Help with WorldSavedData and custom objects

[powerLineDayDreams]

Hello, I have created a custom mod object "Empire" that contains a lot of diverse data (Integers, Longs, Strings, Maps, etc.) and I want to store a list or array of all of the "Empires" in a world using WorldSavedData.  I'm struggling trying to figure out how to store such a list using NBT.  Is anyone able to help?

 

Here's my class code (the ????? mark the spots that I'm having trouble at):

package com.example.examplemod.common.core.empire;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.example.examplemod.Ref;

import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.world.World;
import net.minecraft.world.storage.MapStorage;
import net.minecraft.world.storage.WorldSavedData;

public class EmpireList extends WorldSavedData
{
	private static final String DATA_NAME = Ref.MODID + "_EmpireList";
	
	private List<Empire> empires = new ArrayList<Empire> ();
	
	public EmpireList() 
	{
		super(DATA_NAME);
	}

	public EmpireList(String s)
	{
		super(s);
	}

	@Override
	public void readFromNBT(NBTTagCompound nbt) 
	{
		empires = ?????;
	}

	@Override
	public NBTTagCompound writeToNBT(NBTTagCompound nbt) 
	{
		nbt.???????("empires", empires);
		return nbt;
	}
	
	public List<Empire> getEmpireList()
	{
		return empires;
	}
	
	public boolean addEmpire(Empire empire)
	{
		markDirty();
		return !empires.contains(empire) ? empires.add(empire) : false;
	}
	
	public static EmpireList get(World world)
	{
		MapStorage storage = world.getMapStorage();
		EmpireList instance = (EmpireList)storage.getOrLoadData(EmpireList.class, DATA_NAME);
		
		if (instance == null)
		{
			System.out.println("It was null");
			instance = new EmpireList();
			storage.setData(DATA_NAME, instance);
		}
		
		return instance;
	}
}

 

Thank you in advance

Edited July 23, 2017 by powerLineDayDreams

[Jacky2611]

Have you tried implementing INBTSerializeable?

[powerLineDayDreams]

10 minutes ago, Jacky2611 said:

Have you tried implementing INBTSerializeable?

Hmmmm what would that look like?  Would that go in my Empire (object) class or in my EmpireList (WorldSavedData) class?

[Jacky2611]

Ok, I did some research. First, you could probably use the NBTTagList to store your list.

And NBTTagList is a list that storesd NBTBase objects. So if you make your Empire class a child of NBTBase and overwrite the write and read method you should be fine.

[powerLineDayDreams]

7 minutes ago, Jacky2611 said:

Ok, I did some research. First, you could probably use the NBTTagList to store your list.

And NBTTagList is a list that storesd NBTBase objects. So if you make your Empire class a child of NBTBase and overwrite the write and read method you should be fine.

Thank you for your help!  I'm working on overriding those two methods now, but now I'm running into questions of how exactly I should do that.  I'm really new to this stuff, so I'm sorry if this is something obvious, but what should I be writing, exactly?  Do I need to take my Empire object and break it down into each of its fields and write/read these separately?  A lot of these fields are custom objects unto themselves and can contain an arbitrary amount of data.

[Jacky2611]

class Empire extends NBTBase{
  
   	@Override
    public void write(DataOutput output){
 		//your code here
	}

	@Override
 	public void read(DataInput input, int depth, NBTSizeTracker sizeTracker){
		//your code here
	}


	//other code here

}

Or look at the NBTTagList class.

[powerLineDayDreams]

Oh yeah, I figured out the extends/@Override part, but it seems like I'll have to write each int, long, string, etc. separately.  Is that accurate, or is there an easier way of doing this?

[Franckyi]

Why extending NBTBase ? Just implement INBTSerializable and use Empire#deserializeNBT (create a new instance of Empire before) method in EmpireList#readFromNBT and Empire#serializeNBT in EmpireList#writeToNBT.

[Franckyi]

@diesieben07

Sure, you can use your own methods. I prefer implementing INBTSerializable since it's more flexible than using your own class methods. But if flexibility isn't needed here, you don't have to implement INBTSerializable.

[powerLineDayDreams]

Okay, so then will I want to just integrate the Empire serialization into the read/writeFromNBT methods in the EmpireList class or add some new methods in my EmpireList class or in my Empire class to do that.  I've also included my Empire class below.  Resource, Tile, City are all custom objects with a lot of fields themselves.  Does this seem doable to store in WorldSavedData?

 

Thank you for all the help so far.

 

package com.example.examplemod.common.core.empire;

import java.util.Map;

import com.example.examplemod.common.caps.turn.EmpireTurn;
import com.example.examplemod.common.core.city.City;
import com.example.examplemod.common.core.turn.WorldTurn;
import com.example.examplemod.common.map.tile.Tile;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.world.World;

public class Empire
{
    private int empireID = 0;
    private boolean exists = false;
    private String empireName = "";
    private World empireWorld = null;
    private EmpireTurn empireTurn = null;
    private Map<EntityPlayer, String> playerList = null;
    private Map<Resource, Long> resources = null;
    private Map<Tile, Integer> territory = null;
    private Map<Empire, Integer> vassalList = null;
    private Map<City, Integer> cityList = null;
    
    public Empire(String empireName, World world, EntityPlayer player, String playerPosition, Map<Resource, Long> startingResources, Tile tile)
    {
        
        this.empireID = this.createEmpireID(world);
        this.exists = true;
        int turn = WorldTurn.get(world).getTurn();
        
        this.empireName = empireName;
        this.empireWorld = world;
        this.empireTurn = new EmpireTurn(world, this.empireID);
        this.playerList.put(player, playerPosition);
        this.resources.putAll(startingResources);
        this.territory.put(tile, turn);
        
