1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.codec;
19
20 import java.util.Comparator;
21
22 /**
23 * Compares Strings using a {@link StringEncoder}. This comparator is used to sort Strings by an encoding scheme such as
24 * Soundex, Metaphone, etc. This class can come in handy if one need to sort Strings by an encoded form of a name such
25 * as Soundex.
26 *
27 * @author Apache Software Foundation
28 * @version $Id: StringEncoderComparator.java 1201520 2011-11-13 21:36:18Z ggregory $
29 */
30 public class StringEncoderComparator implements Comparator {
31
32 /**
33 * Internal encoder instance.
34 */
35 private final StringEncoder stringEncoder;
36
37 /**
38 * Constructs a new instance.
39 *
40 * @deprecated Creating an instance without a {@link StringEncoder} leads to a {@link NullPointerException}. Will be
41 * removed in 2.0.
42 */
43 public StringEncoderComparator() {
44 this.stringEncoder = null; // Trying to use this will cause things to break
45 }
46
47 /**
48 * Constructs a new instance with the given algorithm.
49 *
50 * @param stringEncoder
51 * the StringEncoder used for comparisons.
52 */
53 public StringEncoderComparator(StringEncoder stringEncoder) {
54 this.stringEncoder = stringEncoder;
55 }
56
57 /**
58 * Compares two strings based not on the strings themselves, but on an encoding of the two strings using the
59 * StringEncoder this Comparator was created with.
60 *
61 * If an {@link EncoderException} is encountered, return <code>0</code>.
62 *
63 * @param o1
64 * the object to compare
65 * @param o2
66 * the object to compare to
67 * @return the Comparable.compareTo() return code or 0 if an encoding error was caught.
68 * @see Comparable
69 */
70 public int compare(Object o1, Object o2) {
71
72 int compareCode = 0;
73
74 try {
75 Comparable s1 = (Comparable) this.stringEncoder.encode(o1);
76 Comparable s2 = (Comparable) this.stringEncoder.encode(o2);
77 compareCode = s1.compareTo(s2);
78 } catch (EncoderException ee) {
79 compareCode = 0;
80 }
81 return compareCode;
82 }
83
84 }