org.apache.lucene.analysis.miscellaneous.PerFieldAnalyzerWrapper Maven / Gradle / Ivy
/*
* 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.miscellaneous;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.DelegatingAnalyzerWrapper;
import java.util.Collections;
import java.util.Map;
/**
* This analyzer is used to facilitate scenarios where different
* fields require different analysis techniques. Use the Map
* argument in {@link #PerFieldAnalyzerWrapper(Analyzer, java.util.Map)}
* to add non-default analyzers for fields.
*
* Example usage:
*
*
* {@code
* Map analyzerPerField = new HashMap<>();
* analyzerPerField.put("firstname", new KeywordAnalyzer());
* analyzerPerField.put("lastname", new KeywordAnalyzer());
*
* PerFieldAnalyzerWrapper aWrapper =
* new PerFieldAnalyzerWrapper(new StandardAnalyzer(version), analyzerPerField);
* }
*
*
* In this example, StandardAnalyzer will be used for all fields except "firstname"
* and "lastname", for which KeywordAnalyzer will be used.
*
*
A PerFieldAnalyzerWrapper can be used like any other analyzer, for both indexing
* and query parsing.
*
* @since 3.1
*/
public final class PerFieldAnalyzerWrapper extends DelegatingAnalyzerWrapper {
private final Analyzer defaultAnalyzer;
private final Map fieldAnalyzers;
/**
* Constructs with default analyzer.
*
* @param defaultAnalyzer Any fields not specifically
* defined to use a different analyzer will use the one provided here.
*/
public PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer) {
this(defaultAnalyzer, null);
}
/**
* Constructs with default analyzer and a map of analyzers to use for
* specific fields.
*
* @param defaultAnalyzer Any fields not specifically
* defined to use a different analyzer will use the one provided here.
* @param fieldAnalyzers a Map (String field name to the Analyzer) to be
* used for those fields
*/
public PerFieldAnalyzerWrapper(Analyzer defaultAnalyzer,
Map fieldAnalyzers) {
super(PER_FIELD_REUSE_STRATEGY);
this.defaultAnalyzer = defaultAnalyzer;
this.fieldAnalyzers = (fieldAnalyzers != null) ? fieldAnalyzers : Collections.emptyMap();
}
@Override
protected Analyzer getWrappedAnalyzer(String fieldName) {
Analyzer analyzer = fieldAnalyzers.get(fieldName);
return (analyzer != null) ? analyzer : defaultAnalyzer;
}
@Override
public String toString() {
return "PerFieldAnalyzerWrapper(" + fieldAnalyzers + ", default=" + defaultAnalyzer + ")";
}
}