Check for specific entity and help

[KillBill61]

Check for specific entity

 

Hello,
I am new to this and I simple was not able to find an answer. I need to know how to check items, entities etc. if they are really items entities I want.
Something like this:
 

if(entityItem.getUniqueID() == Blocks.OAK_SAPLING.getUniqueID())

or maybe

if(entityItem instanceof ......)

Basically I want to compare the existing one with the pattern. It could be mob, item in hand, item in inventory, item on ground, block on specific position etc. (is there difference?)

 

 

Help

I somehow learned how to use events with @SubscribeEvent and some basic log outputs works ^^

So I wanted to create (to practice understanding this) "auto plant for saplings". Others do this with "ItemExpireEvent" and set despawn time for saplings really low. I don't want to do that that way, because I want normal despawn and differentiate when player throws it and when sapling spawns because leaves vanished or something else spawned it.

When player throws it - it won't auto plant itself. In other cases it auto plant itself.

So I need some "event" or some detection when this "in world item" (item on ground) spawns. I found that "ItemEvent" doesn't detect items spawned by dispenser or when leaves vanishes. Only that were thrown away are detected. This is basically that problem, that I don't know how to detect it. Other problem is that I don't know how to check it if it is (for practice) that SPECIFIC sapling.

 

Can somebody help my second steps?

[DaemonUmbra]

You could detect the ItemEntity Joining the World, and if it's ItemStack's item is a sapling, you could schedule a task to check again after a specific delay, and if the entity still hasn't been picked up (and it's not sitting inside a planted sapling), kill it and set the block at that position to a planted sapling

[KillBill61]

Thank you so much  It was little hard to find the methods when you didn't write it as code, but I did it - thanks

 

Just one question - I found that lot of people use "instanceof" rather than some method.

For example - is there any difference in this?

if(tmpEntity instanceof ItemEntity) {...

and

if(tmpEntity.getType() == EntityType.ITEM) {...

Let's say there is no difference and I want to be effective. I read that calling method with comparison should be much quicker than calling "instanceof" in java.

 

But when I want to know if block is plantable:

if(block instanceof IPlantable) {...

I don't have method for that and I need to use "instanceof" (if I don't want to list all plantable blocks - that is bad, because when I want to add new plant I have to manually put this plant into my list so this is not the way I want).

 

To summarize questions:

1) Is there difference between the first two codes?

2) Should I use "instanceof" often or is there often some method that do the same thing?

[KillBill61]

  On 12/27/2019 at 7:47 PM, diesieben07 said:

Yes. The first one checks for any entities that extend ItemEntity (or ItemEntity itself). The second one only checks for the vanilla item entity.

 

This is completely hand-wavey and has no significance without any actual proof. Always remember the quote: Premature optimization is the root of all evil. Also, instanceof in Java is stupidly fast, its one of the fastest operations (probably faster than a method call, but that also depends on the type of method call, etc.). Performance measurements are ridiculously hard in Java, due to the optimizing JIT compiler.

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Thank you so much for perfect explanation ^^