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 */
017package org.apache.commons.lang3.text.translate;
018
019import java.io.IOException;
020import java.io.Writer;
021import java.util.HashMap;
022import java.util.HashSet;
023
024/**
025 * Translates a value using a lookup table.
026 *
027 * @since 3.0
028 * @deprecated As of 3.6, use Apache Commons Text
029 * <a href="https://commons.apache.org/proper/commons-text/javadocs/api-release/org/apache/commons/text/translate/LookupTranslator.html">
030 * LookupTranslator</a> instead
031 */
032@Deprecated
033public class LookupTranslator extends CharSequenceTranslator {
034
035    private final HashMap<String, String> lookupMap;
036    private final HashSet<Character> prefixSet;
037    private final int shortest;
038    private final int longest;
039
040    /**
041     * Define the lookup table to be used in translation
042     *
043     * Note that, as of Lang 3.1, the key to the lookup table is converted to a
044     * java.lang.String. This is because we need the key to support hashCode and
045     * equals(Object), allowing it to be the key for a HashMap. See LANG-882.
046     *
047     * @param lookup CharSequence[][] table of size [*][2]
048     */
049    public LookupTranslator(final CharSequence[]... lookup) {
050        lookupMap = new HashMap<>();
051        prefixSet = new HashSet<>();
052        int tmpShortest = Integer.MAX_VALUE;
053        int tmpLongest = 0;
054        if (lookup != null) {
055            for (final CharSequence[] seq : lookup) {
056                this.lookupMap.put(seq[0].toString(), seq[1].toString());
057                this.prefixSet.add(seq[0].charAt(0));
058                final int sz = seq[0].length();
059                if (sz < tmpShortest) {
060                    tmpShortest = sz;
061                }
062                if (sz > tmpLongest) {
063                    tmpLongest = sz;
064                }
065            }
066        }
067        this.shortest = tmpShortest;
068        this.longest = tmpLongest;
069    }
070
071    /**
072     * {@inheritDoc}
073     */
074    @Override
075    public int translate(final CharSequence input, final int index, final Writer out) throws IOException {
076        // check if translation exists for the input at position index
077        if (prefixSet.contains(input.charAt(index))) {
078            int max = longest;
079            if (index + longest > input.length()) {
080                max = input.length() - index;
081            }
082            // implement greedy algorithm by trying maximum match first
083            for (int i = max; i >= shortest; i--) {
084                final CharSequence subSeq = input.subSequence(index, index + i);
085                final String result = lookupMap.get(subSeq.toString());
086
087                if (result != null) {
088                    out.write(result);
089                    return i;
090                }
091            }
092        }
093        return 0;
094    }
095}