org.apache.lucene.analysis.CustomAnalyzerWrapper Maven / Gradle / Ivy
/*
* Licensed to ElasticSearch and Shay Banon under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. ElasticSearch 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;
import java.io.Reader;
/**
* Extension to {@link Analyzer} suitable for Analyzers which wrap
* other Analyzers.
*
* {@link #getWrappedAnalyzer(String)} allows the Analyzer
* to wrap multiple Analyzers which are selected on a per field basis.
*
* {@link #wrapComponents(String, Analyzer.TokenStreamComponents)} allows the
* TokenStreamComponents of the wrapped Analyzer to then be wrapped
* (such as adding a new {@link TokenFilter} to form new TokenStreamComponents.
*/
public abstract class CustomAnalyzerWrapper extends Analyzer {
/**
* Creates a new CustomAnalyzerWrapper. Since the {@link Analyzer.ReuseStrategy} of
* the wrapped Analyzers are unknown, {@link Analyzer.PerFieldReuseStrategy} is assumed
*/
protected CustomAnalyzerWrapper() {
super(new PerFieldReuseStrategy());
}
/**
* Retrieves the wrapped Analyzer appropriate for analyzing the field with
* the given name
*
* @param fieldName Name of the field which is to be analyzed
* @return Analyzer for the field with the given name. Assumed to be non-null
*/
protected abstract Analyzer getWrappedAnalyzer(String fieldName);
/**
* Wraps / alters the given TokenStreamComponents, taken from the wrapped
* Analyzer, to form new components. It is through this method that new
* TokenFilters can be added by AnalyzerWrappers.
*
*
* @param fieldName Name of the field which is to be analyzed
* @param components TokenStreamComponents taken from the wrapped Analyzer
* @return Wrapped / altered TokenStreamComponents.
*/
protected abstract TokenStreamComponents wrapComponents(String fieldName, TokenStreamComponents components);
@Override
protected final TokenStreamComponents createComponents(String fieldName, Reader aReader) {
return wrapComponents(fieldName, getWrappedAnalyzer(fieldName).createComponents(fieldName, aReader));
}
@Override
public int getPositionIncrementGap(String fieldName) {
return getWrappedAnalyzer(fieldName).getPositionIncrementGap(fieldName);
}
@Override
public int getOffsetGap(String fieldName) {
return getWrappedAnalyzer(fieldName).getOffsetGap(fieldName);
}
@Override
public final Reader initReader(String fieldName, Reader reader) {
return getWrappedAnalyzer(fieldName).initReader(fieldName, reader);
}
}