[Tutorial] How to access the config.yml in an external class! (Constructors)

I have created this tutorial to explain how to access the config.yml file from an external class. (Not the main class) Personally, I occasionally forget how to do this, so I would like to help everyone else who doesn't know how to do this.

I hope I can explain this thoroughly to help you understand constructors fully.

This also works for any other methods that are accessed in the main class, that cannot be accessed in an external one.

I understand this is a rather easy tutorial, but this is for more beginners than pros


What a constructor is in terms of Java itself?

Explanation (open) Explanation (close)

A constructor makes you able to do many things. A constructor runs as soon as it is called in the main code, so as soon as you have:

Code:

<Class> <Variable> = new <class>();

it will run what is in the constructor of that class.



Now if you have parameters such as a string, this can be used to set a variable.

Example:

Code:java

 //For this I will use the class name: Apples
 
public class Apples {
 
String name;
 
public Apples(String name) {
this.name = name;
 
}
}

Now that the constructor has been made, in the MAIN class, you need to call it.

Code:java

Apples apple = new Apples("Trevor");

With the above code, what it does it is sets the string 'name' in the class Apples to your parameters. In this case it is 'Trevor.' So now, when ever you access the string 'name' from the class Apples it will return what is in your parameters.

Example:

Code:java

public class Main{
 
public static void main(String[] args) {
Apples apple = new Apples("Trevor");
 
System.out.println(apple.name);
}
 
}

This will print "Trevor" because that is what is in the parameters.

What you need:
Items/Programs:

• A code writing program
• Basic understanding of java

What you will create/do:
At the end of this tutorial, you will know how to:

• Access the config.yml externally(not main class)
• create a basic constructor

First:
First, you will need to establish the plugin object in the external class. To do so, use the below code.
Code:

Code:java

public <Main_Class_Name> plugin;

Second:
Second, you will need to create a constructor in the external class. To do that, you need to use the code below.
Code:

Code:java

public <class_name>(<Main_Class_Name> plugin){
this.plugin = plugin;
}

Finally:
Finally, all you need to do is run the line to access the config. To do so, you will have to use 'plugin' before getConfig().
Code/Example:

Code:java

plugin.getConfig()*etc*;

Now you should be able to access the config from ANY class & you should have a better understanding of Constructors!

Proof?

is in the pudding! (open) is in the pudding! (close)

Thanks for reading, and I hope I helped you!
Please answer the poll as to if I helped you!

 

Very good tutorial

Support

 

This isn't really a tutorial on accessing the config in an external class, rather accessing variables from other classes.

 

zachoooo Good point, but I have found many people asking how to access the config, rather than any other variables.

 

I see

 

If i make methods inside external class then how would i call them corretly with plugin working too, i cant seem to get that working.

//Methods is my external class
Methods m = new Methods(plugin);
and now if i do m.methodName(); then it gives an error

I think i need to do something on onEnable but not sure

 

I wish I had this tutorial like 5 months ago

 

FozZeW What is the error, and what is the contstructor you have in your external class?

 

I don't want to be THAT GUY, but you need to learn Java. I don't mean this in any negative way, but if you just watched a couple basic tutorials or read a basic book it would sum it up right away.

 

I have same costructor as your tutorial

 

thanks a lot for this i am a beginner and this helps!

 

Okey i got mine to work now

 

tanveergt5 Of course

FozZeW Great! Post if you have another issue, I will gladly help.

 

Well.. this is kind of for extreme beginners. ;l Not really useful for people with basic Java knowledge.

 

Rprrr Yes, and you have 8 plugins, but the majority of people here don't...

 

Thank you for this! Hopefully there won't be as many people asking the same questions that can be solved with a constructor now

 

Axe2760 Thanks! I hope so too

It's my first tutorial, so I just thought I would start with something simple

 

Well I can't say anything against the principle of passing in variables via the constructor to use them, BUT when talking about referencing the plugin instance, I don't like it. Not just because I always need to have the plugin reference in the class where I'm instantiating the other class which needs the plugin instance, but also because now my reference is everywhere. A singleton is, in my eyes, a way better solution to this, especially because the JavaPlugin is more or less already a singleton since there will always be only one plugin instance at the time. Because this is already given, the principle of a singleton is way easier to implement and to use, as long as you clean it up properly (one line is most likely enough), then it's all fine.

 

This is the proper way to do it. If you're talking about using a single static instance, that's not good practice

 

zachoooo Not really. It's considered a totally valid design pattern and is widely accepted. That being said, if you use it properly it can in fact be seen as good practice.

 

This tutorial was one of the most helpful tutorials ever. However, it does not work if the external class is implementing CommandExecutor. Help?

I need answer to this ASAP. Thanks!

