Scoreboard creation in different class

Hi!

Im rewriting my plugin to make it more clean and nicer,
and in my first version I had a scoreboard, which was made in my onEnable() method.

This time, I've created a new package + class for just my scoreboard, and I want to know how to make a scoreboard outside of the onEnable().

Scoreboard class:

Code:java

package com.dubehh.ScoreBoard;
 
import org.bukkit.Bukkit;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;
 
public class ScoreBoard {
 
public static ScoreboardManager manager;
public static Scoreboard board;
public Objective obj;
 
// onEnable - ish {
manager = Bukkit.getServer().getScoreboardManager();
board = manager.getNewScoreboard();
}
 
 
 
 
}
 

Main

Code:java

package com.dubehh.CoreDefense;
 
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.java.JavaPlugin;
 
import com.dubehh.GameMechanics.GameState;
import com.dubehh.Teams.Commands;
 
public class Main extends JavaPlugin {
 
private static Plugin plugin;
 
public static Plugin getPlugin() {
return plugin;
}
 
 
public void onEnable(){
getLogger().info(" Enabled!");
GameState.setGameState(GameState.LOBBY);
loadCmd();
// Something directing to the Scoreboard class here?
}
 
public void onDisable(){
getLogger().info(" Disabled!");
}
 
public void loadCmd(){
getCommand("Team").setExecutor(new Commands());
}
 
 
 
}

Thank you

Actually,
I would rather know how to
acces the 'onEnable()' method overall, not just using scoreboards.

I tried using a static method in the 'Scoreboard' class, which gave me a NPE.

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

 

Step 1: remove static
Step 2: stop using static
Probably will solve most of the solutions + you will encounter less random (which are actually quite logical if you understand static) problems

 

fireblast709

Thank you, but how would I be able to 'create' this scoreboard without having a onEnable in my class?
+ Isn't static supposed to be there so I can acces it through all classes? Or did I got the wrong impression of it?

Im not an expert of Java, so please don't be too harsh.

 

Dubehh the issue with a lot of new programmers is that they treat static as this magical keyword that will solve all of their issues. You can call

Code:java

Bukkit.getScoreboardManager().getNewScoreboard();

from all methods already, so that should be no issue. If you, for example, need your main class somewhere (perhaps for runnables), you can just use the constructor to pass it along.

Code:java

public class SomeClass
{
    private final <main class> plugin;
 
    public SomeClass(<main class> plugin)
    {
        this.plugin = plugin;
    }
 
    public void anyMethod()
    {
        this.plugin.<any method you can call in plugin, can be called here>
    }
}

And the best thing is: no static involved whatsoever!

To get back to your question about static, that is not the reason it was created. Static fields and methods are class methods. They belong to the class, rather than to a specific instance of that class. And since you can access the class (assuming it is public) everywhere, you can access the fields and methods anywhere.

But they can be hard to work with. You see a lot of people trying to use them, and causing 'random' NullPointerExceptions in the process. That is why I discourage people to use it, until you actually understand how it works and how to deal with it.

 

fireblast709

Thanks
That actually helped.

fireblast709
Hi,

How about the other way around?
What if I want to call a method from another class into the onEnable() ?

because I have this Scoreboard which needs to be called when the server starts up.

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

 

Dubehh I'd suggest you looking at some Java Tutorials. What you are looking for are basics of OOP http://docs.oracle.com/javase/tutorial/java/javaOO/usingobject.html

 

L33m4n123 fireblast709

Hi both,

I am getting a NPE on start up.

main

Code:java

public final ScoreBoard score;
    public Main(){
        score = new ScoreBoard();
    }
 
    public void onEnable(){
        getLogger().info(" Enabled!");
        GameState.setGameState(GameState.LOBBY);
        loadCmd();
        loadScoreBoard();
 
    }
 
    public void onDisable(){
        getLogger().info(" Disabled!");
    }
 
    public void loadCmd(){
        getCommand("Team").setExecutor(new Commands());
    }
    void loadScoreBoard(){
        score.newSb(); //scoreboard class
    }

Scoreboard class

Code:java

public class ScoreBoard {
 
    Scoreboard board;
    ScoreboardManager manager;
    Objective obj;
 
    public void newSb(){
        board = manager.getNewScoreboard();
        obj = board.registerNewObjective("Test", "dummy");
        obj.setDisplaySlot(DisplaySlot.SIDEBAR);
        obj.setDisplayName(ChatColor.DARK_AQUA + "board");
 
