gt:             double[] d2y = d2[1];
context: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2013, 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.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
   * Other names may be trademarks of their respective owners.]
   *
   * ---------------------
   * DefaultXYDataset.java
   * ---------------------
   * (C) Copyright 2006-2008, by Object Refinery Limited and Contributors.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   -;
   *
   * Changes
   * -------
   * 06-Jul-2006 : Version 1 (DG);
   * 02-Nov-2006 : Fixed a problem with adding a new series with the same key
   *               as an existing series (see bug 1589392) (DG);
   * 25-Jan-2007 : Implemented PublicCloneable (DG);
   *
   */
  
  package org.jfree.data.xy;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  
  import org.jfree.data.DomainOrder;
  import org.jfree.data.general.DatasetChangeEvent;
  import org.jfree.util.PublicCloneable;
  
  /**
   * A default implementation of the {@link XYDataset} interface that stores
   * data values in arrays of double primitives.
   *
   * @since 1.0.2
   */
  public class DefaultXYDataset extends AbstractXYDataset
          implements XYDataset, PublicCloneable {
  
      /**
       * Storage for the series keys.  This list must be kept in sync with the
       * seriesList.
       */
      private List seriesKeys;
  
      /**
       * Storage for the series in the dataset.  We use a list because the
       * order of the series is significant.  This list must be kept in sync
       * with the seriesKeys list.
       */
      private List seriesList;
  
      /**
       * Creates a new <code>DefaultXYDataset</code> instance, initially
       * containing no data.
       */
      public DefaultXYDataset() {
          this.seriesKeys = new java.util.ArrayList();
          this.seriesList = new java.util.ArrayList();
      }
  
      /**
       * Returns the number of series in the dataset.
       *
       * @return The series count.
       */
      public int getSeriesCount() {
          return this.seriesList.size();
      }
  
      /**
       * Returns the key for a series.
       *
       * @param series  the series index (in the range <code>0</code> to
       *     <code>getSeriesCount() - 1</code>).
       *
       * @return The key for the series.
       *
       * @throws IllegalArgumentException if <code>series</code> is not in the
       *     specified range.
       */
      public Comparable getSeriesKey(int series) {
          if ((series < 0) || (series >= getSeriesCount())) {
              throw new IllegalArgumentException("Series index out of bounds");
          }
          return (Comparable) this.seriesKeys.get(series);
      }
  
      /**
       * Returns the index of the series with the specified key, or -1 if there
       * is no such series in the dataset.
       *
       * @param seriesKey  the series key (<code>null</code> permitted).
       *
       * @return The index, or -1.
       */
      public int indexOf(Comparable seriesKey) {
          return this.seriesKeys.indexOf(seriesKey);
      }
  
      /**
       * Returns the order of the domain (x-) values in the dataset.  In this
       * implementation, we cannot guarantee that the x-values are ordered, so
       * this method returns <code>DomainOrder.NONE</code>.
       *
       * @return <code>DomainOrder.NONE</code>.
       */
      public DomainOrder getDomainOrder() {
          return DomainOrder.NONE;
      }
  
      /**
       * Returns the number of items in the specified series.
       *
       * @param series  the series index (in the range <code>0</code> to
       *     <code>getSeriesCount() - 1</code>).
       *
       * @return The item count.
       *
       * @throws IllegalArgumentException if <code>series</code> is not in the
       *     specified range.
       */
      public int getItemCount(int series) {
          if ((series < 0) || (series >= getSeriesCount())) {
              throw new IllegalArgumentException("Series index out of bounds");
          }
          double[][] seriesArray = (double[][]) this.seriesList.get(series);
          return seriesArray[0].length;
      }
  
      /**
       * Returns the x-value for an item within a series.
       *
       * @param series  the series index (in the range <code>0</code> to
       *     <code>getSeriesCount() - 1</code>).
       * @param item  the item index (in the range <code>0</code> to
       *     <code>getItemCount(series)</code>).
       *
       * @return The x-value.
       *
       * @throws ArrayIndexOutOfBoundsException if <code>series</code> is not
       *     within the specified range.
       * @throws ArrayIndexOutOfBoundsException if <code>item</code> is not
       *     within the specified range.
       *
       * @see #getX(int, int)
       */
      public double getXValue(int series, int item) {
          double[][] seriesData = (double[][]) this.seriesList.get(series);
          return seriesData[0][item];
      }
  
      /**
       * Returns the x-value for an item within a series.
       *
       * @param series  the series index (in the range <code>0</code> to
       *     <code>getSeriesCount() - 1</code>).
       * @param item  the item index (in the range <code>0</code> to
       *     <code>getItemCount(series)</code>).
       *
       * @return The x-value.
       *
       * @throws ArrayIndexOutOfBoundsException if <code>series</code> is not
       *     within the specified range.
       * @throws ArrayIndexOutOfBoundsException if <code>item</code> is not
       *     within the specified range.
       *
       * @see #getXValue(int, int)
       */
      public Number getX(int series, int item) {
          return new Double(getXValue(series, item));
      }
  
