001 /**
002 * Copyright 2005-2011 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package org.kuali.rice.krad.util;
017
018 import org.apache.commons.beanutils.PropertyUtils;
019 import org.apache.commons.collections.comparators.ComparableComparator;
020 import org.kuali.rice.core.api.exception.KualiException;
021 import org.kuali.rice.core.api.util.type.TypeUtils;
022
023 import java.beans.PropertyDescriptor;
024 import java.io.Serializable;
025 import java.lang.reflect.InvocationTargetException;
026 import java.util.Collections;
027 import java.util.Comparator;
028 import java.util.Iterator;
029 import java.util.List;
030
031 /**
032 * This class compares the two beans using multiple property names.
033 *
034 *
035 */
036 public class BeanPropertyComparator implements Comparator, Serializable {
037 private static final long serialVersionUID = -2675700473766186018L;
038 boolean ignoreCase;
039 private List propertyNames;
040 private Comparator stringComparator;
041 private Comparator booleanComparator;
042 private Comparator genericComparator;
043
044 /**
045 * Constructs a PropertyComparator for comparing beans using the properties named in the given List; if the List is null, the
046 * beans will be compared directly (by Properties will be compared in the order in which they are listed. Case will be ignored
047 * in String comparisons.
048 *
049 * @param propertyNames List of property names (as Strings) used to compare beans
050 */
051 public BeanPropertyComparator(List propertyNames) {
052 this(propertyNames, true);
053 }
054
055 /**
056 * Constructs a PropertyComparator for comparing beans using the properties named in the given List. Properties will be compared
057 * in the order in which they are listed. Case will be ignored if ignoreCase is true.
058 *
059 * @param propertyNames List of property names (as Strings) used to compare beans
060 * @param ignoreCase if true, case will be ignored during String comparisons
061 */
062 public BeanPropertyComparator(List propertyNames, boolean ignoreCase) {
063 if (propertyNames == null) {
064 throw new IllegalArgumentException("invalid (null) propertyNames list");
065 }
066 if (propertyNames.size() == 0) {
067 throw new IllegalArgumentException("invalid (empty) propertyNames list");
068 }
069 this.propertyNames = Collections.unmodifiableList(propertyNames);
070 this.ignoreCase = ignoreCase;
071
072 if (ignoreCase) {
073 this.stringComparator = String.CASE_INSENSITIVE_ORDER;
074 }
075 else {
076 this.stringComparator = ComparableComparator.getInstance();
077 }
078 this.booleanComparator = new Comparator() {
079 public int compare(Object o1, Object o2) {
080 int compared = 0;
081
082 Boolean b1 = (Boolean) o1;
083 Boolean b2 = (Boolean) o2;
084
085 if (!b1.equals(b2)) {
086 if (b1.equals(Boolean.FALSE)) {
087 compared = -1;
088 }
089 else {
090 compared = 1;
091 }
092 }
093
094 return compared;
095 }
096
097 };
098 this.genericComparator = ComparableComparator.getInstance();
099 }
100
101
102 /**
103 * Compare two JavaBeans by the properties given to the constructor. If no propertues
104 *
105 * @param o1 Object The first bean to get data from to compare against
106 * @param o2 Object The second bean to get data from to compare
107 * @return int negative or positive based on order
108 */
109 public int compare(Object o1, Object o2) {
110 int compared = 0;
111
112 try {
113 for (Iterator i = propertyNames.iterator(); (compared == 0) && i.hasNext();) {
114 String currentProperty = i.next().toString();
115
116 // choose appropriate comparator
117 Comparator currentComparator = null;
118 try {
119 PropertyDescriptor propertyDescriptor = PropertyUtils.getPropertyDescriptor(o1, currentProperty);
120 Class propertyClass = propertyDescriptor.getPropertyType();
121 if (propertyClass.equals(String.class)) {
122 currentComparator = this.stringComparator;
123 }
124 else if (TypeUtils.isBooleanClass(propertyClass)) {
125 currentComparator = this.booleanComparator;
126 }
127 else {
128 currentComparator = this.genericComparator;
129 }
130 }
131 catch (NullPointerException e) {
132 throw new BeanComparisonException("unable to find property '" + o1.getClass().getName() + "." + currentProperty + "'", e);
133 }
134
135 // compare the values
136 Object value1 = PropertyUtils.getProperty(o1, currentProperty);
137 Object value2 = PropertyUtils.getProperty(o2, currentProperty);
138 /* Fix for KULRICE-5170 : BeanPropertyComparator throws exception when a null value is found in sortable non-string data type column */
139 if ( value1 == null && value2 == null)
140 return 0;
141 else if ( value1 == null)
142 return -1;
143 else if ( value2 == null )
144 return 1;
145 /* End KULRICE-5170 Fix*/
146 compared = currentComparator.compare(value1, value2);
147 }
148 }
149 catch (IllegalAccessException e) {
150 throw new BeanComparisonException("unable to compare property values", e);
151 }
152 catch (NoSuchMethodException e) {
153 throw new BeanComparisonException("unable to compare property values", e);
154 }
155 catch (InvocationTargetException e) {
156 throw new BeanComparisonException("unable to compare property values", e);
157 }
158
159 return compared;
160 }
161
162 public static class BeanComparisonException extends KualiException {
163 private static final long serialVersionUID = 2622379680100640029L;
164
165 /**
166 * @param message
167 * @param t
168 */
169 public BeanComparisonException(String message, Throwable t) {
170 super(message, t);
171 }
172 }
173 }