package org.apache.lucene.analysis;
/**
* 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.
*/
import org.apache.lucene.document.Fieldable;
import java.io.Reader;
import java.io.IOException;
import java.util.Map;
import java.util.HashMap;
/**
* 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.
*
* <p>Example usage:
*
* <pre>
* Map analyzerPerField = new HashMap();
* analyzerPerField.put("firstname", new KeywordAnalyzer());
* analyzerPerField.put("lastname", new KeywordAnalyzer());
*
* PerFieldAnalyzerWrapper aWrapper =
* new PerFieldAnalyzerWrapper(new StandardAnalyzer(), analyzerPerField);
* </pre>
*
* <p>In this example, StandardAnalyzer will be used for all fields except "firstname"
* and "lastname", for which KeywordAnalyzer will be used.
*
* <p>A PerFieldAnalyzerWrapper can be used like any other analyzer, for both indexing
* and query parsing.
*/
public final class PerFieldAnalyzerWrapper extends Analyzer {
private final Analyzer defaultAnalyzer;
private final Map<String,Analyzer> analyzerMap = new HashMap<String,Analyzer>();
/**
* 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<String,Analyzer> fieldAnalyzers) {
this.defaultAnalyzer = defaultAnalyzer;
if (fieldAnalyzers != null) {
analyzerMap.putAll(fieldAnalyzers);
}
}
/**
* Defines an analyzer to use for the specified field.
*
* @param fieldName field name requiring a non-default analyzer
* @param analyzer non-default analyzer to use for field
* @deprecated Changing the Analyzer for a field after instantiation prevents
* reusability. Analyzers for fields should be set during construction.
*/
@Deprecated
public void addAnalyzer(String fieldName, Analyzer analyzer) {
analyzerMap.put(fieldName, analyzer);
}
@Override
public TokenStream tokenStream(String fieldName, Reader reader) {
Analyzer analyzer = analyzerMap.get(fieldName);
if (analyzer == null) {
analyzer = defaultAnalyzer;
}
return analyzer.tokenStream(fieldName, reader);
}
@Override
public TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException {
Analyzer analyzer = analyzerMap.get(fieldName);
if (analyzer == null)
analyzer = defaultAnalyzer;
return analyzer.reusableTokenStream(fieldName, reader);
}
/** Return the positionIncrementGap from the analyzer assigned to fieldName */
@Override
public int getPositionIncrementGap(String fieldName) {
Analyzer analyzer = analyzerMap.get(fieldName);
if (analyzer == null)
analyzer = defaultAnalyzer;
return analyzer.getPositionIncrementGap(fieldName);
}
/** Return the offsetGap from the analyzer assigned to field */
@Override
public int getOffsetGap(Fieldable field) {
Analyzer analyzer = analyzerMap.get(field.name());
if (analyzer == null)
analyzer = defaultAnalyzer;
return analyzer.getOffsetGap(field);
}
@Override
public String toString() {
return "PerFieldAnalyzerWrapper(" + analyzerMap + ", default=" + defaultAnalyzer + ")";
}
}