org.neo4j.kernel.ha.cluster.modeswitch.AbstractComponentSwitcher Maven / Gradle / Ivy
/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see .
*/
package org.neo4j.kernel.ha.cluster.modeswitch;
import org.neo4j.kernel.ha.DelegateInvocationHandler;
/**
* A component switcher deals with how internal services should react when changing
* between different cluster states, and allows them to switch to the new state
* that reflects that.
*
* @param
*/
public abstract class AbstractComponentSwitcher implements ComponentSwitcher
{
private final DelegateInvocationHandler delegate;
protected AbstractComponentSwitcher( DelegateInvocationHandler delegate )
{
this.delegate = delegate;
}
protected abstract T getMasterImpl();
protected abstract T getSlaveImpl();
@Override
public void switchToMaster()
{
shutdownCurrent();
T component = getMasterImpl();
updateDelegate( component );
}
@Override
public void switchToSlave()
{
shutdownCurrent();
T component = getSlaveImpl();
updateDelegate( component );
}
@Override
public void switchToPending()
{
shutdownCurrent();
}
protected void shutdownCurrent()
{
updateDelegate( null );
}
private void updateDelegate( T newValue )
{
delegate.setDelegate( newValue );
}
}
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