001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * -----------------------------------
028 * StandardXYSeriesLabelGenerator.java
029 * -----------------------------------
030 * (C) Copyright 2004-2008, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 16-Nov-2004 : Version 1 (DG);
038 * ------------- JFREECHART 1.0.x ---------------------------------------------
039 * 24-Nov-2006 : Fixed equals() method and updated API docs (DG);
040 * 31-Mar-2008 : Added hashCode() method to appease FindBugs (DG);
041 *
042 */
043
044package org.jfree.chart.labels;
045
046import java.io.Serializable;
047import java.text.MessageFormat;
048
049import org.jfree.chart.HashUtilities;
050import org.jfree.data.xy.XYDataset;
051import org.jfree.util.PublicCloneable;
052
053/**
054 * A standard series label generator for plots that use data from
055 * an {@link org.jfree.data.xy.XYDataset}.
056 * <br><br>
057 * This class implements <code>PublicCloneable</code> by mistake but we retain
058 * this for the sake of backward compatibility.
059 */
060public class StandardXYSeriesLabelGenerator implements XYSeriesLabelGenerator,
061        Cloneable, PublicCloneable, Serializable {
062
063    /** For serialization. */
064    private static final long serialVersionUID = 1916017081848400024L;
065
066    /** The default item label format. */
067    public static final String DEFAULT_LABEL_FORMAT = "{0}";
068
069    /** The format pattern. */
070    private String formatPattern;
071
072    /**
073     * Creates a default series label generator (uses
074     * {@link #DEFAULT_LABEL_FORMAT}).
075     */
076    public StandardXYSeriesLabelGenerator() {
077        this(DEFAULT_LABEL_FORMAT);
078    }
079
080    /**
081     * Creates a new series label generator.
082     *
083     * @param format  the format pattern (<code>null</code> not permitted).
084     */
085    public StandardXYSeriesLabelGenerator(String format) {
086        if (format == null) {
087            throw new IllegalArgumentException("Null 'format' argument.");
088        }
089        this.formatPattern = format;
090    }
091
092    /**
093     * Generates a label for the specified series.  This label will be
094     * used for the chart legend.
095     *
096     * @param dataset  the dataset (<code>null</code> not permitted).
097     * @param series  the series.
098     *
099     * @return A series label.
100     */
101    public String generateLabel(XYDataset dataset, int series) {
102        if (dataset == null) {
103            throw new IllegalArgumentException("Null 'dataset' argument.");
104        }
105        String label = MessageFormat.format(
106            this.formatPattern, createItemArray(dataset, series)
107        );
108        return label;
109    }
110
111    /**
112     * Creates the array of items that can be passed to the
113     * {@link MessageFormat} class for creating labels.
114     *
115     * @param dataset  the dataset (<code>null</code> not permitted).
116     * @param series  the series (zero-based index).
117     *
118     * @return The items (never <code>null</code>).
119     */
120    protected Object[] createItemArray(XYDataset dataset, int series) {
121        Object[] result = new Object[1];
122        result[0] = dataset.getSeriesKey(series).toString();
123        return result;
124    }
125
126    /**
127     * Returns an independent copy of the generator.  This is unnecessary,
128     * because instances are immutable anyway, but we retain this
129     * behaviour for backwards compatibility.
130     *
131     * @return A clone.
132     *
133     * @throws CloneNotSupportedException if cloning is not supported.
134     */
135    public Object clone() throws CloneNotSupportedException {
136        return super.clone();
137    }
138
139    /**
140     * Tests this object for equality with an arbitrary object.
141     *
142     * @param obj  the other object (<code>null</code> permitted).
143     *
144     * @return A boolean.
145     */
146    public boolean equals(Object obj) {
147        if (obj == this) {
148            return true;
149        }
150        if (!(obj instanceof StandardXYSeriesLabelGenerator)) {
151            return false;
152        }
153        StandardXYSeriesLabelGenerator that
154                = (StandardXYSeriesLabelGenerator) obj;
155        if (!this.formatPattern.equals(that.formatPattern)) {
156            return false;
157        }
158        return true;
159    }
160
161    /**
162     * Returns a hash code for this instance.
163     *
164     * @return A hash code.
165     */
166    public int hashCode() {
167        int result = 127;
168        result = HashUtilities.hashCode(result, this.formatPattern);
169        return result;
170    }
171
172}