Thread: Object-Orientated Items?

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Originally Posted by veer

I think I know how to implement item tracking, and I think it's fairly easy.
Most items in game can be treated as what in the domain-driven mindset call value objects. These objects have attributes but no conceptual individual identity... you can see an example of this in the fact most private servers merely keep an item ID or some other reference to a definition (ItemDef).
It should be very clear items have been treated like this in private servers for some time now as it makes sense... an item ID or ItemDef reference are adequate because they are distinct from one another by their attributes, each item's definition.

When people exchange dollar bills, they generally do not distinguish between each unique bill; they only are concerned about the face value of the dollar bill. In this context, dollar bills are value objects.

The concept of value objects contrasts with that of entities, which are not defined merely by their attributes but yet by that very trait value objects lack, a sense of identity.

However, the Federal Reserve may be concerned about each unique bill; in this context each bill would be an entity.

What you can see here is that you are asking how to change items in game from value objects into entities... it is very much possible, but is it practical and worth it?
It'd require quite a change in the codebase. A simple item ID would not be adequate here as instead we would now need to track the identity of each item, distinct from their attributes. Something perhaps like:

Code:

public class Item {

    private UUID id;
    private ItemDefinition definition;
    ....
}

Each individual item in the game could be tracked now by their unique ID distinct from others with the same attributes.
Is it practical, though? Surprisingly so. Good luck.

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As a side note, I'm a little surprised object didn't delve into this... I mean, he was the one who introduced me to DDD in the first place a couple odd years ago.

Originally Posted by Graham

Servers like Hyperion already do this (the normal Hyperion doesn't store anything other than id/amount, but you could add additional attributes if required).

Originally Posted by super_

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Sweet, ill look into doing this then.

Are you planning to log all transactions/track items or something?

i think from his post he's merely interested in being able to retain state with instances of items (like the degradation of barrows items) versus the de facto canonical approach of treating items as value objects and merely keeping references to definitions e.g. using the item ID
i don't actually know how useful it would be, however... don't different states of items have their own respective ID?

Originally Posted by Scu11

Oh by the way the barrows degrading thing is based on your account not the item. If someone uses a "dharoks axe" down to the point where it's 1 point from degrading, and they give you it, it wont degrade until you use up your 'points for it to degrade'. They get around this by not letting you trade them (but that's how it would work).

You can try this by having multiple of the same barrows item at the same degradable state. Get one down to near degrading, put on the other one and it wll degrade instead.

Also @super_ how are you going to keep track of individual items, in things such as stacks? What if I had a stack of 2147M dharok's platebodies. Is the server really supposed to track each one is at what index of the stack? (This is another reason why jagex go the easier way).

So If I have two dharok axes and they're both at say the 75 mark I use one of the axes till it's one point from degrading to the 50 mark then I switch to the other axe and it will degrade as if it was the axe I used down to one point from being at the 50 mark?

you would have a reference to each individual item in the stack, of course...