org.apache.flink.table.runtime.functions.table.lookup

Class CachingAsyncLookupFunction

java.lang.Object

org.apache.flink.table.functions.UserDefinedFunction

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

org.apache.flink.table.functions.AsyncLookupFunction

org.apache.flink.table.runtime.functions.table.lookup.CachingAsyncLookupFunction

All Implemented Interfaces:

Serializable, FunctionDefinition

public class CachingAsyncLookupFunction
extends AsyncLookupFunction

A wrapper function around user-provided async lookup function with a cache layer.

This function will check the cache on lookup request and return entries directly on cache hit, otherwise the function will invoke the actual lookup function, and store the entry into the cache after lookup for later use.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	LOOKUP_CACHE_METRIC_GROUP_NAME

Constructor Summary

Constructors

Constructor and Description
CachingAsyncLookupFunction(LookupCache cache, AsyncLookupFunction delegate)

Method Summary

Modifier and Type	Method and Description
CompletableFuture<Collection<RowData>>	asyncLookup(RowData keyRow) Asynchronously lookup rows matching the lookup keys.
void	close() Tear-down method for user-defined function.
LookupCache	getCache()
void	open(FunctionContext context) Setup method for user-defined function.

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

eval

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

getKind, getTypeInference

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

functionIdentifier, 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

Field Detail

LOOKUP_CACHE_METRIC_GROUP_NAME

public static final String LOOKUP_CACHE_METRIC_GROUP_NAME

See Also:

Constant Field Values

Constructor Detail

CachingAsyncLookupFunction

public CachingAsyncLookupFunction(LookupCache cache,
                                  AsyncLookupFunction delegate)

Method Detail

open

public void open(FunctionContext context)
          throws Exception

Description copied from class: UserDefinedFunction

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

Overrides:

open in class UserDefinedFunction

Throws:

Exception

asyncLookup

public CompletableFuture<Collection<RowData>> asyncLookup(RowData keyRow)

Description copied from class: AsyncLookupFunction

Asynchronously lookup rows matching the lookup keys.

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

Specified by:

asyncLookup in class AsyncLookupFunction

Parameters:

keyRow - - A RowData that wraps lookup keys.

Returns:

A collection of all matching rows in the lookup table.

close

public void close()
           throws Exception

Description copied from class: UserDefinedFunction

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

Overrides:

close in class UserDefinedFunction

Throws:

Exception

getCache

@VisibleForTesting
public LookupCache getCache()