Observability Lab

Every button runs an intent through a droppable dispatcher while several observers watch at the same time: JMetrics, a custom observer that fills the event log, and the debug overlay.

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Try it

1. Press Succeed and watch the counters and the event log. The log shows the intent starting and finishing, and the state change attributed to that intent.
2. Press Fail. The intent throws, and the failure is observed through onIntentFailed.
3. Press Cancel. The intent cancels itself and is reported as cancelled instead of dispatched.
4. Press Drop one. It fires two intents back to back; the droppable dispatcher discards the second and onIntentDropped fires.
5. Open the debug overlay (bottom-right button) to see the same events inside the app.

Registering an observer

class AnalyticsObserver extends JObserverDelegate {
  @override
  void onIntentFailed(JIntent intent, Object error, StackTrace stackTrace) {
    report(intent.runtimeType, error, stackTrace);
  }
}

final remove = JObserver.addObserver(AnalyticsObserver());

Observers compose, and one that throws never affects the code it observes. See the observability guide for metrics, correlation and extension points.