2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
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14 * See the License for the specific language governing permissions and
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18 package org.apache.lucene.analysis;
20 import java.io.Reader;
23 * CharStream adds {@link #correctOffset}
24 * functionality over {@link Reader}. All Tokenizers accept a
25 * CharStream instead of {@link Reader} as input, which enables
26 * arbitrary character based filtering before tokenization.
27 * The {@link #correctOffset} method fixed offsets to account for
28 * removal or insertion of characters, so that the offsets
29 * reported in the tokens match the character offsets of the
32 public abstract class CharStream extends Reader {
35 * Called by CharFilter(s) and Tokenizer to correct token offset.
37 * @param currentOff offset as seen in the output
38 * @return corrected offset based on the input
40 public abstract int correctOffset(int currentOff);