org.apache.flink.api.java.record.operators

Annotation Type ReduceOperator.Combinable

@Retention(value=RUNTIME)
 @Target(value=TYPE)
public static @interface ReduceOperator.Combinable

This annotation marks reduce stubs as eligible for the usage of a combiner. The following code excerpt shows how to make a simple reduce stub combinable (assuming here that the reducer function and combiner function do the same): \@Combinable public static class CountWords extends ReduceFunction<StringValue> { private final IntValue theInteger = new IntValue(); \@Override public void reduce(StringValue key, Iterator<Record> records, Collector out) throws Exception { Record element = null; int sum = 0; while (records.hasNext()) { element = records.next(); element.getField(1, this.theInteger); // we could have equivalently used IntValue i = record.getField(1, IntValue.class); sum += this.theInteger.getValue(); } element.setField(1, this.theInteger); out.collect(element); } public void combine(StringValue key, Iterator<Record> records, Collector out) throws Exception { this.reduce(key, records, out); } }