gt:         if (that.getItemCount() != count) {
context: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2007, 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.]
   *
   * -------------------------
   * CategoryToPieDataset.java
   * -------------------------
   * (C) Copyright 2003-2007, by Object Refinery Limited.
   *
   * Original Author:  David Gilbert (for Object Refinery Limited);
   * Contributor(s):   Christian W. Zuckschwerdt;
   *
   * Changes
   * -------
   * 23-Jan-2003 : Version 1 (DG);
   * 30-Jul-2003 : Pass through DatasetChangeEvent (CZ);
   * 29-Jan-2004 : Replaced 'extract' int with TableOrder (DG);
   * 11-Jan-2005 : Removed deprecated code in preparation for the 1.0.0 
   *               release (DG);
   * ------------- JFREECHART 1.0.x RELEASED ------------------------------------
   * 26-Jul-2006 : Added serialVersionUID, changed constructor to allow null
   *               for source, and added getSource(), getExtractType() and
   *               getExtractIndex() methods - see feature request 1477915 (DG);
   * 21-Jun-2007 : Removed JCommon dependencies (DG);
   * 
   */
  
  package org.jfree.data.category;
  
  import java.util.Collections;
  import java.util.List;
  
  import org.jfree.chart.util.TableOrder;
  import org.jfree.data.general.AbstractDataset;
  import org.jfree.data.general.DatasetChangeEvent;
  import org.jfree.data.general.DatasetChangeListener;
  import org.jfree.data.general.PieDataset;
  
  /**
   * A {@link PieDataset} implementation that obtains its data from one row or 
   * column of a {@link CategoryDataset}.
   */
  public class CategoryToPieDataset extends AbstractDataset 
                                    implements PieDataset, DatasetChangeListener {
  
      static final long serialVersionUID = 5516396319762189617L;
  
      /** The source. */
      private CategoryDataset source;
  
      /** The extract type. */
      private TableOrder extract;
  
      /** The row or column index. */
      private int index;
  
      /**
       * An adaptor class that converts any {@link CategoryDataset} into a 
       * {@link PieDataset}, by taking the values from a single row or column.
       * <p>
       * If <code>source</code> is <code>null</code>, the created dataset will 
       * be empty.
       *
       * @param source  the source dataset (<code>null</code> permitted).
       * @param extract  extract data from rows or columns? (<code>null</code> 
       *                 not permitted).
       * @param index  the row or column index.
       */
      public CategoryToPieDataset(CategoryDataset source, 
                                  TableOrder extract, 
                                  int index) {
          if (extract == null) {
              throw new IllegalArgumentException("Null 'extract' argument.");
          }
          this.source = source;
          if (this.source != null) {
              this.source.addChangeListener(this);
          }
          this.extract = extract;
          this.index = index;
      }
      
      /**
       * Returns the underlying dataset.
       * 
       * @return The underlying dataset (possibly <code>null</code>).
       * 
       * @since 1.0.2
       */
      public CategoryDataset getUnderlyingDataset() {
          return this.source;
      }
      
      /**
       * Returns the extract type, which determines whether data is read from
       * one row or one column of the underlying dataset.
       * 
       * @return The extract type.
       * 
       * @since 1.0.2
       */
      public TableOrder getExtractType() {
          return this.extract;
      }
      
      /**
       * Returns the index of the row or column from which to extract the data.
       * 
       * @return The extract index.
       * 
       * @since 1.0.2
       */
      public int getExtractIndex() {
          return this.index;
      }
  
      /**
       * Returns the number of items (values) in the collection.  If the 
       * underlying dataset is <code>null</code>, this method returns zero.
       *
       * @return The item count.
       */
      public int getItemCount() {
          int result = 0;
          if (this.source != null) {
              if (this.extract == TableOrder.BY_ROW) {
                  result = this.source.getColumnCount();
              }
              else if (this.extract == TableOrder.BY_COLUMN) {
                  result = this.source.getRowCount();
              }
          }
          return result;
      }
  
