Package org.apache.beam.sdk.transforms

Class Combine.BinaryCombineIntegerFn

java.lang.Object
org.apache.beam.sdk.transforms.Combine.CombineFn<Integer,int[],Integer>
org.apache.beam.sdk.transforms.Combine.BinaryCombineIntegerFn
All Implemented Interfaces:
Serializable, CombineFnBase.GlobalCombineFn<Integer,int[],Integer>, HasDisplayData
Enclosing class:
Combine
public abstract static class Combine.BinaryCombineIntegerFn extends Combine.CombineFn<Integer,int[],Integer>
An abstract subclass of Combine.CombineFn for implementing combiners that are more easily and efficiently expressed as binary operations on ints

It uses int[0] as the mutable accumulator.

See Also:

  • Constructor Details

    • BinaryCombineIntegerFn

      public BinaryCombineIntegerFn()

  • Method Details

    • apply

      public abstract int apply(int left, int right)
      Applies the binary operation to the two operands, returning the result.

    • identity

      public abstract int identity()
      Returns the identity element of this operation, i.e. an element e such that apply(e, x) == apply(x, e) == x for all values of x.

    • createAccumulator

      public int[] createAccumulator()
      Description copied from class: Combine.CombineFn
      Returns a new, mutable accumulator value, representing the accumulation of zero input values.
      Specified by:
      createAccumulator in class Combine.CombineFn<Integer,int[],Integer>

    • addInput

      public int[] addInput(int[] accumulator, Integer input)
      Description copied from class: Combine.CombineFn
      Adds the given input value to the given accumulator, returning the new accumulator value.
      Specified by:
      addInput in class Combine.CombineFn<Integer,int[],Integer>
      Parameters:
      accumulator - may be modified and returned for efficiency
      input - should not be mutated

    • mergeAccumulators

      public int[] mergeAccumulators(Iterable<int[]> accumulators)
      Description copied from class: Combine.CombineFn
      Returns an accumulator representing the accumulation of all the input values accumulated in the merging accumulators.
      Specified by:
      mergeAccumulators in class Combine.CombineFn<Integer,int[],Integer>
      Parameters:
      accumulators - only the first accumulator may be modified and returned for efficiency; the other accumulators should not be mutated, because they may be shared with other code and mutating them could lead to incorrect results or data corruption.

    • extractOutput

      public Integer extractOutput(int[] accumulator)
      Description copied from class: Combine.CombineFn
      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.CombineFn<Integer,int[],Integer>
      Parameters:
      accumulator - can be modified for efficiency

    • getAccumulatorCoder

      public Coder<int[]> getAccumulatorCoder(CoderRegistry registry, Coder<Integer> inputCoder)
      Description copied from interface: CombineFnBase.GlobalCombineFn
      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 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.GlobalCombineFn<Integer,int[],Integer>

    • getDefaultOutputCoder

      public Coder<Integer> getDefaultOutputCoder(CoderRegistry registry, Coder<Integer> inputCoder)
      Description copied from interface: CombineFnBase.GlobalCombineFn
      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 input InputT values and the enclosing Pipeline's CoderRegistry to try to infer the Coder for OutputT values.

      Specified by:
      getDefaultOutputCoder in interface CombineFnBase.GlobalCombineFn<Integer,int[],Integer>

    • getIncompatibleGlobalWindowErrorMessage

      public String getIncompatibleGlobalWindowErrorMessage()
      Description copied from interface: CombineFnBase.GlobalCombineFn
      Returns the error message for not supported default values in Combine.globally().
      Specified by:
      getIncompatibleGlobalWindowErrorMessage in interface CombineFnBase.GlobalCombineFn<InputT,AccumT,OutputT>

    • 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.

    • 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: