defaultpiedataset.java

Web图形化的Java库

/* ======================================
 * JFreeChart : a free Java chart library
 * ======================================
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 * Project Lead:  David Gilbert ([e-mail]);
 *
 * (C) Copyright 2000-2003, by Object Refinery Limited and Contributors.
 *
 * 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., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * ----------------------
 * DefaultPieDataset.java
 * ----------------------
 * (C) Copyright 2001-2003, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   Sam (oldman);
 *
 * $Id: DefaultPieDataset.java,v 1.5 2003/08/20 12:16:13 mungady Exp $
 *
 * Changes
 * -------
 * 17-Nov-2001 : Version 1 (DG);
 * 22-Jan-2002 : Removed legend methods from dataset implementations (DG);
 * 07-Apr-2002 : Modified implementation to guarantee data sequence to remain in the order
 *               categories are added (oldman);
 * 23-Oct-2002 : Added getCategory(int) method and getItemCount() method, in line with changes
 *               to the PieDataset interface (DG);
 * 04-Feb-2003 : Changed underlying data storage to DefaultKeyedValues (DG);
 * 04-Mar-2003 : Inserted DefaultKeyedValuesDataset class into hierarchy (DG);
 * 24-Apr-2003 : Switched places with DefaultKeyedValuesDataset (DG);
 * 18-Aug-2003 : Implemented Cloneable (DG);
 * 
 */

package org.jfree.data;

import java.io.Serializable;
import java.util.Collections;
import java.util.List;

/**
 * A default implementation of the {@link PieDataset} interface.
 *
 * @author David Gilbert
 */
public class DefaultPieDataset extends AbstractDataset
                               implements PieDataset, Cloneable, Serializable {

    /** Storage for the data. */
    private DefaultKeyedValues data;

    /**
     * Constructs a new dataset, initially empty.
     */
    public DefaultPieDataset() {

        this.data = new DefaultKeyedValues();

    }

    /**
     * Creates a new dataset that uses the data from a {@link KeyedValues} instance.
     *
     * @param data  the data.
     */
    public DefaultPieDataset(KeyedValues data) {

        this.data = new DefaultKeyedValues();
        for (int i = 0; i < data.getItemCount(); i++) {
            this.data.addValue(data.getKey(i), data.getValue(i));
        }
    }

    /**
     * Returns the number of items in the dataset.
     *
     * @return the item count.
     */
    public int getItemCount() {
        return this.data.getItemCount();
    }

    /**
     * Returns the categories in the dataset.
     *
     * @return the categories in the dataset.
     */
    public List getKeys() {
        return Collections.unmodifiableList(this.data.getKeys());
    }

    /**
     * Returns the key for an item.
     *
     * @param item  the item index (zero-based).
     *
     * @return the category.
     */
    public Comparable getKey(int item) {

        Comparable result = null;
        if (getItemCount() > item) {
            result = this.data.getKey(item);
        }
        return result;

    }

    /**
     * Returns the index for a key.
     *
     * @param key  the key.
     *
     * @return the key index.
     */
    public int getIndex(Comparable key) {

        return this.data.getIndex(key);

    }

    /**
     * Returns a value.
     *
     * @param item  the value index.
     *
     * @return the value (possibly <code>null</code>).
     */
    public Number getValue(int item) {

        Number result = null;
        if (getItemCount() > item) {
            result = (Number) this.data.getValue(item);
        }
        return result;

    }

    /**
     * Returns the data value associated with a key.
     *
     * @param key  the key.
     *
     * @return The value (possibly <code>null</code>).
     */
    public Number getValue(Comparable key) {

        // check arguments...
        if (key == null) {
            throw new IllegalArgumentException("PieDataset: null key not allowed.");
        }

        // fetch the value...
        return this.data.getValue(key);

    }

    /**
     * Sets the data value for a key.
     *
     * @param key  the key.
     * @param value  the value.
     */
    public void setValue(Comparable key, Number value) {

        this.data.setValue(key, value);
        fireDatasetChanged();

    }

    /**
     * Sets the data value for a key.
     *
     * @param key  the key.
     * @param value  the value.
     */
    public void setValue(Comparable key, double value) {

        setValue(key, new Double(value));

    }

    /**
     * Tests if this object is equal to another.
     *
     * @param o  the other object.
     *
     * @return A boolean.
     */
    public boolean equals(Object o) {

        if (o == null) {
            return false;
        }
        if (o == this) {
            return true;
        }

        if (o instanceof PieDataset) {
            PieDataset pd = (PieDataset) o;
            int count = getItemCount();
            for (int i = 0; i < count; i++) {
                Comparable k1 = getKey(i);
                Comparable k2 = pd.getKey(i);
                if (k1.equals(k2)) {
                    Number v1 = getValue(i);
                    Number v2 = pd.getValue(i);
                    if (v1 == null) {
                        if (v2 != null) {
                            return false;
                        }
                    }
                    else {
                        if (!v1.equals(v2)) {
                            return false;
                        }
                    }
                }
                else {
                    return false;
                }
            }
            return true;
        }

        return false;

    }
    
    /**
     * Returns a clone.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException This class will not throw this exception, but subclasses
     *         (if any) might.
     */
    public Object clone() throws CloneNotSupportedException {
        DefaultPieDataset clone = (DefaultPieDataset) super.clone();
        clone.data = (DefaultKeyedValues) this.data.clone();
        return clone;    
    }
    
}