org.apache.commons.codec.language.bm.PhoneticEngine Maven / Gradle / Ivy
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* 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
* limitations under the License.
*/
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.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
/**
* Converts words into potential phonetic representations.
*
* 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.
*
* 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.
*
* Ported from phoneticengine.php
*
* @since 1.6
* @version $Id: PhoneticEngine.java 1465848 2013-04-09 00:41:12Z sebb $
*/
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(Collections.singleton(new Rule.Phoneme("", languages)));
}
private final Set phonemes;
private PhonemeBuilder(final Set phonemes) {
this.phonemes = phonemes;
}
/**
* Creates a new phoneme builder containing all phonemes in this one extended by str.
*
* @param str the characters to append to the phonemes
* @return a new phoneme builder lenghtened by str
*/
public PhonemeBuilder append(final CharSequence str) {
final Set newPhonemes = new LinkedHashSet();
for (final Rule.Phoneme ph : this.phonemes) {
newPhonemes.add(ph.append(str));
}
return new PhonemeBuilder(newPhonemes);
}
/**
* Creates a new phoneme builder containing the application of the expression to all phonemes in this builder.
*
* This will lengthen phonemes that have compatible language sets to the expression, and drop those that are
* incompatible.
*
* @param phonemeExpr the expression to apply
* @param maxPhonemes the maximum number of phonemes to build up
* @return a new phoneme builder containing the results of phonemeExpr applied to each phoneme
* in turn
*/
public PhonemeBuilder apply(final Rule.PhonemeExpr phonemeExpr, final int maxPhonemes) {
final Set newPhonemes = new LinkedHashSet();
EXPR: for (final Rule.Phoneme left : this.phonemes) {
for (final Rule.Phoneme right : phonemeExpr.getPhonemes()) {
final Rule.Phoneme join = left.join(right);
if (!join.getLanguages().isEmpty()) {
if (newPhonemes.size() < maxPhonemes) {
newPhonemes.add(join);
} else {
break EXPR;
}
}
}
}
return new PhonemeBuilder(newPhonemes);
}
/**
* Gets underlying phoneme set. Please don't mutate.
*
* @return the phoneme set
*/
public Set getPhonemes() {
return this.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() {
final StringBuilder sb = new StringBuilder();
for (final Rule.Phoneme ph : this.phonemes) {
if (sb.length() > 0) {
sb.append("|");
}
sb.append(ph.getPhonemeText());
}
return sb.toString();
}
}
/**
* A function closure capturing the application of a list of rules to an input sequence at a particular offset.
* After invocation, the values i and found are updated. i points to the
* index of the next char in input that must be processed next (the input up to that index having been
* processed already), and found indicates if a matching rule was found or not. In the case where a
* matching rule was found, phonemeBuilder is replaced with a new builder containing the phonemes
* updated by the matching rule.
*
* 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.
* @since 1.6
*/
private static final class RulesApplication {
private final List finalRules;
private final CharSequence input;
private PhonemeBuilder phonemeBuilder;
private int i;
private final int maxPhonemes;
private boolean found;
public RulesApplication(final List finalRules, final CharSequence input,
final PhonemeBuilder phonemeBuilder, final int i, final int maxPhonemes) {
if (finalRules == null) {
throw new NullPointerException("The finalRules argument must not be null");
}
this.finalRules = finalRules;
this.phonemeBuilder = phonemeBuilder;
this.input = input;
this.i = i;
this.maxPhonemes = maxPhonemes;
}
public int getI() {
return this.i;
}
public PhonemeBuilder getPhonemeBuilder() {
return this.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, i is advanced one and the character is silently dropped from the phonetic spelling.
