"
 			if (!alias.startsWith("/") || alias.endsWith("/")) //$NON-NLS-1$ //$NON-NLS-2$
 			{
 				throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_ALIAS_INVALID_EXCEPTION, alias));
 			}
 		}
 	}

 	protected ServletRegistration registerServlet(Bundle bundle, String alias, Servlet servlet, Dictionary initparams, HttpContext httpContext) throws ServletException, NamespaceException {
 		synchronized (registrations) {
 			if (Http.DEBUG) {
 				http.logDebug("HttpService -- Registering Servlet -- Alias = " + alias); //$NON-NLS-1$
 			}

 			checkAlias(alias);

 			checkNamespace(alias);

 			if (servlet == null) {
 				throw new IllegalArgumentException(HttpMsg.HTTP_SERVLET_NULL_EXCEPTION);
 			}

 			if (http.servlets.contains(servlet)) {
 				throw new ServletException(HttpMsg.HTTP_SERVLET_ALREADY_REGISTERED_EXCEPTION);
 			}
 			/* Determine the ServletContext */
 			ServletContextImpl servletContext = getServletContext(httpContext);
 			//Create registration object
 			ServletRegistration registration = new ServletRegistration(bundle, alias, servlet, httpContext, servletContext);

 			//call servlet's init() method
 			try {
 				servlet.init(new ServletConfigImpl(servletContext, initparams));
 			} catch (ServletException e) {
 				ungetServletContext(httpContext);

 				throw e;
 			} catch (Throwable t) {
 				ungetServletContext(httpContext);

 				throw new ServletException(HttpMsg.HTTP_SERVET_INIT_EXCEPTION, t);
 			}

 			http.servlets.addElement(servlet);
 			registrations.put(alias, registration);
 			return (registration);
 		}
 	}

 	protected void unregister(Bundle bundle, String alias) throws IllegalArgumentException {
 		synchronized (registrations) {
 			Registration registration = (Registration) registrations.get(alias);
 			if (registration != null) {
 				//this is to prevent other bundles from unregistering a bundle's resource/servlet
 				if (registration.getBundle() != bundle) {
 					registration = null;
 				}
 			}

 			removeRegistration(registration);
 		}
 	}

 	protected HttpContext createDefaultHttpContext(Bundle bundle) {
 		return (new DefaultHttpContext(bundle, http.securityTracker));
 	}

 	protected ServletContextImpl getServletContext(HttpContext httpContext) {
 		/* Determine the ServletContext */
 		ServletContextImpl servletContext = (ServletContextImpl) servletContexts.get(httpContext);

 		if (servletContext == null) {
 			servletContext = new ServletContextImpl(http, this, httpContext);
 			servletContexts.put(httpContext, servletContext);
 		}

 		servletContext.incrUseCount();

 		return (servletContext);
 	}

 	protected void ungetServletContext(HttpContext httpContext) {
 		ServletContextImpl servletContext = (ServletContextImpl) servletContexts.get(httpContext);

 		if (servletContext != null) {
 			int useCount = servletContext.decrUseCount();

 			if (useCount <= 0) {
 				servletContexts.remove(httpContext);
 			}
 		}
 	}

 	protected void destroyBundle(Bundle bundle) {
 		if (registrations != null) {
 			if (Http.DEBUG) {
 				http.logDebug("Removing bundle " + bundle + //$NON-NLS-1$
 						" from HttpListener"); //$NON-NLS-1$
 			}

 			synchronized (registrations) {
 				Enumeration e = registrations.elements();

 				while (e.hasMoreElements()) {
 					Registration reg = (Registration) e.nextElement();

 					if (bundle == reg.getBundle()) {
 						removeRegistration(reg);
 					}
 				}
 			}
 		}
 	}

 	private void checkNamespace(String uri) throws NamespaceException {
 		if (uri == null)
 			throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_ALIAS_INVALID_EXCEPTION, uri));
 		// If alias already exists in master resource table,
 		// throw NamespaceException
 		if (registrations.get(uri) != null) {
 			throw new NamespaceException(NLS.bind(HttpMsg.HTTP_ALIAS_ALREADY_REGISTERED_EXCEPTION, uri));
 		}
 	}

 	public Registration getRegistration(String uri) {
 		synchronized (registrations) {
 			while (uri != null) {
 				Registration reg = (Registration) registrations.get(uri);

 				if (reg != null) {
 					return (reg);
 				}
 				uri = reduceURI(uri);
 			}
 			return (null);
 		}
 	}

