org.apache.beam.sdk.transforms

Class SimpleFunction<InputT,OutputT>

java.lang.Object

org.apache.beam.sdk.transforms.SimpleFunction<InputT,OutputT>

All Implemented Interfaces:

java.io.Serializable, HasDisplayData, SerializableFunction<InputT,OutputT>

Direct Known Subclasses:

BeamJoinTransforms.ExtractJoinFields, BeamJoinTransforms.JoinParts2WholeRow, BeamSetOperatorsTransforms.BeamSqlRow2KvFn

public abstract class SimpleFunction<InputT,OutputT>
extends java.lang.Object
implements SerializableFunction<InputT,OutputT>, HasDisplayData

A SerializableFunction which is not a functional interface. Concrete subclasses allow us to infer type information, which in turn aids Coder inference.

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SimpleFunction()
protected	SimpleFunction(SerializableFunction<InputT,OutputT> fn)

Method Summary

Modifier and Type	Method and Description
OutputT	apply(InputT input) Returns the result of invoking this function on the given input.
static <InputT,OutputT> SimpleFunction<InputT,OutputT>	fromSerializableFunctionWithOutputType(SerializableFunction<InputT,OutputT> fn, TypeDescriptor<OutputT> outputType)
TypeDescriptor<InputT>	getInputTypeDescriptor() Returns a TypeDescriptor capturing what is known statically about the input type of this SimpleFunction instance's most-derived class.
TypeDescriptor<OutputT>	getOutputTypeDescriptor() Returns a TypeDescriptor capturing what is known statically about the output type of this SimpleFunction instance's most-derived class.
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

SimpleFunction

protected SimpleFunction()

SimpleFunction

protected SimpleFunction(SerializableFunction<InputT,OutputT> fn)

Method Detail

apply

public OutputT apply(InputT input)

Description copied from interface: SerializableFunction

Returns the result of invoking this function on the given input.

Specified by:

apply in interface SerializableFunction<InputT,OutputT>

fromSerializableFunctionWithOutputType

public static <InputT,OutputT> SimpleFunction<InputT,OutputT> fromSerializableFunctionWithOutputType(SerializableFunction<InputT,OutputT> fn,
                                                                                                     TypeDescriptor<OutputT> outputType)

getInputTypeDescriptor

public TypeDescriptor<InputT> getInputTypeDescriptor()

Returns a TypeDescriptor capturing what is known statically about the input type of this SimpleFunction instance's most-derived class.

See getOutputTypeDescriptor() for more discussion.

getOutputTypeDescriptor

public TypeDescriptor<OutputT> getOutputTypeDescriptor()

Returns a TypeDescriptor capturing what is known statically about the output type of this SimpleFunction instance's most-derived class.

In the normal case of a concrete SimpleFunction subclass with no generic type parameters of its own (including anonymous inner classes), this will be a complete non-generic type, which is good for choosing a default output Coder<OutputT> for the output PCollection<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