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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.chukwa.datacollection.writer;
19  
20  import java.util.List;
21  import org.apache.hadoop.chukwa.Chunk;
22  import org.apache.hadoop.conf.Configuration;
23  import org.apache.log4j.Logger;
24  import org.apache.hadoop.chukwa.util.ExceptionUtil;
25  
26  /**
27   * Minimal writer; does nothing with data.
28   * 
29   * Useful primarily as an end-of-pipeline stage, if stuff in the middle
30   * is accomplishing something useful.
31   *
32   */
33  public class NullWriter implements ChukwaWriter {
34    private static final Logger log = Logger.getLogger(NullWriter.class);
35    
36    //in kb per sec
37    int maxDataRate = Integer.MAX_VALUE;
38    public static final String RATE_OPT_NAME = "nullWriter.dataRate";
39    @Override
40    public CommitStatus add(List<Chunk> chunks) throws WriterException {
41      try {
42        int dataBytes =0;
43        for(Chunk c: chunks)
44          dataBytes +=c.getData().length;
45        if(maxDataRate > 0)
46          Thread.sleep(dataBytes / maxDataRate);
47      } catch(Exception e) {
48        log.debug(ExceptionUtil.getStackTrace(e));
49      }
50      return COMMIT_OK;
51    }
52  
53    @Override
54    public void close() throws WriterException {
55    }
56  
57    @Override
58    public void init(Configuration c) throws WriterException {
59      maxDataRate = c.getInt(RATE_OPT_NAME, 0);
60    }
61  
62  }