Package org.apache.beam.sdk.extensions.sketching

Class SketchFrequencies.CountMinSketchFn<InputT>

java.lang.Object

org.apache.beam.sdk.transforms.Combine.CombineFn<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

org.apache.beam.sdk.extensions.sketching.SketchFrequencies.CountMinSketchFn<InputT>

Type Parameters:

InputT - the type of the elements in the input PCollection

All Implemented Interfaces:

Serializable, CombineFnBase.GlobalCombineFn<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>, HasDisplayData

Enclosing class:

SketchFrequencies

public static class SketchFrequencies.CountMinSketchFn<InputT>
extends Combine.CombineFn<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

Implements the Combine.CombineFn of SketchFrequencies transforms.

See Also:

• Serialized Form

Method Summary

Modifier and Type	Method	Description
SketchFrequencies.Sketch<InputT>	addInput(SketchFrequencies.Sketch<InputT> accumulator, InputT element)	Adds the given input value to the given accumulator, returning the new accumulator value.
static <InputT> SketchFrequencies.CountMinSketchFn<InputT>	create(Coder<InputT> coder)	Returns a SketchFrequencies.CountMinSketchFn combiner with the given input coder.
SketchFrequencies.Sketch<InputT>	createAccumulator()	Returns a new, mutable accumulator value, representing the accumulation of zero input values.
SketchFrequencies.Sketch<InputT>	extractOutput(SketchFrequencies.Sketch<InputT> accumulator)	Output the whole structure so it can be queried, reused or stored easily.
TypeVariable<?>	getAccumTVariable()	Returns the TypeVariable of AccumT.
Coder<SketchFrequencies.Sketch<InputT>>	getAccumulatorCoder(CoderRegistry registry, Coder inputCoder)	Returns the Coder to use for accumulator AccumT values, or null if it is not able to be inferred.
Coder<SketchFrequencies.Sketch<InputT>>	getDefaultOutputCoder(CoderRegistry registry, Coder<InputT> inputCoder)	Returns the Coder to use by default for output OutputT values, or null if it is not able to be inferred.
String	getIncompatibleGlobalWindowErrorMessage()	Returns the error message for not supported default values in Combine.globally().
TypeVariable<?>	getInputTVariable()	Returns the TypeVariable of InputT.
TypeVariable<?>	getOutputTVariable()	Returns the TypeVariable of OutputT.
SketchFrequencies.Sketch<InputT>	mergeAccumulators(Iterable<SketchFrequencies.Sketch<InputT>> 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.
SketchFrequencies.CountMinSketchFn<InputT>	withAccuracy(double epsilon, double confidence)	Returns a new SketchFrequencies.CountMinSketchFn combiner with new precision accuracy parameters epsilon and confidence.

Methods inherited from class org.apache.beam.sdk.transforms.Combine.CombineFn

apply, compact, defaultValue, getInputType, getOutputType

Methods inherited from class java.lang.Object

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

Method Details

create

public static <InputT>
SketchFrequencies.CountMinSketchFn<InputT> create(Coder<InputT> coder)

Returns a SketchFrequencies.CountMinSketchFn combiner with the given input coder.
Warning : the coder must be deterministic.

Parameters:

coder - the coder that encodes the elements' type

withAccuracy

public SketchFrequencies.CountMinSketchFn<InputT> withAccuracy(double epsilon,
 double confidence)

Returns a new SketchFrequencies.CountMinSketchFn combiner with new precision accuracy parameters epsilon and confidence.

Keep in mind that the lower the epsilon value, the greater the width, and the greater the confidence, the greater the depth.

Parameters:

epsilon - the error relative to the total number of distinct elements

confidence - the confidence in the result to not exceed the relative error

createAccumulator

public SketchFrequencies.Sketch<InputT> 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<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

addInput

public SketchFrequencies.Sketch<InputT> addInput(SketchFrequencies.Sketch<InputT> accumulator,
 InputT element)

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<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

Parameters:

accumulator - may be modified and returned for efficiency

element - should not be mutated

mergeAccumulators

public SketchFrequencies.Sketch<InputT> mergeAccumulators(Iterable<SketchFrequencies.Sketch<InputT>> 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<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

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 SketchFrequencies.Sketch<InputT> extractOutput(SketchFrequencies.Sketch<InputT> accumulator)

Output the whole structure so it can be queried, reused or stored easily.

Specified by:

extractOutput in class Combine.CombineFn<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

Parameters:

accumulator - can be modified for efficiency

getAccumulatorCoder

public Coder<SketchFrequencies.Sketch<InputT>> getAccumulatorCoder(CoderRegistry registry,
 Coder 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<InputT,SketchFrequencies.Sketch<InputT>,SketchFrequencies.Sketch<InputT>>

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<SketchFrequencies.Sketch<InputT>> getDefaultOutputCoder(CoderRegistry registry,
 Coder<InputT> inputCoder)
                                                              throws CannotProvideCoderException

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<InputT,AccumT,OutputT>

Throws:

CannotProvideCoderException

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.