org.apache.flink.runtime.state

Interface KeyExtractorFunction<T>

Type Parameters:

T - type of the element from which we extract the key.

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface KeyExtractorFunction<T>

Function to extract a key from a given object.

Field Summary

Fields

Modifier and Type	Field and Description
static KeyExtractorFunction<? extends Keyed<?>>	FOR_KEYED_OBJECTS

Method Summary

Modifier and Type	Method and Description
Object	extractKeyFromElement(T element) Returns the key for the given element by which the key-group can be computed.
static <T extends Keyed<?>> KeyExtractorFunction<T>	forKeyedObjects()

Field Detail

FOR_KEYED_OBJECTS

static final KeyExtractorFunction<? extends Keyed<?>> FOR_KEYED_OBJECTS

Method Detail

extractKeyFromElement

@Nonnull
Object extractKeyFromElement(@Nonnull
                                      T element)

Returns the key for the given element by which the key-group can be computed.

forKeyedObjects

static <T extends Keyed<?>> KeyExtractorFunction<T> forKeyedObjects()