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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  import java.util.HashSet;
23  
24  /**
25   * Translates a value using a lookup table.
26   *
27   * @since 3.0
28   * @deprecated as of 3.6, use commons-text
29   * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/translate/LookupTranslator.html">
30   * LookupTranslator</a> instead
31   */
32  @Deprecated
33  public class LookupTranslator extends CharSequenceTranslator {
34  
35      private final HashMap<String, String> lookupMap;
36      private final HashSet<Character> prefixSet;
37      private final int shortest;
38      private final int longest;
39  
40      /**
41       * Define the lookup table to be used in translation
42       *
43       * Note that, as of Lang 3.1, the key to the lookup table is converted to a
44       * java.lang.String. This is because we need the key to support hashCode and
45       * equals(Object), allowing it to be the key for a HashMap. See LANG-882.
46       *
47       * @param lookup CharSequence[][] table of size [*][2]
48       */
49      public LookupTranslator(final CharSequence[]... lookup) {
50          lookupMap = new HashMap<>();
51          prefixSet = new HashSet<>();
52          int _shortest = Integer.MAX_VALUE;
53          int _longest = 0;
54          if (lookup != null) {
55              for (final CharSequence[] seq : lookup) {
56                  this.lookupMap.put(seq[0].toString(), seq[1].toString());
57                  this.prefixSet.add(seq[0].charAt(0));
58                  final int sz = seq[0].length();
59                  if (sz < _shortest) {
60                      _shortest = sz;
61                  }
62                  if (sz > _longest) {
63                      _longest = sz;
64                  }
65              }
66          }
67          shortest = _shortest;
68          longest = _longest;
69      }
70  
71      /**
72       * {@inheritDoc}
73       */
74      @Override
75      public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
76          // check if translation exists for the input at position index
77          if (prefixSet.contains(input.charAt(index))) {
78              int max = longest;
79              if (index + longest > input.length()) {
80                  max = input.length() - index;
81              }
82              // implement greedy algorithm by trying maximum match first
83              for (int i = max; i >= shortest; i--) {
84                  final CharSequence subSeq = input.subSequence(index, index + i);
85                  final String result = lookupMap.get(subSeq.toString());
86  
87                  if (result != null) {
88                      out.write(result);
89                      return i;
90                  }
91              }
92          }
93          return 0;
94      }
95  }