Java tutorial
/* =========================================================== * 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.] * * ------------------------- * CategoryToPieDataset.java * ------------------------- * (C) Copyright 2003-2013, 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 1.0.0 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); * 03-Jul-2013 : Use ParamChecks (DG); * */ package org.jfree.data.category; import java.util.Collections; import java.util.List; import org.jfree.chart.util.ParamChecks; import org.jfree.data.general.AbstractDataset; import org.jfree.data.general.DatasetChangeEvent; import org.jfree.data.general.DatasetChangeListener; import org.jfree.data.general.PieDataset; import org.jfree.util.TableOrder; /** * 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 { /** For serialization. */ 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) { ParamChecks.nullNotPermitted(extract, "extract"); 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. */ @Override 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>. */ @Override 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. */ @Override 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>. */ @Override 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. */ @Override 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>). */ @Override 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). */ @Override 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. */ @Override public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof PieDataset)) { return false; } PieDataset that = (PieDataset) obj; int count = getItemCount(); if (that.getItemCount() != count) { return false; } for (int i = 0; i < count; i++) { Comparable k1 = getKey(i); Comparable k2 = that.getKey(i); if (!k1.equals(k2)) { return false; } Number v1 = getValue(i); Number v2 = that.getValue(i); if (v1 == null) { if (v2 != null) { return false; } } else { if (!v1.equals(v2)) { return false; } } } return true; } }