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 package org.apache.commons.lang3.text.translate;
18
19 import java.io.IOException;
20 import java.io.Writer;
21 import java.util.HashMap;
22
23 /**
24 * Translates a value using a lookup table.
25 *
26 * @since 3.0
27 * @version $Id: LookupTranslator.java 1436770 2013-01-22 07:09:45Z ggregory $
28 */
29 public class LookupTranslator extends CharSequenceTranslator {
30
31 private final HashMap<CharSequence, CharSequence> lookupMap;
32 private final int shortest;
33 private final int longest;
34
35 /**
36 * Define the lookup table to be used in translation
37 *
38 * @param lookup CharSequence[][] table of size [*][2]
39 */
40 public LookupTranslator(final CharSequence[]... lookup) {
41 lookupMap = new HashMap<CharSequence, CharSequence>();
42 int _shortest = Integer.MAX_VALUE;
43 int _longest = 0;
44 if (lookup != null) {
45 for (final CharSequence[] seq : lookup) {
46 this.lookupMap.put(seq[0], seq[1]);
47 final int sz = seq[0].length();
48 if (sz < _shortest) {
49 _shortest = sz;
50 }
51 if (sz > _longest) {
52 _longest = sz;
53 }
54 }
55 }
56 shortest = _shortest;
57 longest = _longest;
58 }
59
60 /**
61 * {@inheritDoc}
62 */
63 @Override
64 public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
65 int max = longest;
66 if (index + longest > input.length()) {
67 max = input.length() - index;
68 }
69 // descend so as to get a greedy algorithm
70 for (int i = max; i >= shortest; i--) {
71 final CharSequence subSeq = input.subSequence(index, index + i);
72 final CharSequence result = lookupMap.get(subSeq);
73 if (result != null) {
74 out.write(result.toString());
75 return i;
76 }
77 }
78 return 0;
79 }
80 }