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:

public abstract class Behavior {
    public Behavior() {
        ...
    }

    public void action(IContext context) {
        ...
    }
}

Correct:

public class Behavior {
    protected Behavior() {
        ...
    }

    public void action(IContext context) {
        ...
    }
}