CombineFns.ComposedKeyedCombineFn (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. After August 12, 2020, you can use unsupported SDKs temporarily while you upgrade your pipelines. For more information, see Using an unsupported SDK.

For information on migrating from the 1.x SDK, see Migrating from Dataflow SDK 1.x for Java.

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com.google.cloud.dataflow.sdk.transforms

Class CombineFns.ComposedKeyedCombineFn<DataT,K>

• java.lang.Object
• • com.google.cloud.dataflow.sdk.transforms.Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>
  • • com.google.cloud.dataflow.sdk.transforms.CombineFns.ComposedKeyedCombineFn<DataT,K>

• All Implemented Interfaces:

  CombineFnBase.PerKeyCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>, HasDisplayData, Serializable

  Enclosing class:

  CombineFns

  ---

  
  

  public static class CombineFns.ComposedKeyedCombineFn<DataT,K>
  extends Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

  A composed Combine.KeyedCombineFn that applies multiple KeyedCombineFns.

  For each Combine.KeyedCombineFn it extracts inputs from DataT with the extractInputFn and combines them, and then it outputs each combined value with a TupleTag to a CombineFns.CoCombineResult.

  See Also:

  Serialized Form

• • Method Summary

    All Methods Instance Methods Concrete Methods 

    Modifier and Type	Method and Description
    Object[]	addInput(K key, Object[] accumulator, DataT value) Adds the given input value to the given accumulator, returning the new accumulator value.
    Object[]	compact(K key, Object[] accumulator) Returns an accumulator that represents the same logical value as the input accumulator, but may have a more compact representation.
    Object[]	createAccumulator(K key) Returns a new, mutable accumulator value representing the accumulation of zero input values.
    CombineFns.CoCombineResult	extractOutput(K key, Object[] accumulator) Returns the output value that is the result of combining all the input values represented by the given accumulator.
    TypeVariable<?>	getAccumTVariable() Returns the TypeVariable of AccumT.
    Coder<Object[]>	getAccumulatorCoder(CoderRegistry registry, Coder<K> keyCoder, Coder<DataT> dataCoder) Returns the Coder to use for accumulator AccumT values, or null if it is not able to be inferred.
    Coder<OutputT>	getDefaultOutputCoder(CoderRegistry registry, Coder<K> keyCoder, Coder<InputT> inputCoder) Returns the Coder to use by default for output OutputT values, or null if it is not able to be inferred.
    TypeVariable<?>	getInputTVariable() Returns the TypeVariable of InputT.
    TypeVariable<?>	getKTypeVariable() Returns the TypeVariable of K.
    TypeVariable<?>	getOutputTVariable() Returns the TypeVariable of OutputT.
    Object[]	mergeAccumulators(K key, Iterable<Object[]> accumulators) Returns an accumulator representing the accumulation of all the input values accumulated in the merging accumulators.
    void	populateDisplayData(DisplayData.Builder builder) Register display data for the given transform or component.
    <InputT,OutputT> CombineFns.ComposedKeyedCombineFn<DataT,K>	with(SimpleFunction<DataT,InputT> extractInputFn, Combine.CombineFn<InputT,?,OutputT> keyedCombineFn, TupleTag<OutputT> outputTag) Returns a CombineFns.ComposedKeyedCombineFn with an additional Combine.CombineFn.
    <InputT,OutputT> CombineFns.ComposedKeyedCombineFn<DataT,K>	with(SimpleFunction<DataT,InputT> extractInputFn, Combine.KeyedCombineFn<K,InputT,?,OutputT> keyedCombineFn, TupleTag<OutputT> outputTag) Returns a CombineFns.ComposedKeyedCombineFn with an additional Combine.KeyedCombineFn.
    <InputT,OutputT> CombineFns.ComposedKeyedCombineFnWithContext<DataT,K>	with(SimpleFunction<DataT,InputT> extractInputFn, CombineWithContext.CombineFnWithContext<InputT,?,OutputT> keyedCombineFn, TupleTag<OutputT> outputTag) Returns a CombineFns.ComposedKeyedCombineFnWithContext with an additional CombineWithContext.CombineFnWithContext.
    <InputT,OutputT> CombineFns.ComposedKeyedCombineFnWithContext<DataT,K>	with(SimpleFunction<DataT,InputT> extractInputFn, CombineWithContext.KeyedCombineFnWithContext<K,InputT,?,OutputT> keyedCombineFn, TupleTag<OutputT> outputTag) Returns a CombineFns.ComposedKeyedCombineFnWithContext with an additional CombineWithContext.KeyedCombineFnWithContext.

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

      apply, forKey

    • Methods inherited from class java.lang.Object

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

• • Method Detail

    • with

      public <InputT,OutputT> CombineFns.ComposedKeyedCombineFn<DataT,K> with(SimpleFunction<DataT,InputT> extractInputFn,
                                                                              Combine.KeyedCombineFn<K,InputT,?,OutputT> keyedCombineFn,
                                                                              TupleTag<OutputT> outputTag)

      Returns a CombineFns.ComposedKeyedCombineFn with an additional Combine.KeyedCombineFn.

    • with

      public <InputT,OutputT> CombineFns.ComposedKeyedCombineFnWithContext<DataT,K> with(SimpleFunction<DataT,InputT> extractInputFn,
                                                                                         CombineWithContext.KeyedCombineFnWithContext<K,InputT,?,OutputT> keyedCombineFn,
                                                                                         TupleTag<OutputT> outputTag)

      Returns a CombineFns.ComposedKeyedCombineFnWithContext with an additional CombineWithContext.KeyedCombineFnWithContext.

