Package org.apache.flink.table.functions

Class UserDefinedFunctionHelper

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunctionHelper

@Internal
public final class UserDefinedFunctionHelper
extends Object

Utility for dealing with subclasses of UserDefinedFunction. The purpose of this class is to keep the user-facing APIs clean and offer methods/constants from here.

It contains methods for instantiating, validating and extracting types during function registration in a catalog.

Field Summary

Fields

Modifier and Type	Field	Description
static String	AGGREGATE_ACCUMULATE
static String	AGGREGATE_MERGE
static String	AGGREGATE_RETRACT
static String	ASYNC_SCALAR_EVAL
static String	ASYNC_TABLE_EVAL
static String	DEFAULT_ACCUMULATOR_NAME
static String	PROCESS_TABLE_EVAL
static String	PROCESS_TABLE_ON_TIMER
static String	SCALAR_EVAL
static String	TABLE_AGGREGATE_ACCUMULATE
static String	TABLE_AGGREGATE_EMIT
static String	TABLE_AGGREGATE_EMIT_RETRACT
static String	TABLE_AGGREGATE_MERGE
static String	TABLE_AGGREGATE_RETRACT
static String	TABLE_EVAL

Method Summary

Modifier and Type	Method	Description
static UserDefinedFunction	createSpecializedFunction(String functionName, FunctionDefinition definition, CallContext callContext, ClassLoader builtInClassLoader, org.apache.flink.configuration.ReadableConfig configuration, SpecializedFunction.ExpressionEvaluatorFactory evaluatorFactory)	Creates the runtime implementation of a FunctionDefinition as an instance of UserDefinedFunction.
static String	generateInlineFunctionName(UserDefinedFunction function)	Name for anonymous, inline functions.
static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<ACC>	getAccumulatorTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction)	Tries to infer the TypeInformation of an AggregateFunction's accumulator type.
static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<ACC>	getAccumulatorTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction, org.apache.flink.api.common.typeinfo.TypeInformation<ACC> scalaType)	Tries to infer the TypeInformation of an AggregateFunction's accumulator type.
static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<T>	getReturnTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction)	Tries to infer the TypeInformation of an AggregateFunction's accumulator type.
static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<T>	getReturnTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction, org.apache.flink.api.common.typeinfo.TypeInformation<T> scalaType)	Tries to infer the TypeInformation of an AggregateFunction's accumulator type.
static <T> org.apache.flink.api.common.typeinfo.TypeInformation<T>	getReturnTypeOfTableFunction(TableFunction<T> tableFunction)	Tries to infer the TypeInformation of an AggregateFunction's accumulator type.
static <T> org.apache.flink.api.common.typeinfo.TypeInformation<T>	getReturnTypeOfTableFunction(TableFunction<T> tableFunction, org.apache.flink.api.common.typeinfo.TypeInformation<T> scalaType)	Tries to infer the TypeInformation of an AggregateFunction's accumulator type.
static UserDefinedFunction	instantiateFunction(Class<?> functionClass)	Instantiates a UserDefinedFunction assuming a JVM function with default constructor.
static UserDefinedFunction	instantiateFunction(ClassLoader classLoader, org.apache.flink.configuration.ReadableConfig config, String name, CatalogFunction catalogFunction)	Instantiates a UserDefinedFunction from a CatalogFunction.
static boolean	isClassNameSerializable(UserDefinedFunction function)	Returns whether a UserDefinedFunction can be easily serialized and identified by only a fully qualified class name.
static void	prepareInstance(org.apache.flink.configuration.ReadableConfig config, UserDefinedFunction function)	Prepares a UserDefinedFunction instance for usage in the API.
static void	validateClass(Class<? extends UserDefinedFunction> functionClass)	Validates a UserDefinedFunction class for usage in the API.
static void	validateClassForRuntime(Class<? extends UserDefinedFunction> functionClass, String methodName, Class<?>[] argumentClasses, Class<?> outputClass, String functionName)	Validates a UserDefinedFunction class for usage in the runtime.

Methods inherited from class java.lang.Object

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

Field Detail

SCALAR_EVAL

public static final String SCALAR_EVAL

See Also:

Constant Field Values

ASYNC_SCALAR_EVAL

public static final String ASYNC_SCALAR_EVAL

See Also:

Constant Field Values

TABLE_EVAL

public static final String TABLE_EVAL

See Also:

Constant Field Values

AGGREGATE_ACCUMULATE

public static final String AGGREGATE_ACCUMULATE

See Also:

Constant Field Values

AGGREGATE_RETRACT

public static final String AGGREGATE_RETRACT

See Also:

Constant Field Values

AGGREGATE_MERGE

public static final String AGGREGATE_MERGE

See Also:

Constant Field Values

TABLE_AGGREGATE_ACCUMULATE

public static final String TABLE_AGGREGATE_ACCUMULATE

See Also:

Constant Field Values

TABLE_AGGREGATE_RETRACT

public static final String TABLE_AGGREGATE_RETRACT

See Also:

Constant Field Values

TABLE_AGGREGATE_MERGE

public static final String TABLE_AGGREGATE_MERGE

See Also:

Constant Field Values

TABLE_AGGREGATE_EMIT

public static final String TABLE_AGGREGATE_EMIT

See Also:

Constant Field Values

TABLE_AGGREGATE_EMIT_RETRACT

public static final String TABLE_AGGREGATE_EMIT_RETRACT

See Also:

Constant Field Values

ASYNC_TABLE_EVAL

public static final String ASYNC_TABLE_EVAL

See Also:

Constant Field Values

PROCESS_TABLE_EVAL

public static final String PROCESS_TABLE_EVAL

See Also:

Constant Field Values

PROCESS_TABLE_ON_TIMER

public static final String PROCESS_TABLE_ON_TIMER

See Also:

Constant Field Values

DEFAULT_ACCUMULATOR_NAME

public static final String DEFAULT_ACCUMULATOR_NAME

See Also:

Constant Field Values

Method Detail

getReturnTypeOfAggregateFunction

public static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<T> getReturnTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction)

Tries to infer the TypeInformation of an AggregateFunction's accumulator type.

