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/***************************************************************************
* Copyright (c) 2004 - 2008 Eike Stepper, Germany.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Eike Stepper - initial API and implementation
**************************************************************************/
package org.eclipse.net4j.signal.failover;
import org.eclipse.net4j.channel.IChannel;
import org.eclipse.net4j.connector.IConnector;
import org.eclipse.net4j.internal.util.event.Notifier;
import org.eclipse.net4j.signal.RequestWithConfirmation;
import org.eclipse.net4j.signal.SignalActor;
import org.eclipse.net4j.signal.SignalProtocol;
import org.eclipse.net4j.util.CheckUtil;
import java.util.concurrent.TimeoutException;
/**
* @author Eike Stepper
*/
public abstract class FailOverStrategy extends Notifier implements IFailOverStrategy
{
public FailOverStrategy()
{
}
public <RESULT> RESULT send(RequestWithConfirmation<RESULT> request) throws Exception
{
return send(request, SignalActor.NO_TIMEOUT);
}
public <RESULT> RESULT send(RequestWithConfirmation<RESULT> request, long timeout) throws Exception
{
for (;;)
{
try
{
return request.send(timeout);
}
catch (TimeoutException exeption)
{
failOver(request.getProtocol());
}
}
}
protected void failOver(SignalProtocol protocol)
{
IChannel oldChannel = protocol.getChannel();
IConnector newConnector = getNewConnector(oldChannel);
CheckUtil.checkNull(newConnector, "newConnector");
IChannel newChannel = newConnector.openChannel(protocol);
protocol.setChannel(newChannel);
oldChannel.close();
fireEvent(new FailOverEvent(oldChannel, newChannel, newConnector));
}
/**
* Should be overridden to provide a fail-over <code>IConnector</code>. The oldChannel <i>can</i> be used as a
* hint.
*/
protected abstract IConnector getNewConnector(IChannel oldChannel);
/**
* @author Eike Stepper
*/
private final class FailOverEvent implements IFailOverEvent
{
private IChannel oldChannel;
private IChannel newChannel;
private IConnector newConnector;
public FailOverEvent(IChannel oldChannel, IChannel newChannel, IConnector newConnector)
{
this.oldChannel = oldChannel;
this.newChannel = newChannel;
this.newConnector = newConnector;
}
public IFailOverStrategy getSource()
{
return FailOverStrategy.this;
}
public IChannel getOldChannel()
{
return oldChannel;
}
public IChannel getNewChannel()
{
return newChannel;
}
public IConnector getNewConnector()
{
return newConnector;
}
}
}
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