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

Class JsonObjectAggFunction

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<String,JsonObjectAggFunction.Accumulator>

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

All Implemented Interfaces:

Serializable, FunctionDefinition

@Internal
public class JsonObjectAggFunction
extends BuiltInAggregateFunction<String,JsonObjectAggFunction.Accumulator>

Implementation for BuiltInFunctionDefinitions.JSON_OBJECTAGG_NULL_ON_NULL / BuiltInFunctionDefinitions.JSON_OBJECTAGG_ABSENT_ON_NULL.

Note that this function only ever receives strings to accumulate because WrapJsonAggFunctionArgumentsRule wraps arguments into BuiltInFunctionDefinitions.JSON_STRING.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	JsonObjectAggFunction.Accumulator	Accumulator for JsonObjectAggFunction.

Constructor Summary

Constructors

Constructor	Description
JsonObjectAggFunction(LogicalType[] argumentTypes, boolean skipNulls)

Method Summary

Modifier and Type	Method	Description
void	accumulate(JsonObjectAggFunction.Accumulator acc, StringData keyData, StringData valueData)
JsonObjectAggFunction.Accumulator	createAccumulator()	Creates and initializes the accumulator for this ImperativeAggregateFunction.
DataType	getAccumulatorDataType()
List<DataType>	getArgumentDataTypes()
DataType	getOutputDataType()
String	getValue(JsonObjectAggFunction.Accumulator acc)	Called every time when an aggregation result should be materialized.
void	merge(JsonObjectAggFunction.Accumulator acc, Iterable<JsonObjectAggFunction.Accumulator> others)
void	resetAccumulator(JsonObjectAggFunction.Accumulator acc)
void	retract(JsonObjectAggFunction.Accumulator acc, StringData keyData, StringData valueData)

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

JsonObjectAggFunction

public JsonObjectAggFunction(LogicalType[] argumentTypes,
                             boolean skipNulls)

Method Detail

getArgumentDataTypes

public List<DataType> getArgumentDataTypes()

Overrides:

getArgumentDataTypes in class BuiltInAggregateFunction<String,JsonObjectAggFunction.Accumulator>

getOutputDataType

public DataType getOutputDataType()

Overrides:

getOutputDataType in class BuiltInAggregateFunction<String,JsonObjectAggFunction.Accumulator>

getAccumulatorDataType

public DataType getAccumulatorDataType()

Overrides:

getAccumulatorDataType in class BuiltInAggregateFunction<String,JsonObjectAggFunction.Accumulator>

createAccumulator

public JsonObjectAggFunction.Accumulator 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<String,JsonObjectAggFunction.Accumulator>

Returns:

the accumulator with the initial value

resetAccumulator

public void resetAccumulator(JsonObjectAggFunction.Accumulator acc)

accumulate

public void accumulate(JsonObjectAggFunction.Accumulator acc,
                       StringData keyData,
                       @Nullable
                       StringData valueData)
                throws Exception

Throws:

Exception

retract

public void retract(JsonObjectAggFunction.Accumulator acc,
                    StringData keyData,
                    @Nullable
                    StringData valueData)
             throws Exception

Throws:

Exception

merge

public void merge(JsonObjectAggFunction.Accumulator acc,
                  Iterable<JsonObjectAggFunction.Accumulator> others)
           throws Exception

Throws:

Exception

getValue

public String getValue(JsonObjectAggFunction.Accumulator 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<String,JsonObjectAggFunction.Accumulator>

Parameters:

acc - the accumulator which contains the current intermediate results

Returns:

the aggregation result