Session.java

package org.reldb.rel.v0.server;

import java.net.*;
import java.io.*;

import org.reldb.rel.v0.interpreter.Interpreter;

/** A Session represents an active connection to a client. */
public class Session {
	private static long sessionidgenerator = 0;

	private Server server;
	private Socket socket;
	private boolean running;
	private long sessionid;
	
	/** Create a Session given an open Socket. */
	public Session(final Server owner, Socket channel) {
		sessionid = sessionidgenerator++;
		InetAddress ip = channel.getInetAddress();
		ip.getHostName();
		int remotePort = channel.getPort();
		System.out.println("Session: Open session " + sessionid + " to " + ip + ":" + remotePort);
		server = owner;
		socket = channel;
		Thread sessionThread = new Thread() {
			public void run() {
				try {
					server.addSession(Session.this);
					PrintStream output = new PrintStream(socket.getOutputStream());
					Interpreter interpreter = new Interpreter(owner.getInstance().getDatabase(), output);
					running = true;
					owner.getInstance().announceActive(output);
					output.println("<EOT>");
					output.flush();
					while (running) {
						try {
							int prefix = socket.getInputStream().read();
							if (prefix < 0)
								break;
							if (Character.isWhitespace((char)prefix))
								continue;
							if (prefix == 'E') {
								interpreter.evaluate(socket.getInputStream()).toStream(output);
								output.println();
							}
							else if (prefix == 'X') {
								interpreter.interpret(socket.getInputStream());
								output.println("\nOk.");
							} 
							else if (prefix == 'R') {
								interpreter.reset();
								output.println("\nCancel.");
							}
							else
								output.println("ERROR: Rel server protocol error: expected 'R', 'E' or 'X', but got '" + (char)prefix + "'.");
						} catch (SocketException se) {
							break;
						} catch (Throwable t) {
							interpreter.reset();
							output.println("ERROR: " + t.getMessage());
						}
						output.println("<EOT>");
						output.flush();
					}
					output.close();
				} catch (IOException ioe) {
					System.out.println("Session: " + ioe);
				}
				kill();
			}
		};
		sessionThread.start();
	}

	public long getId() {
		return sessionid;
	}
	
	/** Kill this Session. */
	public synchronized void kill() {
		running = false;
		server.removeSession(this);
		if (socket == null)
			return;
		try {
			System.out.println("Session: Close session " + sessionid);
			socket.close();
			socket = null;
		} catch (IOException ioe) {
			System.out.println("Session: Unable to close socket " + socket);
		}
	}
	
}