@Override
public TupleEntryIterator openForRead( FlowProcess<JobConf> flowProcess, RecordReader<TupleWrapper,
NullWritable> input ) throws IOException {
// input may be null when this method is called on the client side or cluster side when accumulating
// for a HashJoin
return new HadoopTupleEntrySchemeIterator( flowProcess, this, input );
}