# AbstractXYItemLabelGenerator.java

    /* ===========================================================
     * JFreeChart : a free chart library for the Java(tm) platform
     * ===========================================================
     *
     * (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
     *
     * Project Info:  http://www.jfree.org/jfreechart/index.html
     *
     * This library is free software; you can redistribute it and/or modify it
     * under the terms of the GNU Lesser General Public License as published by
     * the Free Software Foundation; either version 2.1 of the License, or
     * (at your option) any later version.
     *
     * This library is distributed in the hope that it will be useful, but
     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
     * License for more details.
     *
     * You should have received a copy of the GNU Lesser General Public
     * License along with this library; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
     * USA.
     *
     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
     * in the United States and other countries.]
     *
     * ---------------------------------
     * AbstractXYItemLabelGenerator.java
     * ---------------------------------
     * (C) Copyright 2004-2008, by Object Refinery Limited.
     *
     * Original Author:  David Gilbert (for Object Refinery Limited);
     * Contributor(s):   -;
     *
     * Changes
     * -------
     * 27-Feb-2004 : Version 1 (DG);
     * 12-May-2004 : Moved default tool tip format to
     *               StandardXYToolTipGenerator (DG);
     * 15-Jul-2004 : Switched getX() with getXValue() and getY() with
     *               getYValue() (DG);
     * 08-Oct-2004 : Modified createItemArray() method to handle null values (DG);
     * 10-Jan-2005 : Updated createItemArray() to use x, y primitives if
     *               possible (DG);
     * ------------- JFREECHART 1.0.x --------------------------------------------
     * 26-Jan-2006 : Minor API doc update (DG);
     * 25-Jan-2007 : Added new constructor and fixed bug in clone() method (DG);
     * 16-Oct-2007 : Removed redundant code (DG);
     * 23-Nov-2007 : Implemented hashCode() (DG);
     * 26-May-2008 : Added accessor methods for nullYString and updated equals()
     *               method (DG);
     *
     */

    package org.jfree.chart.labels;

    import java.io.Serializable;
    import java.text.DateFormat;
    import java.text.MessageFormat;
    import java.text.NumberFormat;
    import java.util.Date;

    import org.jfree.chart.HashUtilities;
    import org.jfree.data.xy.XYDataset;
    import org.jfree.util.ObjectUtilities;

    /**
     * A base class for creating item label generators.
     */
    public class AbstractXYItemLabelGenerator implements Cloneable, Serializable {

        /** For serialization. */
        private static final long serialVersionUID = 5869744396278660636L;

        /** The item label format string. */
        private String formatString;

        /** A number formatter for the x value. */
        private NumberFormat xFormat;

        /** A date formatter for the x value. */
        private DateFormat xDateFormat;

        /** A formatter for the y value. */
        private NumberFormat yFormat;

        /** A date formatter for the y value. */
        private DateFormat yDateFormat;

        /** The string used to represent 'null' for the y-value. */
        private String nullYString = "null";

        /**
         * Creates an item label generator using default number formatters.
         */
        protected AbstractXYItemLabelGenerator() {
            this("{2}", NumberFormat.getNumberInstance(),
                    NumberFormat.getNumberInstance());
        }

        /**
         * Creates an item label generator using the specified number formatters.
         *
         * @param formatString  the item label format string (<code>null</code>
         *                      not permitted).
         * @param xFormat  the format object for the x values (<code>null</code>
         *                 not permitted).
         * @param yFormat  the format object for the y values (<code>null</code>
         *                 not permitted).
         */
        protected AbstractXYItemLabelGenerator(String formatString,
                                               NumberFormat xFormat,
                                               NumberFormat yFormat) {

            if (formatString == null) {
                throw new IllegalArgumentException("Null 'formatString' argument.");
            }
            if (xFormat == null) {
                throw new IllegalArgumentException("Null 'xFormat' argument.");
            }
            if (yFormat == null) {
                throw new IllegalArgumentException("Null 'yFormat' argument.");
            }
            this.formatString = formatString;
            this.xFormat = xFormat;
            this.yFormat = yFormat;

        }

        /**
         * Creates an item label generator using the specified number formatters.
         *
         * @param formatString  the item label format string (<code>null</code>
         *                      not permitted).
         * @param xFormat  the format object for the x values (<code>null</code>
         *                 permitted).
         * @param yFormat  the format object for the y values (<code>null</code>
         *                 not permitted).
         */
        protected AbstractXYItemLabelGenerator(String formatString,
                                               DateFormat xFormat,
                                               NumberFormat yFormat) {

            this(formatString, NumberFormat.getInstance(), yFormat);
            this.xDateFormat = xFormat;

        }

        /**
         * Creates an item label generator using the specified formatters (a
         * number formatter for the x-values and a date formatter for the
         * y-values).
         *
         * @param formatString  the item label format string (<code>null</code>
         *                      not permitted).
         * @param xFormat  the format object for the x values (<code>null</code>
         *                 permitted).
         * @param yFormat  the format object for the y values (<code>null</code>
         *                 not permitted).
         *
         * @since 1.0.4
         */
        protected AbstractXYItemLabelGenerator(String formatString,
                NumberFormat xFormat, DateFormat yFormat) {

            this(formatString, xFormat, NumberFormat.getInstance());
            this.yDateFormat = yFormat;
        }

