1 /*
2 * Copyright 2004-2009 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.springmodules.validation.util.condition.range;
18
19 import java.math.BigDecimal;
20
21
22 /**
23 * A comparator that compares {@link Comparable} instances but treats comparison of {@link Number} instances
24 * in a special manner. In order to support comparison of numbers regardless of their type, this comparator transform
25 * the numbers to {@link BigDecimal} and then does the comparison.
26 *
27 * @author Uri Boness
28 */
29 public class NumberAwareComparableComparator extends ComparableComparator {
30
31 /**
32 * Compares the two given objects. Expects both of them to be {@link Comparable} instances.
33 *
34 * @see ComparableComparator#compare(Object, Object)
35 */
36 public int compare(Object o1, Object o2) {
37 if (Number.class.isInstance(o1) && Number.class.isInstance(o2)) {
38 return compareNumbers((Number) o1, (Number) o2);
39 }
40 return super.compare(o1, o2);
41
42 }
43
44 /**
45 * Compares the two given numbers. These numbers are compared regardless of their type.
46 *
47 * @param n1 The first number.
48 * @param n2 The second number.
49 * @return possitive number if <code>n1 > n2</code>, negative number if <code>n1 < n2</code>, or 0 (Zero) if
50 * <code>n1 == n2</code>.
51 */
52 protected int compareNumbers(Number n1, Number n2) {
53 BigDecimal bd1 = new BigDecimal(n1.toString());
54 BigDecimal bd2 = new BigDecimal(n2.toString());
55 return bd1.compareTo(bd2);
56 }
57
58 }