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

Class MinWithRetractAggFunction<T extends Comparable<T>>

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,MinWithRetractAggFunction.MinWithRetractAccumulator<T>>

org.apache.flink.table.runtime.functions.aggregate.MinWithRetractAggFunction<T>

All Implemented Interfaces:

Serializable, FunctionDefinition

@Internal
public final class MinWithRetractAggFunction<T extends Comparable<T>>
extends BuiltInAggregateFunction<T,MinWithRetractAggFunction.MinWithRetractAccumulator<T>>

Built-in MIN with retraction aggregate function.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MinWithRetractAggFunction.MinWithRetractAccumulator<T> Accumulator for MIN with retraction.

Constructor Summary

Constructors

Constructor and Description
MinWithRetractAggFunction(LogicalType valueType)

Method Summary

Modifier and Type	Method and Description
void	accumulate(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc, T value)
MinWithRetractAggFunction.MinWithRetractAccumulator<T>	createAccumulator() Creates and initializes the accumulator for this ImperativeAggregateFunction.
DataType	getAccumulatorDataType()
List<DataType>	getArgumentDataTypes()
DataType	getOutputDataType()
T	getValue(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc) Called every time when an aggregation result should be materialized.
void	merge(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc, Iterable<MinWithRetractAggFunction.MinWithRetractAccumulator<T>> its)
void	resetAccumulator(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc)
void	retract(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc, T value)

Methods inherited from class org.apache.flink.table.runtime.functions.aggregate.BuiltInAggregateFunction

getRequirements, getTypeInference, isDeterministic

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

getKind

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

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

Methods inherited from interface org.apache.flink.table.functions.FunctionDefinition

supportsConstantFolding

Constructor Detail

MinWithRetractAggFunction

public MinWithRetractAggFunction(LogicalType valueType)

Method Detail

getArgumentDataTypes

public List<DataType> getArgumentDataTypes()

Overrides:

getArgumentDataTypes in class BuiltInAggregateFunction<T extends Comparable<T>,MinWithRetractAggFunction.MinWithRetractAccumulator<T extends Comparable<T>>>

getAccumulatorDataType

public DataType getAccumulatorDataType()

Overrides:

getAccumulatorDataType in class BuiltInAggregateFunction<T extends Comparable<T>,MinWithRetractAggFunction.MinWithRetractAccumulator<T extends Comparable<T>>>

getOutputDataType

public DataType getOutputDataType()

Overrides:

getOutputDataType in class BuiltInAggregateFunction<T extends Comparable<T>,MinWithRetractAggFunction.MinWithRetractAccumulator<T extends Comparable<T>>>

createAccumulator

public MinWithRetractAggFunction.MinWithRetractAccumulator<T> createAccumulator()

Description copied from class: ImperativeAggregateFunction

Creates and initializes the accumulator for this ImperativeAggregateFunction.

The accumulator is an intermediate data structure that stores the aggregated values until a final aggregation result is computed.

Specified by:

createAccumulator in class ImperativeAggregateFunction<T extends Comparable<T>,MinWithRetractAggFunction.MinWithRetractAccumulator<T extends Comparable<T>>>

Returns:

the accumulator with the initial value

accumulate

public void accumulate(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc,
                       T value)
                throws Exception

Throws:

Exception

retract

public void retract(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc,
                    T value)
             throws Exception

Throws:

Exception

merge

public void merge(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc,
                  Iterable<MinWithRetractAggFunction.MinWithRetractAccumulator<T>> its)
           throws Exception

Throws:

Exception

resetAccumulator

public void resetAccumulator(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc)

getValue

public T getValue(MinWithRetractAggFunction.MinWithRetractAccumulator<T> acc)

Description copied from class: AggregateFunction

Called every time when an aggregation result should be materialized. The returned value could be either an early and incomplete result (periodically emitted as data arrives) or the final result of the aggregation.

Specified by:

getValue in class AggregateFunction<T extends Comparable<T>,MinWithRetractAggFunction.MinWithRetractAccumulator<T extends Comparable<T>>>

Parameters:

acc - the accumulator which contains the current intermediate results

Returns:

the aggregation result