Google Cloud Dataflow SDK for Java, version 1.9.1
Class View.AsSingleton<T>
- java.lang.Object
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- com.google.cloud.dataflow.sdk.transforms.PTransform<PCollection<T>,PCollectionView<T>>
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- com.google.cloud.dataflow.sdk.transforms.View.AsSingleton<T>
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- All Implemented Interfaces:
- HasDisplayData, Serializable
- Enclosing class:
- View
public static class View.AsSingleton<T> extends PTransform<PCollection<T>,PCollectionView<T>>
Not intended for direct use by pipeline authors; public only so aPipelineRunner
may override its behavior.See
View.asSingleton()
.- See Also:
- Serialized Form
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Field Summary
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Fields inherited from class com.google.cloud.dataflow.sdk.transforms.PTransform
name
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method and Description PCollectionView<T>
apply(PCollection<T> input)
Applies thisPTransform
on the givenInputT
, and returns itsOutput
.T
defaultValue()
Returns the default value of this transform, or null if there isn't one.boolean
hasDefaultValue()
Returns whether this transform has a default value.void
validate(PCollection<T> input)
Called before invoking apply (which may be intercepted by the runner) to verify this transform is fully specified and applicable to the specified input.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
getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, populateDisplayData, toString
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Method Detail
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hasDefaultValue
public boolean hasDefaultValue()
Returns whether this transform has a default value.
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defaultValue
public T defaultValue()
Returns the default value of this transform, or null if there isn't one.
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withDefaultValue
public View.AsSingleton<T> withDefaultValue(T defaultValue)
Default value to return for windows with no value in them.
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validate
public void validate(PCollection<T> input)
Description copied from class:PTransform
Called before invoking apply (which may be intercepted by the runner) to verify this transform is fully specified and applicable to the specified input.By default, does nothing.
- Overrides:
validate
in classPTransform<PCollection<T>,PCollectionView<T>>
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apply
public PCollectionView<T> apply(PCollection<T> input)
Description copied from class:PTransform
Applies thisPTransform
on the givenInputT
, and returns itsOutput
.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<InputT, OutputT>, InputT)
.- Overrides:
apply
in classPTransform<PCollection<T>,PCollectionView<T>>
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