gus-asf commented on a change in pull request #1995: URL: https://github.com/apache/lucene-solr/pull/1995#discussion_r510861146
########## File path: lucene/analysis/common/src/java/org/apache/lucene/analysis/pattern/PatternTypingFilter.java ########## @@ -0,0 +1,78 @@ +/* + * 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, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.lucene.analysis.pattern; + +import java.io.IOException; +import java.util.LinkedHashMap; +import java.util.Map; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + +import org.apache.lucene.analysis.TokenFilter; +import org.apache.lucene.analysis.TokenStream; +import org.apache.lucene.analysis.tokenattributes.CharTermAttribute; +import org.apache.lucene.analysis.tokenattributes.FlagsAttribute; +import org.apache.lucene.analysis.tokenattributes.TypeAttribute; + +/** + * Set a type attribute to a parameterized value when tokens are matched by any of a several regex patterns. The + * value set in the type attribute is parameterized with the match groups of the regex used for matching. + * In combination with TypeAsSynonymFilter and DropIfFlagged filter this can supply complex synonym patterns + * that are protected from subsequent analysis, and optionally drop the original term based on the flag + * set in this filter. See {@link PatternTypingFilterFactory} for full documentation. + * + * @since 8.8.0 + * @see PatternTypingFilterFactory + */ +public class PatternTypingFilter extends TokenFilter { + + private final Map<Pattern, String> patterns; + private final Map<Pattern, Integer> flags; + private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class); + private final FlagsAttribute flagAtt = addAttribute(FlagsAttribute.class); + private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class); + + public PatternTypingFilter(TokenStream input, LinkedHashMap<Pattern,String> patterns, Map<Pattern,Integer> flags) { + super(input); + this.patterns = patterns; + this.flags = flags; + } + + @Override + public final boolean incrementToken() throws IOException { + if (input.incrementToken()) { + if (hasAttribute(CharTermAttribute.class)) { + String termText = termAtt.toString(); + for (Map.Entry<Pattern, String> patRep : patterns.entrySet()) { + Pattern pattern = patRep.getKey(); + Matcher matcher = pattern.matcher(termText); + String replaced = matcher.replaceFirst(patRep.getValue()); + // N.B. Does not support producing a synonym identical to the original term. + // Avoids having to match() then replace() which performs a second find(). + if (!replaced.equals(termText)) { Review comment: @uschindler any further thoughts? If you agree with the above, I think all would be resolved. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
