i was reading through  https://forge.gemwire.uk/wiki/Capabilities  and one thing caught my eye -

Quote

"Optionally, a Capability Implementation and Capability Provider can also be created. In this case, the provider will be used as described in Attaching a Capability."

question: is there - finally - a nice and elegant way to make simple capabilities for internal use?

i need to attach two integers to a player. no inter-mod interaction perceived.
earlier, when i needed stuff like that, i would just add my field or two into existing nbt tags of an entity and was happy about it.
i refuse and will forever refuse to make two interfaces and four classes to attach a long int to a cow to know when it was last milked.

back in 1.10 or 1.12 days, i made one or two implementations of IExtendedEntityProperties. i liked IExtendedEntityProperties - it gives me what i need - a few fields stored in a nice and clean manner.

but then capabilities came along. and here on the forum nice-new-guy would ask how do i store something in player/itemstack and nice-experienced-guy would say "use capabilities" while an invisible chorus chants "aaaahh" in reverence.

to clarify, i have nothing against capabilities in a "fancy machine" scenario. makes total sense. but for a cow scenario (3 rows above)? no sense at all.

so what's with the wiki page calling parts of this system optional?

Technically, you would only need two classes for this since an interface is not required, but recommended: one for the cap data and one for the provider itself. If you don't want to use the system, you can just try to add persistent data (via #getPersistentData) to the entity nbt directly since the data is relatively small. However, unless you want to build the boilerplate, there is no simple way for adding capabilities with small amounts of data.

As for what the wiki page is calling optional, I believe it's referring to the fact that you technically only need the interface to register a capability. The implementation and provider is only used to actually store the data and is not relevant to the minimum needed to create a capability. In general, you'll almost never see a capability without its implementation and provider.