Package org.apache.beam.sdk.transforms

Class Combine.BinaryCombineLongFn

  • All Implemented Interfaces:
    java.io.Serializable, CombineFnBase.GlobalCombineFn<java.lang.Long,​long[],​java.lang.Long>, HasDisplayData
    Enclosing class:
    Combine
    public abstract static class Combine.BinaryCombineLongFn
extends Combine.CombineFn<java.lang.Long,​long[],​java.lang.Long>
    An abstract subclass of Combine.CombineFn for implementing combiners that are more easily and efficiently expressed as binary operations on longs.

    It uses long[0] as the mutable accumulator.

    See Also:
    Serialized Form

    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      long[] addInput​(long[] accumulator, java.lang.Long input)
      Adds the given input value to the given accumulator, returning the new accumulator value.
      abstract long apply​(long left, long right)
      Applies the binary operation to the two operands, returning the result.
      long[] createAccumulator()
      Returns a new, mutable accumulator value, representing the accumulation of zero input values.
      java.lang.Long extractOutput​(long[] accumulator)
      Returns the output value that is the result of combining all the input values represented by the given accumulator.
      java.lang.reflect.TypeVariable<?> getAccumTVariable()
      Returns the TypeVariable of AccumT.
      Coder<long[]> getAccumulatorCoder​(CoderRegistry registry, Coder<java.lang.Long> inputCoder)
      Returns the Coder to use for accumulator AccumT values, or null if it is not able to be inferred.
      Coder<java.lang.Long> getDefaultOutputCoder​(CoderRegistry registry, Coder<java.lang.Long> inputCoder)
      Returns the Coder to use by default for output OutputT values, or null if it is not able to be inferred.
      java.lang.String getIncompatibleGlobalWindowErrorMessage()
      Returns the error message for not supported default values in Combine.globally().
      java.lang.reflect.TypeVariable<?> getInputTVariable()
      Returns the TypeVariable of InputT.
      java.lang.reflect.TypeVariable<?> getOutputTVariable()
      Returns the TypeVariable of OutputT.
      abstract long identity()
      Returns the identity element of this operation, i.e.
      long[] mergeAccumulators​(java.lang.Iterable<long[]> 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.

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • BinaryCombineLongFn

        public BinaryCombineLongFn()

    • Method Detail

      • apply

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

      • identity

        public abstract long 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 long[] 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<java.lang.Long,​long[],​java.lang.Long>

      • addInput

        public long[] addInput​(long[] accumulator,
                       java.lang.Long 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<java.lang.Long,​long[],​java.lang.Long>
        Parameters:
        accumulator - may be modified and returned for efficiency
        input - should not be mutated

      • mergeAccumulators

        public long[] mergeAccumulators​(java.lang.Iterable<long[]> 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<java.lang.Long,​long[],​java.lang.Long>
        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 java.lang.Long extractOutput​(long[] 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<java.lang.Long,​long[],​java.lang.Long>
        Parameters:
        accumulator - can be modified for efficiency

      • getAccumulatorCoder

        public Coder<long[]> getAccumulatorCoder​(CoderRegistry registry,
                                         Coder<java.lang.Long> 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<java.lang.Long,​long[],​java.lang.Long>

      • getDefaultOutputCoder

        public Coder<java.lang.Long> getDefaultOutputCoder​(CoderRegistry registry,
                                                   Coder<java.lang.Long> 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<java.lang.Long,​long[],​java.lang.Long>

      • getInputTVariable

        public java.lang.reflect.TypeVariable<?> getInputTVariable()
        Returns the TypeVariable of InputT.

      • getAccumTVariable

        public java.lang.reflect.TypeVariable<?> getAccumTVariable()
        Returns the TypeVariable of AccumT.

      • getOutputTVariable

        public java.lang.reflect.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:
        HasDisplayData