Examples of org.apache.hadoop.mapred.Mapper.map()

org.apache.hadoop.mapred.Mapper.map()

Maps a single input key/value pair into an intermediate key/value pair.

Output pairs need not be of the same types as input pairs. A given input pair may map to zero or many output pairs. Output pairs are collected with calls to {@link OutputCollector#collect(WritableComparable,Writable)}.

Applications can use the {@link Reporter} provided to report progress or just indicate that they are alive. In scenarios where the application takes an insignificant amount of time to process individual key/value pairs, this is crucial since the framework might assume that the task has timed-out and kill that task. The other way of avoiding this is to set mapred.task.timeout to a high-enough value (or even zero for no time-outs).

@param key the input key. @param value the input value. @param output collects mapped keys and values. @param reporter facility to report progress.

  @SuppressWarnings({"unchecked"})
  public void map(Object key, Object value, OutputCollector output,
                  Reporter reporter) throws IOException {
    Mapper mapper = chain.getFirstMap();
    if (mapper != null) {
      mapper.map(key, value, chain.getMapperCollector(0, output, reporter),
                 reporter);
    }
  }


  /**

  @SuppressWarnings({"unchecked"})
  public void map(Object key, Object value, OutputCollector output,
                  Reporter reporter) throws IOException {
    Mapper mapper = chain.getFirstMap();
    if (mapper != null) {
      mapper.map(key, value, chain.getMapperCollector(0, output, reporter),
                 reporter);
    }
  }


  /**

  @SuppressWarnings({"unchecked"})
  public void map(Object key, Object value, OutputCollector output,
                  Reporter reporter) throws IOException {
    Mapper mapper = chain.getFirstMap();
    if (mapper != null) {
      mapper.map(key, value, chain.getMapperCollector(0, output, reporter),
                 reporter);
    }
  }


  /**

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