@Override
    public String[] getLocations() throws IOException {
      return locations.toArray(new String[locations.size()]);
    }
@param hadoopConf
@param bucket bucket to be processed by this split
@param files actual files this split should process.  It is assumed the caller has already
             parsed out the files in base and deltas to populate this list.  Includes copy_N
@param base directory of the base, or the partition/table location if the files are in old
            style.  Can be null.
@param deltas directories of the delta files.
@throws IOException
ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/MRCompactor.java