Parameters:

aggregateFunction - The AggregateFunction for which the accumulator type is inferred.

Returns:

The inferred accumulator type of the AggregateFunction.

getReturnTypeOfAggregateFunction

public static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<T> getReturnTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction,
                                                                                                                     org.apache.flink.api.common.typeinfo.TypeInformation<T> scalaType)

Tries to infer the TypeInformation of an AggregateFunction's accumulator type.

Parameters:

aggregateFunction - The AggregateFunction for which the accumulator type is inferred.

scalaType - The implicitly inferred type of the accumulator type.

Returns:

The inferred accumulator type of the AggregateFunction.

getAccumulatorTypeOfAggregateFunction

public static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<ACC> getAccumulatorTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction)

Tries to infer the TypeInformation of an AggregateFunction's accumulator type.

Parameters:

aggregateFunction - The AggregateFunction for which the accumulator type is inferred.

Returns:

The inferred accumulator type of the AggregateFunction.

getAccumulatorTypeOfAggregateFunction

public static <T,ACC> org.apache.flink.api.common.typeinfo.TypeInformation<ACC> getAccumulatorTypeOfAggregateFunction(ImperativeAggregateFunction<T,ACC> aggregateFunction,
                                                                                                                            org.apache.flink.api.common.typeinfo.TypeInformation<ACC> scalaType)

Tries to infer the TypeInformation of an AggregateFunction's accumulator type.

Parameters:

aggregateFunction - The AggregateFunction for which the accumulator type is inferred.

scalaType - The implicitly inferred type of the accumulator type.

Returns:

The inferred accumulator type of the AggregateFunction.

getReturnTypeOfTableFunction

public static <T> org.apache.flink.api.common.typeinfo.TypeInformation<T> getReturnTypeOfTableFunction(TableFunction<T> tableFunction)

Tries to infer the TypeInformation of an AggregateFunction's accumulator type.

Parameters:

tableFunction - The TableFunction for which the accumulator type is inferred.

Returns:

The inferred accumulator type of the AggregateFunction.

getReturnTypeOfTableFunction

public static <T> org.apache.flink.api.common.typeinfo.TypeInformation<T> getReturnTypeOfTableFunction(TableFunction<T> tableFunction,
                                                                                                       org.apache.flink.api.common.typeinfo.TypeInformation<T> scalaType)

Tries to infer the TypeInformation of an AggregateFunction's accumulator type.

Parameters:

tableFunction - The TableFunction for which the accumulator type is inferred.

scalaType - The implicitly inferred type of the accumulator type.

Returns:

The inferred accumulator type of the AggregateFunction.

instantiateFunction

public static UserDefinedFunction instantiateFunction(ClassLoader classLoader,
                                                      @Nullable
                                                      org.apache.flink.configuration.ReadableConfig config,
                                                      String name,
                                                      CatalogFunction catalogFunction)

Instantiates a UserDefinedFunction from a CatalogFunction.

Requires access to ReadableConfig if Python functions should be supported.

instantiateFunction

public static UserDefinedFunction instantiateFunction(Class<?> functionClass)

Instantiates a UserDefinedFunction assuming a JVM function with default constructor.

prepareInstance

public static void prepareInstance(org.apache.flink.configuration.ReadableConfig config,
                                   UserDefinedFunction function)

Prepares a UserDefinedFunction instance for usage in the API.

isClassNameSerializable

public static boolean isClassNameSerializable(UserDefinedFunction function)

Returns whether a UserDefinedFunction can be easily serialized and identified by only a fully qualified class name. It must have a default constructor and no serializable fields.

Other properties (such as checks for abstract classes) are validated at the entry points of the API, see prepareInstance(ReadableConfig, UserDefinedFunction).

generateInlineFunctionName

public static String generateInlineFunctionName(UserDefinedFunction function)

Name for anonymous, inline functions.

validateClass

public static void validateClass(Class<? extends UserDefinedFunction> functionClass)

Validates a UserDefinedFunction class for usage in the API.

Note: This is an initial validation to indicate common errors early. The concrete signature validation happens in the code generation when the actual DataTypes for arguments and result are known.

validateClassForRuntime

public static void validateClassForRuntime(Class<? extends UserDefinedFunction> functionClass,
                                           String methodName,
                                           Class<?>[] argumentClasses,
                                           Class<?> outputClass,
                                           String functionName)

Validates a UserDefinedFunction class for usage in the runtime.

Note: This is for the final validation when actual DataTypes for arguments and result are known.

createSpecializedFunction

public static UserDefinedFunction createSpecializedFunction(String functionName,
                                                            FunctionDefinition definition,
                                                            CallContext callContext,
                                                            ClassLoader builtInClassLoader,
                                                            @Nullable
                                                            org.apache.flink.configuration.ReadableConfig configuration,
                                                            @Nullable
                                                            SpecializedFunction.ExpressionEvaluatorFactory evaluatorFactory)

Creates the runtime implementation of a FunctionDefinition as an instance of UserDefinedFunction.

See Also:

SpecializedFunction