org.apache.flink.table.functions

类 UserDefinedFunction

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunction

所有已实现的接口:

Serializable

直接已知子类:

AggregateFunction, ScalarFunction, TableFunction

@PublicEvolving
public abstract class UserDefinedFunction
extends Object
implements Serializable

Base class for all user-defined functions such as scalar functions, table functions, or aggregation functions.

另请参阅:

序列化表格

构造器概要

构造器

构造器和说明
UserDefinedFunction()

方法概要

限定符和类型	方法和说明
void	close() Tear-down method for user-defined function.
String	functionIdentifier() Returns a unique, serialized representation for this function.
boolean	isDeterministic() Returns information about the determinism of the function's results.
void	open(FunctionContext context) Setup method for user-defined function.
String	toString() Returns the name of the UDF that is used for plan explain and logging.

从类继承的方法 java.lang.Object

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

构造器详细资料

UserDefinedFunction

public UserDefinedFunction()

方法详细资料

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.

抛出:

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.

抛出:

Exception

isDeterministic

public boolean isDeterministic()

Returns information about the determinism of the function's results.

返回:

true if and only if a call to this function is guaranteed to always return the same result given the same parameters. true is assumed by default. If the function is not pure functional like random(), date(), now(), ... this method must return false.

toString

public String toString()

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

覆盖:

toString 在类中 Object