Package org.apache.flink.table.runtime.functions.aggregate

Class BuiltInAggregateFunction<T,ACC>

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunction

org.apache.flink.table.functions.ImperativeAggregateFunction<T,ACC>

org.apache.flink.table.functions.AggregateFunction<T,ACC>

org.apache.flink.table.runtime.functions.aggregate.BuiltInAggregateFunction<T,ACC>

All Implemented Interfaces:

Serializable, org.apache.flink.table.functions.FunctionDefinition

Direct Known Subclasses:

BatchApproxCountDistinctAggFunctions.ApproxCountDistinctAggFunction, CollectAggFunction, FirstValueAggFunction, FirstValueWithRetractAggFunction, JsonArrayAggFunction, JsonObjectAggFunction, LagAggFunction, LastValueAggFunction, LastValueWithRetractAggFunction, ListAggWithRetractAggFunction, ListAggWsWithRetractAggFunction, MaxWithRetractAggFunction, MinWithRetractAggFunction

@Internal
public abstract class BuiltInAggregateFunction<T,ACC>
extends org.apache.flink.table.functions.AggregateFunction<T,ACC>

Base class for runtime implementation represented as AggregateFunction that is constructed from BuiltInFunctionDefinition.specialize(SpecializedContext).

Subclasses must offer a constructor that takes SpecializedFunction.SpecializedContext if they are constructed from a BuiltInFunctionDefinition. Otherwise the BuiltInAggregateFunction() constructor might be more appropriate.

By default, all built-in functions work on internal data structures. However, this can be changed by overriding getArgumentDataTypes(), getAccumulatorDataType(), and getOutputDataType(). Or by overriding getTypeInference(DataTypeFactory) directly.

Since the accumulator type is runtime specific, it must be declared explicitly; otherwise it is derived from the output type.

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BuiltInAggregateFunction()
protected	BuiltInAggregateFunction(org.apache.flink.table.functions.BuiltInFunctionDefinition definition, org.apache.flink.table.functions.SpecializedFunction.SpecializedContext context)

Method Summary

Modifier and Type	Method	Description
org.apache.flink.table.types.DataType	getAccumulatorDataType()
List<org.apache.flink.table.types.DataType>	getArgumentDataTypes()
org.apache.flink.table.types.DataType	getOutputDataType()
Set<org.apache.flink.table.functions.FunctionRequirement>	getRequirements()
org.apache.flink.table.types.inference.TypeInference	getTypeInference(org.apache.flink.table.catalog.DataTypeFactory typeFactory)
boolean	isDeterministic()

Methods inherited from class org.apache.flink.table.functions.AggregateFunction

getKind, getValue

Methods inherited from class org.apache.flink.table.functions.ImperativeAggregateFunction

createAccumulator, getAccumulatorType, getResultType

Methods inherited from class org.apache.flink.table.functions.UserDefinedFunction

close, functionIdentifier, open, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

BuiltInAggregateFunction

protected BuiltInAggregateFunction(org.apache.flink.table.functions.BuiltInFunctionDefinition definition,
                                   org.apache.flink.table.functions.SpecializedFunction.SpecializedContext context)

BuiltInAggregateFunction

protected BuiltInAggregateFunction()

Method Detail

getArgumentDataTypes

public List<org.apache.flink.table.types.DataType> getArgumentDataTypes()

getAccumulatorDataType

public org.apache.flink.table.types.DataType getAccumulatorDataType()

getOutputDataType

public org.apache.flink.table.types.DataType getOutputDataType()

getTypeInference

public org.apache.flink.table.types.inference.TypeInference getTypeInference(org.apache.flink.table.catalog.DataTypeFactory typeFactory)

Specified by:

getTypeInference in interface org.apache.flink.table.functions.FunctionDefinition

Overrides:

getTypeInference in class org.apache.flink.table.functions.AggregateFunction<T,ACC>

getRequirements

public Set<org.apache.flink.table.functions.FunctionRequirement> getRequirements()

isDeterministic

public boolean isDeterministic()