org.apache.flink.table.functions

Class UserDefinedFunction

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunction

All Implemented Interfaces:

Serializable, FunctionDefinition

Direct Known Subclasses:

AsyncTableFunction, ScalarFunction, TableFunction, UserDefinedAggregateFunction

@PublicEvolving
public abstract class UserDefinedFunction
extends Object
implements FunctionDefinition, Serializable

Base class for all user-defined functions.

User-defined functions combine the logical definition of a function for validation and planning and contain a corresponding runtime implementation.

See Also:

ScalarFunction, TableFunction, AsyncTableFunction, AggregateFunction, TableAggregateFunction, Serialized Form

Constructor Summary

Constructors

Constructor and Description
UserDefinedFunction()

Method Summary

Modifier and Type	Method and Description
void	close() Tear-down method for user-defined function.
String	functionIdentifier() Returns a unique, serialized representation for this function.
void	open(FunctionContext context) Setup method for user-defined function.
String	toString() Returns the name of the UDF that is used for plan explanation and logging.

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

getKind, getRequirements, isDeterministic

Constructor Detail

UserDefinedFunction

public UserDefinedFunction()

Method Detail

functionIdentifier

public final String functionIdentifier()

Returns a unique, serialized representation for this function.

open

public void open(FunctionContext context)
          throws Exception

Setup method for user-defined function. It can be used for initialization work. By default, this method does nothing.

Throws:

Exception

close

public void close()
           throws Exception

Tear-down method for user-defined function. It can be used for clean up work. By default, this method does nothing.

Throws:

Exception

toString

public String toString()

Returns the name of the UDF that is used for plan explanation and logging.

Overrides:

toString in class Object