JSchSession.java

/*
 *  Copyright 2010 jOpenRay, ILM Informatique  
 *  Copyright 2007 ymnk, JCraft,Inc.
 *
 * 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, see <http://www.gnu.org/licenses/>
 */

package com.jcraft.jcterm;

import java.util.Hashtable;

import com.jcraft.jsch.*;

public class JSchSession {
	private static JSch jsch = null;
	private static SessionFactory sessionFactory = null;

	private static Hashtable<String, JSchSession> pool = new Hashtable<String, JSchSession>();

	private String key = null;
	private Session session = null;

	public static JSchSession getSession(String username, String password,
			String hostname, int port, UserInfo userinfo, Proxy proxy)
			throws JSchException {
		String key = getPoolKey(username, hostname, port);
		try {
			JSchSession jschSession = pool.get(key);
			if (jschSession != null && !jschSession.getSession().isConnected()) {
				pool.remove(key);
				jschSession = null;
			}
			if (jschSession == null) {
				Session session = null;
				try {
					session = createSession(username, password, hostname, port,
							userinfo, proxy);
				} catch (JSchException e) {
					if (isAuthenticationFailure(e)) {
						session = createSession(username, password, hostname,
								port, userinfo, proxy);
					} else {
						throw e;
					}
				}

				if (session == null)
					throw new JSchException("The JSch service is not available");

				JSchSession schSession = new JSchSession(session, key);
				pool.put(key, schSession);

				return schSession;
			}
			return jschSession;
		} catch (JSchException e) {
			pool.remove(key);
			throw e;
		}
	}

	private static synchronized JSch getJSch() {
		if (jsch == null) {
			jsch = new JSch();
		}
		return jsch;
	}

	private static Session createSession(String username, String password,
			String hostname, int port, UserInfo userinfo, Proxy proxy)
			throws JSchException {
		Session session = null;
		if (sessionFactory == null) {
			session = getJSch().getSession(username, hostname, port);
		} else {
			session = sessionFactory.getSession(username, hostname, port);
		}
		session.setTimeout(60000);
		if (password != null)
			session.setPassword(password);
		session.setUserInfo(userinfo);
		if (proxy != null)
			session.setProxy(proxy);
		session.connect(60000);
		session.setServerAliveInterval(60000);
		return session;
	}

	private static String getPoolKey(String username, String hostname, int port) {
		return username + "@" + hostname + ":" + port;
	}

	private JSchSession(Session session, String key) {
		this.session = session;
		this.key = key;
	}

	public Session getSession() {
		return session;
	}

	public void dispose() {
		if (session.isConnected()) {
			session.disconnect();
		}
		pool.remove(key);
	}

	public static boolean isAuthenticationFailure(JSchException ee) {
		return ee.getMessage().equals("Auth fail");
	}

	public static interface SessionFactory {
		Session getSession(String username, String hostname, int port)
				throws JSchException;
	}

	public static void setSessionFactory(SessionFactory sf) {
		sessionFactory = sf;
	}
}