 	/**
 	 * Reduce the input URI per the HttpService spec.
 	 *
 	 * @param uri input URI to be reduced.
 	 * @return Reduced URI or null if no further reduction possible.
 	 */
 	private String reduceURI(String uri) {
 		if (uri.equals("/")) //$NON-NLS-1$
 		{
 			return (null);
 		}

 		int index = uri.lastIndexOf('/');

 		if (index < 0) {
 			return (null);
 		}

 		if (index == 0) {
 			return ("/"); //$NON-NLS-1$
 		}

 		return (uri.substring(0, index));
 	}

 	/**
 	 * Must be called while holding the registrations lock
 	 *
 	 */
 	private void removeRegistration(Registration registration) {
 		if (registration == null) {
 			throw new IllegalArgumentException(HttpMsg.HTTP_ALIAS_UNREGISTER_EXCEPTION);
 		}
 		registrations.remove(registration.getAlias());
 		if (registration instanceof ServletRegistration) {
 			Servlet servlet = ((ServletRegistration) registration).getServlet();
 			http.servlets.removeElement(servlet);
 		}

 		// BUGBUG Must not call servlet.destroy while it is processing requests!
 		// Servlet 2.2 Section 3.3.4
 		registration.destroy();

 		if (registration instanceof ServletRegistration) {
 			ungetServletContext(registration.getHttpContext());
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 1999, 2006 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.equinox.http;

	import java.io.IOException;
	import java.net.InetAddress;
	import java.net.Socket;
	import java.util.*;

	import javax.servlet.Servlet;
	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServletResponse;

	import org.eclipse.equinox.http.servlet.*;
	import org.eclipse.equinox.socket.ServerSocketInterface;
	import org.eclipse.equinox.socket.SocketInterface;
	import org.eclipse.osgi.util.NLS;
	import org.osgi.framework.*;
	import org.osgi.service.http.HttpContext;
	import org.osgi.service.http.NamespaceException;

	public class HttpListener extends Thread implements ServiceFactory {
	protected Http http;
	/** ServerSocket upon which this listener operates */
	protected volatile ServerSocketInterface serverSocket;
	/** Controlling HttpConfiguration object */
	protected HttpConfiguration configuration;
	/** if true this thread must terminate */
	protected volatile boolean running;
	protected ServiceRegistration service;
	private String httpsvcClass = "org.osgi.service.http.HttpService"; //$NON-NLS-1$
	protected Hashtable registrations;
	/** Mapping of HttpContext => ServletContextImpl */
	protected Hashtable servletContexts;
	protected int socketTimeout;
	protected Object lock = new Object();

	/**
	* Constructor.
	*
	*/
	protected HttpListener(Http http, HttpConfiguration configuration, Dictionary properties) throws IOException {
	this.http = http;
	this.configuration = configuration;
	registrations = new Hashtable(51);
	//initialize servletContext Hashtable
	servletContexts = new Hashtable(15);
	setProperties(properties);
	start();
	}

	/**
	* Returns true if this thread has been closed.
	* @return boolean
	*/
	public boolean isClosed() {
	return (!running);
	}

