Temporary blocks tile entity or separate handler

[matthew123]

The server is placing many (thousands of) blocks for an ability. I need to remove those blocks after a certain number of ticks. Which would be less resource intensive:

• making those blocks tile entities, with an internal counter, and have them remove themselves when the counter reaches the threshold

• add the block positions to a persistent world capability, with a HashMap of position and number of ticks, and on every server tick (or every 10, or more, to save performance), iterate trough the hashmap, check every counter, and if it has reached the threshold, remove the block at position, else increment the counter. How do I tell if the block at the block position wasn't replaced?

p.s the block in question is dirt. For #1, I would be creating a tile entity with it's texture. Also, the interval does not have to be very accurate (it would be about one minute or so, about 60*20 ticks)

 

Is there an even better way then the ones above?

[matthew123]

Second option then. But #1 is easy to implement. What is the performance impact of a few thousand function calls and integer writes for the tile entities? Is implementing #2 even worth it? 

[Draco18s]

3 hours ago, matthew123 said:

Second option then. But #1 is easy to implement. What is the performance impact of a few thousand function calls and integer writes for the tile entities? Is implementing #2 even worth it? 

TileEntities have a large overhead. Thousands of them would grind the server to a hault.
#2 is a huge pain in the ass to implement, so don't.
Use random ticks as D7 suggested (look at crops).

[matthew123]

10 hours ago, diesieben07 said:

No. I suggested a third option which requires neither.

Oh, sorry about that. I didn't quite understand what random ticks were. 

Using them seems easy enough. Thanks.

[matthew123]

I decided to also implement #2 for learning purposes. How do I serialize the level then get it back at runtime? I know there is something called dimension ID, but I don't know how to use it.

[matthew123]

Ah, I see that world capabilities are per level. That complicates things. I guess I will need capabilities for every level. That actually removes the need to serialize/deserialize the level.

[matthew123]

How do I get all the worlds in order to get the capability I attached to them?

[matthew123]

I found a private method called getWorldArray on MinecraftServer. Do I use reflection to get it? I could also add my capability objects to a tracking list whenever they are created. Which one should I go for?

[matthew123]

Oh no. I got a race condition!

[matthew123]

The only way this could have happened is if the method to add a block to the list was called in parallel of the method that is called every server tick. This is weird, I will add some break points to try and extract the thread ids.

[matthew123]

They are both on the server thread. Why is this happening?

[matthew123]

It wasn't a threading issue. The java collection did not allow removing items while iterating trough it.

[matthew123]

I 

4 minutes ago, diesieben07 said:

MinecraftServer#getAllLevels

However you can just use WorldTickEvent and not bother with looping through the world list.

I was looking for levelArray usages. Didn't notice the levels map. Thanks!