61 lines
2.4 KiB
Java
61 lines
2.4 KiB
Java
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package it.cavallium.dbengine.database;
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import it.cavallium.dbengine.database.analyzer.N4CharGramAnalyzer;
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import it.cavallium.dbengine.database.analyzer.N4CharGramEdgeAnalyzer;
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import it.cavallium.dbengine.database.analyzer.TextFieldsAnalyzer;
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import it.cavallium.dbengine.database.analyzer.WordAnalyzer;
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import org.apache.lucene.analysis.Analyzer;
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import org.apache.lucene.analysis.LowerCaseFilter;
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import org.apache.lucene.analysis.TokenStream;
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import org.apache.lucene.analysis.en.EnglishPossessiveFilter;
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import org.apache.lucene.analysis.en.KStemFilter;
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import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
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public class LuceneUtils {
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private static final Analyzer lucene4CharGramAnalyzerEdgeInstance = new N4CharGramEdgeAnalyzer();
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private static final Analyzer lucene4CharGramAnalyzerInstance = new N4CharGramAnalyzer();
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private static final Analyzer luceneWordAnalyzerStopWordsAndStemInstance = new WordAnalyzer(true, true);
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private static final Analyzer luceneWordAnalyzerStopWordsInstance = new WordAnalyzer(true, false);
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private static final Analyzer luceneWordAnalyzerStemInstance = new WordAnalyzer(false, true);
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private static final Analyzer luceneWordAnalyzerSimpleInstance = new WordAnalyzer(false, false);
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public static Analyzer getAnalyzer(TextFieldsAnalyzer analyzer) {
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switch (analyzer) {
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case PartialWordsEdge:
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return lucene4CharGramAnalyzerEdgeInstance;
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case PartialWords:
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return lucene4CharGramAnalyzerInstance;
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case FullText:
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return luceneWordAnalyzerStopWordsAndStemInstance;
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case WordWithStopwordsStripping:
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return luceneWordAnalyzerStopWordsInstance;
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case WordWithStemming:
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return luceneWordAnalyzerStemInstance;
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case WordSimple:
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return luceneWordAnalyzerSimpleInstance;
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default:
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throw new UnsupportedOperationException("Unknown analyzer: " + analyzer);
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}
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}
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/**
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*
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* @param stem Enable stem filters on words.
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* Pass false if it will be used with a n-gram filter
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*/
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public static TokenStream newCommonFilter(TokenStream tokenStream, boolean stem) {
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tokenStream = newCommonNormalizer(tokenStream);
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if (stem) {
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tokenStream = new KStemFilter(tokenStream);
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tokenStream = new EnglishPossessiveFilter(tokenStream);
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}
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return tokenStream;
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}
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public static TokenStream newCommonNormalizer(TokenStream tokenStream) {
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tokenStream = new ASCIIFoldingFilter(tokenStream);
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tokenStream = new LowerCaseFilter(tokenStream);
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return tokenStream;
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}
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}
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