        /**
         * Creates an item label generator using the specified number formatters.
         *
         * @param formatString  the item label format string (<code>null</code>
         *                      not permitted).
         * @param xFormat  the format object for the x values (<code>null</code>
         *                 permitted).
         * @param yFormat  the format object for the y values (<code>null</code>
         *                 not permitted).
         */
        protected AbstractXYItemLabelGenerator(String formatString,
                                               DateFormat xFormat,
                                               DateFormat yFormat) {

            this(formatString, NumberFormat.getInstance(),
                    NumberFormat.getInstance());
            this.xDateFormat = xFormat;
            this.yDateFormat = yFormat;

        }

        /**
         * Returns the format string (this controls the overall structure of the
         * label).
         *
         * @return The format string (never <code>null</code>).
         */
        public String getFormatString() {
            return this.formatString;
        }

        /**
         * Returns the number formatter for the x-values.
         *
         * @return The number formatter (possibly <code>null</code>).
         */
        public NumberFormat getXFormat() {
            return this.xFormat;
        }

        /**
         * Returns the date formatter for the x-values.
         *
         * @return The date formatter (possibly <code>null</code>).
         */
        public DateFormat getXDateFormat() {
            return this.xDateFormat;
        }

        /**
         * Returns the number formatter for the y-values.
         *
         * @return The number formatter (possibly <code>null</code>).
         */
        public NumberFormat getYFormat() {
            return this.yFormat;
        }

        /**
         * Returns the date formatter for the y-values.
         *
         * @return The date formatter (possibly <code>null</code>).
         */
        public DateFormat getYDateFormat() {
            return this.yDateFormat;
        }

        /**
         * Generates a label string for an item in the dataset.
         *
         * @param dataset  the dataset (<code>null</code> not permitted).
         * @param series  the series (zero-based index).
         * @param item  the item (zero-based index).
         *
         * @return The label (possibly <code>null</code>).
         */
        public String generateLabelString(XYDataset dataset, int series, int item) {
            String result = null;
            Object[] items = createItemArray(dataset, series, item);
            result = MessageFormat.format(this.formatString, items);
            return result;
        }

        /**
         * Returns the string representing a null value.
         *
         * @return The string representing a null value.
         *
         * @since 1.0.10
         */
        public String getNullYString() {
        	return this.nullYString;
        }

        /**
         * Creates the array of items that can be passed to the
         * {@link MessageFormat} class for creating labels.
         *
         * @param dataset  the dataset (<code>null</code> not permitted).
         * @param series  the series (zero-based index).
         * @param item  the item (zero-based index).
         *
         * @return An array of three items from the dataset formatted as
         *         <code>String</code> objects (never <code>null</code>).
         */
        protected Object[] createItemArray(XYDataset dataset, int series,
                                           int item) {
            Object[] result = new Object[3];
            result[0] = dataset.getSeriesKey(series).toString();

            double x = dataset.getXValue(series, item);
            if (this.xDateFormat != null) {
                result[1] = this.xDateFormat.format(new Date((long) x));
            }
            else {
                result[1] = this.xFormat.format(x);
            }

            double y = dataset.getYValue(series, item);
            if (Double.isNaN(y) && dataset.getY(series, item) == null) {
                result[2] = this.nullYString;
            }
            else {
                if (this.yDateFormat != null) {
                    result[2] = this.yDateFormat.format(new Date((long) y));
                }
                else {
                    result[2] = this.yFormat.format(y);
                }
            }
            return result;
        }

        /**
         * Tests this object for equality with an arbitrary object.
         *
         * @param obj  the other object (<code>null</code> permitted).
         *
         * @return A boolean.
         */
        public boolean equals(Object obj) {
            if (obj == this) {
                return true;
            }
            if (!(obj instanceof AbstractXYItemLabelGenerator)) {
                return false;
            }
            AbstractXYItemLabelGenerator that = (AbstractXYItemLabelGenerator) obj;
            if (!this.formatString.equals(that.formatString)) {
                return false;
            }
            if (!ObjectUtilities.equal(this.xFormat, that.xFormat)) {
                return false;
            }
            if (!ObjectUtilities.equal(this.xDateFormat, that.xDateFormat)) {
                return false;
            }
            if (!ObjectUtilities.equal(this.yFormat, that.yFormat)) {
                return false;
            }
            if (!ObjectUtilities.equal(this.yDateFormat, that.yDateFormat)) {
                return false;
            }
            if (!this.nullYString.equals(that.nullYString)) {
            	return false;
            }
            return true;
        }

        /**
         * Returns a hash code for this instance.
         *
         * @return A hash code.
         */
        public int hashCode() {
            int result = 127;
            result = HashUtilities.hashCode(result, this.formatString);
            result = HashUtilities.hashCode(result, this.xFormat);
            result = HashUtilities.hashCode(result, this.xDateFormat);
            result = HashUtilities.hashCode(result, this.yFormat);
            result = HashUtilities.hashCode(result, this.yDateFormat);
            return result;
        }

        /**
         * Returns an independent copy of the generator.
         *
         * @return A clone.
         *
         * @throws CloneNotSupportedException if cloning is not supported.
         */
        public Object clone() throws CloneNotSupportedException {
            AbstractXYItemLabelGenerator clone
                    = (AbstractXYItemLabelGenerator) super.clone();
            if (this.xFormat != null) {
                clone.xFormat = (NumberFormat) this.xFormat.clone();
            }
            if (this.yFormat != null) {
                clone.yFormat = (NumberFormat) this.yFormat.clone();
            }
            if (this.xDateFormat != null) {
                clone.xDateFormat = (DateFormat) this.xDateFormat.clone();
            }
            if (this.yDateFormat != null) {
                clone.yDateFormat = (DateFormat) this.yDateFormat.clone();
            }
            return clone;
        }

    }