use_in_case 0.1.0

use_in_case: ^0.1.0 copied to clipboard

Use-In-Case Interactor Library #

This package contains the implementation required to add interactors to your project.

Simple Usage #

You can read about the usage in many examples inside the examples folder. Here's a quick example on how to get started:

import 'package:use_in_case/use_in_case.dart';

final class Square extends PRInteractor<double, double> {
  const Square();

  @override
  Future<double> execute(double parameter) async {
    return parameter * parameter;
  }
}

void main() async {
  const square = Square();
  final result = await square(11).get();
  print(result);
}

It's also possible to receive information about the workflow of our invocation.

/// ...
/// Definition on DownloadFileInteractor class
/// ...

void main() async {
  const downloadFile = DownloadFileInteractor();
  final stopwatch = Stopwatch();

  await downloadFile((
    sourceUri: Uri.parse('https://www.my_website.com'),
    destinationPath: 'downloads/my_website_data.txt',
  ))
  .timeout(const Duration(seconds: 30))
  .receiveBusyState((isBusy) {
    if (isBusy) {
      stopwatch.start();
    } else {
      stopwatch.stop();
    }
  })
  .onResult((data) => print('Downloading succeeded after ${stopwatch.elapsed} with $data'),)
  .onException((exception) => print('Downloading failed after ${stopwatch.elapsed} due to $exception'))
  .run();
}

This example shows an example implementation of a ParameterizedResultInteractor / PRInteractor. The first generic type returns the parameter of execute, the second defines the result/return type.

Modifiers usage #

This library provides the ability to add highly customizable modifiers. There are some pre-defined modifiers such as timeout or busy state. More information on these modifiers can be read in their corresponding examples.

// ...

void main() async {
  const square = Square();
  final result = await square(11)
      .timeout(
        const Duration(seconds: 5),
        'Timeout because the computation took longer than 5 seconds.',
      )
      .receiveBusyState(
        (isBusy) => print('${isBusy ? 'start' : 'stop'} at ${DateTime.now()}'),
      )
      .get();

  print(result);
}

Writing custom modifiers #

Due to the limitations of my few implementations of modifiers provided by the library, i've designed the API publically extendable. For more details you may want to take a look into the implemenation of timeout or busy state modifiers.

You can write your own modifier as follows:

final class CustomModifier<Parameter, Result>
    extends ChainedModifier<Parameter, Result> {
  const CustomModifier(super._modifier);

  @override
  EventHandler<Parameter, Result> buildEventHandler() {
    return super.buildEventHandler().after((details, event) {
      event.whenOrNull(
        onStart: (parameter) {
          print('${details.calleName} started with $parameter -->');
        },
        onResult: (result) =>
            print('<-- ${details.calleName} succeeded with $result'),
        onException: (exception) =>
            print('<-- ${details.calleName} failed with $exception'),
      );
    });
  }
}

// ...

void main() async {
    const interactor = // ...
    final result = await interactor()
        .modifier((modifier) => CustomModifier(modifier)).get();

    print(result);
}

Note that this api will definitely change in future!