Class Combine.BinaryCombineDoubleFn
- java.lang.Object
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- org.apache.beam.sdk.transforms.Combine.CombineFn<java.lang.Double,double[],java.lang.Double>
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- org.apache.beam.sdk.transforms.Combine.BinaryCombineDoubleFn
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- All Implemented Interfaces:
java.io.Serializable
,CombineFnBase.GlobalCombineFn<java.lang.Double,double[],java.lang.Double>
,HasDisplayData
- Enclosing class:
- Combine
public abstract static class Combine.BinaryCombineDoubleFn extends Combine.CombineFn<java.lang.Double,double[],java.lang.Double>
An abstract subclass ofCombine.CombineFn
for implementing combiners that are more easily and efficiently expressed as binary operations ondouble
s.It uses
double[0]
as the mutable accumulator.- See Also:
- Serialized Form
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Constructor Summary
Constructors Constructor Description BinaryCombineDoubleFn()
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description double[]
addInput(double[] accumulator, java.lang.Double input)
Adds the given input value to the given accumulator, returning the new accumulator value.abstract double
apply(double left, double right)
Applies the binary operation to the two operands, returning the result.double[]
createAccumulator()
Returns a new, mutable accumulator value, representing the accumulation of zero input values.java.lang.Double
extractOutput(double[] 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 theTypeVariable
ofAccumT
.Coder<double[]>
getAccumulatorCoder(CoderRegistry registry, Coder<java.lang.Double> inputCoder)
Returns theCoder
to use for accumulatorAccumT
values, or null if it is not able to be inferred.Coder<java.lang.Double>
getDefaultOutputCoder(CoderRegistry registry, Coder<java.lang.Double> inputCoder)
Returns theCoder
to use by default for outputOutputT
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 theTypeVariable
ofInputT
.java.lang.reflect.TypeVariable<?>
getOutputTVariable()
Returns theTypeVariable
ofOutputT
.abstract double
identity()
Returns the identity element of this operation, i.e.double[]
mergeAccumulators(java.lang.Iterable<double[]> 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 org.apache.beam.sdk.transforms.Combine.CombineFn
apply, compact, defaultValue, getInputType, getOutputType
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Method Detail
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apply
public abstract double apply(double left, double right)
Applies the binary operation to the two operands, returning the result.
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identity
public abstract double identity()
Returns the identity element of this operation, i.e. an elemente
such thatapply(e, x) == apply(x, e) == x
for all values ofx
.
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createAccumulator
public double[] createAccumulator()
Description copied from class:Combine.CombineFn
Returns a new, mutable accumulator value, representing the accumulation of zero input values.- Specified by:
createAccumulator
in classCombine.CombineFn<java.lang.Double,double[],java.lang.Double>
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addInput
public double[] addInput(double[] accumulator, java.lang.Double 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 classCombine.CombineFn<java.lang.Double,double[],java.lang.Double>
- Parameters:
accumulator
- may be modified and returned for efficiencyinput
- should not be mutated
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mergeAccumulators
public double[] mergeAccumulators(java.lang.Iterable<double[]> 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 classCombine.CombineFn<java.lang.Double,double[],java.lang.Double>
- 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.
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extractOutput
public java.lang.Double extractOutput(double[] 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 classCombine.CombineFn<java.lang.Double,double[],java.lang.Double>
- Parameters:
accumulator
- can be modified for efficiency
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getAccumulatorCoder
public Coder<double[]> getAccumulatorCoder(CoderRegistry registry, Coder<java.lang.Double> inputCoder)
Description copied from interface:CombineFnBase.GlobalCombineFn
Returns theCoder
to use for accumulatorAccumT
values, or null if it is not able to be inferred.By default, uses the knowledge of the
Coder
being used forInputT
values and the enclosingPipeline
'sCoderRegistry
to try to infer the Coder forAccumT
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 interfaceCombineFnBase.GlobalCombineFn<java.lang.Double,double[],java.lang.Double>
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getDefaultOutputCoder
public Coder<java.lang.Double> getDefaultOutputCoder(CoderRegistry registry, Coder<java.lang.Double> inputCoder)
Description copied from interface:CombineFnBase.GlobalCombineFn
Returns theCoder
to use by default for outputOutputT
values, or null if it is not able to be inferred.By default, uses the knowledge of the
Coder
being used for inputInputT
values and the enclosingPipeline
'sCoderRegistry
to try to infer the Coder forOutputT
values.- Specified by:
getDefaultOutputCoder
in interfaceCombineFnBase.GlobalCombineFn<java.lang.Double,double[],java.lang.Double>
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getIncompatibleGlobalWindowErrorMessage
public java.lang.String getIncompatibleGlobalWindowErrorMessage()
Description copied from interface:CombineFnBase.GlobalCombineFn
Returns the error message for not supported default values in Combine.globally().- Specified by:
getIncompatibleGlobalWindowErrorMessage
in interfaceCombineFnBase.GlobalCombineFn<InputT,AccumT,OutputT>
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getInputTVariable
public java.lang.reflect.TypeVariable<?> getInputTVariable()
Returns theTypeVariable
ofInputT
.
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getAccumTVariable
public java.lang.reflect.TypeVariable<?> getAccumTVariable()
Returns theTypeVariable
ofAccumT
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getOutputTVariable
public java.lang.reflect.TypeVariable<?> getOutputTVariable()
Returns theTypeVariable
ofOutputT
.
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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 viaDisplayData.from(HasDisplayData)
. Implementations may callsuper.populateDisplayData(builder)
in order to register display data in the current namespace, but should otherwise usesubcomponent.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 interfaceHasDisplayData
- Parameters:
builder
- The builder to populate with display data.- See Also:
HasDisplayData
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