/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This 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 (at your option) any later version.
*
* This software 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 software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.remoting;
import org.jboss.logging.Logger;
import org.jboss.remoting.transport.ClientInvoker;
import org.jboss.remoting.util.StoppableTimerTask;
import org.jboss.remoting.util.TimerUtil;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.ListIterator;
import java.util.Map;
import java.util.TimerTask;
/**
* @author <a href="mailto:tom.elrod@jboss.com">Tom Elrod</a>
* @author <a href="mailto:ovidiu@jboss.org">Ovidiu Feodorov</a>
*/
public class ConnectionValidator extends TimerTask implements StoppableTimerTask
{
// Constants ------------------------------------------------------------------------------------
private static final Logger log = Logger.getLogger(ConnectionValidator.class.getName());
/**
* Default ping period. Value is 2 seconds.
*/
public static final long DEFAULT_PING_PERIOD = 2000;
// Static ---------------------------------------------------------------------------------------
private static boolean trace = log.isTraceEnabled();
/**
* Will make $PING$ invocation on server. If sucessful, will return true. Otherwise, will throw
* an exception.
*
* @param locator - locator for the server to ping
* @param config - any configuration needed for server
* @return true if alive, false if not
*/
public static boolean checkConnection(InvokerLocator locator, Map config) throws Throwable
{
boolean pingWorked = false;
Map configMap = null;
if (config == null)
{
configMap = new HashMap();
}
else
{
configMap = new HashMap(config);
}
configMap.put("connection_checker", "true");
configMap.put("timeout", "1000");
configMap.put("NumberOfRetries", "1");
ClientInvoker innerClientInvoker = null;
try
{
innerClientInvoker = InvokerRegistry.createClientInvoker(locator, configMap);
if (!innerClientInvoker.isConnected())
{
if (trace) { log.trace("inner client invoker not connected, connecting ..."); }
innerClientInvoker.connect();
}
pingWorked = doCheckConnection(innerClientInvoker);
}
catch (Throwable throwable)
{
log.debug("ConnectionValidator to connect to server " +
innerClientInvoker.getLocator().getProtocol() + "://" +
innerClientInvoker.getLocator().getHost() + ":" +
innerClientInvoker.getLocator().getPort(), throwable);
}
finally
{
if (innerClientInvoker != null)
{
InvokerRegistry.destroyClientInvoker(locator, configMap);
}
}
return pingWorked;
}
private static boolean doCheckConnection(ClientInvoker clientInvoker) throws Throwable
{
boolean pingWorked = false;
try
{
// Sending null client id as don't want to trigger lease on server side. This also means
// that client connection validator will NOT impact client lease, so can not depend on it
// to maintain client lease with the server.
InvocationRequest ir =
new InvocationRequest(null, Subsystem.SELF, "$PING$", null, null, null);
if (trace) { log.trace("pinging, sending " + ir + " over " + clientInvoker); }
clientInvoker.invoke(ir);
if (trace) { log.trace("ConnectionValidator got successful ping using " + clientInvoker);}
pingWorked = true;
}
catch (Throwable t)
{
log.debug("ConnectionValidator failed to ping via " + clientInvoker, t);
}
return pingWorked;
}
// Attributes -----------------------------------------------------------------------------------
private Client client;
private long pingPeriod;
private InvokerLocator locator;
private Map configMap;
private List listeners;
private ClientInvoker clientInvoker;
private Object lock = new Object();
private volatile boolean stopped;
// Constructors ---------------------------------------------------------------------------------
public ConnectionValidator(Client client)
{
this(client, DEFAULT_PING_PERIOD);
}
public ConnectionValidator(Client client, long pingPeriod)
{
this.client = client;
this.pingPeriod = pingPeriod;
this.listeners = new ArrayList();
this.stopped = false;
log.debug(this + " created");
}
// StoppableTimerTask implementation ------------------------------------------------------------
public void stop()
{
if (stopped)
{
return;
}
doStop();
}
// TimerTask overrides --------------------------------------------------------------------------
/**
* The action to be performed by this timer task.
*/
public void run()
{
synchronized(lock)
{
if(!stopped)
{
try
{
if (trace) { log.trace(this + " pinging ..."); }
boolean isValid = doCheckConnection(clientInvoker);
if (!isValid)
{
log.debug(this + "'s connections is invalid");
notifyListeners(new Exception("Could not connect to server!"));
}
}
catch (Throwable thr)
{
log.debug(this + " got throwable while pinging", thr);
notifyListeners(thr);
}
}
}
}
public boolean cancel()
{
return doStop();
}
// Public ---------------------------------------------------------------------------------------
public void addConnectionListener(ConnectionListener listener)
{
if (listener != null)
{
synchronized (listeners)
{
if (listeners.size() == 0)
{
start();
}
listeners.add(listener);
}
}
}
public boolean removeConnectionListener(ConnectionListener listener)
{
boolean isRemoved = false;
if (listener != null)
{
synchronized (listeners)
{
isRemoved = listeners.remove(listener);
if (listeners.size() == 0)
{
stop();
}
}
}
return isRemoved;
}
public long getPingPeriod()
{
if (stopped)
{
return -1;
}
return pingPeriod;
}
public String toString()
{
return "ConnectionValidator[" + clientInvoker + ", pingPeriod=" + pingPeriod + " ms]";
}
// Package protected ----------------------------------------------------------------------------
// Protected ------------------------------------------------------------------------------------
// Private --------------------------------------------------------------------------------------
private void start()
{
if (client.getConfiguration() == null)
{
configMap = new HashMap();
}
else
{
configMap = new HashMap(client.getConfiguration());
}
configMap.put("connection_checker", "true");
configMap.put("timeout", "1000");
configMap.put("NumberOfRetries", "1");
locator = client.getInvoker().getLocator();
try
{
clientInvoker = InvokerRegistry.createClientInvoker(locator, configMap);
}
catch (Exception e)
{
log.error("Unable to create client invoker for locator: " + locator);
throw new RuntimeException("Unable to create client invoker for locator: " + locator, e);
}
if (!clientInvoker.isConnected())
{
if (trace) { log.trace("inner client invoker not connected, connecting ..."); }
clientInvoker.connect();
}
TimerUtil.schedule(this, pingPeriod);
stopped = false;
log.debug(this + " started");
}
private boolean doStop()
{
synchronized(lock)
{
if (!listeners.isEmpty())
{
listeners.clear();
}
stopped = true;
}
if (clientInvoker != null)
{
InvokerRegistry.destroyClientInvoker(locator, configMap);
}
TimerUtil.unschedule(this);
boolean result = super.cancel();
log.debug(this + " stopped, returning " + result);
return result;
}
private void notifyListeners(Throwable thr)
{
final Throwable t = thr;
synchronized (listeners)
{
ListIterator itr = listeners.listIterator();
while (itr.hasNext())
{
final ConnectionListener listener = (ConnectionListener) itr.next();
new Thread()
{
public void run()
{
listener.handleConnectionException(t, client);
}
}.start();
}
}
stop();
listeners.clear();
}
// Inner classes --------------------------------------------------------------------------------
}