    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
    018package org.apache.commons.codec.language.bm;
    019
    020import org.apache.commons.codec.EncoderException;
    021import org.apache.commons.codec.StringEncoder;
    022
    023/**
    024 * Encodes strings into their Beider-Morse phonetic encoding.
    025 * <p>
    026 * Beider-Morse phonetic encodings are optimised for family names. However, they may be useful for a wide range of
    027 * words.
    028 * <p>
    029 * This encoder is intentionally mutable to allow dynamic configuration through bean properties. As such, it is mutable,
    030 * and may not be thread-safe. If you require a guaranteed thread-safe encoding then use {@link PhoneticEngine}
    031 * directly.
    032 * <p>
    033 * <b>Encoding overview</b>
    034 * <p>
    035 * Beider-Morse phonetic encodings is a multi-step process. Firstly, a table of rules is consulted to guess what
    036 * language the word comes from. For example, if it ends in "<code>ault</code>" then it infers that the word is French.
    037 * Next, the word is translated into a phonetic representation using a language-specific phonetics table. Some runs of
    038 * letters can be pronounced in multiple ways, and a single run of letters may be potentially broken up into phonemes at
    039 * different places, so this stage results in a set of possible language-specific phonetic representations. Lastly, this
    040 * language-specific phonetic representation is processed by a table of rules that re-writes it phonetically taking into
    041 * account systematic pronunciation differences between languages, to move it towards a pan-indo-european phonetic
    042 * representation. Again, sometimes there are multiple ways this could be done and sometimes things that can be
    043 * pronounced in several ways in the source language have only one way to represent them in this average phonetic
    044 * language, so the result is again a set of phonetic spellings.
    045 * <p>
    046 * Some names are treated as having multiple parts. This can be due to two things. Firstly, they may be hyphenated. In
    047 * this case, each individual hyphenated word is encoded, and then these are combined end-to-end for the final encoding.
    048 * Secondly, some names have standard prefixes, for example, "<code>Mac/Mc</code>" in Scottish (English) names. As
    049 * sometimes it is ambiguous whether the prefix is intended or is an accident of the spelling, the word is encoded once
    050 * with the prefix and once without it. The resulting encoding contains one and then the other result.
    051 * <p>
    052 * <b>Encoding format</b>
    053 * <p>
    054 * Individual phonetic spellings of an input word are represented in upper- and lower-case roman characters. Where there
    055 * are multiple possible phonetic representations, these are joined with a pipe (<code>|</code>) character. If multiple
    056 * hyphenated words where found, or if the word may contain a name prefix, each encoded word is placed in elipses and
    057 * these blocks are then joined with hyphens. For example, "<code>d'ortley</code>" has a possible prefix. The form
    058 * without prefix encodes to "<code>ortlaj|ortlej</code>", while the form with prefix encodes to "
    059 * <code>dortlaj|dortlej</code>". Thus, the full, combined encoding is "<code>(ortlaj|ortlej)-(dortlaj|dortlej)</code>".
    060 * <p>
    061 * The encoded forms are often quite a bit longer than the input strings. This is because a single input may have many
    062 * potential phonetic interpretations. For example, "<code>Renault</code>" encodes to "
    063 * <code>rYnDlt|rYnalt|rYnult|rinDlt|rinalt|rinult</code>". The <code>APPROX</code> rules will tend to produce larger
    064 * encodings as they consider a wider range of possible, approximate phonetic interpretations of the original word.
    065 * Down-stream applications may wish to further process the encoding for indexing or lookup purposes, for example, by
    066 * splitting on pipe (<code>|</code>) and indexing under each of these alternatives.
    067 * <p>
    068 * <b>Note</b>: this version of the Beider-Morse encoding is equivalent with v3.4 of the reference implementation.
