Package org.apache.flink.table.functions

Class LookupFunction

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunction

org.apache.flink.table.functions.TableFunction<RowData>

org.apache.flink.table.functions.LookupFunction

All Implemented Interfaces:

Serializable, FunctionDefinition

@PublicEvolving
public abstract class LookupFunction
extends TableFunction<RowData>

A wrapper class of TableFunction for synchronously lookup rows matching the lookup keys from external system.

The output type of this table function is fixed as RowData.

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
LookupFunction()

Method Summary

Modifier and Type	Method	Description
final void	eval(Object... keys)	Invoke lookup(org.apache.flink.table.data.RowData) and handle exceptions.
abstract Collection<RowData>	lookup(RowData keyRow)	Synchronously lookup rows matching the lookup keys.

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

collect, finish, getKind, getParameterTypes, getResultType, getTypeInference, setCollector

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

getRequirements, isDeterministic, supportsConstantFolding

Constructor Details

LookupFunction

public LookupFunction()

Method Details

lookup

public abstract Collection<RowData> lookup(RowData keyRow)
                                    throws IOException

Synchronously lookup rows matching the lookup keys.

Please note that the returning collection of RowData shouldn't be reused across invocations.

Parameters:

keyRow - - A RowData that wraps lookup keys.

Returns:

A collection of all matching rows in the lookup table.

Throws:

IOException

eval

public final void eval(Object... keys)

Invoke lookup(org.apache.flink.table.data.RowData) and handle exceptions.