remoteindexserverconnection.java

MG4J (Managing Gigabytes for Java) is a free full-text search engine for large document collections

package it.unimi.dsi.mg4j.index.remote;

/*		 
 * MG4J: Managing Gigabytes for Java
 *
 * Copyright (C) 2006-2007 Sebastiano Vigna 
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 2.1 of the License, or (at your option)
 *  any later version.
 *
 *  This library 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 Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser 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 it.unimi.dsi.fastutil.io.FastBufferedInputStream;
import it.unimi.dsi.fastutil.io.FastBufferedOutputStream;
import it.unimi.dsi.Util;

import java.io.Closeable;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.net.SocketAddress;

import org.apache.log4j.Logger;

/** An index server connection.
 * 
 * <p>Instances of this class provide a convenient way to gather all fields
 * related to a server connection (streams, socket, etc.).
 * 
 * @author Alessandro Arrabito
 * @author Sebastiano Vigna
 */
public class RemoteIndexServerConnection implements Closeable {
	private static final Logger LOGGER = Util.getLogger( RemoteIndexServerConnection.class );

	public final Socket socket;
	/** The stream from the server. */
	public final DataInputStream inputStream;
	/** The stream towards the server. */
	public final DataOutputStream outputStream;
	
	/** Creates a remote index-server connection from a given address and command.
	 * 
	 * <P>Immediately after establishing the connection, <code>command</code> is sent 
	 * to the server, so the stream will be connected to a thread providing a specific service. See {@link IndexServer}.
	 *  
	 * @param address the server address.
	 * @param command the first command sent to the server ({@link IndexServer#GET_CLIENT_INPUT_STREAM},
	 * {@link IndexServer#GET_INDEX_READER}, &hellip;).
	 */
	public RemoteIndexServerConnection( final SocketAddress address, final byte command ) throws IOException {
		socket = new Socket();
		socket.connect( address );
		inputStream = new DataInputStream( new FastBufferedInputStream( socket.getInputStream() ) );
		outputStream = new DataOutputStream( new FastBufferedOutputStream( socket.getOutputStream() ) );
		outputStream.writeByte( command );
		outputStream.flush();
	}
	
	/** Closes the underlying socket. */
	public synchronized void close() throws IOException {
		socket.close();
	}
	
	protected void finalize() throws Throwable {
		try {
			if ( ! socket.isClosed() ) {
				LOGGER.warn( "This " + this.getClass().getName() + " [" + toString() + "] should have been closed." );
				close();
			}
		}
		finally {
			super.finalize();
		}
	}
	
	public String toString() {
		return this.getClass().getName() + ":" + socket.toString();
	}
}