This is a draft for a possible Entity Callback API heavily inspired by Spring Framework's Application Event listeners. Entity callbacks are callbacks for entities that allow for entity modification at certain check points such as before saving an entity or after loading it.
Entity callbacks consist of a marker-interface for all entity callback types and the EntityCallbacks API to dispatch callbacks.
Entity callbacks are picked up from the ApplicationContext and invoked sequentially according to their ordering.
Usage example:
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MyConfig.class);
SimpleEntityCallbacks callbacks = new SimpleEntityCallbacks(ctx);
PersonDocument personDocument = new PersonDocument(null, "Walter", null);
PersonDocument afterCallback = callbacks.callback(personDocument, BeforeSaveCallback.class,
BeforeSaveCallback::onBeforeSave);
Mono<PersonDocument> afterCallback = callbacks.callbackLater(personDocument, ReactiveBeforeSaveCallback.class,
ReactiveBeforeSaveCallback::onBeforeSave);
@Configuration
static class MyConfig {
@Bean
BeforeSaveCallback<Person> personCallback() {
return object -> {
object.setSsn(object.getFirstName().length());
return object;
};
}
@Bean
MyReactiveBeforeSaveCallback callback() {
return new MyReactiveBeforeSaveCallback();
}
}
class MyReactiveBeforeSaveCallback implements ReactiveBeforeSaveCallback<Person> {
@Override
public Mono<Person> onBeforeSave(Person object) {
PersonDocument result = new PersonDocument(object.getFirstName().length(), object.getFirstName(),
object.getLastName());
return Mono.just(result);
}
}
Original Pull Request: #332
52724cd5dd