      /**
       * Returns the y-value for an item within a series.
       *
       * @param series  the series index (in the range <code>0</code> to
       *     <code>getSeriesCount() - 1</code>).
       * @param item  the item index (in the range <code>0</code> to
       *     <code>getItemCount(series)</code>).
       *
       * @return The y-value.
       *
       * @throws ArrayIndexOutOfBoundsException if <code>series</code> is not
       *     within the specified range.
       * @throws ArrayIndexOutOfBoundsException if <code>item</code> is not
       *     within the specified range.
       *
       * @see #getY(int, int)
       */
      public double getYValue(int series, int item) {
          double[][] seriesData = (double[][]) this.seriesList.get(series);
          return seriesData[1][item];
      }
  
      /**
       * Returns the y-value for an item within a series.
       *
       * @param series  the series index (in the range <code>0</code> to
       *     <code>getSeriesCount() - 1</code>).
       * @param item  the item index (in the range <code>0</code> to
       *     <code>getItemCount(series)</code>).
       *
       * @return The y-value.
       *
       * @throws ArrayIndexOutOfBoundsException if <code>series</code> is not
       *     within the specified range.
       * @throws ArrayIndexOutOfBoundsException if <code>item</code> is not
       *     within the specified range.
       *
       * @see #getX(int, int)
       */
      public Number getY(int series, int item) {
          return new Double(getYValue(series, item));
      }
  
      /**
       * Adds a series or if a series with the same key already exists replaces
       * the data for that series, then sends a {@link DatasetChangeEvent} to
       * all registered listeners.
       *
       * @param seriesKey  the series key (<code>null</code> not permitted).
       * @param data  the data (must be an array with length 2, containing two
       *     arrays of equal length, the first containing the x-values and the
       *     second containing the y-values).
       */
      public void addSeries(Comparable seriesKey, double[][] data) {
          if (seriesKey == null) {
              throw new IllegalArgumentException(
                      "The 'seriesKey' cannot be null.");
          }
          if (data == null) {
              throw new IllegalArgumentException("The 'data' is null.");
          }
          if (data.length != 2) {
              throw new IllegalArgumentException(
                      "The 'data' array must have length == 2.");
          }
          if (data[0].length != data[1].length) {
              throw new IllegalArgumentException(
                  "The 'data' array must contain two arrays with equal length.");
          }
          int seriesIndex = indexOf(seriesKey);
          if (seriesIndex == -1) {  // add a new series
              this.seriesKeys.add(seriesKey);
              this.seriesList.add(data);
          }
          else {  // replace an existing series
              this.seriesList.remove(seriesIndex);
              this.seriesList.add(seriesIndex, data);
          }
          notifyListeners(new DatasetChangeEvent(this, this));
      }
  
      /**
       * Removes a series from the dataset, then sends a
       * {@link DatasetChangeEvent} to all registered listeners.
       *
       * @param seriesKey  the series key (<code>null</code> not permitted).
       *
       */
      public void removeSeries(Comparable seriesKey) {
          int seriesIndex = indexOf(seriesKey);
          if (seriesIndex >= 0) {
              this.seriesKeys.remove(seriesIndex);
              this.seriesList.remove(seriesIndex);
              notifyListeners(new DatasetChangeEvent(this, this));
          }
      }
  
      /**
       * Tests this <code>DefaultXYDataset</code> instance for equality with an
       * arbitrary object.  This method returns <code>true</code> if and only if:
       * <ul>
       * <li><code>obj</code> is not <code>null</code>;</li>
       * <li><code>obj</code> is an instance of
       *         <code>DefaultXYDataset</code>;</li>
       * <li>both datasets have the same number of series, each containing
       *         exactly the same values.</li>
       * </ul>
       *
       * @param obj  the object (<code>null</code> permitted).
       *
       * @return A boolean.
       */
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          if (!(obj instanceof DefaultXYDataset)) {
              return false;
          }
          DefaultXYDataset that = (DefaultXYDataset) obj;
          if (!this.seriesKeys.equals(that.seriesKeys)) {
              return false;
          }
          for (int i = 0; i < this.seriesList.size(); i++) {
              double[][] d1 = (double[][]) this.seriesList.get(i);
              double[][] d2 = (double[][]) that.seriesList.get(i);
              double[] d1x = d1[0];
              double[] d2x = d2[0];
              if (!Arrays.equals(d1x, d2x)) {
                  return false;
              }
              double[] d1y = d1[1];
  