PhoneticEngine.java
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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* See the License for the specific language governing permissions and
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package org.apache.commons.codec.language.bm;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.EnumMap;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.TreeMap;
import java.util.stream.Collectors;
import org.apache.commons.codec.language.bm.Languages.LanguageSet;
import org.apache.commons.codec.language.bm.Rule.Phoneme;
/**
* Converts words into potential phonetic representations.
* <p>
* This is a two-stage process. Firstly, the word is converted into a phonetic representation that takes
* into account the likely source language. Next, this phonetic representation is converted into a
* pan-European 'average' representation, allowing comparison between different versions of essentially
* the same word from different languages.
* </p>
* <p>
* This class is intentionally immutable and thread-safe.
* If you wish to alter the settings for a PhoneticEngine, you
* must make a new one with the updated settings.
* </p>
* <p>
* Ported from phoneticengine.php
* </p>
*
* @since 1.6
*/
public class PhoneticEngine {
/**
* Utility for manipulating a set of phonemes as they are being built up. Not intended for use outside
* this package, and probably not outside the {@link PhoneticEngine} class.
*
* @since 1.6
*/
static final class PhonemeBuilder {
/**
* An empty builder where all phonemes must come from some set of languages. This will contain a single
* phoneme of zero characters. This can then be appended to. This should be the only way to create a new
* phoneme from scratch.
*
* @param languages the set of languages
* @return a new, empty phoneme builder
*/
public static PhonemeBuilder empty(final Languages.LanguageSet languages) {
return new PhonemeBuilder(new Rule.Phoneme("", languages));
}
private final Set<Rule.Phoneme> phonemes;
private PhonemeBuilder(final Rule.Phoneme phoneme) {
this.phonemes = new LinkedHashSet<>();
this.phonemes.add(phoneme);
}
private PhonemeBuilder(final Set<Rule.Phoneme> phonemes) {
this.phonemes = phonemes;
}
/**
* Creates a new phoneme builder containing all phonemes in this one extended by {@code str}.
*
* @param str the characters to append to the phonemes
*/
public void append(final CharSequence str) {
phonemes.forEach(ph -> ph.append(str));
}
/**
* Applies the given phoneme expression to all phonemes in this phoneme builder.
* <p>
* This will lengthen phonemes that have compatible language sets to the expression, and drop those that are
* incompatible.
* </p>
*
* @param phonemeExpr the expression to apply
* @param maxPhonemes the maximum number of phonemes to build up
*/
public void apply(final Rule.PhonemeExpr phonemeExpr, final int maxPhonemes) {
final Set<Rule.Phoneme> newPhonemes = new LinkedHashSet<>(Math.min(phonemes.size() * phonemeExpr.size(), maxPhonemes));
EXPR: for (final Rule.Phoneme left : phonemes) {
for (final Rule.Phoneme right : phonemeExpr.getPhonemes()) {
final LanguageSet languages = left.getLanguages().restrictTo(right.getLanguages());
if (!languages.isEmpty()) {
final Rule.Phoneme join = new Phoneme(left, right, languages);
if (newPhonemes.size() < maxPhonemes) {
newPhonemes.add(join);
if (newPhonemes.size() >= maxPhonemes) {
break EXPR;
}
}
}
}
}
phonemes.clear();
phonemes.addAll(newPhonemes);
}
/**
* Gets underlying phoneme set. Please don't mutate.
*
* @return the phoneme set
*/
public Set<Rule.Phoneme> getPhonemes() {
return phonemes;
}
/**
* Stringifies the phoneme set. This produces a single string of the strings of each phoneme,
* joined with a pipe. This is explicitly provided in place of toString as it is a potentially
* expensive operation, which should be avoided when debugging.
*
* @return the stringified phoneme set
*/
public String makeString() {
return phonemes.stream().map(Rule.Phoneme::getPhonemeText).collect(Collectors.joining("|"));
}
}
/**
* A function closure capturing the application of a list of rules to an input sequence at a particular offset.
* After invocation, the values {@code i} and {@code found} are updated. {@code i} points to the
* index of the next char in {@code input} that must be processed next (the input up to that index having been
* processed already), and {@code found} indicates if a matching rule was found or not. In the case where a
* matching rule was found, {@code phonemeBuilder} is replaced with a new builder containing the phonemes
* updated by the matching rule.
* <p>
* Although this class is not thread-safe (it has mutable unprotected fields), it is not shared between threads
* as it is constructed as needed by the calling methods.
* </p>
*
* @since 1.6
*/
private static final class RulesApplication {
private final Map<String, List<Rule>> finalRules;
private final CharSequence input;
private final PhonemeBuilder phonemeBuilder;
private int i;
private final int maxPhonemes;
private boolean found;
public RulesApplication(final Map<String, List<Rule>> finalRules, final CharSequence input, final PhonemeBuilder phonemeBuilder, final int i,
final int maxPhonemes) {
Objects.requireNonNull(finalRules, "finalRules");
this.finalRules = finalRules;
this.phonemeBuilder = phonemeBuilder;
this.input = input;
this.i = i;
this.maxPhonemes = maxPhonemes;
}
public int getI() {
return i;
}
public PhonemeBuilder getPhonemeBuilder() {
return phonemeBuilder;
}
/**
* Invokes the rules. Loops over the rules list, stopping at the first one that has a matching context
* and pattern. Then applies this rule to the phoneme builder to produce updated phonemes. If there was no
* match, {@code i} is advanced one and the character is silently dropped from the phonetic spelling.
