{title:'Listeners', created:'8.0.0'}

As mentioned previously, the lifecycle methods for the {@link oaj.microservice.Microservice} class are explicitly defined as non-final so that they can be overridden by subclasses.

In addition to this support, an interface for defining event listeners for your microservice:

- {@link oaj.microservice.Microservice.Builder}
  - {@link oaj.microservice.Microservice.Builder#listener(MicroserviceListener) listener(MicroserviceListener)}
- {@link oaj.microservice.MicroserviceListener}
  - {@link oaj.microservice.MicroserviceListener#onStart(Microservice) onStart(Microservice)}
  - {@link oaj.microservice.MicroserviceListener#onStop(Microservice) onStop(Microservice)}
  - {@link oaj.microservice.MicroserviceListener#onConfigChange(Microservice,ConfigEvents) onConfigChange(Microservice,ConfigEvents)}
- {@link oaj.microservice.BasicMicroserviceListener}

This listener API can be used for listening for and reacting to configuration changes on the file system.

| public class MyMicroserviceListener extends BasicMicroserviceListener { | | @Override /* MicroserviceListener */ | public void onConfigChange(Microservice microservice, ConfigEvents events) { | | // Restart the microservice if anything was modified in one of our sections | if (events.isSectionChanged("MySection")) | microservice.stop().start(); | } | }

Note that the {@link oaj.microservice.Microservice#onConfigChange(ConfigEvents)} method can also be overridden to react to configuration changes as well:

| public class MyMicroservice extends Microservice { | | @Override /* MicroserviceListener */ | public void onConfigChange(ConfigEvents events) { | | // Restart the microservice if anything was modified in one of our sections | if (events.isSectionChanged("MySection")) | this.stop().start(); | } | }