defaultkeyedvalues.java

jfreechart安装程序和使用说明

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2004, 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., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * -----------------------
 * DefaultKeyedValues.java
 * -----------------------
 * (C) Copyright 2002-2004, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: DefaultKeyedValues.java,v 1.1 2004/08/31 15:21:49 mungady Exp $
 *
 * Changes:
 * --------
 * 31-Oct-2002 : Version 1 (DG);
 * 11-Feb-2003 : Fixed bug in getValue(key) method for unrecognised key (DG);
 * 05-Mar-2003 : Added methods to sort stored data 'by key' or 'by value' (DG);
 * 13-Mar-2003 : Implemented Serializable (DG);
 * 08-Apr-2003 : Modified removeValue(Comparable) method to fix bug 717049 (DG);
 * 18-Aug-2003 : Implemented Cloneable (DG);
 * 27-Aug-2003 : Moved SortOrder from org.jfree.data --> org.jfree.util (DG);
 * 09-Feb-2004 : Modified getIndex() method - see bug report 893256 (DG);
 *
 */

package org.jfree.data;

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

import org.jfree.util.SortOrder;

/**
 * A collection of (key, value) pairs.  This class provides a default implementation of the 
 * {@link KeyedValues} interface.
 */
public class DefaultKeyedValues implements KeyedValues, Cloneable, Serializable {

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

    /**
     * Creates a new collection (initially empty).
     */
    public DefaultKeyedValues() {
        this.data = new java.util.ArrayList();
    }

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

    /**
     * Returns a value.
     *
     * @param item  the item of interest (zero-based index).
     *
     * @return the value.
     */
    public Number getValue(final int item) {

        Number result = null;
        final KeyedValue kval = (KeyedValue) this.data.get(item);
        if (kval != null) {
            result = kval.getValue();
        }
        return result;

    }

    /**
     * Returns a key.
     *
     * @param index  the item index (zero-based).
     *
     * @return the row key.
     */
    public Comparable getKey(final int index) {

        Comparable result = null;
        final KeyedValue item = (KeyedValue) this.data.get(index);
        if (item != null) {
            result = item.getKey();
        }
        return result;

    }

    /**
     * Returns the index for a given key or -1 if the key is not found.
     *
     * @param key  the key.
     *
     * @return the index.
     */
    public int getIndex(final Comparable key) {

        int i = 0;
        final Iterator iterator = this.data.iterator();
        while (iterator.hasNext()) {
            final KeyedValue kv = (KeyedValue) iterator.next();
            if (kv.getKey().equals(key)) {
                return i;
            }
            i++;
        }
        return -1;  // key not found

    }

    /**
     * Returns the keys for the values in the collection.
     *
     * @return The keys (never <code>null</code>).
     */
    public List getKeys() {

        final List result = new java.util.ArrayList();
        final Iterator iterator = this.data.iterator();
        while (iterator.hasNext()) {
            final KeyedValue kv = (KeyedValue) iterator.next();
            result.add(kv.getKey());
        }
        return result;

    }

    /**
     * Returns the value (possibly <code>null</code>) for a given key.  If the key is not 
     * recognised, the method returns <code>null</code>.
     *
     * @param key  the key.
     *
     * @return the value.
     */
    public Number getValue(final Comparable key) {

        Number result = null;
        final int index = getIndex(key);
        if (index >= 0) {
            result = getValue(index);
        }
        return result;

    }

    /**
     * Adds a new value to the collection, or updates an existing value.
     * <P>
     * This is the same as the setValue(...) method.
     *
     * @param key  the key.
     * @param value  the value.
     */
    public void addValue(final Comparable key, final Number value) {
        setValue(key, value);
    }

    /**
     * Updates an existing value, or adds a new value to the collection.
     * <P>
     * This is the same as the addValue(...) method.
     *
     * @param key  the key.
     * @param value  the value.
     */
    public void setValue(final Comparable key, final Number value) {
        final int keyIndex = getIndex(key);
        if (keyIndex >= 0) {
            final DefaultKeyedValue kv = (DefaultKeyedValue) this.data.get(keyIndex);
            kv.setValue(value);
        }
        else {
            final KeyedValue kv = new DefaultKeyedValue(key, value);
            this.data.add(kv);
        }
    }

    /**
     * Removes a value from the collection.
     *
     * @param index  the index of the item to remove.
     */
    public void removeValue(final int index) {
        this.data.remove(index);
    }

    /**
     * Removes a value from the collection.  If there is no value with the specified key,
     * then this method does nothing.
     *
     * @param key  the key of the item to remove.
     */
    public void removeValue(final Comparable key) {
        final int index = getIndex(key);
        if (index >= 0) {
            removeValue(index);
        }
    }

    /**
     * Sorts the items in the list by key.
     *
     * @param order  the sort order (ascending or descending).
     */
    public void sortByKeys(final SortOrder order) {

        final Comparator comparator = new KeyedValueComparator(
            KeyedValueComparatorType.BY_KEY, order
        );
        Collections.sort(this.data, comparator);
    }

    /**
     * Sorts the items in the list by value.  If the list contains <code>null</code> values, they
     * will sort to the end of the list, irrespective of the sort order.
     *
     * @param order  the sort order (ascending or descending).
     */
    public void sortByValues(final SortOrder order) {
        final Comparator comparator = new KeyedValueComparator(
            KeyedValueComparatorType.BY_VALUE, order
        );
        Collections.sort(this.data, comparator);
    }

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

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

        if (!(o instanceof KeyedValues)) {
            return false;
        }

        final KeyedValues kvs = (KeyedValues) o;
        final int count = getItemCount();
        if (count != kvs.getItemCount()) {
            return false;
        }

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

    /**
     * Returns a hash code.
     * 
     * @return a hash code.
     */
    public int hashCode() {
        return (this.data != null ? this.data.hashCode() : 0);
    }

    /**
     * Returns a clone.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException  this class will not throw this exception, but subclasses 
     *         might.
     */
    public Object clone() throws CloneNotSupportedException {
        final DefaultKeyedValues clone = (DefaultKeyedValues) super.clone();
        clone.data = new java.util.ArrayList();
        final Iterator iterator = this.data.iterator();
        while (iterator.hasNext()) {
            final DefaultKeyedValue kv = (DefaultKeyedValue) iterator.next();
            clone.data.add(kv.clone());
        }
        return clone;    
    }
    
}