package it.unimi.dsi.mg4j.query;/*		  * MG4J: Managing Gigabytes for Java * * Copyright (C) 2005-2007 Sebastiano Vigna  * *  This program is free software; you can redistribute it and/or modify it *  under the terms of the GNU General Public License as published by the Free *  Software Foundation; either version 2 of the License, or (at your option) *  any later version. * *  This program is distributed in the hope that it will be useful, but *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *  for more details. * *  You should have received a copy of the GNU General Public License *  along with this program; if not, write to the Free Software *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * */import javax.activation.MimetypesFileTypeMap;import org.mortbay.http.HttpContext;import org.mortbay.http.HttpServer;import org.mortbay.http.SocketListener;import org.mortbay.http.handler.ResourceHandler;/** A minimal, singleton server serving the whole filesystem. *  * <p>For security reasons, some browsers (notably Firefox at the time of this writing) * do not serve <samp>file:</samp> content from a non-<samp>file:</samp> page. The solution * is a minimal server that has the root of the filesystem as document root. *  * <p>To instantiate the server, you just need a variable of type {@link HttpFileServer}. * just retrieve and cache the result of {@link #getServer()} (to * avoid class garbage collection). The port randomly assigned to the server can be retrieved with * {@link #getPort()}. *  * <p>It may happen that the server is not yet started when you call {@link #getPort()}, in which case * an {@link java.lang.IllegalStateException} will be thrown. */public class HttpFileServer {	/** The only server instance. */	private final static HttpServer SERVER;	/** The only instance of this class. */	private final static HttpFileServer INSTANCE = new HttpFileServer();	/** The dynamically assigned port, or 0 if the port has not been detected yet. */	private static int port;	/** An instance of {@link MimetypesFileTypeMap} used to recognise MIME types. */	@SuppressWarnings("unused")	private final static MimetypesFileTypeMap MIME_TYPES_FILE_TYPE_MAP = new MimetypesFileTypeMap();		static {		// This allows symlinks.		System.setProperty( "org.mortbay.util.FileResource.checkAliases", Boolean.FALSE.toString() );	}		/** Returns the only instance of an HTTP file server.	 * 	 * <p>Note that the instance should be cached by the application, to avoid garbage collection.	 * 	 * @return the only instance of an HTTP file server	 */	public static HttpFileServer getServer() {		return INSTANCE;	}		/** Returns the port assigned to the server.	 * 	 * @return the port assigned to the server.	 */		public static int getPort() {		if ( port == 0 ) {			if ( ! SERVER.isStarted() ) throw new IllegalStateException( "The server is not started yet" );			port = SERVER.getListeners()[ 0 ].getPort();		}		return port;	}		private HttpFileServer() {}		static {		// Create the server		SERVER = new HttpServer();		// Create a port listener		final SocketListener listener = new SocketListener();		listener.setPort( 0 );		SERVER.addListener( listener );		// Create a context 		final HttpContext context = new HttpContext();		context.setContextPath( "/" );		context.setResourceBase( "/" );				SERVER.addContext( context );		// Add a resource handler		ResourceHandler resourceHandler = new ResourceHandler();		resourceHandler.setAllowedMethods( new String[] { "GET" } );				context.addHandler( resourceHandler );		// Start the http server		new Thread() {			public void run() {				try {					SERVER.start();				}				catch ( Exception e ) {					throw new RuntimeException();				}			}		}.start();	}}