001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2009, 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 * DefaultCrosshairLabelGenerator.java
029 * -----------------------------------
030 * (C) Copyright 2009, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes:
036 * --------
037 * 13-Feb-2009 : Version 1 (DG);
038 *
039 */
040
041package org.jfree.chart.labels;
042
043import java.io.Serializable;
044import java.text.MessageFormat;
045import java.text.NumberFormat;
046import org.jfree.chart.plot.Crosshair;
047
048/**
049 * A default label generator.
050 *
051 * @since 1.0.13
052 */
053public class StandardCrosshairLabelGenerator implements CrosshairLabelGenerator,
054        Serializable {
055
056    /** The label format string. */
057    private String labelTemplate;
058
059    /** A number formatter for the value. */
060    private NumberFormat numberFormat;
061
062    /**
063     * Creates a new instance with default attributes.
064     */
065    public StandardCrosshairLabelGenerator() {
066        this("{0}", NumberFormat.getNumberInstance());
067    }
068
069    /**
070     * Creates a new instance with the specified attributes.
071     *
072     * @param labelTemplate  the label template (<code>null</code> not
073     *     permitted).
074     * @param numberFormat  the number formatter (<code>null</code> not
075     *     permitted).
076     */
077    public StandardCrosshairLabelGenerator(String labelTemplate,
078            NumberFormat numberFormat) {
079        super();
080        if (labelTemplate == null) {
081            throw new IllegalArgumentException(
082                    "Null 'labelTemplate' argument.");
083        }
084        if (numberFormat == null) {
085            throw new IllegalArgumentException(
086                    "Null 'numberFormat' argument.");
087        }
088        this.labelTemplate = labelTemplate;
089        this.numberFormat = numberFormat;
090    }
091
092    /**
093     * Returns the label template string.
094     *
095     * @return The label template string (never <code>null</code>).
096     */
097    public String getLabelTemplate() {
098        return this.labelTemplate;
099    }
100
101    /**
102     * Returns the number formatter.
103     *
104     * @return The formatter (never <code>null</code>).
105     */
106    public NumberFormat getNumberFormat() {
107        return this.numberFormat;
108    }
109
110    /**
111     * Returns a string that can be used as the label for a crosshair.
112     *
113     * @param crosshair  the crosshair (<code>null</code> not permitted).
114     *
115     * @return The label (possibly <code>null</code>).
116     */
117    public String generateLabel(Crosshair crosshair) {
118        Object[] v = new Object[] { this.numberFormat.format(
119                crosshair.getValue()) };
120        String result = MessageFormat.format(this.labelTemplate, v);
121        return result;
122    }
123
124    /**
125     * Tests this generator for equality with an arbitrary object.
126     * 
127     * @param obj  the object (<code>null</code> permitted).
128     * 
129     * @return A boolean.
130     */
131    public boolean equals(Object obj) {
132        if (obj == this) {
133            return true;
134        }
135        if (!(obj instanceof StandardCrosshairLabelGenerator)) {
136            return false;
137        }
138        StandardCrosshairLabelGenerator that
139                = (StandardCrosshairLabelGenerator) obj;
140        if (!this.labelTemplate.equals(that.labelTemplate)) {
141            return false;
142        }
143        if (!this.numberFormat.equals(that.numberFormat)) {
144            return false;
145        }
146        return true;
147    }
148
149    /**
150     * Returns a hash code for this instance.
151     *
152     * @return A hash code for this instance.
153     */
154    public int hashCode() {
155        return this.labelTemplate.hashCode();
156    }
157
158}