Dart: Inheritance issues

inheritance_issue_example.dart

// Reference: https://talks.golang.org/2014/go4java.slide#41
void main() {
  RunCounter runner = RunCounter("my runner");

  List<Task> tasks = [Task("one"), Task("two"), Task("three")];
  runner.runAll(tasks);

  print("${runner.name} ran ${runner.count} tasks");
}

//void printd(Object object) => print(object);
void printd(Object object) => null;

class Task {
  final String key;

  const Task(this.key);

  run() => print("Running Task $key");
}

class Runner {
  String _name;

  Runner(String name) : _name = name;

  String get name => _name;

  void run(Task task) {
    printd("[Runner($_name).run]");
    task.run();
  }

  void runAll(List<Task> tasks) {
    printd("[Runner($_name).runAll]");
    for (final Task task in tasks) {
      this.run(task);
    }
  }
}

class RunCounter extends Runner {
  int _count;

  RunCounter(String message)
      : _count = 0,
        super(message);

  int get count => _count;

  @override
  void run(Task task) {
    printd("[RunCounter($_name).run]");
    _count++;
    super.run(task);
  }

  @override
  void runAll(List<Task> tasks) {
    printd("[RunCounter($_name).runAll]");
    _count += tasks.length;
    super.runAll(tasks);
  }
}