I'm trying to understand capabilities but since the "system" got recently renewed I can't find any tutorial about it and the forge documentation doesn't give me the info I need.

As I understood there is an interface for the capability and a "handler" class which implements the interface.

I got the following:

interface:

Spoiler

@AutoRegisterCapability
public interface IQuestStatus {
	/**
	 * Saves values from a HashMap as NBT data
	 * @param nbt
	 */
	public void saveNBTData(CompoundTag nbt);
	
	/**
	 * Writes the saved NBT data into a HashMap
	 * @param nbt
	 */
	public void loadNBTData(CompoundTag nbt);
}

 

 

handler:

Spoiler

public class QuestStatusHandler implements IQuestStatus, INBTSerializable<CompoundTag> {
	private HashMap<String, Boolean> questStatus = new HashMap<String, Boolean>();
	private int questsInTotal = 1;
	
	public void saveNBTData(CompoundTag nbt) {
		/* the NBTData is structured like this:
		 * (String questID, boolean value)
		 *	
		 * value == true:	quest is accepted
		 * 
		 * value == false:	quest is not accepted
		*/
		for(int i = 0; i < questStatus.size(); i++) {
			nbt.putBoolean("quest_"+i, questStatus.get("quest_"+i));
		}
	}
	
	
	public void loadNBTData(CompoundTag nbt) {
		for(int i = 0; i < questsInTotal; i++)
			questStatus.put("quest_"+i, nbt.getBoolean("quest_"+i));
	}

	@Override
	public CompoundTag serializeNBT() {
		CompoundTag nbt = new CompoundTag();
		saveNBTData(nbt);
		return nbt;
	}

	@Override
	public void deserializeNBT(CompoundTag nbt) {
		loadNBTData(nbt);
	}
}

 

 

Now, first I wanna know how to load the NBT data when a Player connects and second, how to save the NBT data when a Player disconnects.

Also I only need to change a value saved in the HashMap questStatus then, which is from player to player different right?

If so is there any specific way I have to use or can I somehow access it from the player?

 

Edited November 27, 20222 yr by Ezio214

https://forge.gemwire.uk/wiki/Capabilities

I don't get it. 

So I have my own capability interface and that needs to have the @AutoRegisterCapability annotation so the capability gets registered.

My "Handler" class is the Implementation class of my own capability interface.

 

Do I need now a Capability Provider (Persistent Provider) to access the values I stored or how do I do that?

Relook at that link. The information is there, including a whole worked example at the bottom on how to attach to an entity and store a "damageDealt" field.

You don't need the first part if you are using the annotation for capability registration.

There's also a separate page on that same wiki: https://forge.gemwire.uk/wiki/Capabilities/Attaching

 

So after looking again at the post and at the code example I got to something. I just didn't use the attach-method they have. Instead I used the following SubscribeEvent:

Spoiler

@SubscribeEvent
public static void onAttachCapabilities(AttachCapabilitiesEvent<Entity> event) {
	if(event.getObject() instanceof Player) {
		if(!event.getObject().getCapability(QuestStatusProvider.INSTANCE).isPresent()) {
			System.out.println("[DEBUG]: >>>> attached QuestStatus-Capability to Player <<<<");
			event.addCapability(QuestStatusProvider.IDENTIFIER, new QuestStatusProvider());
		}
	}
}

 

which works. Thank you for that

 

What I dont understand is how I can save the NBT-data and how I can modify it.

Edited November 24, 20222 yr by Ezio214

After a very long (around 4 hours) brainstorm and trying out code without really understanding it, I found the answer.

To anyone courios about how to modify NBT-data or even read it:

// somewhere in your code where you need to read/modify the capability
// for class structure see here: https://gist.github.com/TheCurle/6db954d680f6f067dcdc791355c32c89
player.getCapability(CustomCapabilityProvider.INSTANCE).ifPresent(capability -> {
  // change or read your capability here
};

 

Still I dont know how to save the NBT-data when the player leaves his world/server. As soon as I know I'll let you all know.

Edited November 24, 20222 yr by Ezio214

Found out that capabilities are saved automatically, I just didn't see that because my client and my server don't seem to synchronize.

[12:44:08] [Server thread/INFO] [co.tu.MODID/]: [MODID_DEBUG] :: questStatus quest_0 from player is 1
[12:44:08] [Render thread/INFO] [co.tu.MODID/]: [MODID_DEBUG] :: questStatus quest_0 from player is 0

The Logger gives me this info when I right click my villager to open a Screen only if questStatus equals 0.

As soon as I press a button on that Screen both, client and server, are set to 1 -> that works. But it seems like the nbt-data gets only loaded server-side. How can I load the same values for client-side?

Why do you keep asking questions that are answered in links to docs that have already been posted?

https://forge.gemwire.uk/wiki/Capabilities/Attaching#Synchronizing_Data_with_Clients

It makes me think I am wasting my time being your search engine, if you don't read the links I give you. 🙂 

Your question has also been answered maybe a hundred times in this forum in various forms depending upon the use case.