org/objectweb/proactive/core/ssh/SshTunnelFactory.java

/* 
 * ################################################################
 * 
 * ProActive: The Java(TM) library for Parallel, Distributed, 
 *            Concurrent computing with Security and Mobility
 * 
 * Copyright (C) 1997-2007 INRIA/University of Nice-Sophia Antipolis
 * Contact: proactive@objectweb.org
 * 
 * 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 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 library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 * USA
 *  
 *  Initial developer(s):               The ProActive Team
 *                        http://www.inria.fr/oasis/ProActive/contacts.html
 *  Contributor(s): 
 * 
 * ################################################################
 */ 
package org.objectweb.proactive.core.ssh;

import org.apache.log4j.Logger;
import org.objectweb.proactive.core.ssh.SshTunnel;
import org.objectweb.proactive.core.ssh.UnusedTunnel;
import org.objectweb.proactive.core.util.log.Loggers;
import org.objectweb.proactive.core.util.log.ProActiveLogger;


public class SshTunnelFactory {
    static Logger logger = ProActiveLogger.getLogger(Loggers.SSH);
    private java.util.Hashtable<String, UnusedTunnel> _unused;
    static private SshTunnelFactory _factory = null;

    static private SshTunnelFactory getFactory() {
        if (_factory == null) {
            _factory = new SshTunnelFactory();
        }
        return _factory;
    }

    static public SshTunnel createTunnel(String host, int port)
        throws java.io.IOException {
        return getFactory().create(host, port);
    }

    static public void reportUnusedTunnel(SshTunnel tunnel)
        throws Exception {
        getFactory().reportUnused(tunnel);
    }

    private SshTunnelFactory() {
        _unused = new java.util.Hashtable<String, UnusedTunnel>();
        if (SshParameters.getUseTunnelGC()) {
            Thread gcThread = new Thread() {
                    public void run() {
                        while (true) {
                            try {
                                sleep(1000);
                            } catch (InterruptedException e) {
                            }
                            getFactory().GC();
                        }
                    }
                };
            gcThread.start();
        }
    }

    private String getKey(String host, int port) {
        return host + port;
    }

    private synchronized SshTunnel create(String host, int port)
        throws java.io.IOException {
        if (SshParameters.getUseTunnelGC()) {
            UnusedTunnel unused = _unused.get(getKey(host, port));
            SshTunnel tunnel;
            if (unused == null) {
                logger.debug("create tunnel " + host + ":" + port);
                tunnel = new SshTunnel(host, port);
            } else {
                logger.debug("reuse tunnel " + host + ":" + port);
                _unused.remove(getKey(host, port));
                tunnel = unused.getTunnel();
            }
            return tunnel;
        } else {
            return new SshTunnel(host, port);
        }
    }

    private synchronized void reportUnused(SshTunnel tunnel)
        throws Exception {
        if (tunnel != null) {
            String host = tunnel.getDistantHost();
            int port = tunnel.getDistantPort();
            if (SshParameters.getUseTunnelGC()) {
                UnusedTunnel prev = _unused.get(getKey(host, port));
                if (prev != null) {
                    prev.getTunnel().realClose();
                    _unused.remove(getKey(host, port));
                }
                logger.debug("return unused tunnel " + host + ":" + port);
                _unused.put(getKey(host, port), new UnusedTunnel(tunnel));
            } else {
                logger.debug("kill unused tunnel " + host + ":" + port);
                tunnel.realClose();
            }
        }
    }

    private synchronized void GC() {
        java.util.Enumeration<String> keys = _unused.keys();
        for (; keys.hasMoreElements();) {
            String key =  keys.nextElement();
            UnusedTunnel tunnel = _unused.get(key);
            if (tunnel.isOldEnough()) {
                try {
                    SshTunnel sshTunnel = tunnel.getTunnel();
                    logger.debug("gc kill unused tunnel " +
                        sshTunnel.getDistantHost() + ":" +
                        sshTunnel.getDistantPort());
                    sshTunnel.realClose();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                _unused.remove(key);
            }
        }
    }
}

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