Package org.apache.beam.runners.dataflow.internal

Class DataflowGroupByKey<K,V>

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PCollection<KV<K,V>>,PCollection<KV<K,Iterable<V>>>>

org.apache.beam.runners.dataflow.internal.DataflowGroupByKey<K,V>

All Implemented Interfaces:

Serializable, HasDisplayData

public class DataflowGroupByKey<K,V>
extends PTransform<PCollection<KV<K,V>>,PCollection<KV<K,Iterable<V>>>>

Specialized implementation of GroupByKey for translating Redistribute transform into Dataflow service protos.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	DataflowGroupByKey.Registrar	Registers DataflowGroupByKey.DataflowGroupByKeyTranslator.

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

annotations, displayData, name, resourceHints

Method Summary

Modifier and Type	Method	Description
boolean	allowDuplicates()	Returns whether it allows duplicated elements in the output.
static void	applicableTo(PCollection<?> input)
static <K, V> DataflowGroupByKey<K,V>	create()	Returns a DataflowGroupByKey<K, V> PTransform.
static <K, V> DataflowGroupByKey<K,V>	createWithAllowDuplicates()	Returns a DataflowGroupByKey<K, V> PTransform that its output can have duplicated elements.
PCollection<KV<K,Iterable<V>>>	expand(PCollection<KV<K,V>> input)	Override this method to specify how this PTransform should be expanded on the given InputT.
static <K, V> Coder<V>	getInputValueCoder(Coder<KV<K,V>> inputCoder)	Returns the Coder of the values of the input to this transform.
static <K, V> KvCoder<K,Iterable<V>>	getOutputKvCoder(Coder<KV<K,V>> inputCoder)	Returns the Coder of the output of this transform.
WindowingStrategy<?,?>	updateWindowingStrategy(WindowingStrategy<?,?> inputStrategy)

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

addAnnotation, compose, compose, getAdditionalInputs, getAnnotations, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, getResourceHints, populateDisplayData, setDisplayData, setResourceHints, toString, validate, validate

Methods inherited from class java.lang.Object

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

Method Details

create

public static <K,
V> DataflowGroupByKey<K,V> create()

Returns a DataflowGroupByKey<K, V> PTransform.

Type Parameters:

K - the type of the keys of the input and output PCollections

V - the type of the values of the input PCollection and the elements of the Iterables in the output PCollection

createWithAllowDuplicates

public static <K,
V> DataflowGroupByKey<K,V> createWithAllowDuplicates()

Returns a DataflowGroupByKey<K, V> PTransform that its output can have duplicated elements.

Type Parameters:

K - the type of the keys of the input and output PCollections

V - the type of the values of the input PCollection and the elements of the Iterables in the output PCollection

allowDuplicates

public boolean allowDuplicates()

Returns whether it allows duplicated elements in the output.

applicableTo

public static void applicableTo(PCollection<?> input)

updateWindowingStrategy

public WindowingStrategy<?,?> updateWindowingStrategy(WindowingStrategy<?,?> inputStrategy)

expand

public PCollection<KV<K,Iterable<V>>> expand(PCollection<KV<K,V>> input)

Description copied from class: PTransform

Override this method to specify how this PTransform should be expanded on the given InputT.

NOTE: This method should not be called directly. Instead apply the PTransform should be applied to the InputT using the apply method.

Composite transforms, which are defined in terms of other transforms, should return the output of one of the composed transforms. Non-composite transforms, which do not apply any transforms internally, should return a new unbound output and register evaluators (via backend-specific registration methods).

Specified by:

expand in class PTransform<PCollection<KV<K,V>>,PCollection<KV<K,Iterable<V>>>>

getInputValueCoder

public static <K,
V> Coder<V> getInputValueCoder(Coder<KV<K,V>> inputCoder)

Returns the Coder of the values of the input to this transform.

getOutputKvCoder

public static <K,
V> KvCoder<K,Iterable<V>> getOutputKvCoder(Coder<KV<K,V>> inputCoder)

Returns the Coder of the output of this transform.