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using extended player properties in command


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I'm getting a null pointer exception in this function:


public void processCommand(ICommandSender sender, String[] args) {

        if(args.length == 0){

            PlayerWallet wallet = PlayerWallet.get((EntityPlayer) sender);

            ((EntityPlayer) sender).addChatComponentMessage(new ChatComponentText("£" + wallet.getWallet()));




i know the error occurs at "wallet.getWallet()". i just can't work out what is causing the error :/




the Player wallet class:


public class PlayerWallet implements IExtendedEntityProperties {


    public final static String EXT_PROP_NAME = "PlayerWallet";

    private double funds;



    public void init(Entity entity, World world){


        funds = 0;






    public void loadNBTData(NBTTagCompound nbt){


        NBTTagCompound properties = (NBTTagCompound) nbt.getTag(EXT_PROP_NAME);





    public void saveNBTData(NBTTagCompound nbt){

        NBTTagCompound properties = new NBTTagCompound();

        properties.setDouble("funds", funds);

        nbt.setTag(EXT_PROP_NAME, properties);




    public static final PlayerWallet get(EntityPlayer player)


        return (PlayerWallet) player.getExtendedProperties(EXT_PROP_NAME);




    public static final void register(EntityPlayer player)


        player.registerExtendedProperties(PlayerWallet.EXT_PROP_NAME, new PlayerWallet());



    public double getWallet(){


        return funds;


    public double addFunds(double f){


        funds += f;

        return getWallet();


    public double setFunds(double f){

        funds = f;

        return funds;


    public double removeFunds(double f){

        funds -=f;

        return funds;





The Event handler class:


public class MconomyEventHandler {



    public void onEntityConstructing(EntityEvent.EntityConstructing event)



Be sure to check if the entity being constructed is the correct type for the extended properties you're about to add! The null check may not be necessary - I only use it to make sure properties are only registered once per entity


        if (event.entity instanceof EntityPlayer && PlayerWallet.get((EntityPlayer) event.entity) == null)

// This is how extended properties are registered using our convenient method from earlier

            PlayerWallet.register((EntityPlayer) event.entity);

// That will call the constructor as well as cause the init() method

// to be called automatically






the event is registered here:



    public void init(FMLInitializationEvent event)


// some example code

        MinecraftForge.EVENT_BUS.register(new MconomyEventHandler());




i would really appreciate if anyone can solve this problem for me :)

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I added those 2 bits of code to the end of the first post

@EventHandler is only for the FML events involved in the mod loading process - all other events use @SubscribeEvent.


Next time something doesn't seem to be working, put a println statement inside and watch your console - if it doesn't print, you then have more knowledge of what the problem might be.



public void onEntityConstructing(EntityConstructing event) {
System.out.println("Entity is constructing."); // Doesn't print, so you know the problem has to do with your event


Also, for code, either use [ code ]code here[ / code ] tags (without spaces) or a service like pastebin - it makes it far more readable.

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