C# - public getter and protected setter interface

Question

Hello i'm working on a Unity game and i would like to create living entities.

To perform this, i want to create an interface for all entities having health

Here is my interface for LivingEntities:

public interface ILivingEntity
{
    public float Hp { get; protected set; }
    public float MaxHp { get; protected set; }
    public float HpRegenPerSecond { get; protected set; }

    public event EventHandler Event_died;

    protected virtual void Awake()
    {
        MaxHp = Hp;
    }

    protected virtual void receiveDamage(IAttack attackSource)
    {
        Hp -= attackSource.damage;
        watchForEntityDeadOrNot();
    }

    protected abstract void watchForEntityDeadOrNot();

    protected void regenHp()
    {
        Hp += Time.deltaTime * HpRegenPerSecond;
        if (Hp > MaxHp)
            Hp = MaxHp;
    }
}

The point is:

I need the hp to be public in get
I want to give code in my interface for the hp regeneration per second (to not re implement the same code in each living entity)
I want the hp to be set only from the living entities themself

I saw tricks like this:

in interface:

public float Hp{get;}

and in implementation:

public float Hp{
  get{code...}
  protected set{code...}
}

but in my case, if i define the setter only in the child class implementation, i'm not able to give any code for my 'regenHp' method in interface.

How to perform this ?

user_1038241 · Answer

Rather than using an abstract base class as was suggested in a comment, you can leverage Unity's built in component design which is the standard way of solving such a problem. Its common for game objects to be composed of many components.

You can define a shared component like:

public class LivingComponent : MonoBehavior
{
    ...
}

And then depend on it in your main components:

[RequireComponent(typeof(LivingComponent))]
public class SomeLivingThing : MonoBehavior {}

And if its important that you still have a read-only interface, you can do that too:

public interface ILivingEntity {
   // Getters only here
}

public class LivingComponent : MonoBehavior, ILivingEntity {
   // Implementation
}

// In some other code:
var hp = obj.GetComponent().Hp;

C# - public getter and protected setter interface

1 Answers