http://bukkit.fr/index.php?threads/9059

PlayersInRegion.java

package fr.neatmonster.playersinregion;
 
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.block.Sign;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.BlockBreakEvent;
import org.bukkit.event.block.SignChangeEvent;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.java.JavaPlugin;
 
import com.sk89q.worldguard.bukkit.WGBukkit;
import com.sk89q.worldguard.bukkit.WorldGuardPlugin;
import com.sk89q.worldguard.protection.regions.ProtectedRegion;
 
public class PlayersInRegion extends JavaPlugin implements Listener {
    private final Logger       logger = Logger.getLogger("CraftBukkit");
    private final String       logTag = "[PlayersInRegion] ";
    private final List<String> signs  = new ArrayList<String>();
 
    public void save() {
        getConfig().set("signs", signs);
        saveConfig();
    }
 
    @Override
    public void onEnable() {
        final Plugin worldGuard = Bukkit.getPluginManager().getPlugin("WorldGuard");
        if (worldGuard == null || !(worldGuard instanceof WorldGuardPlugin)) {
            logger.info(logTag + "WorldGuard not found, disabling...");
            Bukkit.getPluginManager().disablePlugin(this);
            return;
        }
        signs.clear();
        if (getConfig().contains("signs"))
            signs.addAll(getConfig().getStringList("signs"));
        Bukkit.getPluginManager().registerEvents(this, this);
        Bukkit.getScheduler().scheduleSyncRepeatingTask(this, new Runnable() {
 
            @Override
            public void run() {
                for (final String locationString : signs) {
                    final String[] locationArray = locationString.split(":");
                    final String worldName = locationArray[0];
                    final int x = Integer.parseInt(locationArray[1]);
                    final int y = Integer.parseInt(locationArray[2]);
                    final int z = Integer.parseInt(locationArray[3]);
                    final Block block = Bukkit.getWorld(worldName).getBlockAt(x, y, z);
                    if (block.getState() != null && block.getState() instanceof Sign) {
                        final Sign sign = (Sign) block.getState();
                        final String[] lines = update(sign.getLines());
                        for (int i = 0; i < 4; i++)
                            sign.setLine(i, lines[i]);
                        sign.update();
                    }
                }
            }
        }, 20L, 20L);
    }
 
    @EventHandler(priority = EventPriority.MONITOR)
    public void onBlockBreak(final BlockBreakEvent event) {
        if (event.getBlock().getState() != null && event.getBlock().getState() instanceof Sign) {
            final Location location = event.getBlock().getLocation();
            signs.remove(location.getWorld().getName() + ":" + location.getBlockX() + ":" + location.getBlockY() + ":" + location.getBlockZ());
        }
    }
 
    @EventHandler
    public void onSignChange(final SignChangeEvent event) {
        final String[] lines = update(event.getLines());
        for (int i = 0; i < 4; i++)
            event.setLine(i, lines[i]);
        if (lines[0].equals(ChatColor.GREEN + "[Players]")) {
            final Location location = event.getBlock().getLocation();
            signs.add(location.getWorld().getName() + ":" + location.getBlockX() + ":" + location.getBlockY() + ":" + location.getBlockZ());
            save();
        }
    }
 
    public String[] update(final String[] lines) {
        if (lines[0].trim().equals("[Players]") || lines[0].equals(ChatColor.GREEN + "[Players]")) {
            if (lines[1].trim().isEmpty() || lines[2].trim().isEmpty())
                return error(lines);
            else
                try {
                    final World world = Bukkit.getWorld(lines[2]);
                    final ProtectedRegion region = WGBukkit.getRegionManager(world).getRegion(lines[1]);
                    int count = 0;
                    for (final Player player : world.getPlayers()) {
                        final Location location = player.getLocation();
                        if (region.contains(location.getBlockX(), location.getBlockY(), location.getBlockZ()))
                            count++;
                    }
                    lines[0] = ChatColor.GREEN + "[Players]";
                    lines[3] = "" + count;
                    return lines;
                } catch (final Exception e) {
                    e.printStackTrace();
                    return error(lines);
                }
        }
        return lines;
    }
 
    public String[] error(final String[] lines) {
        lines[0] = ChatColor.RED + "[Players]";
        lines[1] = lines[2] = lines[3] = "";
        return lines;
    }
}