[1.12.2] How to check if a player is connected to the server?

[WaningMatrix]

I want to check if a player is connected to the server or not like if say Player A joins a server and there is another Player B in the game [like in TAB list] and if the player is there do something and if not do nothing. How do I do it?

 

 

 

EDIT: this is a repost technically but the last one was for 1.8.9 this time im asking for 1.12

Edited January 29, 2019 by WaningMatrix

[WaningMatrix]

On the client like imagine you are on an minigame server and you join a game, if it sees player B in game as well it does something otherwise nothing, I want it everytime a user joins a new world.

Edited January 29, 2019 by WaningMatrix

[WaningMatrix]

Can you write a sample syntax of how to run it based on what I want to do?

[WaningMatrix]

I mean can you write how do I use the Minecraft#player.connection.getPlayerInfo in my problem which I specified at first post?

[Draco18s]

19 minutes ago, WaningMatrix said:

Minecraft#player

The # here means you need an instance of the Minecraft object in order to access the player field.

[WaningMatrix]

Alright so I'm a beginner to Minecraft Modding, so can you explain me like I'm 5 and how will I use this player.ConnectionInfo if Im writing a mod. I have wrote this but can you let me know whether this is correct or not? 

@SubscribeEvent
    public void EntityJoinsNewWorld(EntityJoinWorldEvent event){
        for (NetworkPlayerInfo p : Minecraft.getMinecraft().getNetHandler().getPlayerInfoMap()) {
            if (Settings.SniperList.get().contains(p.getGameProfile().getName())) {
                Minecraft.getMinecraft().thePlayer.sendChatMessage("/lobby");
                Minecraft.getMinecraft().thePlayer.sendChatMessage("/p warp");
            }
        }
    }

SniperList is just an ArrayList and it executes the if statement if there any player joins the world whose name in the ArrayList.

If this is wrong let me know how will it be corrected and also do I need anything else to include in the Main class other than this. 

Edited January 29, 2019 by WaningMatrix

[Cadiboo]

4 hours ago, WaningMatrix said:

getName

Don’t use names, use UUIDs, and you probably want to `break` on success

Edited January 29, 2019 by Cadiboo