Typed proxy support

Requirements

In order to create a type-safe experience for working with orchestrations and activities, the Java SDK for the Durable Task Framework should support type-safe invocation of orchestration and activities.

For example, when calling an activity, instead of the following:

Object activityInput = "World";
String result = context.callActivity("SayHello", activityInput, String.class).get();

...we should be able to instead write:

MyActivities activities = // get a pointer to an activity proxy
String result = activities.sayHello("World");

We'd want the same experience also for orchestrations (created by a client) and sub-orchestrations.

Ideally this support will also allow developers to easily unit test their code.

Design considerations

Java's Proxy support could be a good starting point for such a feature.

Inizia dai requisiti e dalla documentazione Java Proxy collegata. Definisci l’ambito dell’invocazione di attività tipizzate, orchestrazioni e sotto-orchestrazioni, inclusa l’esperienza proposta per gli unit test. Il lavoro è completo quando il Java SDK fornisce un approccio proxy documentato e type-safe che copre tutti e tre i casi di invocazione.