CachedDataView.java

/*
 * CachedDataView.java
 * Copyright 2016 Connor Petty <cpmeister@users.sourceforge.net>
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library 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 for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * 
 * Created on Jan 20, 2016, 4:18:25 PM
 */
package pcgen.gui2.util.treeview;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;

/**
 *
 * @author Connor Petty <cpmeister@users.sourceforge.net>
 */
public abstract class CachedDataView<E> implements DataView<E>
{

	private Map<E, List<Object>> dataCache = new WeakHashMap<>();

	@Override
	public final Object getData(E element, int column)
	{
		if (shouldCache(column))
		{
			List<Object> data = dataCache.get(element);
			if (data == null)
			{
				List<? extends DataViewColumn> columns = getDataColumns();
				data = new ArrayList<>(columns.size());
				for (int i = 0; i < columns.size(); i++)
				{
					if (shouldCache(i))
					{
						data.add(getDataInternal(element, i));
					}
					else
					{
						data.add(null);
					}
				}
				dataCache.put(element, data);
			}
			return data.get(column);
		}
		else
		{
			return getDataInternal(element, column);
		}
	}

	protected abstract Object getDataInternal(E element, int column);
	
	@Override
	public void setData(Object value, E element, int column)
	{
		dataCache.remove(element);
	}

	protected boolean shouldCache(int column){
		return true;
	}
}