    }
 
 
 
}

Error log

Code:

[11:36:06 ERROR]: Error occurred while enabling CoreDefense v0.1 (Is it up to date?)
java.lang.NullPointerException
        at com.dubehh.ScoreBoard.ScoreBoard.newSb(ScoreBoard.java:16) ~[?:?]
        at com.dubehh.CoreDefense.Main.loadScoreBoard(Main.java:32) ~[?:?]
        at com.dubehh.CoreDefense.Main.onEnable(Main.java:20) ~[?:?]
        at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:250) ~[craftbukkit.jar:git-B
ukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:350) [craftbuk
kit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:384) [craftbu
kkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.loadPlugin(CraftServer.java:300) [craftbukkit.
jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.enablePlugins(CraftServer.java:282) [craftbukk
it.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.reload(CraftServer.java:632) [craftbukkit.jar:
git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.Bukkit.reload(Bukkit.java:279) [craftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b0
4d8-b2991jnks]
        at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:199) [craftbukkit.jar:
git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchCommand(CraftServer.java:544) [craftbu
kkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchServerCommand(CraftServer.java:531) [c
raftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.DedicatedServer.aw(DedicatedServer.java:286) [craftbukkit.ja
r:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:251) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:545) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:457) [craftbukkit.j
ar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]

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

 

you get an NPE because you call manager.getNewScoreboard(); yet you never assigned a value to manager

 

L33m4n123

Wow Thanks, that did it!
Thanks for your response.

L33m4n123

Hi! Sorry for the question and all,

but why do I get an NPE here:

TeamClass

Code:java

public class Teams {
 
    public Team red;
    public Team blue;
 
    public final ScoreBoard score;
    public Teams(){
        score = new ScoreBoard();
    }
 
    public void registerTeams() {
        red = score.board.registerNewTeam("red");
        blue = score.board.registerNewTeam("blue");
        red.setAllowFriendlyFire(false);
        blue.setAllowFriendlyFire(false);
        red.setPrefix(ChatColor.RED + "");
        blue.setPrefix(ChatColor.BLUE + "");
    }

(the 'score' class is the same as the code I posted earlier)

Adding:

Code:java

public void addPlayerRed(Player p){
        p.sendMessage(ChatColor.GOLD + "[CoreDefense] " + ChatColor.YELLOW
                + "Welcome in the " + ChatColor.RED + "Red " + ChatColor.YELLOW
                + "team!");
        team.red.addPlayer(p);
    }

When I use the addPlayerRed(Player p) method, in a onCommand,
I get:

Code:

org.bukkit.command.CommandException: Unhandled exception executing command 'team' in plugin CoreDefe
nse v0.1
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[craftbukkit.jar:git-Buk
kit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:199) ~[craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at org.bukkit.craftbukkit.v1_7_R1.CraftServer.dispatchCommand(CraftServer.java:544) ~[craftb
ukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.PlayerConnection.handleCommand(PlayerConnection.java:932) [c
raftbukkit.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.PlayerConnection.a(PlayerConnection.java:814) [craftbukkit.j
ar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.PacketPlayInChat.a(PacketPlayInChat.java:28) [craftbukkit.ja
r:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.PacketPlayInChat.handle(PacketPlayInChat.java:47) [craftbukk
it.jar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.NetworkManager.a(NetworkManager.java:146) [craftbukkit.jar:g
it-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.ServerConnection.c(SourceFile:134) [craftbukkit.jar:git-Bukk
it-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:655) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:250) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:545) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:457) [craftbukkit.j
ar:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [craftbukkit.jar
:git-Bukkit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
Caused by: java.lang.NullPointerException
        at com.dubehh.Teams.TeamMethods.addPlayerRed(TeamMethods.java:32) ~[?:?]
        at com.dubehh.Teams.TeamCmd.onCommand(TeamCmd.java:41) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[craftbukkit.jar:git-Buk
kit-1.7.2-R0.2-14-g15b04d8-b2991jnks]
        ... 13 more

I looked into it, and I have everything assigned right?

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

 

Dubehh Full code please.

