content: package org.apache.lucene.analysis.fa;
  
  /**
   * 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.
   */
  
  import java.io.IOException;
  
  import org.apache.lucene.analysis.CharStream;
  import org.apache.lucene.analysis.CharFilter;
  
  /**
   * CharFilter that replaces instances of Zero-width non-joiner with an
   * ordinary space.
   */
  public class PersianCharFilter extends CharFilter {
  
    public PersianCharFilter(CharStream in) {
      super(in);
    }
    
    @Override
    public int read(char[] cbuf, int off, int len) throws IOException {
      final int charsRead = super.read(cbuf, off, len);
      if (charsRead > 0) {
        final int end = off + charsRead;
        while (off < end) {
          if (cbuf[off] == '\u200C')
            cbuf[off] = ' ';
          off++;
        }
      }
      return charsRead;
    }
  }
  