org.apache.flink.statefun.sdk.java.types

Interface Type<T>

Type Parameters:

T - the Java type of serialized / deserialized instances.

All Known Implementing Classes:

SimpleType, SliceType

public interface Type<T>

This class is the core abstraction used by Stateful Functions's type system, and consists of a few things that StateFun uses to handle Messages and ValueSpecs:

• A TypeName to identify the type.
• A TypeSerializer for serializing and deserializing instances of the type.

Cross-language primitive types

StateFun's type system has cross-language support for common primitive types, such as boolean, integer, long, etc. These primitive types have built-in Types implemented for them already, with predefined TypeNames.

This is of course all transparent for the user, so you don't need to worry about it. Functions implemented in various languages (e.g. Java or Python) can message each other by directly sending supported primitive values as message arguments. Moreover, the type system is used for state values as well; so, you can expect that a function can safely read previous state after reimplementing it in a different language.

Common custom types (e.g. JSON or Protobuf)

The type system is also very easily extensible to support custom message types, such as JSON or Protobuf messages. This is just a matter of implementing your own Type with a custom typename and serializer. Alternatively, you can also use the SimpleType class to do this easily.

Method Summary

Modifier and Type	Method and Description
default java.util.Set<TypeCharacteristics>	typeCharacteristics()
TypeName	typeName()
TypeSerializer<T>	typeSerializer()

Method Detail

typeName

TypeName typeName()

Returns:

The unique TypeName of this type.

typeSerializer

TypeSerializer<T> typeSerializer()

Returns:

A TypeSerializer that can serialize and deserialize this type.

typeCharacteristics

default java.util.Set<TypeCharacteristics> typeCharacteristics()