    069 * </p>
    070 * @see <a href="http://stevemorse.org/phonetics/bmpm.htm">Beider-Morse Phonetic Matching</a>
    071 * @see <a href="http://stevemorse.org/phoneticinfo.htm">Reference implementation</a>
    072 *
    073 * <p>
    074 * This class is Not ThreadSafe
    075 * </p>
    076 * @since 1.6
    077 */
    078public class BeiderMorseEncoder implements StringEncoder {
    079    // Implementation note: This class is a spring-friendly facade to PhoneticEngine. It allows read/write configuration
    080    // of an immutable PhoneticEngine instance that will be delegated to for the actual encoding.
    081
    082    // a cached object
    083    private PhoneticEngine engine = new PhoneticEngine(NameType.GENERIC, RuleType.APPROX, true);
    084
    085    @Override
    086    public Object encode(final Object source) throws EncoderException {
    087        if (!(source instanceof String)) {
    088            throw new EncoderException("BeiderMorseEncoder encode parameter is not of type String");
    089        }
    090        return encode((String) source);
    091    }
    092
    093    @Override
    094    public String encode(final String source) throws EncoderException {
    095        if (source == null) {
    096            return null;
    097        }
    098        return this.engine.encode(source);
    099    }
    100
    101    /**
    102     * Gets the name type currently in operation.
    103     *
    104     * @return the NameType currently being used
    105     */
    106    public NameType getNameType() {
    107        return this.engine.getNameType();
    108    }
    109
    110    /**
    111     * Gets the rule type currently in operation.
    112     *
    113     * @return the RuleType currently being used
    114     */
    115    public RuleType getRuleType() {
    116        return this.engine.getRuleType();
    117    }
    118
    119    /**
    120     * Discovers if multiple possible encodings are concatenated.
    121     *
    122     * @return true if multiple encodings are concatenated, false if just the first one is returned
    123     */
    124    public boolean isConcat() {
    125        return this.engine.isConcat();
    126    }
    127
    128    /**
    129     * Sets how multiple possible phonetic encodings are combined.
    130     *
    131     * @param concat
    132     *            true if multiple encodings are to be combined with a '|', false if just the first one is
    133     *            to be considered
    134     */
    135    public void setConcat(final boolean concat) {
    136        this.engine = new PhoneticEngine(this.engine.getNameType(),
    137                                         this.engine.getRuleType(),
    138                                         concat,
    139                                         this.engine.getMaxPhonemes());
    140    }
    141
    142    /**
    143     * Sets the type of name. Use {@link NameType#GENERIC} unless you specifically want phonetic encodings
    144     * optimized for Ashkenazi or Sephardic Jewish family names.
    145     *
    146     * @param nameType
    147     *            the NameType in use
    148     */
    149    public void setNameType(final NameType nameType) {
    150        this.engine = new PhoneticEngine(nameType,
    151                                         this.engine.getRuleType(),
    152                                         this.engine.isConcat(),
    153                                         this.engine.getMaxPhonemes());
    154    }
    155
    156    /**
    157     * Sets the rule type to apply. This will widen or narrow the range of phonetic encodings considered.
    158     *
    159     * @param ruleType
    160     *            {@link RuleType#APPROX} or {@link RuleType#EXACT} for approximate or exact phonetic matches
    161     */
    162    public void setRuleType(final RuleType ruleType) {
    163        this.engine = new PhoneticEngine(this.engine.getNameType(),
    164                                         ruleType,
    165                                         this.engine.isConcat(),
    166                                         this.engine.getMaxPhonemes());
    167    }
    168
    169    /**
    170     * Sets the number of maximum of phonemes that shall be considered by the engine.
    171     *
    172     * @param maxPhonemes
    173     *            the maximum number of phonemes returned by the engine
    174     * @since 1.7
    175     */
    176    public void setMaxPhonemes(final int maxPhonemes) {
    177        this.engine = new PhoneticEngine(this.engine.getNameType(),
    178                                         this.engine.getRuleType(),
    179                                         this.engine.isConcat(),
    180                                         maxPhonemes);
    181    }
    182
    183}