RetryableUseCaseBuilder<TBloc extends JuiceBloc<TState>, TState extends BlocState, TEvent extends EventBase> class

A use case builder that automatically retries failed operations.

Wraps another use case and intercepts failures, retrying based on configurable backoff strategy and retry conditions.

Basic Usage

class MyBloc extends JuiceBloc<MyState> {
  MyBloc() : super(MyState(), [
    () => RetryableUseCaseBuilder(
      typeOfEvent: FetchDataEvent,
      useCaseGenerator: () => FetchDataUseCase(),
      maxRetries: 3,
      backoff: ExponentialBackoff(initial: Duration(seconds: 1)),
    ),
  ], []);
}

How It Works

1. The wrapped use case executes normally
2. If it calls emitFailure, the error is captured
3. If the error is retryable, waits (backoff) and retries
4. On success (emitUpdate) or non-retryable error, stops
5. After max retries, the final failure is emitted

Retry Conditions

By default, retries when:

• Error is a JuiceException with isRetryable == true
• Error is NOT a JuiceException (assumes retryable)

Custom retry logic:

RetryableUseCaseBuilder(
  // ...
  retryWhen: (error) => error is NetworkException,
)

Cancellation

If the event is CancellableEvent and gets cancelled during a retry backoff, the operation aborts and emits CancelingStatus.