AsyncLookupFunction (Flink : 2.0-preview1 API)

java.lang.Object
- org.apache.flink.table.functions.UserDefinedFunction
- - org.apache.flink.table.functions.AsyncTableFunction<RowData>
  - - org.apache.flink.table.functions.AsyncLookupFunction

All Implemented Interfaces:

Serializable, FunctionDefinition

Direct Known Subclasses:

CachingAsyncLookupFunction, RetryableAsyncLookupFunctionDelegator
```
@PublicEvolving
public abstract class AsyncLookupFunction
extends AsyncTableFunction<RowData>
```
A wrapper class of AsyncTableFunction for asynchronously 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

AsyncLookupFunction()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`abstract CompletableFuture<Collection<RowData>>`	`asyncLookup(RowData keyRow)`	Asynchronously lookup rows matching the lookup keys.
`void`	`eval(CompletableFuture<Collection<RowData>> future, Object... keys)`	Invokes `asyncLookup(org.apache.flink.table.data.RowData)` and chains futures.

Methods inherited from class org.apache.flink.table.functions.AsyncTableFunction
getKind, getTypeInference

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 Detail
  - AsyncLookupFunction
```
public AsyncLookupFunction()
```
- Method Detail
  - asyncLookup
```
public abstract CompletableFuture<Collection<RowData>> asyncLookup(RowData keyRow)
```
    Asynchronously 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.
  - eval
```
public final void eval(CompletableFuture<Collection<RowData>> future,
                       Object... keys)
```
    Invokes asyncLookup(org.apache.flink.table.data.RowData) and chains futures.