Implement Storage for DynamoDB

[kmruiz]

Hello!

I created this issue just to give you tracking about the implementation of the DynamoDB storage delegate. Suggestions are welcome because it will be my first contribution to vlingo!

Assumptions:

• I need to write an Actor that implements TextStateStore (as in the JDBCTextStateStoreActor)
• Interests are like promises

Questions:

• What is the dispatcher doing actually? Where can I find some documentation? Do I need to implement it also in my TextStateStore?

Thanks for your time!

[VaughnVernon]

• Since DynamoDB can support text and binary you should implement TextStateStore and BinaryStateStore. You may be able to have a single abstract base DynamoDBStateStoreActor<T> that works for both Binary and Text. See this example.
• Interests are actors that have an interest in knowing what happened to the requested operation, and is an async callback interface. Interests are not really promises in that they are not a single-write container. Rather, it's more like this:
  • In untyped actor systems a receiver knows its sender and that enables the receiver to reply to the sender with any message of any given type.
  • When using strongly typed actors, the sender must provide a reference to itself as an expected type that adheres to the actor message exchange protocol (contract).
  • In vlingo/actors a Completes is like an async Future and the Promise is represented by its with(T outcome) that causes the completion of the Completes. See BasicCompletes as a reference, but you should normally never need to create a Completes yourself. Just declare any interface/protocol/contract method as returning Completes<T> (where T is some type, such as String).
• In vlingo/symbio the Dispatcher is any Actor that implements this contract and is interested in dispatching the newly written State as a Dispatchable. This might be for the purpose of projecting the new State into a QCRS Query Model. This is represented by this package and its state child package.
  • Of course a projection could also be used to publish some DomainEvent about the new State by means of interpreting its metadata.operation, which was the cause of the new State
  • For an example of this, see these tests, etc.

[kmruiz]

Solved by #2