Architecting Modern Java EE Applications

Realization with Java EE

The following statistics implementation observes the domain event specified earlier and stores the information in the Prometheus counter metric:

import io.prometheus.client.Counter;

@ApplicationScoped
public class ManufacturingStatistics {

    private Counter createdCars;

    @PostConstruct
    private void initMetrics() {
        createdCars = Counter.build("cars_manufactured_total",                "Total number of manufactured cars")
                .labelNames("color", "engine")
                .register();
    }

    public void carCreated(@Observes(during =            TransactionPhase.AFTER_SUCCESS) Specification spec) {        createdCars.labels(spec.getColor().name(),                spec.getEngine().name()).inc();
    }

}

The counter metric is created and registered to the Prometheus Client API. Measured values are qualified ...