/*
* Copyright (C) 2008, Robin Rosenberg <robin.rosenberg@dewire.com>
* Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Git Development Community nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.spearce.jgit.transport;
import com.jcraft.jsch.JSchException;
import com.jcraft.jsch.Session;
/**
* Creates and destroys SSH connections to a remote system.
* <p>
* Different implementations of the session factory may be used to control
* communicating with the end-user as well as reading their personal SSH
* configuration settings, such as known hosts and private keys.
* <p>
* A {@link Session} must be returned to the factory that created it. Callers
* are encouraged to retain the SshSessionFactory for the duration of the period
* they are using the Session.
*/
public abstract class SshSessionFactory {
private static SshSessionFactory INSTANCE = new DefaultSshSessionFactory();
/**
* Get the currently configured JVM-wide factory.
* <p>
* A factory is always available. By default the factory will read from the
* user's <code>$HOME/.ssh</code> and assume OpenSSH compatibility.
*
* @return factory the current factory for this JVM.
*/
public static SshSessionFactory getInstance() {
return INSTANCE;
}
/**
* Change the JVM-wide factory to a different implementation.
*
* @param newFactory
* factory for future sessions to be created through. If null the
* default factory will be restored.s
*/
public static void setInstance(final SshSessionFactory newFactory) {
if (newFactory != null)
INSTANCE = newFactory;
else
INSTANCE = new DefaultSshSessionFactory();
}
/**
* Open (or reuse) a session to a host.
* <p>
* A reasonable UserInfo that can interact with the end-user (if necessary)
* is installed on the returned session by this method.
* <p>
* The caller must connect the session by invoking <code>connect()</code>
* if it has not already been connected.
*
* @param user
* username to authenticate as. If null a reasonable default must
* be selected by the implementation. This may be
* <code>System.getProperty("user.name")</code>.
* @param pass
* optional user account password or passphrase. If not null a
* UserInfo that supplies this value to the SSH library will be
* configured.
* @param host
* hostname (or IP address) to connect to. Must not be null.
* @param port
* port number the server is listening for connections on. May be <=
* 0 to indicate the IANA registered port of 22 should be used.
* @return a session that can contact the remote host.
* @throws JSchException
* the session could not be created.
*/
public abstract Session getSession(String user, String pass, String host,
int port) throws JSchException;
/**
* Close (or recycle) a session to a host.
*
* @param session
* a session previously obtained from this factory's
* {@link #getSession(String,String, String, int)} method.s
*/
public void releaseSession(final Session session) {
if (session.isConnected())
session.disconnect();
}
}