public CombineFileSplit getInputSplitShim() {
      return inputSplitShim;
    }
CombineHiveInputSplit encapsulates an InputSplit with its corresponding
inputFormatClassName. A CombineHiveInputSplit comprises of multiple chunks
from different files. Since, they belong to a single directory, there is a
single inputformat for all the chunks.
ql/src/java/org/apache/hadoop/hive/ql/io/CombineHiveInputFormat.java