ListData.java

/*
 * This file is part of the OpenSCADA project
 * Copyright (C) 2006-2010 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.da.ui.widgets.realtime;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Observable;
import java.util.Observer;
import java.util.Set;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CopyOnWriteArraySet;

import org.openscada.da.ui.connection.data.Item;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ListData implements Observer
{
    private final static Logger logger = LoggerFactory.getLogger ( ListData.class );

    private List<ListEntry> items = new CopyOnWriteArrayList<ListEntry> ();

    private final Set<Listener> listeners = new CopyOnWriteArraySet<Listener> ();

    public List<ListEntry> getItems ()
    {
        return new ArrayList<ListEntry> ( this.items );
    }

    synchronized public void setItems ( final List<ListEntry> items )
    {
        clear ();

        this.items = items;
        fireAdded ( this.items.toArray ( new ListEntry[this.items.size ()] ) );
        for ( final ListEntry entry : items )
        {
            entry.addObserver ( this );
        }
    }

    public void add ( final ListEntry entry )
    {
        if ( this.items.add ( entry ) )
        {
            fireAdded ( new ListEntry[] { entry } );
            entry.addObserver ( this );
        }
    }

    public void add ( final Item item )
    {
        final ListEntry entry = new ListEntry ();
        entry.setDataItem ( item );

        add ( entry );
    }

    public void remove ( final ListEntry entry )
    {
        if ( this.items.remove ( entry ) )
        {
            entry.deleteObserver ( this );
            entry.clear ();
            fireRemoved ( new ListEntry[] { entry } );
        }
    }

    public void removeAll ( final Collection<ListEntry> entries )
    {
        this.items.removeAll ( entries );
        for ( final ListEntry entry : entries )
        {
            entry.deleteObserver ( this );
            entry.clear ();
        }
        fireRemoved ( entries.toArray ( new ListEntry[entries.size ()] ) );
    }

    synchronized public void clear ()
    {
        for ( final ListEntry entry : this.items )
        {
            entry.deleteObserver ( this );
        }
        this.items.clear ();
        fireRemoved ( this.items.toArray ( new ListEntry[this.items.size ()] ) );
    }

    public void addListener ( final Listener listener )
    {
        this.listeners.add ( listener );

        // now fill the new listener with what we already have
        if ( !this.items.isEmpty () )
        {
            listener.added ( this.items.toArray ( new ListEntry[this.items.size ()] ) );
        }
    }

    public void removeListener ( final Listener listener )
    {
        this.listeners.remove ( listener );
    }

    protected void fireAdded ( final ListEntry[] entries )
    {
        logger.debug ( String.format ( "Fire add for %d items", entries.length ) ); //$NON-NLS-1$
        for ( final Listener listener : this.listeners )
        {
            try
            {
                listener.added ( entries );
            }
            catch ( final Exception e )
            {
                logger.warn ( "Failed while sending add notification", e ); //$NON-NLS-1$
            }
        }
    }

    protected void fireRemoved ( final ListEntry[] entries )
    {
        for ( final Listener listener : this.listeners )
        {
            try
            {
                listener.removed ( entries );
            }
            catch ( final Exception e )
            {
                logger.warn ( "Failed while sending remove notification", e ); //$NON-NLS-1$
            }
        }
    }

    protected void fireUpdated ( final ListEntry[] entries )
    {
        logger.debug ( "Updating items: " + entries.length ); //$NON-NLS-1$

        for ( final Listener listener : this.listeners )
        {
            try
            {
                listener.updated ( entries );
            }
            catch ( final Exception e )
            {
                logger.warn ( "Failed while sending update notification", e ); //$NON-NLS-1$
            }
        }
    }

    public void update ( final Observable o, final Object arg )
    {
        if ( o instanceof ListEntry && this.items.contains ( o ) )
        {
            fireUpdated ( new ListEntry[] { (ListEntry)o } );
        }
    }
}