ForwardingPTransform (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

Warning: Cloud Dataflow SDK 1.x for Java is unsupported as of October 16, 2018. See Migrating from Cloud Dataflow SDK 1.x for Java for migration guidance.

Note: If you are using Cloud Dataflow SDK version 2.x, see the Apache Beam API reference documentation.

com.google.cloud.dataflow.sdk.runners.inprocess

Class ForwardingPTransform<InputT extends PInput,OutputT extends POutput>

• java.lang.Object
• • com.google.cloud.dataflow.sdk.transforms.PTransform<InputT,OutputT>
  • • com.google.cloud.dataflow.sdk.runners.inprocess.ForwardingPTransform<InputT,OutputT>

• All Implemented Interfaces:

  HasDisplayData, Serializable

  ---

  
  

  public abstract class ForwardingPTransform<InputT extends PInput,OutputT extends POutput>
  extends PTransform<InputT,OutputT>

  A base class for implementing PTransform overrides, which behave identically to the delegate transform but with overridden methods. Implementors are required to implement delegate(), which returns the object to forward calls to, and apply(PInput).

  See Also:

  Serialized Form

• • Field Summary

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

      name

  • Constructor Summary

    Constructors 

    Constructor and Description
    ForwardingPTransform()

  • Method Summary

    All Methods Instance Methods Abstract Methods Concrete Methods 

    Modifier and Type	Method and Description
    OutputT	apply(InputT input) Applies this PTransform on the given InputT, and returns its Output.
    protected abstract PTransform<InputT,OutputT>	delegate()
    <T> Coder<T>	getDefaultOutputCoder(InputT input, TypedPValue<T> output) Returns the default Coder to use for the given output of this single-output PTransform when applied to the given input.
    String	getName() Returns the transform name.
    void	populateDisplayData(DisplayData.Builder builder) Register display data for the given transform or component.
    void	validate(InputT 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.

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

      getDefaultOutputCoder, getDefaultOutputCoder, getKindString, toString

    • Methods inherited from class java.lang.Object

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

• • Constructor Detail

    • ForwardingPTransform

      public ForwardingPTransform()

  • Method Detail

    • delegate

      protected abstract PTransform<InputT,OutputT> delegate()

    • apply

      public OutputT apply(InputT 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<InputT extends PInput,OutputT extends POutput>

    • validate

      public void validate(InputT 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 class PTransform<InputT extends PInput,OutputT extends POutput>

    • getName

      public String getName()

      Description copied from class: PTransform
      Returns the transform name.

      This name is provided by the transform creator and is not required to be unique.

      Overrides:

      getName in class PTransform<InputT extends PInput,OutputT extends POutput>

    • getDefaultOutputCoder

      public <T> Coder<T> getDefaultOutputCoder(InputT input,
                                                TypedPValue<T> output)
                                         throws CannotProvideCoderException

      Description copied from class: PTransform
      Returns the default Coder to use for the given output of this single-output PTransform when applied to the given input.

      By default, always throws.

      Overrides:

      getDefaultOutputCoder in class PTransform<InputT extends PInput,OutputT extends POutput>

      Throws:

      CannotProvideCoderException - if none can be inferred.

    • populateDisplayData

      public void populateDisplayData(DisplayData.Builder builder)

      Description copied from class: PTransform
      Register display data for the given transform or component.

      populateDisplayData(DisplayData.Builder) is invoked by Pipeline runners to collect display data via DisplayData.from(HasDisplayData). Implementations may call super.populateDisplayData(builder) in order to register display data in the current namespace, but should otherwise use subcomponent.populateDisplayData(builder) to use the namespace of the subcomponent.

      By default, does not register any display data. Implementors may override this method to provide their own display data.

      Specified by:

      populateDisplayData in interface HasDisplayData

      Overrides:

      populateDisplayData in class PTransform<InputT extends PInput,OutputT extends POutput>

      Parameters:

      builder - The builder to populate with display data.

      See Also:

      HasDisplayData