Check if another IP is online?

I want a basic bit of code to check if a server IP is online or offline, in a boolean.
I cant find a website that says true/false to grab HTML from, or any quicker ways.

Thanks,
TheBigDolphin1.

 

Something like:

Code:

public boolean checkIPisOnline(Player player, String ip){
 for(Player p : Bukkit.getServer().getOnlinePlayers()){
  if(p.getAddress().getIp() == player.getAddress().getIp()){
  return false;
}

I know this code won't work, but what to do is iterate over online players, and onJoin check if a player online already has the IP

 

I don't think he wants to check if there's a player with a certain IP online, but I think he wants to check if a server is online / offline.

 

^ Correct

Anyone?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

which programming language are you requesting this in?

 

Assume it's java, most plugins are. Although it is a reasonable request.

 

Here is an incredibly simple way to check if the server is online. I'm fairly positive that it will return a false-positive if the server is "frozen" but still on.

Code:

public static boolean isRemoteOnline(String host, int port){
try{
new Socket(host,port).close();
return true;
}catch(Exception e){ return false;}
}

 

skore87 this method works great. Only one problem: It takes like 10 seconds to obtain the server.
Is this the fastest way?

 

10 seconds?? What kind of backwards ISP are you or the server running on? It should be relatively quick.

 

Hmm ok.
Thanks.
It was probably slow cos I test plugins on my 1Mb/s internet!

 

This is one of the cases where an async task makes sense. But make sure to make this thread safe: What is 'Thread-Safety' and how it affects me?

 

This. As long as you aren't calling Bukkit methods or accessing variables in other threads that aren't thread safe, do it in another thread. And since you aren't, I think it should be fine.