001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
006 *
007 * Project Info:  http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
022 * USA.
023 *
024 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 * -----------------------------
028 * PieSectionLabelGenerator.java
029 * -----------------------------
030 * (C) Copyright 2001-2008, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 13-Dec-2001 : Version 1 (DG);
038 * 16-Jan-2002 : Completed Javadocs (DG);
039 * 26-Sep-2002 : Fixed errors reported by Checkstyle (DG);
040 * 30-Oct-2002 : Category is now a Comparable instance (DG);
041 * 07-Mar-2003 : Changed to KeyedValuesDataset and added pieIndex
042 *               parameter (DG);
043 * 21-Mar-2003 : Updated Javadocs (DG);
044 * 24-Apr-2003 : Switched around PieDataset and KeyedValuesDataset (DG);
045 * 13-Aug-2003 : Added clone() method (DG);
046 * 19-Aug-2003 : Renamed PieToolTipGenerator --> PieItemLabelGenerator (DG);
047 * 11-Nov-2003 : Removed clone() method (DG);
048 * 30-Jan-2004 : Added generateSectionLabel() method (DG);
049 * 15-Apr-2004 : Moved generateToolTip() method into separate interface and
050 *               renamed this interface PieSectionLabelGenerator (DG);
051 *
052 */
053
054package org.jfree.chart.labels;
055
056import java.awt.Font;
057import java.awt.Paint;
058import java.awt.font.TextAttribute;
059import java.text.AttributedString;
060
061import org.jfree.data.general.PieDataset;
062
063/**
064 * Interface for a label generator for plots that use data from
065 * a {@link PieDataset}.
066 */
067public interface PieSectionLabelGenerator {
068
069    /**
070     * Generates a label for a pie section.
071     *
072     * @param dataset  the dataset (<code>null</code> not permitted).
073     * @param key  the section key (<code>null</code> not permitted).
074     *
075     * @return The label (possibly <code>null</code>).
076     */
077    public String generateSectionLabel(PieDataset dataset, Comparable key);
078
079    /**
080     * Generates an attributed label for the specified series, or
081     * <code>null</code> if no attributed label is available (in which case,
082     * the string returned by
083     * {@link #generateSectionLabel(PieDataset, Comparable)} will
084     * provide the fallback).  Only certain attributes are recognised by the
085     * code that ultimately displays the labels:
086     * <ul>
087     * <li>{@link TextAttribute#FONT}: will set the font;</li>
088     * <li>{@link TextAttribute#POSTURE}: a value of
089     *     {@link TextAttribute#POSTURE_OBLIQUE} will add {@link Font#ITALIC} to
090     *     the current font;</li>
091     * <li>{@link TextAttribute#WEIGHT}: a value of
092     *     {@link TextAttribute#WEIGHT_BOLD} will add {@link Font#BOLD} to the
093     *     current font;</li>
094     * <li>{@link TextAttribute#FOREGROUND}: this will set the {@link Paint}
095     *     for the current</li>
096     * <li>{@link TextAttribute#SUPERSCRIPT}: the values
097     *     {@link TextAttribute#SUPERSCRIPT_SUB} and
098     *     {@link TextAttribute#SUPERSCRIPT_SUPER} are recognised.</li>
099     * </ul>
100     *
101     * @param dataset  the dataset.
102     * @param key  the key.
103     *
104     * @return An attributed label (possibly <code>null</code>).
105     */
106    public AttributedString generateAttributedSectionLabel(PieDataset dataset,
107                                                           Comparable key);
108
109}