org.apache.flink.api.java.operators

Class ReduceOperator<IN>

java.lang.Object

org.apache.flink.api.java.DataSet<OUT>

org.apache.flink.api.java.operators.Operator<OUT,O>

org.apache.flink.api.java.operators.SingleInputOperator<IN,OUT,O>

org.apache.flink.api.java.operators.SingleInputUdfOperator<IN,IN,ReduceOperator<IN>>

org.apache.flink.api.java.operators.ReduceOperator<IN>

Type Parameters:

IN - The type of the data set reduced by the operator.

All Implemented Interfaces:

UdfOperator<ReduceOperator<IN>>

@Public
public class ReduceOperator<IN>
extends SingleInputUdfOperator<IN,IN,ReduceOperator<IN>>

This operator represents the application of a "reduce" function on a data set, and the result data set produced by the function.

See Also:

ReduceFunction

Field Summary

Fields inherited from class org.apache.flink.api.java.operators.Operator

minResources, name, parallelism, preferredResources

Fields inherited from class org.apache.flink.api.java.DataSet

context

Constructor Summary

Constructors

Constructor and Description
ReduceOperator(DataSet<IN> input, ReduceFunction<IN> function, String defaultName) This is the case for a reduce-all case (in contrast to the reduce-per-group case).
ReduceOperator(Grouping<IN> input, ReduceFunction<IN> function, String defaultName)

Method Summary

Modifier and Type	Method and Description
protected ReduceFunction<IN>	getFunction()
SingleInputSemanticProperties	getSemanticProperties() Gets the semantic properties that have been set for the user-defined functions (UDF).
ReduceOperator<IN>	setCombineHint(ReduceOperatorBase.CombineHint strategy) Sets the strategy to use for the combine phase of the reduce.
protected SingleInputOperator<?,IN,?>	translateToDataFlow(Operator<IN> input) Translates this operation to a data flow operator of the common data flow API.

Methods inherited from class org.apache.flink.api.java.operators.SingleInputUdfOperator

extractSemanticAnnotations, getAnalyzedUdfSemanticsFlag, getBroadcastSets, getParameters, returns, returns, returns, setAnalyzedUdfSemanticsFlag, setSemanticProperties, udfWithForwardedFieldsAnnotation, withBroadcastSet, withForwardedFields, withParameters

Methods inherited from class org.apache.flink.api.java.operators.SingleInputOperator

getInput, getInputType

Methods inherited from class org.apache.flink.api.java.operators.Operator

getMinResources, getName, getParallelism, getPreferredResources, getResultType, name, setParallelism

Methods inherited from class org.apache.flink.api.java.DataSet

aggregate, checkSameExecutionContext, clean, coGroup, collect, combineGroup, count, cross, crossWithHuge, crossWithTiny, distinct, distinct, distinct, distinct, fillInType, filter, first, flatMap, fullOuterJoin, fullOuterJoin, getExecutionEnvironment, getType, groupBy, groupBy, groupBy, iterate, iterateDelta, join, join, joinWithHuge, joinWithTiny, leftOuterJoin, leftOuterJoin, map, mapPartition, max, maxBy, min, minBy, output, partitionByHash, partitionByHash, partitionByHash, partitionByRange, partitionByRange, partitionByRange, partitionCustom, partitionCustom, partitionCustom, print, print, printOnTaskManager, printToErr, printToErr, project, rebalance, reduce, reduceGroup, rightOuterJoin, rightOuterJoin, runOperation, sortPartition, sortPartition, sortPartition, sum, union, write, write, writeAsCsv, writeAsCsv, writeAsCsv, writeAsCsv, writeAsFormattedText, writeAsFormattedText, writeAsText, writeAsText

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReduceOperator

public ReduceOperator(DataSet<IN> input,
                      ReduceFunction<IN> function,
                      String defaultName)

This is the case for a reduce-all case (in contrast to the reduce-per-group case).

Parameters:

input -

function -

ReduceOperator

public ReduceOperator(Grouping<IN> input,
                      ReduceFunction<IN> function,
                      String defaultName)

Method Detail

getFunction

protected ReduceFunction<IN> getFunction()

Specified by:

getFunction in class SingleInputUdfOperator<IN,IN,ReduceOperator<IN>>

getSemanticProperties

@Internal
public SingleInputSemanticProperties getSemanticProperties()

Description copied from interface: UdfOperator

Gets the semantic properties that have been set for the user-defined functions (UDF).

Specified by:

getSemanticProperties in interface UdfOperator<ReduceOperator<IN>>

Overrides:

getSemanticProperties in class SingleInputUdfOperator<IN,IN,ReduceOperator<IN>>

Returns:

The semantic properties of the UDF.

translateToDataFlow

protected SingleInputOperator<?,IN,?> translateToDataFlow(Operator<IN> input)

Description copied from class: SingleInputOperator

Translates this operation to a data flow operator of the common data flow API.

Specified by:

translateToDataFlow in class SingleInputOperator<IN,IN,ReduceOperator<IN>>

Parameters:

input - The data flow operator that produces this operation's input data.

Returns:

The translated data flow operator.

setCombineHint

@PublicEvolving
public ReduceOperator<IN> setCombineHint(ReduceOperatorBase.CombineHint strategy)

Sets the strategy to use for the combine phase of the reduce.

If this method is not called, then the default hint will be used. (ReduceOperatorBase.CombineHint.OPTIMIZER_CHOOSES)

Parameters:

strategy - The hint to use.

Returns:

The ReduceOperator object, for function call chaining.