    • with

      public <InputT,OutputT> CombineFns.ComposedKeyedCombineFn<DataT,K> with(SimpleFunction<DataT,InputT> extractInputFn,
                                                                              Combine.CombineFn<InputT,?,OutputT> keyedCombineFn,
                                                                              TupleTag<OutputT> outputTag)

      Returns a CombineFns.ComposedKeyedCombineFn with an additional Combine.CombineFn.

    • with

      public <InputT,OutputT> CombineFns.ComposedKeyedCombineFnWithContext<DataT,K> with(SimpleFunction<DataT,InputT> extractInputFn,
                                                                                         CombineWithContext.CombineFnWithContext<InputT,?,OutputT> keyedCombineFn,
                                                                                         TupleTag<OutputT> outputTag)

      Returns a CombineFns.ComposedKeyedCombineFnWithContext with an additional CombineWithContext.CombineFnWithContext.

    • createAccumulator

      public Object[] createAccumulator(K key)

      Description copied from class: Combine.KeyedCombineFn
      Returns a new, mutable accumulator value representing the accumulation of zero input values.

      Specified by:

      createAccumulator in class Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

      Parameters:

      key - the key that all the accumulated values using the accumulator are associated with

    • addInput

      public Object[] addInput(K key,
                               Object[] accumulator,
                               DataT value)

      Description copied from class: Combine.KeyedCombineFn
      Adds the given input value to the given accumulator, returning the new accumulator value.

      For efficiency, the input accumulator may be modified and returned.

      Specified by:

      addInput in class Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

      Parameters:

      key - the key that all the accumulated values using the accumulator are associated with

    • mergeAccumulators

      public Object[] mergeAccumulators(K key,
                                        Iterable<Object[]> accumulators)

      Description copied from class: Combine.KeyedCombineFn
      Returns an accumulator representing the accumulation of all the input values accumulated in the merging accumulators.

      May modify any of the argument accumulators. May return a fresh accumulator, or may return one of the (modified) argument accumulators.

      Specified by:

      mergeAccumulators in class Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

      Parameters:

      key - the key that all the accumulators are associated with

    • extractOutput

      public CombineFns.CoCombineResult extractOutput(K key,
                                                      Object[] accumulator)

      Description copied from class: Combine.KeyedCombineFn
      Returns the output value that is the result of combining all the input values represented by the given accumulator.

      Specified by:

      extractOutput in class Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

      Parameters:

      key - the key that all the accumulated values using the accumulator are associated with

    • compact

      public Object[] compact(K key,
                              Object[] accumulator)

      Description copied from class: Combine.KeyedCombineFn
      Returns an accumulator that represents the same logical value as the input accumulator, but may have a more compact representation.

      For most CombineFns this would be a no-op, but should be overridden by CombineFns that (for example) buffer up elements and combine them in batches.

      For efficiency, the input accumulator may be modified and returned.

      By default returns the original accumulator.

      Overrides:

      compact in class Combine.KeyedCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

    • getAccumulatorCoder

      public Coder<Object[]> getAccumulatorCoder(CoderRegistry registry,
                                                 Coder<K> keyCoder,
                                                 Coder<DataT> dataCoder)
                                          throws CannotProvideCoderException

      Description copied from interface: CombineFnBase.PerKeyCombineFn
      Returns the Coder to use for accumulator AccumT values, or null if it is not able to be inferred.

      By default, uses the knowledge of the Coder being used for K keys and input InputT values and the enclosing Pipeline's CoderRegistry to try to infer the Coder for AccumT values.

      This is the Coder used to send data through a communication-intensive shuffle step, so a compact and efficient representation may have significant performance benefits.

      Specified by:

      getAccumulatorCoder in interface CombineFnBase.PerKeyCombineFn<K,DataT,Object[],CombineFns.CoCombineResult>

      Throws:

      CannotProvideCoderException

    • populateDisplayData

      public void populateDisplayData(DisplayData.Builder builder)

      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

      Parameters:

      builder - The builder to populate with display data.

      See Also:

      HasDisplayData

    • getDefaultOutputCoder

      public Coder<OutputT> getDefaultOutputCoder(CoderRegistry registry,
                                                  Coder<K> keyCoder,
                                                  Coder<InputT> inputCoder)
                                           throws CannotProvideCoderException

      Description copied from interface: CombineFnBase.PerKeyCombineFn
      Returns the Coder to use by default for output OutputT values, or null if it is not able to be inferred.

      By default, uses the knowledge of the Coder being used for K keys and input InputT values and the enclosing Pipeline's CoderRegistry to try to infer the Coder for OutputT values.

      Specified by:

      getDefaultOutputCoder in interface CombineFnBase.PerKeyCombineFn<K,InputT,AccumT,OutputT>

      Throws:

      CannotProvideCoderException

    • getKTypeVariable

      public TypeVariable<?> getKTypeVariable()

      Returns the TypeVariable of K.

    • getInputTVariable

      public TypeVariable<?> getInputTVariable()

      Returns the TypeVariable of InputT.

    • getAccumTVariable

      public TypeVariable<?> getAccumTVariable()

      Returns the TypeVariable of AccumT.

    • getOutputTVariable

      public TypeVariable<?> getOutputTVariable()

      Returns the TypeVariable of OutputT.