Package org.apache.beam.sdk.schemas.transforms

Class Group.AggregateCombiner<InputT>

java.lang.Object

org.apache.beam.sdk.transforms.PTransform<PCollection<InputT>,PCollection<Row>>

org.apache.beam.sdk.schemas.transforms.Group.AggregateCombiner<InputT>

Type Parameters:

InputT -

All Implemented Interfaces:

Serializable, HasDisplayData

Direct Known Subclasses:

Group.ByFields, Group.CombineFieldsByFields, Group.CombineFieldsGlobally

Enclosing class:

Group

public abstract static class Group.AggregateCombiner<InputT>
extends PTransform<PCollection<InputT>,PCollection<Row>>

a PTransform that does a combine using an aggregation built up by calls to aggregateField and aggregateFields. The output of this transform will have a schema that is determined by the output types of all the composed combiners.

See Also:

• Serialized Form

Field Summary

Fields inherited from class org.apache.beam.sdk.transforms.PTransform

annotations, displayData, name, resourceHints

Constructor Summary

Constructors

Constructor	Description
AggregateCombiner()

Method Summary

Modifier and Type	Method	Description
abstract <CombineInputT, AccumT, CombineOutputT> Group.AggregateCombiner<InputT>	aggregateField(int inputFieldId, Combine.CombineFn<CombineInputT,AccumT,CombineOutputT> fn, Schema.Field outputField)	Build up an aggregation function over the input elements.
abstract <CombineInputT, AccumT, CombineOutputT> Group.AggregateCombiner<InputT>	aggregateField(String inputFieldName, Combine.CombineFn<CombineInputT,AccumT,CombineOutputT> fn, Schema.Field outputField)	Build up an aggregation function over the input elements.
abstract <CombineInputT, AccumT, CombineOutputT> Group.AggregateCombiner<InputT>	aggregateFieldsById(List<Integer> inputFieldIds, Combine.CombineFn<CombineInputT,AccumT,CombineOutputT> fn, Schema.Field outputField)	Build up an aggregation function over the input elements by field id.

Methods inherited from class org.apache.beam.sdk.transforms.PTransform

addAnnotation, compose, compose, expand, getAdditionalInputs, getAnnotations, getDefaultOutputCoder, getDefaultOutputCoder, getDefaultOutputCoder, getKindString, getName, getResourceHints, populateDisplayData, setDisplayData, setResourceHints, toString, validate, validate

Methods inherited from class java.lang.Object

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

Constructor Details

AggregateCombiner

public AggregateCombiner()

Method Details

aggregateField

public abstract <CombineInputT,
AccumT,
CombineOutputT>
Group.AggregateCombiner<InputT> aggregateField(int inputFieldId,
 Combine.CombineFn<CombineInputT,AccumT,CombineOutputT> fn,
 Schema.Field outputField)

Build up an aggregation function over the input elements.

This method specifies an aggregation over single field of the input. The union of all calls to aggregateField and aggregateFields will determine the output schema.

aggregateField

public abstract <CombineInputT,
AccumT,
CombineOutputT>
Group.AggregateCombiner<InputT> aggregateField(String inputFieldName,
 Combine.CombineFn<CombineInputT,AccumT,CombineOutputT> fn,
 Schema.Field outputField)

Build up an aggregation function over the input elements.

This method specifies an aggregation over single field of the input. The union of all calls to aggregateField and aggregateFields will determine the output schema.

aggregateFieldsById

public abstract <CombineInputT,
AccumT,
CombineOutputT>
Group.AggregateCombiner<InputT> aggregateFieldsById(List<Integer> inputFieldIds,
 Combine.CombineFn<CombineInputT,AccumT,CombineOutputT> fn,
 Schema.Field outputField)

Build up an aggregation function over the input elements by field id.

This method specifies an aggregation over multiple fields of the input. The union of all calls to aggregateField and aggregateFields will determine the output schema.

Field types in the output schema will be inferred from the provided combine function. Sometimes the field type cannot be inferred due to Java's type erasure. In that case, use the overload that allows setting the output field type explicitly.