How do you access the current dedicated server instance? [SOLVED]

[Laike_Endaril]

Edit 3 ======================================================

In general, the answer is:

FMLCommonHandler.instance().getMinecraftServerInstance()

Credits to VoidWalker for this bit of code

End Edit 3 ==================================================

 

 

If I wanted the integrated server instance on a client, I could use this:

Minecraft.getMinecraft().getIntegratedServer()

But for a dedicated server, I cannot find any way to obtain the currently running server instance.

This train of thought spawned from trying to get the dedicated server and integrated server player lists.

Which spawned from trying to determine whether an entity is a player or not WITHOUT using this:

    public static boolean isPlayer(Entity entity)
    {
        Minecraft.getMinecraft().getIntegratedServer()
        return entity instanceof EntityPlayer;
    }

 

Honestly, for the mod I'm making right now, instanceof (though slow) is good enough, but for the future, I would really like to know how to get the running server instance.  Apparently, there used to be a static accessor:

MinecraftServer.getServer()

But it no longer seems to exist!  There IS a non-static accessor (in MinecraftServer.java):

public MinecraftServer getServer()
{
	return this;
}

But obviously in order to use it, you already need the instance!  Isn't this pointless?  My best guess is that someone mistakenly changed the static method to a non-static method?  Am I missing something here?

 

Sorry for the excitement.  Hopefully I'm just missing something obvious.  My current forge version is 14.23.5.2768.

 

 

Edit 1 ======================================================================

With a bit more snooping around in MinecraftServer.java, I found this line (line 976), along with several others similar to it:

return MinecraftServer.this.profiler.profilingEnabled ? MinecraftServer.this.profiler.getNameOfLastSection() : "N/A (disabled)";

 

Notice where it says "MinecraftServer.this...."

I'm guessing someone did a find and replace on a static field that used to exist within MinecraftServer which used to reference a field containing the MinecraftServer instance, which would have been set in its constructor?  I don't know, but it's really triggering my OCD after looking around for the last few hours.

 

Edit 2 =====================================================================

I also found out that the DedicatedServer constructor is only ever called once, inside the main() method of MinecraftServer, assigned to a method-scoped variable and inaccessible from anywhere else, so how on earth are you supposed to access eg. DedicatedServer::getPlayerList()?  I'm really not seeing any way for modders to access the server or playerlist in general?

Edited November 4, 2018 by Laike_Endaril

[V0idWa1k3r]

  public static boolean isPlayer(Entity entity)
    {
        Minecraft.getMinecraft().getIntegratedServer()
        return entity instanceof EntityPlayer;
    }

Uhh... fitst of all this code doesn't even compile. Secondly there is exactly zero need to get a server to determine whether the entity is a player. Even in this snippet you've provided getting the server does absolutely nothing.

 

  On 11/4/2018 at 11:14 PM, Laike_Endaril said:

instanceof (though slow) is good enough

Expand  

instanceof in java8+ is one of the fastest operations the JVM can perform.

 

  On 11/4/2018 at 11:14 PM, Laike_Endaril said:

But obviously in order to use it, you already need the instance!  Isn't this pointless?  My best guess is that someone mistakenly changed the static method to a non-static method?  Am I missing something here?

Expand  

It is kinda useless for the MinecraftServer class itself but different implementations of that class may override the method to do something else.

 

If you want the DedicatedServer you can use FMLServerHandler#getServer, that one is pretty much guaranteed to return a DedicatedServer. However remember that DedicatedServer class only exists on the physical server, so if you access it in any way you need to do it in your server proxy. In a lot of cases a simple MinecraftServer will suffice and you can get that through FMLCommonHander#getMinecraftServerInstance which will return either an IntegratedServer(client) or a DedicatedServer(server). 

Again though, you do not need a server instance for your issue.

 

  On 11/4/2018 at 11:14 PM, Laike_Endaril said:

Notice where it says "MinecraftServer.this...."

I'm guessing someone did a find and replace on a static field that used to exist within MinecraftServer which used to reference a field containing the MinecraftServer instance, which would have been set in its constructor?  I don't know, but it's really triggering my OCD after looking around for the last few hours.

Expand  

Object.this has nothing to do with what you are talking about, it's just a way to access the parent instance of inner non-static class instances. 

Edited November 4, 2018 by V0idWa1k3r

[Laike_Endaril]

  On 11/4/2018 at 11:27 PM, V0idWa1k3r said:

Uhh... fitst of all this code doesn't even compile. Secondly there is exactly zero need to get a server to determine whether the entity is a player. Even in this snippet you've provided getting the server does absolutely nothing.

Expand  

Sorry, part of that code should have been removed, I was only using the first line to exploit intellJ's Ctrl+B lookup.  The actual code there should be:

public static boolean isPlayer(Entity entity)
{
	return entity instanceof EntityPlayer;
}

 

  On 11/4/2018 at 11:27 PM, V0idWa1k3r said:

instanceof in java8+ is one of the fastest operations the JVM can perform.

Expand  

That is wonderful news.  Honestly it's been a while since I did much java, and it used to be horrendously slow, so that makes me feel a bit better.

 

  On 11/4/2018 at 11:27 PM, V0idWa1k3r said:

If you want the DedicatedServer you can use FMLServerHandler#getServer, that one is pretty much guaranteed to return a DedicatedServer. However remember that DedicatedServer class only exists on the physical server, so if you access it in any way you need to do it in your server proxy. In a lot of cases a simple MinecraftServer will suffice and you can get that through FMLCommonHander#getMinecraftServerInstance which will return either an IntegratedServer(client) or a DedicatedServer(server). 

Again though, you do not need a server instance for your issue.

Expand  

This is extremely helpful, so thank you!  I have a lot to say about forge's naming sense though.  Anyone using an IDE class lookup will be searching the word "server" and "FMLCommonHandler" is most certainly not going to appear.  Was that covered in the forge documentation somewhere?  In any case, that's what I was looking for, so thanks again.

 

  On 11/4/2018 at 11:27 PM, V0idWa1k3r said:

Object.this has nothing to do with what you are talking about, it's just a way to access the parent instance of inner non-static class instances.

Expand  

Right, I meant that the functionality of "MinecraftServer.this" would have been identical accessing a theoretically-once-existed-but-no-longer-does static field within MinecraftServer containing the parent instance.

 

Thanks again!

[Laike_Endaril]

For posterity, the code you are looking for is:

FMLCommonHandler.instance().getMinecraftServerInstance()

Thanks again to VoidWalker!