001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-present, by David Gilbert 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 * AbstractPieLabelDistributor.java
029 * --------------------------------
030 * (C) Copyright 2007-present, by David Gilbert and Contributors.
031 *
032 * Original Author:  David Gilbert;
033 * Contributor(s):   -;
034 * 
035 */
036
037package org.jfree.chart.plot;
038
039import java.io.Serializable;
040import java.util.List;
041import org.jfree.chart.util.Args;
042
043/**
044 * A base class for handling the distribution of pie section labels.  Create
045 * your own subclass and set it using the
046 * {@link PiePlot#setLabelDistributor(AbstractPieLabelDistributor)} method
047 * if you want to customise the label distribution.
048 */
049public abstract class AbstractPieLabelDistributor implements Serializable {
050
051    /** The label records. */
052    protected List labels;
053
054    /**
055     * Creates a new instance.
056     */
057    public AbstractPieLabelDistributor() {
058        this.labels = new java.util.ArrayList();
059    }
060
061    /**
062     * Returns a label record from the list.
063     *
064     * @param index  the index.
065     *
066     * @return The label record.
067     */
068    public PieLabelRecord getPieLabelRecord(int index) {
069        return (PieLabelRecord) this.labels.get(index);
070    }
071
072    /**
073     * Adds a label record.
074     *
075     * @param record  the label record ({@code null} not permitted).
076     */
077    public void addPieLabelRecord(PieLabelRecord record) {
078        Args.nullNotPermitted(record, "record");
079        this.labels.add(record);
080    }
081
082    /**
083     * Returns the number of items in the list.
084     *
085     * @return The item count.
086     */
087    public int getItemCount() {
088        return this.labels.size();
089    }
090
091    /**
092     * Clears the list of labels.
093     */
094    public void clear() {
095        this.labels.clear();
096    }
097
098    /**
099     * Called by the {@link PiePlot} class.  Implementations should distribute
100     * the labels in this.labels then return.
101     *
102     * @param minY  the y-coordinate for the top of the label area.
103     * @param height  the height of the label area.
104     */
105    public abstract void distributeLabels(double minY, double height);
106
107}