'Radius' expert needed

I'm trying to create a player tracking system whereby if a player is standing on a diamond block & has a diamond within their inventory, it will show the coordinates of their target player, BUT i would like it to only look within a 5000 block radius, to make it less over powered as its a raid server.
This is the working code so far, I need help implementing this radius check though:

Code:java

 
if(commandLabel.equalsIgnoreCase("track")){
if(args.length == 0){
player.sendMessage(ChatColor.DARK_RED + "Correcct use: /track (player)");
}else if(args.length == 1){
Player player2 = Bukkit.getPlayer(args[0]);
Block block = player.getLocation().getBlock().getRelative(BlockFace.DOWN);
Location tpl = player2.getLocation();
if( player2 != null && player2.isOnline() ) {
if(block.getType().equals(Material.DIAMOND_BLOCK)){
if(pinv.contains(Material.DIAMOND)){
player.sendMessage(ChatColor.RED + args[0] + ChatColor.GREEN + " X: " + ChatColor.WHITE + Math.round(tpl.getX())
+ ChatColor.GREEN + " Y: " +ChatColor.WHITE + Math.round(tpl.getY()) +ChatColor.GREEN + " Z: " +
ChatColor.WHITE + Math.round(tpl.getZ()));
pinv.removeItem(new ItemStack(Material.DIAMOND, 1));
}else{
player.sendMessage(ChatColor.DARK_RED + "It costs 1 diamond to attempt to track players!");
}
}else{
player.sendMessage (ChatColor.DARK_RED + "You must be on a Diamond Block to track players!");
player.setHealth(player.getHealth()-3);
}
}else{
player.sendMessage(ChatColor.DARK_RED + "Player is not online or does not exist");
}
}
}
[/syntax=java]

 

That's actually pretty straight forward.

Code:java

if (player1.getLocation().getDistance(player2.getLocation()) < 5000)

should get you there.

 

sqrt((player1x - player2x)^2 + (player1z-player2z)^2) <= 5000

Or what minoneer said.

 

minoneer player1.getLocation().distance(player2.getLocation()).

 

do if (player1.getLocation().distanceSquared(players.getLocation()) <= 25000000)
if uses less memory

 

Good advice, but the pedant in me has to point out: It doesn't use less memory, but it does use less CPU (Math.sqrt() is a fairly expensive calculation).

 

Good point, although I don't think it makes a huge difference in this case, since he's only doing 1 calculation per command.

 

Thanks guys, Implementing now, Didn't think it was that straight forward

EDIT: it works great! any idea how to list all players within a radius? I've heard about getNearbyEntities() but am having trouble using it.

 

Code:

List<Player> Players = new Arraylist<>();
for (Entity entity : player.getNearbyEntities(2500, 128, 2500)) {
  if (entity instanceof Player) {
    Players.add((Player) entity);
  }
}

 

Thanks! that worked great other than
List<Player> Players = new Arraylist<>();
needed to be
ArrayList<Player> Players = new ArrayList<Player>();
Thanks to everyone thet helped

 

Hm, I use NetBeans, it suggest to just use a diamond interface (just ArrayList<>()), thought that was universal on all IDE's

 

The diamond operator is a Java 7 construct. If you want your code to be backwards compatible (generally a good idea), you need to include the parameterised type too.

 

Ah, thank you, I did not know.

 

One final thing, I'm trying to 'list players' in chat - for the sender, and this is my code

Code:java

 
if(block.getType().equals(Material.DIAMOND_BLOCK)){
ArrayList<Player> Players = new ArrayList<Player>();
for (Entity entity : player.getNearbyEntities(1000, 256, 1000)) {
if (entity instanceof Player) {
Players.add((Player) entity);
}
}
player.sendMessage(ChatColor.GREEN + "Players Within Range: " + ChatColor.WHITE + Players);
pinv.removeItem(new ItemStack(Material.DIAMOND, 5));
player.sendMessage(ChatColor.GREEN + "Operation costed 5 Diamonds.");
}
 

Which works all fine, but when it lists the player it comes up like: [CraftPlayer{name=ambyboo}] and thats looks very unprofessional so is there anyway of only displaying their IGN? i've tried .getDisplayName() - did not work.

 

Player.getDisplayName() gives you the name, including all prefixes. If you just want the name itselv, use Player.getName(). In order to show all online Players, you have to loop through the list and add them all, i.e.

Code:java

StringBuilder sb = new StringBuilder()
for (Player p : players) {
    sb.append(p.getName()).append(' ');
}
player.sendMessage(ChatColor.GREEN + "Players Within Range: " + ChatColor.WHITE + sb.toString());
 

 

'Players' is a ArrayList of Player, if you want to create a List of their names do this:

Code:

 ArrayList<String> Players = new ArrayList<String>();
for (Entity entity : player.getNearbyEntities(1000, 256, 1000)) {
if (entity instanceof Player) {
Players.add(((Player) entity).getName());
}
}
player.sendMessage(ChatColor.GREEN + "Players Within Range: " + ChatColor.WHITE + StringUtils.join(Players, ", "));
pinv.removeItem(new ItemStack(Material.DIAMOND, 5));
player.sendMessage(ChatColor.GREEN + "Operation costed 5 Diamonds.");

 

It seems to work with minoneers suggestion:

Code:java

 
if(pinv.contains(Material.DIAMOND, 5)){
ArrayList<Player> Players = new ArrayList<Player>();
for (Entity entity : player.getNearbyEntities(1000, 256, 1000)) {
 if (entity instanceof Player) {
   Players.add((Player) entity);
 }
}
for (Player p : Players) {
   sb.append(p.getName()).append(' ');
}
player.sendMessage(ChatColor.GREEN + "Players Within Range: " + ChatColor.WHITE + sb.toString());
pinv.removeItem(new ItemStack(Material.DIAMOND, 5));
player.sendMessage(ChatColor.GREEN + "Operation costed 5 Diamonds.");
}else{
player.sendMessage(ChatColor.RED + "This operation costs 5 diamonds!");
}
 

- Anyways the system is almost complete just a final bug that i've been scouting the forums for an answer to for at least an hour now.

Code:java

 
//onCommand
if(player2 != null && player2.isOnline()) {
//code
}else{
player.sendMessage(ChatColor.RED + "player isn't online");
 

But when i use the command and the player IS NOT online it says 'an internal error occured...'
Any ideas?