Add `outputAs|inputFrom(WorkflowModel workflowInput)` method to DSL

[mcruzdev]

What would you like to be added:

To have a better experience on handling workflow data.

Actually we need to have this one:

agent("scoreSubmission",
    (uniqueId, proposal) -> reviewer.scoreSubmission(proposal), Proposal.class)
    .outputAs(buildSubmissionOutput(), Long.class),
    // ...
    private static JavaContextFunction<Long, ScoreSubmissionOutput> buildSubmissionOutput() {
        return (score, workflowContext) ->
                new ScoreSubmissionOutput(score, workflowContext.instanceData().input().as(Proposal.class).orElseThrow());
    }

For every time we need to get the workflowContext.instanceData().input() we need to write a lot. It would be great if we have something more easy, like:

.outputAs((WorfklowModel inputModel, T lastState), Class<T> lastStateClass);

.inputFrom((WorfklowModel inputModel, T lastState), Class<T> lastStateClass);

.outputAs((WorfklowModel inputModel), Class<T> outputClass);

.inputFrom((WorfklowModel inputModel), Class<T> outputClass);

Why is this needed:

To make give a better experience when developing workflow with DSL

[mcruzdev]

@ricardozanini @fjtirado If you agree I can implement this one.

[ricardozanini]

Go ahead! I thought we already had that thou, looks like we don't - and this is a must to enhance UX.

[fjtirado]

Yes, I believe we already had too ;)
Also, @mcruzdev, I think we are missing scheduling on the DSL too (that will be a different PR)

[fjtirado]

Lets improve usability in a different way, rather than adding a new overloaded outputAs method as the one proposed, keep the original fluent definition and add a static utility method to make easier access to the original input from the workflow context.

That method will be

public static input (WorkflowContext context, Class<T> outputClass) {
   return context.instanceData().input().as(outputClass).orElseThrow();
}

The proposed example will look like this

agent("scoreSubmission",
    (uniqueId, proposal) -> reviewer.scoreSubmission(proposal), Proposal.class)
    .outputAs(buildSubmissionOutput(), Long.class),
    // ...
    private static JavaContextFunction<Long, ScoreSubmissionOutput> buildSubmissionOutput() {
        return (score, workflowContext) ->
                new ScoreSubmissionOutput(score, input(workflowContext,Proposal.class));
    } 

it can look even better

agent("scoreSubmission",
    (uniqueId, proposal) -> reviewer.scoreSubmission(proposal), Proposal.class)
    .outputAs(this::submissionOutput, Long.class),
    // ...
    private  ScoreSubmissionOutput submissionOutput(Long uniqueId, WorkflowContext context) {
        return   new ScoreSubmissionOutput(score, input(context,Proposal.class));
    }