	/**
	* Close this thread.
	*/
	public void close() {
	running = false;
	try {
	setProperties(null);
	} catch (IOException e) {
	/* this will not occur when calling with null */
	}

	servletContexts = null;
	}

	/*
	* ----------------------------------------------------------------------
	* ServiceFactory Interface implementation
	* ----------------------------------------------------------------------
	*/
	public Object getService(Bundle bundle, ServiceRegistration reg) {
	return (new HttpService(this, bundle));
	}

	public void ungetService(Bundle bundle, ServiceRegistration reg, Object httpService) {
	((HttpService) httpService).destroy();
	}

	public synchronized void setProperties(Dictionary properties) throws IOException {
	ServerSocketInterface oldServerSocket = serverSocket;

	if (properties != null) {
	String address = (String) properties.get(HttpConfiguration.keyHttpAddress);
	int port = ((Integer) (properties.get(HttpConfiguration.keyHttpPort))).intValue();
	String scheme = (String) properties.get(HttpConfiguration.keyHttpScheme);
	socketTimeout = ((Integer) (properties.get(HttpConfiguration.keyHttpTimeout))).intValue() * 1000;

	if ("ALL".equalsIgnoreCase(address)) { //$NON-NLS-1$
	address = null;
	}

	if ((serverSocket == null) \|\| (port != serverSocket.getLocalPort()) \|\| !scheme.equals(serverSocket.getScheme())) {
	serverSocket = configuration.createServerSocket(address, port, scheme);
	closeServerSocket(oldServerSocket);
	} else if ((serverSocket.getAddress() != null && !serverSocket.getAddress().equals(address)) \|\| (serverSocket.getAddress() == null && address != null)) {
	serverSocket = null;
	closeServerSocket(oldServerSocket);
	serverSocket = configuration.createServerSocket(address, port, scheme);
	synchronized (lock) {
	lock.notify();
	}
	}

	properties.put(HttpConfiguration.keyHttpPort, new Integer(serverSocket.getLocalPort()));
	if (service == null) {
	service = http.context.registerService(httpsvcClass, this, properties);
	} else {
	service.setProperties(properties);
	}
	} else {
	serverSocket = null;
	closeServerSocket(oldServerSocket);
	service.unregister();
	service = null;
	}
	}

	protected Object getProperty(String key) {
	return service.getReference().getProperty(key);
	}

	private void closeServerSocket(ServerSocketInterface oldServerSocket) {
	if (oldServerSocket != null) {
	try {
	try {
	Socket phonyClient = new Socket(InetAddress.getByName(oldServerSocket.getAddress()), oldServerSocket.getLocalPort());
	phonyClient.close();
	} catch (IOException e) {
	http.logWarning(HttpMsg.HTTP_UNEXPECTED_IOEXCEPTION, e);
	}
	} finally {
	try {
	oldServerSocket.close();
	} catch (IOException e) {
	http.logWarning(HttpMsg.HTTP_UNEXPECTED_IOEXCEPTION, e);
	}
	}

	configuration.pool.recallThreads();
	}
	}

	public void run() {
	running = true;

	while (running) {
	SocketInterface socket = null;

	try {
	if (serverSocket == null) {
	if (running) {
	try {
	synchronized (lock) {
	lock.wait(5000);
	}
	} catch (InterruptedException e) {
	// ignore and check exit condition
	}
	if (serverSocket == null) {
	running = false;
	continue;
	}
	} else {
	continue;
	}
	}
	ServerSocketInterface tempServerSocket = this.serverSocket;
	socket = tempServerSocket.acceptSock();

	if (tempServerSocket != this.serverSocket) /* socket changed while we were waiting */
	{
	try {
	socket.close();
	} catch (IOException e) {
	// TODO: consider logging
	}

	socket = null;
	}
	} catch (IOException e) {
	if (serverSocket != null) {
	http.logError(NLS.bind(HttpMsg.HTTP_ACCEPT_SOCKET_EXCEPTION, new Integer(serverSocket.getLocalPort())), e);
	}
	}

	if (socket != null) {
	HttpThread thread = configuration.pool.getThread();

	if (thread != null) {
	thread.handleConnection(new HttpConnection(http, this, socket, socketTimeout));
	} else {
	try {
	socket.close();
	} catch (Exception e) {
	// TODO: consider logging
	}
	}
	}
	}
	}

	protected void handleConnection(SocketInterface socket) throws IOException, ServletException {
	/* Create the servlet request and response objects */
	HttpServletResponseImpl response = new HttpServletResponseImpl(socket, http);

