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 * AbstractPieLabelDistributor.java
029 * --------------------------------
030 * (C) Copyright 2007-2013, by Object Refinery Limited and Contributors.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 14-Jun-2007 : Version 1 (DG);
038 * 03-Jul-2013 : Use ParamChecks (DG);
039 * 
040 */
041
042package org.jfree.chart.plot;
043
044import java.io.Serializable;
045import java.util.List;
046import org.jfree.chart.util.ParamChecks;
047
048/**
049 * A base class for handling the distribution of pie section labels.  Create
050 * your own subclass and set it using the
051 * {@link PiePlot#setLabelDistributor(AbstractPieLabelDistributor)} method
052 * if you want to customise the label distribution.
053 */
054public abstract class AbstractPieLabelDistributor implements Serializable {
055
056    /** The label records. */
057    protected List labels;
058
059    /**
060     * Creates a new instance.
061     */
062    public AbstractPieLabelDistributor() {
063        this.labels = new java.util.ArrayList();
064    }
065
066    /**
067     * Returns a label record from the list.
068     *
069     * @param index  the index.
070     *
071     * @return The label record.
072     */
073    public PieLabelRecord getPieLabelRecord(int index) {
074        return (PieLabelRecord) this.labels.get(index);
075    }
076
077    /**
078     * Adds a label record.
079     *
080     * @param record  the label record (<code>null</code> not permitted).
081     */
082    public void addPieLabelRecord(PieLabelRecord record) {
083        ParamChecks.nullNotPermitted(record, "record");
084        this.labels.add(record);
085    }
086
087    /**
088     * Returns the number of items in the list.
089     *
090     * @return The item count.
091     */
092    public int getItemCount() {
093        return this.labels.size();
094    }
095
096    /**
097     * Clears the list of labels.
098     */
099    public void clear() {
100        this.labels.clear();
101    }
102
103    /**
104     * Called by the {@link PiePlot} class.  Implementations should distribute
105     * the labels in this.labels then return.
106     *
107     * @param minY  the y-coordinate for the top of the label area.
108     * @param height  the height of the label area.
109     */
110    public abstract void distributeLabels(double minY, double height);
111
112}