Abstract Class Declaration (ACD)

Description:

ACD checks declarations of abstract classes. It issues a warning message if:

• An abstract class does not contain abstract methods. In this case, it should be converted into a non-abstract class with a protected constructor to prevent creation of instances of this class.
• An abstract class contains public constructors. A public access modifier is useless because constructors of an abstract class can be invoked only from its subclasses or from the class itself.

Incorrect:

type
  Behavior = class abstract
    public
    constructor Create;
    procedure action;
  end;

Correct:

type
  Behavior = class
    protected
      constructor Create;

    public
      procedure action;
  end;