@Override
public int compare(InputSplit o1, InputSplit o2) {
try {
long len1 = o1.getLength();
long len2 = o2.getLength();
if (len1 < len2) {
return 1;
} else if (len1 == len2) {
return 0;
} else {
return -1;
}
} catch (IOException ie) {
throw new RuntimeException("exception in compare", ie);
} catch (InterruptedException ie) {
throw new RuntimeException("exception in compare", ie);
}
}
@Override
@SuppressWarnings("unchecked")
public void run(final JobConf job, final TaskUmbilicalProtocol umbilical) throws IOException {
final Reporter reporter = getReporter(umbilical);
// start thread that will handle communication with parent
startCommunicationThread(umbilical);
int numReduceTasks = conf.getNumReduceTasks();
LOG.info("numReduceTasks: " + numReduceTasks);
MapOutputCollector collector = null;
if (numReduceTasks > 0) {
collector = new MapOutputBuffer(umbilical, job, reporter);
} else {
collector = new DirectMapOutputCollector(umbilical, job, reporter);
}
// reinstantiate the split
try {
instantiatedSplit =
(InputSplit) ReflectionUtils.newInstance(job.getClassByName(splitClass), job);
} catch (ClassNotFoundException exp) {
IOException wrap = new IOException("Split class " + splitClass + " not found");
wrap.initCause(exp);
throw wrap;
}
DataInputBuffer splitBuffer = new DataInputBuffer();
splitBuffer.reset(split.get(), 0, split.getSize());
instantiatedSplit.readFields(splitBuffer);
// if it is a file split, we can give more details
if (instantiatedSplit instanceof FileSplit) {
FileSplit fileSplit = (FileSplit) instantiatedSplit;
job.set("map.input.file", fileSplit.getPath().toString());
job.setLong("map.input.start", fileSplit.getStart());
job.setLong("map.input.length", fileSplit.getLength());
}
RecordReader rawIn = // open input
job.getInputFormat().getRecordReader(instantiatedSplit, job, reporter);
RecordReader in = new TrackedRecordReader(rawIn, getCounters());
MapRunnable runner = (MapRunnable) ReflectionUtils.newInstance(job.getMapRunnerClass(), job);
try {
runner.run(in, collector, reporter);
collector.flush();
} finally {
// close
in.close(); // close input
collector.close();
}
done(umbilical);
}