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/*
* Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
* or more contributor license agreements. Licensed under the Elastic License
* 2.0 and the Server Side Public License, v 1; you may not use this file except
* in compliance with, at your election, the Elastic License 2.0 or the Server
* Side Public License, v 1.
*/
package org.elasticsearch.index.analysis;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.miscellaneous.DisableGraphAttribute;
import org.apache.lucene.analysis.shingle.ShingleFilter;
import org.elasticsearch.Version;
import org.elasticsearch.common.logging.DeprecationCategory;
import org.elasticsearch.common.logging.DeprecationLogger;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.env.Environment;
import org.elasticsearch.index.IndexSettings;
public class ShingleTokenFilterFactory extends AbstractTokenFilterFactory {
private static final DeprecationLogger DEPRECATION_LOGGER = DeprecationLogger.getLogger(ShingleTokenFilterFactory.class);
private final Factory factory;
public ShingleTokenFilterFactory(IndexSettings indexSettings, Environment environment, String name, Settings settings) {
super(indexSettings, name, settings);
int maxAllowedShingleDiff = indexSettings.getMaxShingleDiff();
Integer maxShingleSize = settings.getAsInt("max_shingle_size", ShingleFilter.DEFAULT_MAX_SHINGLE_SIZE);
Integer minShingleSize = settings.getAsInt("min_shingle_size", ShingleFilter.DEFAULT_MIN_SHINGLE_SIZE);
Boolean outputUnigrams = settings.getAsBoolean("output_unigrams", true);
int shingleDiff = maxShingleSize - minShingleSize + (outputUnigrams ? 1 : 0);
if (shingleDiff > maxAllowedShingleDiff) {
if (indexSettings.getIndexVersionCreated().onOrAfter(Version.V_7_0_0)) {
throw new IllegalArgumentException(
"In Shingle TokenFilter the difference between max_shingle_size and min_shingle_size (and +1 if outputting unigrams)"
+ " must be less than or equal to: ["
+ maxAllowedShingleDiff
+ "] but was ["
+ shingleDiff
+ "]. This limit"
+ " can be set by changing the ["
+ IndexSettings.MAX_SHINGLE_DIFF_SETTING.getKey()
+ "] index level setting."
);
} else {
deprecationLogger.warn(
DeprecationCategory.ANALYSIS,
"excessive_shingle_diff",
"Deprecated big difference between maxShingleSize and minShingleSize"
+ " in Shingle TokenFilter, expected difference must be less than or equal to: ["
+ maxAllowedShingleDiff
+ "]"
);
}
}
Boolean outputUnigramsIfNoShingles = settings.getAsBoolean("output_unigrams_if_no_shingles", false);
String tokenSeparator = settings.get("token_separator", ShingleFilter.DEFAULT_TOKEN_SEPARATOR);
String fillerToken = settings.get("filler_token", ShingleFilter.DEFAULT_FILLER_TOKEN);
factory = new Factory(
"shingle",
minShingleSize,
maxShingleSize,
outputUnigrams,
outputUnigramsIfNoShingles,
tokenSeparator,
fillerToken
);
}
@Override
public TokenStream create(TokenStream tokenStream) {
return factory.create(tokenStream);
}
@Override
public TokenFilterFactory getSynonymFilter() {
if (indexSettings.getIndexVersionCreated().onOrAfter(Version.V_7_0_0)) {
throw new IllegalArgumentException("Token filter [" + name() + "] cannot be used to parse synonyms");
} else {
DEPRECATION_LOGGER.warn(
DeprecationCategory.ANALYSIS,
"synonym_tokenfilters",
"Token filter " + name() + "] will not be usable to parse synonym after v7.0"
);
}
return this;
}
public Factory getInnerFactory() {
return this.factory;
}
public static final class Factory implements TokenFilterFactory {
private final int maxShingleSize;
private final boolean outputUnigrams;
private final boolean outputUnigramsIfNoShingles;
private final String tokenSeparator;
private final String fillerToken;
private int minShingleSize;
private final String name;
public Factory(String name) {
this(
name,
ShingleFilter.DEFAULT_MIN_SHINGLE_SIZE,
ShingleFilter.DEFAULT_MAX_SHINGLE_SIZE,
true,
false,
ShingleFilter.DEFAULT_TOKEN_SEPARATOR,
ShingleFilter.DEFAULT_FILLER_TOKEN
);
}
Factory(
String name,
int minShingleSize,
int maxShingleSize,
boolean outputUnigrams,
boolean outputUnigramsIfNoShingles,
String tokenSeparator,
String fillerToken
) {
this.maxShingleSize = maxShingleSize;
this.outputUnigrams = outputUnigrams;
this.outputUnigramsIfNoShingles = outputUnigramsIfNoShingles;
this.tokenSeparator = tokenSeparator;
this.minShingleSize = minShingleSize;
this.fillerToken = fillerToken;
this.name = name;
}
@Override
public TokenStream create(TokenStream tokenStream) {
ShingleFilter filter = new ShingleFilter(tokenStream, minShingleSize, maxShingleSize);
filter.setOutputUnigrams(outputUnigrams);
filter.setOutputUnigramsIfNoShingles(outputUnigramsIfNoShingles);
filter.setTokenSeparator(tokenSeparator);
filter.setFillerToken(fillerToken);
if (outputUnigrams || (minShingleSize != maxShingleSize)) {
/**
* We disable the graph analysis on this token stream
* because it produces shingles of different size.
* Graph analysis on such token stream is useless and dangerous as it may create too many paths
* since shingles of different size are not aligned in terms of positions.
*/
filter.addAttribute(DisableGraphAttribute.class);
}
return filter;
}
public int getMaxShingleSize() {
return maxShingleSize;
}
public int getMinShingleSize() {
return minShingleSize;
}
public boolean getOutputUnigrams() {
return outputUnigrams;
}
public boolean getOutputUnigramsIfNoShingles() {
return outputUnigramsIfNoShingles;
}
@Override
public String name() {
return name;
}
}
}