WorldData.class

public class WorldData extends WorldSavedData{

    public static final String DATA_ID=Refs.MODID+"_DATA";
    private String DATA_WORLD_ID;
    private boolean isNewSave;
    private boolean isWorldCreated;

    public WorldData() {
        super(DATA_ID);
    }

    public WorldData(String ID) {
        super(ID);
    }

    public String getWorldID(){
        return this.DATA_WORLD_ID;
    }

    public void setWorldID(String worldID){
        this.DATA_WORLD_ID=worldID;
        this.sendUpdate();
    }

    public void setNewSave(boolean isNewSave){
        this.isNewSave=isNewSave;
        this.sendUpdate();
    }

    public boolean isNewSave(){
        return this.isNewSave;
    }

    public boolean isWorldCreated() {
        return this.isWorldCreated;
    }

    public void setWorldCreated(boolean isWorldCreated) {
        this.isWorldCreated = isWorldCreated;
        this.sendUpdate();
    }

    public static WorldData forWorld(World world){
        MapStorage storage=world.getMapStorage();
        WorldData data=(WorldData)storage.getOrLoadData(WorldData.class, DATA_ID);
        if(data==null){
            data=new WorldData();
            storage.setData(DATA_ID,data);
        }
        return data;
    }

    public void sendUpdate(){
        this.markDirty();
    }

    @Override
    public void readFromNBT(NBTTagCompound nbt) {
        this.DATA_WORLD_ID=nbt.getString("worldID");
        this.isNewSave=nbt.getBoolean("isNewSave");
        this.isWorldCreated=nbt.hasKey("isWorldCreated")?nbt.getBoolean("isWorldCreated"):true;
    }

    @Override
    public NBTTagCompound writeToNBT(NBTTagCompound nbt) {
        nbt.setString("worldID", DATA_WORLD_ID);
        nbt.setBoolean("isNewSave", this.isNewSave);
        nbt.setBoolean("isWorldCreated", this.isWorldCreated);
        return nbt;
    }

}