      /**
       * Returns a value from the dataset.
       *
       * @param item  the item index (zero-based).
       *
       * @return The value (possibly <code>null</code>).
       * 
       * @throws IndexOutOfBoundsException if <code>item</code> is not in the 
       *     range <code>0</code> to <code>getItemCount() - 1</code>.
       */
      public Number getValue(int item) {
          Number result = null;
          if (item < 0 || item >= getItemCount()) {
              // this will include the case where the underlying dataset is null
              throw new IndexOutOfBoundsException(
                      "The 'item' index is out of bounds.");
          }
          if (this.extract == TableOrder.BY_ROW) {
              result = this.source.getValue(this.index, item);
          }
          else if (this.extract == TableOrder.BY_COLUMN) {
              result = this.source.getValue(item, this.index);
          }
          return result;
      }
  
      /**
       * Returns the key at the specified index.
       *
       * @param index  the item index (in the range <code>0</code> to 
       *     <code>getItemCount() - 1</code>).
       *
       * @return The key.
       * 
       * @throws IndexOutOfBoundsException if <code>index</code> is not in the 
       *     specified range.
       */
      public Comparable getKey(int index) {
          Comparable result = null;
          if (index < 0 || index >= getItemCount()) {
              // this includes the case where the underlying dataset is null
              throw new IndexOutOfBoundsException("Invalid 'index': " + index);
          }
          if (this.extract == TableOrder.BY_ROW) {
              result = this.source.getColumnKey(index);
          }
          else if (this.extract == TableOrder.BY_COLUMN) {
              result = this.source.getRowKey(index);
          }
          return result;
      }
  
      /**
       * Returns the index for a given key, or <code>-1</code> if there is no
       * such key.
       *
       * @param key  the key.
       *
       * @return The index for the key, or <code>-1</code>.
       */
      public int getIndex(Comparable key) {
          int result = -1;
          if (this.source != null) {
              if (this.extract == TableOrder.BY_ROW) {
                  result = this.source.getColumnIndex(key);
              }
              else if (this.extract == TableOrder.BY_COLUMN) {
                  result = this.source.getRowIndex(key);
              }
          }
          return result;
      }
  
      /**
       * Returns the keys for the dataset.
       * <p>
       * If the underlying dataset is <code>null</code>, this method returns an
       * empty list.
       *
       * @return The keys.
       */
      public List getKeys() {
          List result = Collections.EMPTY_LIST;
          if (this.source != null) {
              if (this.extract == TableOrder.BY_ROW) {
                  result = this.source.getColumnKeys();
              }
              else if (this.extract == TableOrder.BY_COLUMN) {
                  result = this.source.getRowKeys();
              }
          }
          return result;
      }
  
      /**
       * Returns the value for a given key.  If the key is not recognised, the 
       * method should return <code>null</code> (but note that <code>null</code> 
       * can be associated with a valid key also).
       *
       * @param key  the key.
       *
       * @return The value (possibly <code>null</code>).
       */
      public Number getValue(Comparable key) {
          Number result = null;
          int keyIndex = getIndex(key);
          if (keyIndex != -1) {
              if (this.extract == TableOrder.BY_ROW) {
                  result = this.source.getValue(this.index, keyIndex);
              }
              else if (this.extract == TableOrder.BY_COLUMN) {
                  result = this.source.getValue(keyIndex, this.index);
              }
          }
          return result;
      }
      
      /**
       * Sends a {@link DatasetChangeEvent} to all registered listeners, with
       * this (not the underlying) dataset as the source.
       * 
       * @param event  the event (ignored, a new event with this dataset as the
       *     source is sent to the listeners).
       */
      public void datasetChanged(DatasetChangeEvent event) {
          fireDatasetChanged();
      }
      
      /**
       * Tests this dataset for equality with an arbitrary object, returning
       * <code>true</code> if <code>obj</code> is a dataset containing the same
       * keys and values in the same order as this dataset.
       * 
       * @param obj  the object to test (<code>null</code> permitted).
       * 
       * @return A boolean.
       */
      public boolean equals(Object obj) {
          if (obj == this) {
              return true;
          }
          if (!(obj instanceof PieDataset)) {
              return false;
          }
          PieDataset that = (PieDataset) obj;
          int count = getItemCount();
  