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.hadoop.chukwa.datacollection.adaptor.filetailer;
  
  
  import org.apache.hadoop.chukwa.ChunkImpl;
  import org.apache.hadoop.chukwa.datacollection.ChunkReceiver;
  import java.util.ArrayList;
  
  /**
   * A subclass of FileTailingAdaptor that reads UTF8/ascii files and splits
   * records at carriage returns.
   * 
   */
  public class CharFileTailingAdaptorUTF8 extends FileTailingAdaptor {
  
    private static final char SEPARATOR = '\n';
  
    private ArrayList<Integer> offsets = new ArrayList<Integer>();
  
    /**
     * 
     * Note: this method uses a temporary ArrayList (shared across instances).
     * This means we're copying ints each time. This could be a performance issue.
     * Also, 'offsets' never shrinks, and will be of size proportional to the
     * largest number of lines ever seen in an event.
     */
    @Override
    protected int extractRecords(ChunkReceiver eq, long buffOffsetInFile,
        byte[] buf) throws InterruptedException {
      for (int i = 0; i < buf.length; ++i) {
        if (buf[i] == SEPARATOR) {
          offsets.add(i);
        }
      }
  
      if (offsets.size() > 0) {
        int[] offsets_i = new int[offsets.size()];
        for (int i = 0; i < offsets_i.length; ++i)
          offsets_i[i] = offsets.get(i);
  
        int bytesUsed = offsets_i[offsets_i.length - 1] + 1; // char at last
                                                             // offset uses a byte
        assert bytesUsed > 0 : " shouldn't send empty events";
        ChunkImpl event = new ChunkImpl(type, toWatch.getAbsolutePath(),
            buffOffsetInFile + bytesUsed, buf, this);
  
        event.setRecordOffsets(offsets_i);
        eq.add(event);
  
        offsets.clear();
        return bytesUsed;
      } else
        return 0;
  
    }
  
  }
  