/*
* Copyright 2004-2005 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.springmodules.validation.util.condition.range;
import java.math.BigDecimal;
import org.springframework.util.comparator.ComparableComparator;
/**
* A comparator that compares {@link Comparable} instances but treats comparison of {@link Number} instances
* in a special manner. In order to support comparison of numbers regardless of their type, this comparator transform
* the numbers to {@link BigDecimal} and then does the comparison.
*
* @author Uri Boness
*/
public class NumberAwareComparableComparator extends ComparableComparator {
/**
* Compares the two given objects. Expects both of them to be {@link Comparable} instances.
*
* @see ComparableComparator#compare(Object, Object)
*/
public int compare(Object o1, Object o2) {
if (Number.class.isInstance(o1) && Number.class.isInstance(o2)) {
return compareNumbers((Number) o1, (Number) o2);
}
return super.compare(o1, o2);
}
/**
* Compares the two given numbers. These numbers are compared regardless of their type.
*
* @param n1 The first number.
* @param n2 The second number.
* @return possitive number if <code>n1 > n2</code>, negative number if <code>n1 < n2</code>, or 0 (Zero) if
* <code>n1 == n2</code>.
*/
protected int compareNumbers(Number n1, Number n2) {
BigDecimal bd1 = new BigDecimal(n1.toString());
BigDecimal bd2 = new BigDecimal(n2.toString());
return bd1.compareTo(bd2);
}
}