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 }