SortValidator.java 文件源码

public void configure(JobConf job) {
  // 'key' == sortInput for sort-input; key == sortOutput for sort-output
  key = deduceInputFile(job);

  if (key == sortOutput) {
    partitioner = new HashPartitioner<WritableComparable, Writable>();

    // Figure the 'current' partition and no. of reduces of the 'sort'
    try {
      URI inputURI = new URI(job.get(JobContext.MAP_INPUT_FILE));
      String inputFile = inputURI.getPath();
      // part file is of the form part-r-xxxxx
      partition = Integer.valueOf(inputFile.substring(
        inputFile.lastIndexOf("part") + 7)).intValue();
      noSortReducers = job.getInt(SORT_REDUCES, -1);
    } catch (Exception e) {
      System.err.println("Caught: " + e);
      System.exit(-1);
    }
  }
}