    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
    006     *
    007     * Project Info:  http://www.jfree.org/jfreechart/index.html
    008     *
    009     * This library is free software; you can redistribute it and/or modify it
    010     * under the terms of the GNU Lesser General Public License as published by
    011     * the Free Software Foundation; either version 2.1 of the License, or
    012     * (at your option) any later version.
    013     *
    014     * This library is distributed in the hope that it will be useful, but
    015     * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    016     * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
    017     * License for more details.
    018     *
    019     * You should have received a copy of the GNU Lesser General Public
    020     * License along with this library; if not, write to the Free Software
    021     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
    022     * USA.
    023     *
    024     * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
    025     * in the United States and other countries.]
    026     *
    027     * -------------------------
    028     * KeyedValueComparator.java
    029     * -------------------------
    030     * (C) Copyright 2003-2005, by Object Refinery Limited.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   -;
    034     *
    035     * $Id: KeyedValueComparator.java,v 1.4.2.1 2005/10/25 21:29:13 mungady Exp $
    036     *
    037     * Changes:
    038     * --------
    039     * 05-Mar-2003 : Version 1 (DG);
    040     * 27-Aug-2003 : Moved SortOrder from org.jfree.data --> org.jfree.util (DG);
    041     * 12-Jan-2005 : Added accessor methods (DG);
    042     *
    043     */
    044
    045    package org.jfree.data;
    046
    047    import java.util.Comparator;
    048
    049    import org.jfree.util.SortOrder;
    050
    051    /**
    052     * A utility class that can compare and order two {@link KeyedValue} instances
    053     * and sort them into ascending or descending order by key or by value.
    054     */
    055    public class KeyedValueComparator implements Comparator {
    056
    057        /** The comparator type. */
    058        private KeyedValueComparatorType type;
    059
    060        /** The sort order. */
    061        private SortOrder order;
    062
    063        /**
    064         * Creates a new comparator.
    065         *
    066         * @param type  the type (<code>BY_KEY</code> or <code>BY_VALUE</code>,
    067         *              <code>null</code> not permitted).
    068         * @param order  the order (<code>null</code> not permitted).
    069         */
    070        public KeyedValueComparator(KeyedValueComparatorType type,
    071                                    SortOrder order) {
    072            if (order == null) {
    073                throw new IllegalArgumentException("Null 'order' argument.");
    074            }
    075            this.type = type;
    076            this.order = order;
    077        }
    078
    079        /**
    080         * Returns the type.
    081         *
    082         * @return The type (never <code>null</code>).
    083         */
    084        public KeyedValueComparatorType getType() {
    085            return this.type;
    086        }
    087
    088        /**
    089         * Returns the sort order.
    090         *
    091         * @return The sort order (never <code>null</code>).
    092         */
    093        public SortOrder getOrder() {
    094            return this.order;
    095        }
    096
    097        /**
    098         * Compares two {@link KeyedValue} instances and returns an
    099         * <code>int</code> that indicates the relative order of the two objects.
    100         *
    101         * @param o1  object 1.
    102         * @param o2  object 2.
    103         *
    104         * @return An int indicating the relative order of the objects.
    105         */
    106        public int compare(Object o1, Object o2) {
    107
    108            if (o2 == null) {
    109                return -1;
    110            }
    111            if (o1 == null) {
    112                return 1;
    113            }
    114
    115            int result;
    116
    117            KeyedValue kv1 = (KeyedValue) o1;
    118            KeyedValue kv2 = (KeyedValue) o2;
    119
    120            if (this.type == KeyedValueComparatorType.BY_KEY) {
    121                if (this.order.equals(SortOrder.ASCENDING)) {
    122                    result = kv1.getKey().compareTo(kv2.getKey());
    123                }
    124                else if (this.order.equals(SortOrder.DESCENDING)) {
    125                    result = kv2.getKey().compareTo(kv1.getKey());
    126                }
    127                else {
    128                    throw new IllegalArgumentException("Unrecognised sort order.");
    129                }
    130            }
    131            else if (this.type == KeyedValueComparatorType.BY_VALUE) {
    132                Number n1 = kv1.getValue();
    133                Number n2 = kv2.getValue();
    134                if (n2 == null) {
    135                    return -1;
    136                }
    137                if (n1 == null) {
    138                    return 1;
    139                }
    140                double d1 = n1.doubleValue();
    141                double d2 = n2.doubleValue();
    142                if (this.order.equals(SortOrder.ASCENDING)) {
    143                    if (d1 > d2) {
    144                        result = 1;
    145                    }
    146                    else if (d1 < d2) {
    147                        result = -1;
    148                    }
    149                    else {
    150                        result = 0;
    151                    }
    152                }
    153                else if (this.order.equals(SortOrder.DESCENDING)) {
    154                    if (d1 > d2) {
    155                        result = -1;
    156                    }
    157                    else if (d1 < d2) {
    158                        result = 1;
    159                    }
    160                    else {
    161                        result = 0;
    162                    }
    163                }
    164                else {
    165                    throw new IllegalArgumentException("Unrecognised sort order.");
    166                }
    167            }
    168            else {
    169                throw new IllegalArgumentException("Unrecognised type.");
    170            }
    171
    172            return result;
    173        }
    174
    175    }