Command API

A CommandAPISet provides a CommandAPI for each of the aggregates added. The CommandAPI has methods to publish commands, and wait for the result to these commands.

The CommandAPISet is created by the client builder.

Note that result of the command only will only be whether the command succeeded or failed:

• If successful, the command sequence number
• If failure, the reason(s) for failure

Here is an example, submitting a command, and when this returns, submits another.

CommandAPI commandAPI = ...;
return commandAPI
    .publishAndQueryCommand(new CommandAPI.Request<>(
        key,
        Sequence.first(),
        UUID.randomUUID(),
        new UserCommand.InsertUser(firstName, lastName)),
        Duration.ofMinutes(2L)
    )
    .flatMap(sequences -> {
        logger.info("Received result {} new sequences", sequences);
        return commandAPI.publishAndQueryCommand(new CommandAPI.Request<>(
            key,
            sequences.last(),
            UUID.randomUUID(),
            new UserCommand.UpdateName("Sarah Jones", lastName)),
            Duration.ofMinutes(2L)
        );
    });

A Simple Sourcing application will often be deployed as a service that exposes endpoints for the commands that will be executed. These endpoints interact with the CommandAPI interface.