Asynchronous startup task

Sometimes we might need to do some async work inside a startup task, like doing a REST request to the server to fetch some data, in this case we might be interested in blocking the bootstrapping of the application until the data request is succeeded and data is processed, in this case we create an Async startup task by extending from the AsyncClientStartupTask and annotate the class with @StartupTask, then in the execute method we add our logic, but for Async tasks we must call the complete method to mark the task as completed, and until we do so the task will block the application bootstrapping.

Async Tasks are ordered and grouped, you can change the order and group of an async task by overriding the order method, all Async task with a specific order should be completed be fore any startup task with the next order can be executed.

Async task look like the following

@StartupTask
public class SampleAsyncStartUpTask extends AsyncClientStartupTask<SomeObject> {

    @Override
    public void execute() {
        asyncCallToTheServer
                .onSuccess(someObjectResponse -> {
                    complete(someObjectResponse);
                })
                .onFailed(err -> {
                    LOGGER.error("server call failed : ", err);
                    complete(defaultObjectInstance);
                })
    }

    @Override
    public int order() {
        return 1;
    }
}

For Async tasks you need to make sure to call the complete method or otherwise the application will be blocked and will not start.