	HttpServletRequestImpl request = new HttpServletRequestImpl(socket, http, response);

	/* After the request and response objects are successfully created,
	* we enter a try/finally block to ensure that the response is
	* always closed.
	*/
	try {
	//Get the URI from socket
	String uri = request.getRequestURI();
	//Get Registration object associated with the request
	Registration registration = getRegistration(uri);

	while (registration != null) {
	try {
	if (registration.getHttpContext().handleSecurity(request, response)) {
	//Service Request
	registration.service(request, response);
	}

	return;
	} catch (ResourceUnavailableException e) {
	uri = reduceURI(uri);

	if (uri == null) {
	registration = null;
	} else {
	registration = getRegistration(uri);
	}
	}
	}

	if (registration == null) {
	if (Http.DEBUG) {
	http.logDebug("File " + request.getRequestURI() + //$NON-NLS-1$
	" not found -- No Registration object"); //$NON-NLS-1$
	}

	response.sendError(HttpServletResponse.SC_NOT_FOUND);
	}
	} finally {
	response.close(); /* close (and flush) the response output */
	}
	}

	protected ResourceRegistration registerResources(Bundle bundle, String alias, String name, HttpContext httpContext) throws NamespaceException {
	synchronized (registrations) {
	if (Http.DEBUG) {
	http.logDebug("HttpService -- Registering Resource -- Alias = " + //$NON-NLS-1$
	alias + " Name = " + name); //$NON-NLS-1$
	}

	checkAlias(alias);

	//check to see if name is valid
	if (name == null)
	throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_RESOURCE_NAME_INVALID_EXCEPTION, name));
	int length = name.length();
	if (length > 1) { //we need to allow "/" and ""
	if (name.endsWith("/")) //$NON-NLS-1$
	{
	throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_RESOURCE_NAME_INVALID_EXCEPTION, name));
	}
	}

	checkNamespace(alias);

	ResourceRegistration registration = new ResourceRegistration(bundle, alias, name, httpContext, http);

	registrations.put(alias, registration);

	return (registration);
	}
	}

	private void checkAlias(String alias) {
	if (alias == null)
	throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_ALIAS_INVALID_EXCEPTION, alias));
	//check to see if the alias is valid
	if (!alias.equals("/")) //$NON-NLS-1$
	{ //so one can register at "/"
	if (!alias.startsWith("/") \|\| alias.endsWith("/")) //$NON-NLS-1$ //$NON-NLS-2$
	{
	throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_ALIAS_INVALID_EXCEPTION, alias));
	}
	}
	}

	protected ServletRegistration registerServlet(Bundle bundle, String alias, Servlet servlet, Dictionary initparams, HttpContext httpContext) throws ServletException, NamespaceException {
	synchronized (registrations) {
	if (Http.DEBUG) {
	http.logDebug("HttpService -- Registering Servlet -- Alias = " + alias); //$NON-NLS-1$
	}

	checkAlias(alias);

	checkNamespace(alias);

	if (servlet == null) {
	throw new IllegalArgumentException(HttpMsg.HTTP_SERVLET_NULL_EXCEPTION);
	}

	if (http.servlets.contains(servlet)) {
	throw new ServletException(HttpMsg.HTTP_SERVLET_ALREADY_REGISTERED_EXCEPTION);
	}
	/* Determine the ServletContext */
	ServletContextImpl servletContext = getServletContext(httpContext);
	//Create registration object
	ServletRegistration registration = new ServletRegistration(bundle, alias, servlet, httpContext, servletContext);

