Class GafferReducer<KEY,VALUE>
- java.lang.Object
-
- org.apache.hadoop.mapreduce.Reducer<KEY,VALUE,KEY,VALUE>
-
- uk.gov.gchq.gaffer.hdfs.operation.reducer.GafferReducer<KEY,VALUE>
-
- Direct Known Subclasses:
AccumuloKeyValueReducer
public abstract class GafferReducer<KEY,VALUE> extends org.apache.hadoop.mapreduce.Reducer<KEY,VALUE,KEY,VALUE>
Reducer for use in bulk import of data into a Gaffer Store. It merges all values associated to the KEY by converting them into
Properties
and then merges those, and then converts them back to an VALUE.It contains an optimisation so that if there is only one value, we simply output it rather than incurring the cost of deserialising them and then reserialising them.
-
-
Constructor Summary
Constructors Constructor Description GafferReducer()
-