/*
* SSHTools - Java SSH2 API
*
* Copyright (C) 2002-2003 Lee David Painter and Contributors.
*
* Contributions made by:
*
* Brett Smith
* Richard Pernavas
* Erwin Bolwidt
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package com.sshtools.j2ssh.transport;
import com.sshtools.j2ssh.SshThread;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.IOException;
/**
* <p>
* Extends the simple <code>Service</code> class to provide an asyncronous
* messaging service for the transport protocol.
* </p>
*
* @author Lee David Painter
* @version $Revision: 1.28 $
*
* @since 0.2.0
*/
public abstract class AsyncService extends Service implements Runnable {
private static Log log = LogFactory.getLog(Service.class);
/** */
protected SshThread thread;
/**
* <p>
* Constructs an asyncronous service.
* </p>
*
* @param serviceName the name of the service
*
* @since 0.2.0
*/
public AsyncService(String serviceName) {
super(serviceName);
}
/**
* <p>
* Implements the abstract <code>Service</code> method and starts the
* service thread.
* </p>
*
* @throws IOException if an IO error occurs
*
* @since 0.2.0
*/
protected void onStart() throws IOException {
if (Thread.currentThread() instanceof SshThread) {
thread = ((SshThread) Thread.currentThread()).cloneThread(this,
getServiceName());
} else {
thread = new SshThread(this, getServiceName(), true);
}
log.info("Starting " + getServiceName() + " service thread");
thread.start();
}
/**
* <p>
* Implements the asyncronous services message loop.
* </p>
*
* @since 0.2.0
*/
public final void run() {
int[] messageFilter = getAsyncMessageFilter();
state.setValue(ServiceState.SERVICE_STARTED);
SshMessage msg = null;
while ((state.getValue() == ServiceState.SERVICE_STARTED) &&
transport.isConnected()) {
try {
// Get the next message from the message store
msg = messageStore.getMessage(messageFilter);
if (state.getValue() == ServiceState.SERVICE_STOPPED) {
break;
}
if (log.isDebugEnabled()) {
log.debug("Routing " + msg.getMessageName());
}
onMessageReceived(msg);
if (log.isDebugEnabled()) {
log.debug("Finished processing " + msg.getMessageName());
}
} catch (MessageStoreEOFException eof) {
stop();
} catch (Exception ex) {
if ((state.getValue() != ServiceState.SERVICE_STOPPED) &&
transport.isConnected()) {
log.fatal("Service message loop failed!", ex);
stop();
}
}
}
onStop();
log.info(getServiceName() + " thread is exiting");
thread = null;
}
/**
* <p>
* The service thread calls this method when the thread is exiting.
* </p>
*
* @since 0.2.0
*/
protected abstract void onStop();
/**
* <p>
* Implement this method by returning the message ids of the asyncrounous
* messages your implementation wants to receive.
* </p>
*
* @return an int array of message ids
*
* @since 0.2.0
*/
protected abstract int[] getAsyncMessageFilter();
/**
* <p>
* Called by the service thread when an asyncronous message is received.
* </p>
*
* @param msg the message received
*
* @throws IOException if an IO error occurs
*
* @since 0.2.0
*/
protected abstract void onMessageReceived(SshMessage msg)
throws IOException;
}