 

fireblast709
TeamMethods

Code:java

public class TeamMethods {
 
    public final Teams team;
    public TeamMethods(){
        team = new Teams();
    }
 
    public boolean isInTeam(Player p){
        if(team.blue.hasPlayer(p) || team.red.hasPlayer(p))
            return true;
        return false;
    }
 
    public boolean isRed(Player p){
        if(team.red.hasPlayer(p)) return true;
        return false;
    }
    public boolean isBlue(Player p){
        if(team.blue.hasPlayer(p)) return true;
        return false;
    }
 
    public void addPlayerRed(Player p){
        p.sendMessage(ChatColor.GOLD + "[CoreDefense] " + ChatColor.YELLOW
                + "Welcome in the " + ChatColor.RED + "Red " + ChatColor.YELLOW
                + "team!");
        team.red.addPlayer(p);
    }
    public void addPlayerBlue(Player p){
        p.sendMessage(ChatColor.GOLD + "[CoreDefense] " + ChatColor.YELLOW
                + "Welcome in the " + ChatColor.BLUE + "Blue " + ChatColor.YELLOW
                + "team!");
        team.blue.addPlayer(p);
    }
}    

Registering Teams

Code:java

public class Teams {
 
    public Team red;
    public Team blue;
 
    public final ScoreBoard score;
    public Teams(){
        score = new ScoreBoard();
    }
 
    public void registerTeams() {
        red = score.board.registerNewTeam("red");
        blue = score.board.registerNewTeam("blue");
        red.setAllowFriendlyFire(false);
        blue.setAllowFriendlyFire(false);
        red.setPrefix(ChatColor.RED + "");
        blue.setPrefix(ChatColor.BLUE + "");
    }

TeamCmd

Code:java

public class TeamCmd implements CommandExecutor {
 
    public final Teams team;
    public final TeamMethods teammethods;
    public TeamCmd(){
        team = new Teams();
        teammethods = new TeamMethods();
    }
 
 
    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String label,
            String[] args) {
 
        String prefix = ChatColor.GOLD + "[CoreDefense] ";
 
        if(!(sender instanceof Player)){
            sender.sendMessage(prefix + ChatColor.YELLOW + "You must be ingame to execute this command.");
            return true;
        }
        Player p = (Player) sender;
        if(cmd.getName().equalsIgnoreCase("Team")){
            if(args.length == 0){
                p.sendMessage(ChatColor.GOLD + "[CoreDefense] "
                        + ChatColor.YELLOW + "/Team <team color>");
                return true;
            }else if(args[0].equalsIgnoreCase("red")){
                teammethods.addPlayerRed(p);
            }
        }
 
 
 
        return false;
    }
 
}
 

Incase you want the updated ScoreBoard class

Code:java

public class ScoreBoard {
 
    public Scoreboard board;
    public ScoreboardManager manager;
    public Objective obj;
    public Map<String, Integer> teamScores = new HashMap<String, Integer>();
 
    public void newSb() {
        manager = Bukkit.getScoreboardManager();
        board = manager.getNewScoreboard();
        obj = board.registerNewObjective("Test", "dummy");
        teamScores.put("Core", 70);
        teamScores.put("Core2", 70);
 
        try{
            this.update(obj);
        }catch (NullPointerException e){
            e.printStackTrace();
        }
 
    }

It has trouble finding the team. So I've missed something , I probably did not assign the 'team' right, since I get a NPE

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

 

Dubehh you create like 4 instances of Teams, that will give a lot of issues later since if you change one, the other one remains unchanged. Also Team has two uninitialized fields, blue and red

 

fireblast709

But I did:

Code:java

 red = score.board.registerNewTeam("red");
blue = score.board.registerNewTeam("blue");

?

And call you tell me how to do it proper?
Because I created instance's to acces them w/o making them static

 

Dubehh You never called that method, did you? Your Teams object should be in your main class instead (the one that extends JavaPlugin), and you should create a getter method for it so other classes can access it.

 

fireblast709
I understand what you mean,

but why does the Scoreboard work, and the Teams not?

It is basically the same idea right?

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

 

Dubehh To repeat myself: first you create like 4 instances of the Teams class, which will never work like you expect it to. Secondly, you never call the method that initializes Team red and Team blue.

 

fireblast709
Hey
Sorry for the late response,
but I fixed it by removing every instance, and only using one instance for the Main Class,
I can call every method I want w/o making it static and I managed to make the teams outside of the onEnable (and w/o errors).

Thanks!