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

 

SourceForums
What are you talking about? It works just fine if the class implements CommandExecutor. You must've done something wrong. May I see your code?

 

Assist
Thanks for your quick reply. Here's my code for the main class:

Code:java

package net.sourceforums.sourcecraft;
 
import java.util.logging.Logger;
 
import net.sourceforums.sourcecraft.SourceCraft;
import net.sourceforums.sourcecraft.Commands.CommandBroadcast;
import net.sourceforums.sourcecraft.Commands.CommandBurn;
import net.sourceforums.sourcecraft.Commands.CommandFly;
import net.sourceforums.sourcecraft.Commands.CommandForce;
import net.sourceforums.sourcecraft.Commands.CommandGetpos;
import net.sourceforums.sourcecraft.Commands.CommandHat;
import net.sourceforums.sourcecraft.Commands.CommandHeal;
import net.sourceforums.sourcecraft.Commands.CommandHub;
import net.sourceforums.sourcecraft.Commands.CommandInvsee;
import net.sourceforums.sourcecraft.Commands.CommandMotd;
import net.sourceforums.sourcecraft.Commands.CommandNick;
import net.sourceforums.sourcecraft.Commands.CommandRules;
import net.sourceforums.sourcecraft.Commands.CommandWarning;
import net.sourceforums.sourcecraft.Listeners.MainPlayerListener;
import net.sourceforums.sourcecraft.Listeners.SuperCraftBrosBrawlPlayerListener;
 
import org.bukkit.plugin.java.JavaPlugin;
 
public class SourceCraft extends JavaPlugin{
    public final Logger logger = Logger.getLogger("Minecraft");
 
    public static SourceCraft plugin;
 
    @Override
    public void onEnable(){
        new MainPlayerListener(this);
        new SuperCraftBrosBrawlPlayerListener(this);
        this.saveDefaultConfig();
        getCommand("broadcast").setExecutor(new CommandBroadcast());
        getCommand("burn").setExecutor(new CommandBurn());
        getCommand("fly").setExecutor(new CommandFly());
        getCommand("force").setExecutor(new CommandForce());
        getCommand("getpos").setExecutor(new CommandGetpos());
        getCommand("hat").setExecutor(new CommandHat());
        getCommand("heal").setExecutor(new CommandHeal());
        getCommand("hub").setExecutor(new CommandHub());
        getCommand("invsee").setExecutor(new CommandInvsee());
        getCommand("motd").setExecutor(new CommandMotd());
        getCommand("nick").setExecutor(new CommandNick());
        getCommand("rules").setExecutor(new CommandRules());
        getCommand("warning").setExecutor(new CommandWarning());
        getCommand("gear").setExecutor(new CommandWarning());
    }
}

Also, here's my code for the class with CommandExecutor:

Code:java

package net.sourceforums.sourcecraft.Commands;
 
import net.sourceforums.sourcecraft.SourceCraft;
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.PlayerInventory;
import org.bukkit.inventory.meta.BookMeta;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.potion.PotionEffect;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;
 
public class CommandHub  implements CommandExecutor{
    public SourceCraft plugin;
 
