I am trying to store custom data into a chunk so that

 

1) The data is preserved if the chunk is unloaded

2) I can read the data if I have a Chunk instance.

 

I tried the ChunkDataEvent.Load and ChunkDataEvent.Save events but did not figure out how to solve (2).

 

How do I achieve this? Thanks in advance.

You have to store the data in a

Map<Chunk, [data]>

(

HashMap

is the obvious implementation choice[/code]). You have to unload from this Map using

ChunkEvent.Unload

.

Then make a

WorldSavedData

instance to attach this Map to a World instance. You can see an example of this here. Note that the WorldSavedData is not actually saving anything to disk (hence never call

markDirty

on it), it is purely to attach your Map to the World.

Do I have to write the data using the readFromNBT and writeToNBT methods?

 

I have tried using ChunkEvent.Load/Unload but did not find a way to write data into the chunk. I am thinking about using ChunkDataEvent.Load/Save but not sure if it is good practice.

FYI:

ChunkDataEvent is for reading/writing to disk, but in no way tells you that the chunk has been removed from memory and to disassociate any extra data from your Map.

ChunkEvent.Load/Unload on the other hand, runs on a separate thread.  (ConcurrentHashMap is needed, fortunately this Map alone should be sufficient to solve that problem).

 

You'll still have to figure out a couple other problems (the sequence of events that get fired is not simple); just don't do something like

world.getChunkFromChunkCoords(x, z).isChunkLoaded

because that'll load the chunk and be useless.