com.google.cloud.dataflow.sdk.transforms

Class Count.Globally<T>

java.lang.Object

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

com.google.cloud.dataflow.sdk.transforms.Count.Globally<T>

Type Parameters:

T - the type of the elements of the input PCollection

All Implemented Interfaces:

Serializable

Enclosing class:

Count

public static class Count.Globally<T>
extends PTransform<PCollection<T>,PCollection<Long>>

Count.Globally<T> takes a PCollection<T> and returns a PCollection<Long> containing a single element that is the total number of elements in the PCollection.

Example of use:

 
 PCollection<String> words = ...;
 PCollection<Long> wordCount =
     words.apply(Count.<String>globally());
  

See Also:

Serialized Form

Field Summary

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

name

Constructor Summary

Constructors

Constructor and Description
Globally()

Method Summary

Modifier and Type	Method and Description
PCollection<Long>	apply(PCollection<T> input) Applies this PTransform on the given InputT, and returns its Output.
Count.Globally<T>	withHotKeyFanout(int fanout) Returns a PTransform identical to Globally(), but that uses an intermedate combining node to improve performance.
Count.Globally<T>	withoutDefaults() Returns a PTransform identical to Globally(), but that does not attempt to provide a default value in the case of empty input.

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

getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, toString, validate

Methods inherited from class java.lang.Object

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

Constructor Detail

Globally

public Globally()

Method Detail

withoutDefaults

public Count.Globally<T> withoutDefaults()

Returns a PTransform identical to Globally(), but that does not attempt to provide a default value in the case of empty input.

withHotKeyFanout

public Count.Globally<T> withHotKeyFanout(int fanout)

Returns a PTransform identical to Globally(), but that uses an intermedate combining node to improve performance. See Combine.Globally.withFanout(int).

apply

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

Description copied from class: PTransform

Applies this PTransform on the given InputT, 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<InputT, OutputT>, InputT).

Overrides:

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