com.google.cloud.dataflow.sdk.transforms

Class View.AsSingleton<T>

java.lang.Object

com.google.cloud.dataflow.sdk.transforms.PTransform<PCollection<T>,PCollectionView<T>>

com.google.cloud.dataflow.sdk.transforms.View.AsSingleton<T>

All Implemented Interfaces:

java.io.Serializable

Enclosing class:

View

public static class View.AsSingleton<T>
extends PTransform<PCollection<T>,PCollectionView<T>>

A PTransform that produces a PCollectionView of a singleton PCollection yielding the single element it contains.

Instantiate via View.asIterable().

See Also:

Serialized Form

Field Summary

Fields inherited from class com.google.cloud.dataflow.sdk.transforms.PTransform

name

Method Summary

Methods

Modifier and Type	Method and Description
PCollectionView<T>	apply(PCollection<T> input) Applies this PTransform on the given Input, and returns its Output.
View.AsSingleton<T>	withDefaultValue(T defaultValue) Default value to return for windows with no value in them.

Methods inherited from class com.google.cloud.dataflow.sdk.transforms.PTransform

finishSpecifying, getCoderRegistry, getDefaultName, getDefaultOutputCoder, getDefaultOutputCoder, getInput, getKindString, getName, getOutput, getPipeline, setName, setPipeline, toString, withName

Methods inherited from class java.lang.Object

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

Method Detail

withDefaultValue

public View.AsSingleton<T> withDefaultValue(T defaultValue)

Default value to return for windows with no value in them.

apply

public PCollectionView<T> apply(PCollection<T> input)

Description copied from class: PTransform

Applies this PTransform on the given Input, and returns its Output.

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).

The default implementation throws an exception. A derived class must either implement apply, or else each runner must supply a custom implementation via PipelineRunner.apply(com.google.cloud.dataflow.sdk.transforms.PTransform<Input, Output>, Input).

Overrides:

apply in class PTransform<PCollection<T>,PCollectionView<T>>