*
* @return this
*/
public RulesApplication invoke() {
this.found = false;
int patternLength = 0;
for (final Rule rule : this.finalRules) {
final String pattern = rule.getPattern();
patternLength = pattern.length();
if (!rule.patternAndContextMatches(this.input, this.i)) {
continue;
}
this.phonemeBuilder = this.phonemeBuilder.apply(rule.getPhoneme(), maxPhonemes);
this.found = true;
break;
}
if (!this.found) {
patternLength = 1;
}
this.i += patternLength;
return this;
}
public boolean isFound() {
return this.found;
}
}
private static final Map> 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"))));
}
/**
* This is a performance hack to avoid overhead associated with very frequent CharSequence.subSequence calls.
*
* @param cached the character sequence to cache
* @return a CharSequence that internally caches subSequence values
*/
private static CharSequence cacheSubSequence(final CharSequence cached) {
// return cached;
final CharSequence[][] cache = new CharSequence[cached.length()][cached.length()];
return new CharSequence() {
@Override
public char charAt(final int index) {
return cached.charAt(index);
}
@Override
public int length() {
return cached.length();
}
@Override
public CharSequence subSequence(final int start, final int end) {
if (start == end) {
return "";
}
CharSequence res = cache[start][end - 1];
if (res == null) {
res = cached.subSequence(start, end);
cache[start][end - 1] = res;
}
return res;
}
};
}
/**
* 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 strings interleaved by sep
*/
private static String join(final Iterable strings, final String sep) {
final StringBuilder sb = new StringBuilder();
final Iterator si = strings.iterator();
if (si.hasNext()) {
sb.append(si.next());
}
while (si.hasNext()) {
sb.append(sep).append(si.next());
}
return sb.toString();
}
private static final int DEFAULT_MAX_PHONEMES = 20;
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 concat
* if it will concatenate multiple encodings
*/
public PhoneticEngine(final NameType nameType, final RuleType ruleType, final boolean concat) {
this(nameType, ruleType, concat, 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 concat
* 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 concat,
final int maxPhonemes) {
if (ruleType == RuleType.RULES) {
throw new IllegalArgumentException("ruleType must not be " + RuleType.RULES);
}
this.nameType = nameType;
this.ruleType = ruleType;
this.concat = concat;
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 List finalRules) {
if (finalRules == null) {
throw new NullPointerException("finalRules can not be null");
}
if (finalRules.isEmpty()) {
return phonemeBuilder;
}
final Set phonemes = new TreeSet(Rule.Phoneme.COMPARATOR);
for (final Rule.Phoneme phoneme : phonemeBuilder.getPhonemes()) {
PhonemeBuilder subBuilder = PhonemeBuilder.empty(phoneme.getLanguages());
final CharSequence phonemeText = cacheSubSequence(phoneme.getPhonemeText());
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 = subBuilder.append(phonemeText.subSequence(i, i + 1));
}
i = rulesApplication.getI();
}
phonemes.addAll(subBuilder.getPhonemes());
}
return new PhonemeBuilder(phonemes);
}
/**
* 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
* @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 List rules = Rule.getInstance(this.nameType, RuleType.RULES, languageSet);
// rules common across many (all) languages
final List finalRules1 = Rule.getInstance(this.nameType, this.ruleType, "common");
// rules that apply to a specific language that may be ambiguous or wrong if applied to other languages
final List finalRules2 = Rule.getInstance(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.length() >= 2 && input.substring(0, 2).equals("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 words = Arrays.asList(input.split("\\s+"));
final List words2 = new ArrayList();
// special-case handling of word prefixes based upon the name type
switch (this.nameType) {
case SEPHARDIC:
for (final String aWord : words) {
final String[] parts = aWord.split("'");
final String lastPart = parts[parts.length - 1];
words2.add(lastPart);
}
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 {
// encode each word in a multi-word name separately (normally used for approx matches)
final StringBuilder result = new StringBuilder();
for (final String word : words2) {
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
final CharSequence inputCache = cacheSubSequence(input);
for (int i = 0; i < inputCache.length();) {
final RulesApplication rulesApplication =
new RulesApplication(rules, inputCache, 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 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;
}
/**
* 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;
}
}