*
* @return {@code this}
*/
public RulesApplication invoke() {
found = false;
int patternLength = 1;
final List<Rule> rules = finalRules.get(input.subSequence(i, i + patternLength));
if (rules != null) {
for (final Rule rule : rules) {
final String pattern = rule.getPattern();
patternLength = pattern.length();
if (rule.patternAndContextMatches(input, i)) {
phonemeBuilder.apply(rule.getPhoneme(), maxPhonemes);
found = true;
break;
}
}
}
if (!found) {
patternLength = 1;
}
i += patternLength;
return this;
}
public boolean isFound() {
return found;
}
}
private static final int DEFAULT_MAX_PHONEMES = 20;
private static final Map<NameType, Set<String>> NAME_PREFIXES = new EnumMap<>(NameType.class);
static {
NAME_PREFIXES.put(NameType.ASHKENAZI,
Collections.unmodifiableSet(
new HashSet<>(Arrays.asList("bar", "ben", "da", "de", "van", "von"))));
NAME_PREFIXES.put(NameType.SEPHARDIC,
Collections.unmodifiableSet(
new HashSet<>(Arrays.asList("al", "el", "da", "dal", "de", "del", "dela", "de la",
"della", "des", "di", "do", "dos", "du", "van", "von"))));
NAME_PREFIXES.put(NameType.GENERIC,
Collections.unmodifiableSet(
new HashSet<>(Arrays.asList("da", "dal", "de", "del", "dela", "de la", "della",
"des", "di", "do", "dos", "du", "van", "von"))));
}
/**
* Joins some strings with an internal separator.
*
* @param strings Strings to join
* @param sep String to separate them with
* @return a single String consisting of each element of {@code strings} interleaved by {@code sep}
*/
private static String join(final List<String> strings, final String sep) {
return strings.stream().collect(Collectors.joining(sep));
}
private final Lang lang;
private final NameType nameType;
private final RuleType ruleType;
private final boolean concat;
private final int maxPhonemes;
/**
* Generates a new, fully-configured phonetic engine.
*
* @param nameType
* the type of names it will use
* @param ruleType
* the type of rules it will apply
* @param concatenate
* if it will concatenate multiple encodings
*/
public PhoneticEngine(final NameType nameType, final RuleType ruleType, final boolean concatenate) {
this(nameType, ruleType, concatenate, DEFAULT_MAX_PHONEMES);
}
/**
* Generates a new, fully-configured phonetic engine.
*
* @param nameType
* the type of names it will use
* @param ruleType
* the type of rules it will apply
* @param concatenate
* if it will concatenate multiple encodings
* @param maxPhonemes
* the maximum number of phonemes that will be handled
* @since 1.7
*/
public PhoneticEngine(final NameType nameType, final RuleType ruleType, final boolean concatenate, final int maxPhonemes) {
if (ruleType == RuleType.RULES) {
throw new IllegalArgumentException("ruleType must not be " + RuleType.RULES);
}
this.nameType = nameType;
this.ruleType = ruleType;
this.concat = concatenate;
this.lang = Lang.instance(nameType);
this.maxPhonemes = maxPhonemes;
}
/**
* Applies the final rules to convert from a language-specific phonetic representation to a
* language-independent representation.
*
* @param phonemeBuilder the current phonemes
* @param finalRules the final rules to apply
* @return the resulting phonemes
*/
private PhonemeBuilder applyFinalRules(final PhonemeBuilder phonemeBuilder,
final Map<String, List<Rule>> finalRules) {
Objects.requireNonNull(finalRules, "finalRules");
if (finalRules.isEmpty()) {
return phonemeBuilder;
}
final Map<Rule.Phoneme, Rule.Phoneme> phonemes = new TreeMap<>(Rule.Phoneme.COMPARATOR);
phonemeBuilder.getPhonemes().forEach(phoneme -> {
PhonemeBuilder subBuilder = PhonemeBuilder.empty(phoneme.getLanguages());
final String phonemeText = phoneme.getPhonemeText().toString();
for (int i = 0; i < phonemeText.length();) {
final RulesApplication rulesApplication = new RulesApplication(finalRules, phonemeText, subBuilder, i, maxPhonemes).invoke();
final boolean found = rulesApplication.isFound();
subBuilder = rulesApplication.getPhonemeBuilder();
if (!found) {
// not found, appending as-is
subBuilder.append(phonemeText.subSequence(i, i + 1));
}
i = rulesApplication.getI();
}
// the phonemes map orders the phonemes only based on their text, but ignores the language set
// when adding new phonemes, check for equal phonemes and merge their language set, otherwise
// phonemes with the same text but different language set get lost
subBuilder.getPhonemes().forEach(newPhoneme -> {
if (phonemes.containsKey(newPhoneme)) {
final Rule.Phoneme oldPhoneme = phonemes.remove(newPhoneme);
final Rule.Phoneme mergedPhoneme = oldPhoneme.mergeWithLanguage(newPhoneme.getLanguages());
phonemes.put(mergedPhoneme, mergedPhoneme);
} else {
phonemes.put(newPhoneme, newPhoneme);
}
});
});
return new PhonemeBuilder(phonemes.keySet());
}
/**
* Encodes a string to its phonetic representation.
