content: /**
   * 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.lucene.analysis;
  
  import java.io.IOException;
  
  /**
   * Subclasses of CharFilter can be chained to filter CharStream.
   * They can be used as {@link java.io.Reader} with additional offset
   * correction. {@link Tokenizer}s will automatically use {@link #correctOffset}
   * if a CharFilter/CharStream subclass is used.
   */
  public abstract class CharFilter extends CharStream {
  
    protected CharStream input;
  
    protected CharFilter(CharStream in) {
      input = in;
    }
  
    /**
     * Subclass may want to override to correct the current offset.
     *
     * @param currentOff current offset
     * @return corrected offset
     */
    protected int correct(int currentOff) {
      return currentOff;
    }
  
    /**
     * Chains the corrected offset through the input
     * CharFilter.
     */
    @Override
    public final int correctOffset(int currentOff) {
      return input.correctOffset(correct(currentOff));
    }
  
    @Override
    public void close() throws IOException {
      input.close();
    }
  
    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
      return input.read(cbuf, off, len);
    }
  
    @Override
    public boolean markSupported(){
      return input.markSupported();
    }
  
    @Override
    public void mark( int readAheadLimit ) throws IOException {
      input.mark(readAheadLimit);
    }
  
    @Override
    public void reset() throws IOException {
      input.reset();
    }
  }
  