    public CommandHub(SourceCraft plugin){
        this.plugin = plugin;
    }
 
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args){
    Player player = (Player) sender;
    PlayerInventory inventory = player.getInventory();
    if(args.length == 0){
        int creditsValue = plugin.getConfig().getInt(player.getName() + ".economy.credits");
        ScoreboardManager boardManager = Bukkit.getScoreboardManager();
        Scoreboard stats = boardManager.getNewScoreboard();
        Objective objective = stats.registerNewObjective("stats", "dummy");
        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
        objective.setDisplayName(ChatColor.WHITE + "Stats");
        Score credits = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.GOLD + "Credits: "));
        credits.setScore(creditsValue);
        Score online = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.GREEN + "Online: "));
        online.setScore(Bukkit.getOnlinePlayers().length);
        player.setScoreboard(stats);
        plugin.saveConfig();
        ItemStack book = new ItemStack(Material.WRITTEN_BOOK, 1);
        ItemStack compass = new ItemStack(Material.COMPASS, 1);
        ItemStack clock = new ItemStack(Material.WATCH, 1);
        ItemStack emerald = new ItemStack(Material.EMERALD, 1);
        ItemStack air = new ItemStack(Material.AIR, 1);
        BookMeta bookMeta = (BookMeta) book.getItemMeta();
        ItemMeta compassMeta = (ItemMeta) compass.getItemMeta();
        ItemMeta clockMeta = (ItemMeta) clock.getItemMeta();
        ItemMeta emeraldMeta = (ItemMeta) emerald.getItemMeta();
        bookMeta.setTitle(ChatColor.GOLD + "Welcome");
        bookMeta.setAuthor(ChatColor.GOLD + "SourceForums");
        bookMeta.addPage(ChatColor.GOLD + "WELCOME TO SOURCECRAFT"
                + "                                      "
                + ChatColor.BLACK + "CONTENT"
                + "                                              "
                + "1) ABILITIES"
                + "            "
                + "2) RANKS"
                + "                "
                + "3) CONTACT US");
        bookMeta.addPage(ChatColor.GOLD + "ABILITIES - DEFAULT"
                + ChatColor.BLACK + "                                "
                + "1) /hub"
                + "                    "
                + "2) /list"
                + "                    "
                + "3) /motd"
                + "                  "
                + "4) /rules"
                + "                  "
                + "5) /tell"
                + "                  "
                + "6) Default Abilities");
        bookMeta.addPage(ChatColor.GOLD + "ABILITIES - VIP/EIP"
                + ChatColor.BLACK + "                                "
                + "1) /getpos"
                + "                "
                + "2) /me"
                + "                    "
                + "3) /nick"
                + "                "
                + "4) /fly"
                + "                                              "
                + "5-1) 2x Credits (VIP)"
                + "  "
                + "5-2) 3x Credits (EIP)");
        bookMeta.addPage(ChatColor.GOLD + "RANKS"
                + ChatColor.BLACK  + "                                                  "
                + "1) DEFAULT"
                + "            "
                + "2) VIP"
                + "                    "
                + "3) EIP"
                + "                    "
                + "4) MOJ/YT/SW"
                + "          "
                + "5) ADMIN"
                + "                  "
                + "6) SPECIAL ADMIN");
        bookMeta.addPage(ChatColor.GOLD + "CONTACT US"
                + ChatColor.BLACK + "                                            "
                + "All Contacts on:"
                + "                "
                + "[url]http://sourceforums.net/about[/url]");
        compassMeta.setDisplayName(ChatColor.GOLD + "Teleport");
        clockMeta.setDisplayName(ChatColor.GOLD + "Visibility");
        emeraldMeta.setDisplayName(ChatColor.GOLD + "Store");
        book.setItemMeta(bookMeta);
        compass.setItemMeta(compassMeta);
        clock.setItemMeta(clockMeta);
        emerald.setItemMeta(emeraldMeta);
        inventory.clear();
        for(PotionEffect effect : player.getActivePotionEffects()){
            player.removePotionEffect(effect.getType());
        }
        inventory.setHelmet(air);
        inventory.setChestplate(air);
        inventory.setLeggings(air);
        inventory.setBoots(air);
        inventory.addItem(book);
        inventory.addItem(compass);
        inventory.addItem(clock);
        inventory.addItem(emerald);
        player.setExp(0);
        player.teleport(new Location(Bukkit.getWorld("Hub"), -2, 70, -5));
        }
    return false;
    }
}
 

The error is: getCommand("hub").setExecutor(new CommandHub());

 

SourceForums
That's because your CommandHub class constructor has a parameter. Use this instead

Code:

getCommand("hub").setExecutor(new CommandHub(this));

 

Assist Thanks for that, hadn't been on recently.

SourceForums What Assist said should fix your problem

 

Thanks so much guys!

 

Ok been having this issue for quite some time and still I can't figure it out. heres a partial main:

Code:

public class EasyKits extends JavaPlugin{
 
    public static EasyKits plugin;
    public final Logger log = Logger.getLogger("Minecraft");
    private EventListener eventlistener;
    private CommandHandler cmdExecutor;
 
    @Override
    public void onEnable(){
     
        new DataSource(this);

and here's the class that's causing problems:

Code:

public class DataSource extends SQLMethods{
 
    private EasyKits plugin;
    public DataSource(EasyKits plugin) {
        this.plugin = plugin;
    }
 
    public static DataSource instance = new DataSource(EasyKits.plugin);
 
    public String getStringConfig(){
        String test = this.plugin.getConfig().getString("Test-String"); <--- NullPointerException!
        return test;
    }

And a note Test-String does exist in config. Works fine in my EventListener class and my CommandExecutor class. I've made three plugins in the past and this has happened in all the them.. What am I missing?


NOTE: I know I need to learn Java a little better. Respectfully keep it to yourself's people, I'm just looking for an extra push.

 

TrenTech Since that isn't registered in the main, like for commandexecutor or listener, I don't believe it will see it as a connection.

Unless anyone can help me out with this answer, I would say the best choice is to make a variable method in the class to get the plugin... i.e.

Code:

private EasyKits getPlugin(){
    return new EasyKits();
}

 

This appears to have solved my problem

Code:

    private static EasyKits plugin;
    public DataSource(EasyKits plugin) {
        DataSource.plugin = plugin;
    }

 

Can u give the full screenshot? plz