The Pipeline Framework

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Operator Invocation Internals ​

Build-Time Flow ​

Core Build Items ​

  • PipelineConfigBuildItem: parsed operator step declarations.
  • OperatorBuildItem: resolved class/method/input/normalized return/category metadata.

Resolution Contract ​

  • Jandex-only resolution for operator classes and methods.
  • Fail-fast diagnostics for unresolved or ambiguous methods.
  • Return-type normalization to reactive metadata (Uni<T> / Multi<T>).

OperatorLinkValidationBuildSteps validates adjacent links before generation:

  • cardinality constraints,
  • assignability checks (with generic compatibility),
  • mapper presence checks when direct assignability fails.

Invoker Generation Contract ​

OperatorInvokerBuildSteps generates operator invoker bytecode with Gizmo:

  • direct invocation (no reflection lookup),
  • CDI bean registration,
  • unary reactive contract (ReactiveService),
  • checked/runtime exceptions adapted to Uni.createFrom().failure(e).

Note: this is specific to operator invokers in the Quarkus build-step path. Other generation paths in the annotation processor still render Java sources with JavaPoet.

Generated Equivalent (Conceptual) ​

Non-reactive operator ​

java
@Singleton
public class EnrichPaymentOperatorInvoker implements ReactiveService<PaymentIn, PaymentOut> {

    @Inject
    PaymentOperators target;

    @Override
    public Uni<PaymentOut> process(PaymentIn input) {
        try {
            PaymentOut out = target.enrich(input);
            return Uni.createFrom().item(out);
        } catch (Exception e) {
            return Uni.createFrom().failure(e);
        }
    }
}

Reactive operator ​

java
@Singleton
public class ScorePaymentOperatorInvoker implements ReactiveService<PaymentIn, PaymentScore> {

    @Inject
    PaymentScoringOperators target;

    @Override
    public Uni<PaymentScore> process(PaymentIn input) {
        try {
            return target.score(input);
        } catch (Exception e) {
            return Uni.createFrom().failure(e);
        }
    }
}

Current Scope ​

  • Unary invocation is the supported path for generated operator invokers.
  • Streaming service interfaces exist in runtime and transport layers, but operator invoker generation is still unary-scoped.