An example in Dart based on BiCycle class Example in Java

BiCycle.dart

class BiCycle {
  int _speed = 0;
  int gear;
  int cadence;

  BiCycle(this.gear, this.cadence);

  int get speed => _speed;

  void applyBrake(int decrement) {
    _speed -= decrement;
  }

  void speedUp(int increment) {
    _speed += increment;
  }

  @override
  String toString() => 'Bicycle: Speed $_speed mph';
}

void main() {
  var bike = BiCycle(0, 1);
  print(bike);
  bike.speedUp(10);
  print(bike);
  bike.applyBrake(5);
  print(bike);
  var message = 'Bike details : Gear = ${bike.gear}, Cadence = ${bike.cadence}';
  print(message);
}