org.apache.solr.analysis.RemoveDuplicatesTokenFilter 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.solr.analysis;

import org.apache.lucene.analysis.Token;
import org.apache.lucene.analysis.TokenStream;
import org.apache.solr.util.ArraysUtils;

import java.io.IOException;

/**
 * A TokenFilter which filters out Tokens at the same position and Term
 * text as the previous token in the stream.
 */
public class RemoveDuplicatesTokenFilter extends BufferedTokenStream {
  public RemoveDuplicatesTokenFilter(TokenStream input) {super(input);}
  protected Token process(Token t) throws IOException {
    Token tok = read();
    while (tok != null && tok.getPositionIncrement()==0) {
      if (null != t) {
        write(t);
        t = null;
      }
      boolean dup=false;
      for (Token outTok : output()) {
        int tokLen = tok.termLength();
        if (outTok.termLength() == tokLen && ArraysUtils.equals(outTok.termBuffer(), 0, tok.termBuffer(), 0, tokLen)) {
          dup=true;
          //continue;;
        }
      }
      if (!dup){
        write(tok);
      }
      tok = read();
    }
    if (tok != null) {
      pushBack(tok);
    }
    return t;
  }
}