*
* @param input
* the String to encode
* @return the encoding of the input
*/
public String encode(final String input) {
final Languages.LanguageSet languageSet = this.lang.guessLanguages(input);
return encode(input, languageSet);
}
/**
* Encodes an input string into an output phonetic representation, given a set of possible origin languages.
*
* @param input
* String to phoneticise; a String with dashes or spaces separating each word
* @param languageSet
* set of possible origin languages
* @return a phonetic representation of the input; a String containing '-'-separated phonetic representations of the
* input
*/
public String encode(String input, final Languages.LanguageSet languageSet) {
final Map<String, List<Rule>> rules = Rule.getInstanceMap(this.nameType, RuleType.RULES, languageSet);
// rules common across many (all) languages
final Map<String, List<Rule>> finalRules1 = Rule.getInstanceMap(this.nameType, this.ruleType, "common");
// rules that apply to a specific language that may be ambiguous or wrong if applied to other languages
final Map<String, List<Rule>> finalRules2 = Rule.getInstanceMap(this.nameType, this.ruleType, languageSet);
// tidy the input
// lower case is a locale-dependent operation
input = input.toLowerCase(Locale.ENGLISH).replace('-', ' ').trim();
if (this.nameType == NameType.GENERIC) {
if (input.startsWith("d'")) { // check for d'
final String remainder = input.substring(2);
final String combined = "d" + remainder;
return "(" + encode(remainder) + ")-(" + encode(combined) + ")";
}
for (final String l : NAME_PREFIXES.get(this.nameType)) {
// handle generic prefixes
if (input.startsWith(l + " ")) {
// check for any prefix in the words list
final String remainder = input.substring(l.length() + 1); // input without the prefix
final String combined = l + remainder; // input with prefix without space
return "(" + encode(remainder) + ")-(" + encode(combined) + ")";
}
}
}
final List<String> words = Arrays.asList(input.split("\\s+"));
final List<String> words2 = new ArrayList<>();
// special-case handling of word prefixes based upon the name type
switch (this.nameType) {
case SEPHARDIC:
words.forEach(aWord -> {
final String[] parts = aWord.split("'", -1);
words2.add(parts[parts.length - 1]);
});
words2.removeAll(NAME_PREFIXES.get(this.nameType));
break;
case ASHKENAZI:
words2.addAll(words);
words2.removeAll(NAME_PREFIXES.get(this.nameType));
break;
case GENERIC:
words2.addAll(words);
break;
default:
throw new IllegalStateException("Unreachable case: " + this.nameType);
}
if (this.concat) {
// concat mode enabled
input = join(words2, " ");
} else if (words2.size() == 1) {
// not a multi-word name
input = words.iterator().next();
} else if (!words2.isEmpty()) {
// encode each word in a multi-word name separately (normally used for approx matches)
final StringBuilder result = new StringBuilder();
words2.forEach(word -> result.append("-").append(encode(word)));
// return the result without the leading "-"
return result.substring(1);
}
PhonemeBuilder phonemeBuilder = PhonemeBuilder.empty(languageSet);
// loop over each char in the input - we will handle the increment manually
for (int i = 0; i < input.length();) {
final RulesApplication rulesApplication =
new RulesApplication(rules, input, phonemeBuilder, i, maxPhonemes).invoke();
i = rulesApplication.getI();
phonemeBuilder = rulesApplication.getPhonemeBuilder();
}
// Apply the general rules
phonemeBuilder = applyFinalRules(phonemeBuilder, finalRules1);
// Apply the language-specific rules
phonemeBuilder = applyFinalRules(phonemeBuilder, finalRules2);
return phonemeBuilder.makeString();
}
/**
* Gets the Lang language guessing rules being used.
*
* @return the Lang in use
*/
public Lang getLang() {
return this.lang;
}
/**
* Gets the maximum number of phonemes the engine will calculate for a given input.
*
* @return the maximum number of phonemes
* @since 1.7
*/
public int getMaxPhonemes() {
return this.maxPhonemes;
}
/**
* Gets the NameType being used.
*
* @return the NameType in use
*/
public NameType getNameType() {
return this.nameType;
}
/**
* Gets the RuleType being used.
*
* @return the RuleType in use
*/
public RuleType getRuleType() {
return this.ruleType;
}
/**
* Gets if multiple phonetic encodings are concatenated or if just the first one is kept.
*
* @return true if multiple phonetic encodings are returned, false if just the first is
*/
public boolean isConcat() {
return this.concat;
}
}