/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 
 * USA.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ------------------------
 * PieToolTipGenerator.java
 * ------------------------
 * (C) Copyright 2001-2004, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: PieToolTipGenerator.java,v 1.2.2.1 2005/10/25 20:49:02 mungady Exp $
 *
 * Changes
 * -------
 * 15-Apr-2004 : Version 1, split from PieItemLabelGenerator (DG);
 *
 */

package org.jfree.chart.labels;

import org.jfree.data.general.PieDataset;

/**
 * A tool tip generator that is used by the 
 * {@link org.jfree.chart.plot.PiePlot} class.
 */
public interface PieToolTipGenerator {
    
    /**
     * Generates a tool tip text item for the specified item in the dataset.  
     * This method can return <code>null</code> to indicate that no tool tip 
     * should be displayed for an item.
     *
     * @param dataset  the dataset (<code>null</code> not permitted).
     * @param key  the section key (<code>null</code> not permitted).
     *
     * @return The tool tip text (possibly <code>null</code>).
     */
    public String generateToolTip(PieDataset dataset, Comparable key);
        
}