org.springframework.ldap.support.ListComparator Maven / Gradle / Ivy
/*
* Copyright 2005-2010 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.ldap.support;
import java.io.Serializable;
import java.util.Comparator;
import java.util.List;
/**
* Comparator for comparing lists of Comparable objects.
*
* @author Mattias Hellborg Arthursson
*/
public class ListComparator implements Comparator, Serializable {
private static final long serialVersionUID = -3068381879731157178L;
/**
* Compare two lists of Comparable objects.
*
* @param o1 the first object to be compared.
* @param o2 the second object to be compared.
* @throws ClassCastException if any of the lists contains an object that
* is not Comparable.
*/
public int compare(Object o1, Object o2) {
List list1 = (List) o1;
List list2 = (List) o2;
for (int i = 0; i < list1.size(); i++) {
if (list2.size() > i) {
Comparable component1 = (Comparable) list1.get(i);
Comparable component2 = (Comparable) list2.get(i);
int componentsCompared = component1.compareTo(component2);
if (componentsCompared != 0) {
return componentsCompared;
}
}
else {
// First instance has more components, so that instance is
// greater.
return 1;
}
}
// All components so far are equal - if the other instance has
// more components it is greater otherwise they are equal.
if (list2.size() > list1.size()) {
return -1;
}
else {
return 0;
}
}
}