    001    /* ===========================================================
    002     * JFreeChart : a free chart library for the Java(tm) platform
    003     * ===========================================================
    004     *
    005     * (C) Copyright 2000-2008, 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 2003-2008, by Object Refinery Limited.
    031     *
    032     * Original Author:  David Gilbert (for Object Refinery Limited);
    033     * Contributor(s):   -;
    034     *
    035     * Changes:
    036     * --------
    037     * 05-Mar-2003 : Version 1 (DG);
    038     * 27-Aug-2003 : Moved SortOrder from org.jfree.data --> org.jfree.util (DG);
    039     * 12-Jan-2005 : Added accessor methods (DG);
    040     *
    041     */
    042
    043    package org.jfree.data;
    044
    045    import java.util.Comparator;
    046
    047    import org.jfree.util.SortOrder;
    048
    049    /**
    050     * A utility class that can compare and order two {@link KeyedValue} instances
    051     * and sort them into ascending or descending order by key or by value.
    052     */
    053    public class KeyedValueComparator implements Comparator {
    054
    055        /** The comparator type. */
    056        private KeyedValueComparatorType type;
    057
    058        /** The sort order. */
    059        private SortOrder order;
    060
    061        /**
    062         * Creates a new comparator.
    063         *
    064         * @param type  the type (<code>BY_KEY</code> or <code>BY_VALUE</code>,
    065         *              <code>null</code> not permitted).
    066         * @param order  the order (<code>null</code> not permitted).
    067         */
    068        public KeyedValueComparator(KeyedValueComparatorType type,
    069                                    SortOrder order) {
    070            if (order == null) {
    071                throw new IllegalArgumentException("Null 'order' argument.");
    072            }
    073            this.type = type;
    074            this.order = order;
    075        }
    076
    077        /**
    078         * Returns the type.
    079         *
    080         * @return The type (never <code>null</code>).
    081         */
    082        public KeyedValueComparatorType getType() {
    083            return this.type;
    084        }
    085
    086        /**
    087         * Returns the sort order.
    088         *
    089         * @return The sort order (never <code>null</code>).
    090         */
    091        public SortOrder getOrder() {
    092            return this.order;
    093        }
    094
    095        /**
    096         * Compares two {@link KeyedValue} instances and returns an
    097         * <code>int</code> that indicates the relative order of the two objects.
    098         *
    099         * @param o1  object 1.
    100         * @param o2  object 2.
    101         *
    102         * @return An int indicating the relative order of the objects.
    103         */
    104        public int compare(Object o1, Object o2) {
    105
    106            if (o2 == null) {
    107                return -1;
    108            }
    109            if (o1 == null) {
    110                return 1;
    111            }
    112
    113            int result;
    114
    115            KeyedValue kv1 = (KeyedValue) o1;
    116            KeyedValue kv2 = (KeyedValue) o2;
    117
    118            if (this.type == KeyedValueComparatorType.BY_KEY) {
    119                if (this.order.equals(SortOrder.ASCENDING)) {
    120                    result = kv1.getKey().compareTo(kv2.getKey());
    121                }
    122                else if (this.order.equals(SortOrder.DESCENDING)) {
    123                    result = kv2.getKey().compareTo(kv1.getKey());
    124                }
    125                else {
    126                    throw new IllegalArgumentException("Unrecognised sort order.");
    127                }
    128            }
    129            else if (this.type == KeyedValueComparatorType.BY_VALUE) {
    130                Number n1 = kv1.getValue();
    131                Number n2 = kv2.getValue();
    132                if (n2 == null) {
    133                    return -1;
    134                }
    135                if (n1 == null) {
    136                    return 1;
    137                }
    138                double d1 = n1.doubleValue();
    139                double d2 = n2.doubleValue();
    140                if (this.order.equals(SortOrder.ASCENDING)) {
    141                    if (d1 > d2) {
    142                        result = 1;
    143                    }
    144                    else if (d1 < d2) {
    145                        result = -1;
    146                    }
    147                    else {
    148                        result = 0;
    149                    }
    150                }
    151                else if (this.order.equals(SortOrder.DESCENDING)) {
    152                    if (d1 > d2) {
    153                        result = -1;
    154                    }
    155                    else if (d1 < d2) {
    156                        result = 1;
    157                    }
    158                    else {
    159                        result = 0;
    160                    }
    161                }
    162                else {
    163                    throw new IllegalArgumentException("Unrecognised sort order.");
    164                }
    165            }
    166            else {
    167                throw new IllegalArgumentException("Unrecognised type.");
    168            }
    169
    170            return result;
    171        }
    172
    173    }