/*
* This file is part of the OpenSCADA project
* Copyright (C) 2006-2011 TH4 SYSTEMS GmbH (http://th4-systems.com)
*
* OpenSCADA is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 3
* only, as published by the Free Software Foundation.
*
* OpenSCADA 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 version 3 for more details
* (a copy is included in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with OpenSCADA. If not, see
* <http://opensource.org/licenses/lgpl-3.0.html> for a copy of the LGPLv3 License.
*/
package org.openscada.hd.ui.data;
import org.openscada.core.connection.provider.ConnectionIdTracker;
import org.openscada.core.connection.provider.ConnectionService;
import org.openscada.core.connection.provider.ConnectionTracker.Listener;
import org.openscada.hd.QueryParameters;
import org.osgi.framework.BundleContext;
public class ServiceQueryBuffer extends AbstractQueryBuffer implements Listener
{
private final ConnectionIdTracker tracker;
private org.openscada.hd.connection.provider.ConnectionService connection;
public ServiceQueryBuffer ( final BundleContext context, final String connectionId, final String itemId, final QueryParameters initialRequestParameters )
{
super ( itemId );
setRequestParameters ( initialRequestParameters );
this.tracker = new ConnectionIdTracker ( context, connectionId, this, org.openscada.hd.connection.provider.ConnectionService.class );
this.tracker.open ();
}
@Override
public void close ()
{
super.close ();
this.tracker.close ();
detachConnection ();
}
@Override
public void setConnection ( final ConnectionService connectionService )
{
detachConnection ();
if ( connectionService != null )
{
attachConnection ( connectionService );
}
}
private void attachConnection ( final ConnectionService connectionService )
{
if ( connectionService == null )
{
return;
}
if ( ! ( connectionService instanceof org.openscada.hd.connection.provider.ConnectionService ) )
{
return;
}
this.connection = (org.openscada.hd.connection.provider.ConnectionService)connectionService;
createQuery ( this.connection.getConnection (), this.itemId );
}
private void detachConnection ()
{
if ( this.connection == null )
{
return;
}
this.connection = null;
}
}