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/***************************************************************************
* Copyright (c) 2004 - 2007 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;
import org.eclipse.net4j.IChannel;
import org.eclipse.net4j.IConnector;
import org.eclipse.net4j.internal.util.event.Notifier;
import java.util.concurrent.TimeoutException;
/**
* @author Eike Stepper
*/
public 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 connector = getNewConnector(oldChannel);
if (connector == null)
{
throw new IllegalStateException("connector == null");
}
IChannel newChannel = connector.openChannel(protocol);
protocol.setChannel(newChannel);
oldChannel.close();
fireEvent(new FailOverEvent(oldChannel, newChannel));
}
/**
* Should be overridden to provide a fail-over <code>IConnector</code>. The
* oldChannel <i>can</i> be used as a hint.
*/
protected IConnector getNewConnector(IChannel oldChannel)
{
if (oldChannel == null)
{
throw new IllegalArgumentException("oldChannel == null");
}
return oldChannel.getConnector();
}
/**
* @author Eike Stepper
*/
private final class FailOverEvent implements IFailOverEvent
{
private IChannel oldChannel;
private IChannel newChannel;
public FailOverEvent(IChannel oldChannel, IChannel newChannel)
{
this.oldChannel = oldChannel;
this.newChannel = newChannel;
}
public IFailOverStrategy getSource()
{
return FailOverStrategy.this;
}
public IChannel getOldChannel()
{
return oldChannel;
}
public IChannel getNewChannel()
{
return newChannel;
}
}
}
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