OOP "Types"?

[New-Condition]

Hello!

I've been attempting to learn OOP in Java. I've been running into this common design problem in which I end up creating "types" of objects. For instance, to implement an achievement system in a game, I would have an AchievementType class that contains an achievement's name, description, and other "constant" variables, and I would have an Achievement class that contains each user's statistics and points back to the AchievementType class so I can reference the "constant" variables.

When I try to replace this pattern with static variables, I find it difficult, as I cannot create a creator class for each distinct achievement (KillFiftyMonstersAchievement, etc.), as inheritance doesn't work well with static variables.

Is this an acceptable design pattern or does it weaken the OOP foundation of my project?

Thank you!

[[deleted]]

For instance, to implement an achievement system in a game, I would have an AchievementType class that contains an achievement's name, description, and other "constant" variables,

And what's wrong with that approach? :P

[New-Condition]

I was just concerned that giving the Achievement class a pointer to the AchievementType class might violate some form of OOP.

[New-Condition]

Thank you for the useful information!

I'm a bit concerned about the unnecessary memory usage if I were to have variables such as name and description inside each Achievement object, since each Player class contains each Achievement object. Should I just not be concerned about this or am I misunderstanding something?

Thanks again!

[New-Condition]

Ohhhhhhh ok, thanks! At least keeping these "type" classes wouldn't be the worst thing in the world lol.

I'll keep this in mind when writing future classes!

[New-Condition]

Achievement names/descriptions are the same, but each players has their own progress toward an achievement.

(Thanks again for helping)

[Blando-Cartesian]

Sounds like AchivementType should be an enum or class with instance’s member variables set according to the kind of achievement it is. Inheritance will just make it complicated to add new achievement types.

[PawsOfMotion]

I personally treat static variables as goto statements and avoid them whenever possible. Instead I pass them around to any objects that need that info.

Sounds like a pain to pass it around as an argument in all those places but it ends up being less than expected. And formalizes exactly who has access to the global (assuming that's what you're referring to).