	//call servlet's init() method
	try {
	servlet.init(new ServletConfigImpl(servletContext, initparams));
	} catch (ServletException e) {
	ungetServletContext(httpContext);

	throw e;
	} catch (Throwable t) {
	ungetServletContext(httpContext);

	throw new ServletException(HttpMsg.HTTP_SERVET_INIT_EXCEPTION, t);
	}

	http.servlets.addElement(servlet);
	registrations.put(alias, registration);
	return (registration);
	}
	}

	protected void unregister(Bundle bundle, String alias) throws IllegalArgumentException {
	synchronized (registrations) {
	Registration registration = (Registration) registrations.get(alias);
	if (registration != null) {
	//this is to prevent other bundles from unregistering a bundle's resource/servlet
	if (registration.getBundle() != bundle) {
	registration = null;
	}
	}

	removeRegistration(registration);
	}
	}

	protected HttpContext createDefaultHttpContext(Bundle bundle) {
	return (new DefaultHttpContext(bundle, http.securityTracker));
	}

	protected ServletContextImpl getServletContext(HttpContext httpContext) {
	/* Determine the ServletContext */
	ServletContextImpl servletContext = (ServletContextImpl) servletContexts.get(httpContext);

	if (servletContext == null) {
	servletContext = new ServletContextImpl(http, this, httpContext);
	servletContexts.put(httpContext, servletContext);
	}

	servletContext.incrUseCount();

	return (servletContext);
	}

	protected void ungetServletContext(HttpContext httpContext) {
	ServletContextImpl servletContext = (ServletContextImpl) servletContexts.get(httpContext);

	if (servletContext != null) {
	int useCount = servletContext.decrUseCount();

	if (useCount <= 0) {
	servletContexts.remove(httpContext);
	}
	}
	}

	protected void destroyBundle(Bundle bundle) {
	if (registrations != null) {
	if (Http.DEBUG) {
	http.logDebug("Removing bundle " + bundle + //$NON-NLS-1$
	" from HttpListener"); //$NON-NLS-1$
	}

	synchronized (registrations) {
	Enumeration e = registrations.elements();

	while (e.hasMoreElements()) {
	Registration reg = (Registration) e.nextElement();

	if (bundle == reg.getBundle()) {
	removeRegistration(reg);
	}
	}
	}
	}
	}

	private void checkNamespace(String uri) throws NamespaceException {
	if (uri == null)
	throw new IllegalArgumentException(NLS.bind(HttpMsg.HTTP_ALIAS_INVALID_EXCEPTION, uri));
	// If alias already exists in master resource table,
	// throw NamespaceException
	if (registrations.get(uri) != null) {
	throw new NamespaceException(NLS.bind(HttpMsg.HTTP_ALIAS_ALREADY_REGISTERED_EXCEPTION, uri));
	}
	}

	public Registration getRegistration(String uri) {
	synchronized (registrations) {
	while (uri != null) {
	Registration reg = (Registration) registrations.get(uri);

	if (reg != null) {
	return (reg);
	}
	uri = reduceURI(uri);
	}
	return (null);
	}
	}

	/**
	* Reduce the input URI per the HttpService spec.
	*
	* @param uri input URI to be reduced.
	* @return Reduced URI or null if no further reduction possible.
	*/
	private String reduceURI(String uri) {
	if (uri.equals("/")) //$NON-NLS-1$
	{
	return (null);
	}

	int index = uri.lastIndexOf('/');

	if (index < 0) {
	return (null);
	}

	if (index == 0) {
	return ("/"); //$NON-NLS-1$
	}

	return (uri.substring(0, index));
	}

	/**
	* Must be called while holding the registrations lock
	*
	*/
	private void removeRegistration(Registration registration) {
	if (registration == null) {
	throw new IllegalArgumentException(HttpMsg.HTTP_ALIAS_UNREGISTER_EXCEPTION);
	}
	registrations.remove(registration.getAlias());
	if (registration instanceof ServletRegistration) {
	Servlet servlet = ((ServletRegistration) registration).getServlet();
	http.servlets.removeElement(servlet);
	}

	// BUGBUG Must not call servlet.destroy while it is processing requests!
	// Servlet 2.2 Section 3.3.4
	registration.destroy();

	if (registration instanceof ServletRegistration) {
	ungetServletContext(registration.getHttpContext());
	}
	}
	}