DirectPipelineRunner.TestCombineDoFn (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

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

Class DirectPipelineRunner.TestCombineDoFn<K,InputT,AccumT,OutputT>

• java.lang.Object
• • com.google.cloud.dataflow.sdk.transforms.DoFn<KV<K,Iterable<InputT>>,KV<K,OutputT>>
  • • com.google.cloud.dataflow.sdk.runners.DirectPipelineRunner.TestCombineDoFn<K,InputT,AccumT,OutputT>

• All Implemented Interfaces:

  HasDisplayData, Serializable

  Enclosing class:

  DirectPipelineRunner

  ---

  
  

  public static class DirectPipelineRunner.TestCombineDoFn<K,InputT,AccumT,OutputT>
  extends DoFn<KV<K,Iterable<InputT>>,KV<K,OutputT>>

  The implementation may split the Combine.KeyedCombineFn into ADD, MERGE and EXTRACT phases ( see com.google.cloud.dataflow.sdk.runners.worker.CombineValuesFn). In order to emulate this for the DirectPipelineRunner and provide an experience closer to the service, go through heavy serializability checks for the equivalent of the results of the ADD phase, but after the GroupByKey shuffle, and the MERGE phase. Doing these checks ensure that not only is the accumulator coder serializable, but the accumulator coder can actually serialize the data in question.

  See Also:

  Serialized Form

• • Nested Class Summary

    • Nested classes/interfaces inherited from class com.google.cloud.dataflow.sdk.transforms.DoFn

      DoFn.Context, DoFn.ProcessContext, DoFn.RequiresWindowAccess

  • Constructor Summary

    Constructors 

    Constructor and Description
    TestCombineDoFn(com.google.cloud.dataflow.sdk.util.PerKeyCombineFnRunner<? super K,? super InputT,AccumT,OutputT> fnRunner, Coder<AccumT> accumCoder, boolean testSerializability, Random rand)

  • Method Summary

    All Methods Static Methods Instance Methods Concrete Methods 

    Modifier and Type	Method and Description
    static <K,AccumT,InputT> List<AccumT>	addInputsRandomly(com.google.cloud.dataflow.sdk.util.PerKeyCombineFnRunner<? super K,? super InputT,AccumT,?> fnRunner, K key, Iterable<InputT> values, Random random, DoFn.ProcessContext c) Create a random list of accumulators from the given list of values.
    static <K,InputT,AccumT,OutputT> DirectPipelineRunner.TestCombineDoFn<K,InputT,AccumT,OutputT>	create(Combine.GroupedValues<K,InputT,OutputT> transform, PCollection<KV<K,Iterable<InputT>>> input, boolean testSerializability, Random rand)
    <T> T	ensureSerializableByCoder(Coder<T> coder, T value, String errorContext)
    void	processElement(DoFn.ProcessContext c) Processes one input element.

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

      createAggregator, createAggregator, finishBundle, getAllowedTimestampSkew, getInputTypeDescriptor, getOutputTypeDescriptor, populateDisplayData, startBundle

    • Methods inherited from class java.lang.Object

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

• • Constructor Detail

    • TestCombineDoFn

      public TestCombineDoFn(com.google.cloud.dataflow.sdk.util.PerKeyCombineFnRunner<? super K,? super InputT,AccumT,OutputT> fnRunner,
                             Coder<AccumT> accumCoder,
                             boolean testSerializability,
                             Random rand)

  • Method Detail

    • create

      public static <K,InputT,AccumT,OutputT> DirectPipelineRunner.TestCombineDoFn<K,InputT,AccumT,OutputT> create(Combine.GroupedValues<K,InputT,OutputT> transform,
                                                                                                                   PCollection<KV<K,Iterable<InputT>>> input,
                                                                                                                   boolean testSerializability,
                                                                                                                   Random rand)

    • processElement

      public void processElement(DoFn.ProcessContext c)
                          throws Exception

      Description copied from class: DoFn
      Processes one input element.

      The current element of the input PCollection is returned by c.element(). It should be considered immutable. The Dataflow runtime will not mutate the element, so it is safe to cache, etc. The element should not be mutated by any of the DoFn methods, because it may be cached elsewhere, retained by the Dataflow runtime, or used in other unspecified ways.

      A value is added to the main output PCollection by DoFn.Context.output(OutputT). Once passed to output the element should be considered immutable and not be modified in any way. It may be cached elsewhere, retained by the Dataflow runtime, or used in other unspecified ways.

      Specified by:

      processElement in class DoFn<KV<K,Iterable<InputT>>,KV<K,OutputT>>

      Throws:

      Exception

      See Also:

      DoFn.ProcessContext

    • addInputsRandomly

      public static <K,AccumT,InputT> List<AccumT> addInputsRandomly(com.google.cloud.dataflow.sdk.util.PerKeyCombineFnRunner<? super K,? super InputT,AccumT,?> fnRunner,
                                                                     K key,
                                                                     Iterable<InputT> values,
                                                                     Random random,
                                                                     DoFn.ProcessContext c)

      Create a random list of accumulators from the given list of values.

      Visible for testing purposes only.

    • ensureSerializableByCoder

      public <T> T ensureSerializableByCoder(Coder<T> coder,
                                             T value,
                                             String errorContext)