defaultkeyedvalues.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.
 *
 * -----------------------
 * DefaultKeyedValues.java
 * -----------------------
 * (C) Copyright 2002, 2003 by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: DefaultKeyedValues.java,v 1.6 2003/08/28 16:37:03 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);
 *
 */

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.
 * <P>
 * This class provides a default implementation of the {@link KeyedValues} interface.
 *
 * @author David Gilbert
 */
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(int item) {

        Number result = null;
        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(int index) {

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

    }

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

        int result = -1;
        int i = 0;
        Iterator iterator = this.data.iterator();
        while (iterator.hasNext()) {
            KeyedValue kv = (KeyedValue) iterator.next();
            if (kv.getKey().equals(key)) {
                result = i;
            }
            i++;
        }
        return result;

    }

    /**
     * Returns the keys.
     *
     * @return the keys.
     */
    public List getKeys() {

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

    }

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

        Number result = null;
        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(Comparable key, 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(Comparable key, Number value) {
        int keyIndex = getIndex(key);
        if (keyIndex >= 0) {
            DefaultKeyedValue kv = (DefaultKeyedValue) this.data.get(keyIndex);
            kv.setValue(value);
        }
        else {
            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(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(Comparable key) {
        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(SortOrder order) {

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

    /**
     * Sorts the items in the list by value.
     *
     * @param order  the sort order (ascending or descending).
     */
    public void sortByValues(SortOrder order) {
        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(Object o) {

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

        if (o instanceof KeyedValues) {
            KeyedValues kvs = (KeyedValues) o;
            int count = getItemCount();
            for (int i = 0; i < count; i++) {
                Comparable k1 = getKey(i);
                Comparable k2 = kvs.getKey(i);
                if (k1.equals(k2)) {
                    Number v1 = getValue(i);
                    Number v2 = kvs.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 
     *         might.
     */
    public Object clone() throws CloneNotSupportedException {
        DefaultKeyedValues clone = (DefaultKeyedValues) super.clone();
        clone.data = new java.util.ArrayList();
        Iterator iterator = this.data.iterator();
        while (iterator.hasNext()) {
            DefaultKeyedValue kv = (DefaultKeyedValue) iterator.next();
            clone.data.add(kv.clone());
        }
        return clone;    
    }
    
}