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// original code from Apache Solr - ported to work with Lucene 3.x and reformatted to Search coding style
/**
 * 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.solr.analysis;

import java.io.IOException;
import java.io.Reader;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;

/**
 * @version $Id: SolrAnalyzer.java 804726 2009-08-16 17:28:58Z yonik $
 */
public abstract class SolrAnalyzer extends Analyzer {
	int posIncGap = 0;

	public void setPositionIncrementGap(int gap) {
		posIncGap = gap;
	}

	public int getPositionIncrementGap(String fieldName) {
		return posIncGap;
	}

	/**
	 * wrap the reader in a CharStream, if appropriate
	 */
	public Reader charStream(Reader reader) {
		return reader;
	}

	@Override
	public TokenStream tokenStream(String fieldName, Reader reader) {
		return getStream( fieldName, reader ).getTokenStream();
	}

	public static class TokenStreamInfo {
		private final Tokenizer tokenizer;
		private final TokenStream tokenStream;

		public TokenStreamInfo(Tokenizer tokenizer, TokenStream tokenStream) {
			this.tokenizer = tokenizer;
			this.tokenStream = tokenStream;
		}

		public Tokenizer getTokenizer() {
			return tokenizer;
		}

		public TokenStream getTokenStream() {
			return tokenStream;
		}
	}


	public abstract TokenStreamInfo getStream(String fieldName, Reader reader);

	@Override
	public TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException {
		// if (true) return tokenStream(fieldName, reader);
		TokenStreamInfo tsi = ( TokenStreamInfo ) getPreviousTokenStream();
		if ( tsi != null ) {
			tsi.getTokenizer().reset( charStream( reader ) );
			// the consumer will currently call reset() on the TokenStream to hit all the filters.
			// this isn't necessarily guaranteed by the APIs... but is currently done
			// by lucene indexing in DocInverterPerField, and in the QueryParser
			return tsi.getTokenStream();
		}
		else {
			tsi = getStream( fieldName, reader );
			setPreviousTokenStream( tsi );
			return tsi.getTokenStream();
		}
	}
}