TestJobCounters.java 文件源码

public void map(WritableComparable key, Writable val, 
                OutputCollector<WritableComparable, Writable> output,
                Reporter reporter)
throws IOException {
  assertNotNull("Mapper not configured!", loader);

  // load the memory
  loader.load();

  // work as identity mapper
  output.collect(key, val);
}