Package org.apache.beam.runners.flink.translation.functions

Class FlinkPartialReduceFunction<K,InputT,AccumT,W extends BoundedWindow>

java.lang.Object

org.apache.flink.api.common.functions.AbstractRichFunction

org.apache.flink.api.common.functions.RichGroupCombineFunction<WindowedValue<KV<K,InputT>>,WindowedValue<KV<K,AccumT>>>

org.apache.beam.runners.flink.translation.functions.FlinkPartialReduceFunction<K,InputT,AccumT,W>

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.GroupCombineFunction<WindowedValue<KV<K,InputT>>,WindowedValue<KV<K,AccumT>>>, org.apache.flink.api.common.functions.RichFunction

public class FlinkPartialReduceFunction<K,InputT,AccumT,W extends BoundedWindow>
extends org.apache.flink.api.common.functions.RichGroupCombineFunction<WindowedValue<KV<K,InputT>>,WindowedValue<KV<K,AccumT>>>

This is the first step for executing a Combine.PerKey on Flink. The second part is FlinkReduceFunction. This function performs a local combine step before shuffling while the latter does the final combination after a shuffle.

The input to combine(Iterable, Collector) are elements of the same key but for different windows. We have to ensure that we only combine elements of matching windows.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected final CombineFnBase.GlobalCombineFn<InputT,AccumT,?>	combineFn
protected final org.apache.beam.runners.core.construction.SerializablePipelineOptions	serializedOptions
protected final Map<PCollectionView<?>,WindowingStrategy<?,?>>	sideInputs
protected final WindowingStrategy<Object,W>	windowingStrategy

Constructor Summary

Constructors

Constructor	Description
FlinkPartialReduceFunction(CombineFnBase.GlobalCombineFn<InputT,AccumT,?> combineFn, WindowingStrategy<Object,W> windowingStrategy, Map<PCollectionView<?>,WindowingStrategy<?,?>> sideInputs, PipelineOptions pipelineOptions)
FlinkPartialReduceFunction(CombineFnBase.GlobalCombineFn<InputT,AccumT,?> combineFn, WindowingStrategy<Object,W> windowingStrategy, Map<PCollectionView<?>,WindowingStrategy<?,?>> sideInputs, PipelineOptions pipelineOptions, boolean groupedByWindow)

Method Summary

Modifier and Type	Method	Description
void	combine(Iterable<WindowedValue<KV<K,InputT>>> elements, org.apache.flink.util.Collector<WindowedValue<KV<K,AccumT>>> out)
void	open(org.apache.flink.configuration.Configuration parameters)

Methods inherited from class org.apache.flink.api.common.functions.AbstractRichFunction

close, getIterationRuntimeContext, getRuntimeContext, setRuntimeContext

Methods inherited from class java.lang.Object

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

Field Details

combineFn

protected final CombineFnBase.GlobalCombineFn<InputT,AccumT,?> combineFn

windowingStrategy

protected final WindowingStrategy<Object,W extends BoundedWindow> windowingStrategy

serializedOptions

protected final org.apache.beam.runners.core.construction.SerializablePipelineOptions serializedOptions

sideInputs

protected final Map<PCollectionView<?>,WindowingStrategy<?,?>> sideInputs

Constructor Details

FlinkPartialReduceFunction

public FlinkPartialReduceFunction(CombineFnBase.GlobalCombineFn<InputT,AccumT,?> combineFn,
 WindowingStrategy<Object,W> windowingStrategy,
 Map<PCollectionView<?>,WindowingStrategy<?,?>> sideInputs,
 PipelineOptions pipelineOptions)

FlinkPartialReduceFunction

public FlinkPartialReduceFunction(CombineFnBase.GlobalCombineFn<InputT,AccumT,?> combineFn,
 WindowingStrategy<Object,W> windowingStrategy,
 Map<PCollectionView<?>,WindowingStrategy<?,?>> sideInputs,
 PipelineOptions pipelineOptions,
 boolean groupedByWindow)

Method Details

open

public void open(org.apache.flink.configuration.Configuration parameters)

Specified by:

open in interface org.apache.flink.api.common.functions.RichFunction

Overrides:

open in class org.apache.flink.api.common.functions.AbstractRichFunction

combine

public void combine(Iterable<WindowedValue<KV<K,InputT>>> elements,
 org.apache.flink.util.Collector<WindowedValue<KV<K,AccumT>>> out)
             throws Exception

Specified by:

combine in interface org.apache.flink.api.common.functions.GroupCombineFunction<K,InputT>

Specified by:

combine in class org.apache.flink.api.common.functions.RichGroupCombineFunction<WindowedValue<KV<K,InputT>>,WindowedValue<KV<K,AccumT>>>

Throws:

Exception