MetadataStorage.jav

package com.comphenix.example;

import java.util.Random;

import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.Listener;
import org.bukkit.metadata.FixedMetadataValue;
import org.bukkit.metadata.MetadataValue;
import org.bukkit.metadata.Metadatable;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.java.JavaPlugin;

public class MetadataStorage extends JavaPlugin implements Listener {
    private static String[] ABILITIES = { "BLINK", "INVISIBILITY", "FIREBALL" };
    
    // Probably a good idea to use your namespace here
    private static final String ABILITY_KEY = "com.comphenix.ability";
    
    private Random rnd = new Random();
    
    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (sender instanceof Player) {
            Player p = (Player) sender;
            
            // Sub commands
            if (args.length == 1) {
                final String subCommand = args[0];
                
                if ("set".equalsIgnoreCase(subCommand)) {
                    String ability = ABILITIES[rnd.nextInt(ABILITIES.length)];
                    
                    setMetadata(p, ABILITY_KEY, ability);
                    sender.sendMessage(ChatColor.GOLD + "Setting ability to " + ability);
                    
                } else if ("get".equalsIgnoreCase(subCommand)) {
                    sender.sendMessage(ChatColor.GOLD + "Current ability is: " + getMetadata(p, ABILITY_KEY));
                    
                } else {
                    sender.sendMessage(ChatColor.RED + "Unknown sub command: " + subCommand);
                }
            } else {
                sender.sendMessage(ChatColor.RED + "Must specify one sub command");
            }
        }
        return true;
    }
    
    private void setMetadata(Metadatable target, String key, String value) {
        target.setMetadata(key, new FixedMetadataValue(this, value));
    }
    
    private String getMetadata(Metadatable source, String key) {
        for (MetadataValue value : source.getMetadata(key)) {
            Plugin owner = value.getOwningPlugin();
            
            // The previous plugin instance might have be collected
            if (owner == null || owner.getName().equals(getName())) {
                return value.asString();
            }
        }
        return null;
    }
}