GafferReducer (uk.gov.gchq.gaffer:gaffer2 2.2.0 API)

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.

- Nested Class Summary
  - Nested classes/interfaces inherited from class org.apache.hadoop.mapreduce.Reducer
    org.apache.hadoop.mapreduce.Reducer.Context
- Constructor Summary
  
  Constructors
  Constructor Description
  
  GafferReducer()
- Method Summary
  - Methods inherited from class org.apache.hadoop.mapreduce.Reducer
    run
  - Methods inherited from class java.lang.Object
    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - GafferReducer
```
public GafferReducer()
```