Dart.Language.Classes & Implementation the interfaces

main.dart

void main() {
  final entity = Entity();

  print(entity is Disposable);
  print(entity is Clonable);
  print(entity is Comparable);
  print(entity is BaseEntity);
  //  entity.
}

abstract class Clonable {
  dynamic clone();
}

abstract class Disposable {
  void dispose();
}

abstract class Comparable {
  int compare();
}

abstract class BaseEntity {
  int get id;
}

class Entity extends BaseEntity implements Clonable, Disposable, Comparable {
  @override
  clone() {
    throw UnimplementedError();
  }

  @override
  int compare() {
    throw UnimplementedError();
  }

  @override
  void dispose() {}

  @override
  int get id => throw UnimplementedError();
}