001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.commons.codec; 019 020 import java.util.Comparator; 021 022 /** 023 * Compares Strings using a {@link StringEncoder}. This comparator is used to sort Strings by an encoding scheme such as 024 * Soundex, Metaphone, etc. This class can come in handy if one need to sort Strings by an encoded form of a name such 025 * as Soundex. 026 * 027 * @author Apache Software Foundation 028 * @version $Id: StringEncoderComparator.java 1080701 2011-03-11 17:52:27Z ggregory $ 029 */ 030 public class StringEncoderComparator implements Comparator { 031 032 /** 033 * Internal encoder instance. 034 */ 035 private final StringEncoder stringEncoder; 036 037 /** 038 * Constructs a new instance. 039 * 040 * @deprecated Creating an instance without a {@link StringEncoder} leads to a {@link NullPointerException}. Will be 041 * removed in 2.0. 042 */ 043 public StringEncoderComparator() { 044 this.stringEncoder = null; // Trying to use this will cause things to break 045 } 046 047 /** 048 * Constructs a new instance with the given algorithm. 049 * 050 * @param stringEncoder 051 * the StringEncoder used for comparisons. 052 */ 053 public StringEncoderComparator(StringEncoder stringEncoder) { 054 this.stringEncoder = stringEncoder; 055 } 056 057 /** 058 * Compares two strings based not on the strings themselves, but on an encoding of the two strings using the 059 * StringEncoder this Comparator was created with. 060 * 061 * If an {@link EncoderException} is encountered, return <code>0</code>. 062 * 063 * @param o1 064 * the object to compare 065 * @param o2 066 * the object to compare to 067 * @return the Comparable.compareTo() return code or 0 if an encoding error was caught. 068 * @see Comparable 069 */ 070 public int compare(Object o1, Object o2) { 071 072 int compareCode = 0; 073 074 try { 075 Comparable s1 = (Comparable) this.stringEncoder.encode(o1); 076 Comparable s2 = (Comparable) this.stringEncoder.encode(o2); 077 compareCode = s1.compareTo(s2); 078 } catch (EncoderException ee) { 079 compareCode = 0; 080 } 081 return compareCode; 082 } 083 084 }