this.isMultipleSources = this.tupleMRConfig.getNumIntermediateSchemas() >= 2;
this.serInfo = tupleMRConfig.getSerializationInfo();
this.groupSchema = this.serInfo.getGroupSchema();
if(!isMultipleSources) {
/* schema id 0 is the only intermediate schema defined */
this.groupTuple = new ViewTuple(groupSchema,
this.serInfo.getGroupSchemaIndexTranslation(0));
} else {
this.groupTuple = new ViewTuple(groupSchema);
}
List<String> groupFields = tupleMRConfig.getGroupByFields();
this.maxDepth = groupFields.size() - 1;
this.minDepth = tupleMRConfig.calculateRollupBaseFields().size() - 1;
this.tupleIterator = new TupleIterator<OUTPUT_KEY, OUTPUT_VALUE>(context);