        //EmpireList.get(world).addEmpire(this);
        tile.setOwnership(this, turn);
    }
    
    private int createEmpireID(World world)
    {
        return 0; //EmpireList.get(world).getEmpireList().size();
    }
    
    public boolean addCity(City city)
    {
        if(!this.canAddCity()) return false;
        WorldTurn worldTurn = WorldTurn.get(this.empireWorld);
        
        cityList.put(city, worldTurn.getTurn());
        return true;
    }
    
    public boolean addVassal(Empire empire)
    {
        if(!this.canAddVassal(empire.getEmpireValue())) return false;
        WorldTurn worldTurn = WorldTurn.get(this.empireWorld);
        
        vassalList.put(empire,worldTurn.getTurn());
        return true;
    }
    
    public void addResource(Resource resource, long amount)
    {
        if (this.resources.putIfAbsent(resource, amount) != null)
        {
            this.resources.put(resource, this.resources.get(resource) + amount);
        }
    }
    
    public boolean canAddVassal(int empireValue)
    {
        return false;
    }
    
    public boolean canAddCity()
    {
        return true;
    }
    
    public void changeName(String name)
    {
        this.empireName = name;
    }
    
    public Map<City, Integer> getCities()
    {
        return this.cityList;
    }
    
    public int getMaximumVassalSize()
    {
        return 0;
    }
    
    public int getEmpireValue()
    {
        return 0;
    }
    
    public boolean empireExists()
    {
        return this.exists;
    }
    
    public long getResourceValue(Resource resource)
    {
        return this.resources.get(resource) != null ? this.resources.get(resource) : 0L;
    }
    
    public EmpireTurn getEmpireTurn()
    {
        return this.empireTurn;
    }
    
    public Map<Empire, Integer> getVassals()
    {
        return this.vassalList;
    }
    
    public String getName()
    {
        return this.empireName;
    }
    
    public int getID()
    {
        return this.empireID;
    }
    
    public Map<EntityPlayer, String> getPlayers()
    {
        return this.playerList;
    }
    
    public void destroyEmpire()
    {
        this.exists = false;
    }
    
    public void rebirthEmpire()
    {
        this.exists = true;
    }
}

 

[powerLineDayDreams]

2 minutes ago, diesieben07 said:

You can store everything in NBT. You need to recursively decompose the objects into their primitives. I would create a writeToNbt method in Empire and a readFromNbt (static) that re-creates the empire.

Awesome, I will do that!  Thank you for the guidance.  Related question, I will be storing Tiles and Cities separately in NBT in a WorldSavedData TileList and CityList.  Would it be a problem to have them stored this way?  Will Minecraft recognize that someTile stored in someEmpire's territory Map and in the TileList are the same thing?

[powerLineDayDreams]

Okay, so this is what I've come up with so far for my Empire class.  I opted to outsource the NBT generation for each of my custom objects to the classes for each of them (I haven't actually written these methods, though).  Are there any obvious issues with what I've done thus far?

 

public NBTTagCompound writeToNBT (NBTTagCompound nbt, @Nullable String externalID)
	{
		if(externalID == null)
		{
			externalID = "";
		}
		
		else
		{
			externalID = externalID + "_";
		}
		
		nbt.setInteger(externalID + "empireID", this.empireID);
		nbt.setBoolean(externalID + "empireExists", this.exists);
		nbt.setString(externalID + "empireName", this.empireName);
		nbt = this.empireTurn.writeToNBT(nbt, externalID);
		nbt.setInteger(externalID + "playerListSize", this.playerList.size());
		
		if(this.playerList.size() > 0)
		{
			int i = 0;
			for(Map.Entry<EntityPlayer, String> entry : this.playerList.entrySet())
			{
				String playerNumber = externalID + "#player_" + i;
				String playerPosition = externalID + "@player_" + i;
				nbt.setInteger(playerNumber, entry.getKey().getEntityId());
				nbt.setString(playerPosition, entry.getValue());
				
				i++;
			}
		}
		
		nbt.setInteger("resourceListSize", this.resources.size());
		
		if(this.resources.size() > 0)
		{
			int i = 0;
			for(Map.Entry<Resource, Long> entry : this.resources.entrySet())
			{
				String resourceID = externalID + "#resource_" + i;
				nbt = entry.getKey().writeToNBT(nbt, resourceID);
				nbt.setLong(resourceID + "_amount", entry.getValue());
				
				i++;
			}
		}
		
		nbt.setInteger("territorySize", this.territory.size());
		
		if(this.territory.size() > 0)
		{
			int i = 0;
			for(Map.Entry<Tile, Integer> entry : this.territory.entrySet())
			{
				String tileID = externalID + "#tile_" + i;
				nbt = entry.getKey().writeToNBT(nbt, tileID);
				nbt.setLong(tileID + "_length", entry.getValue());
				
				i++;
			}
		}
		
		nbt.setInteger("vassalListSize", this.vassalList.size());
		
		if(this.vassalList.size() > 0)
		{
			int i = 0;
			for(Map.Entry<Empire, Integer> entry : this.vassalList.entrySet())
			{
				String vassalID = externalID + "#vassal_" + i;
				nbt = entry.getKey().writeToNBT(nbt, vassalID);
				nbt.setInteger(vassalID + "_length", entry.getValue());
				
				i++;
			}
		}
		
		nbt.setInteger("cityListSize", this.cityList.size());
		
		if(this.cityList.size() > 0)
		{
			int i = 0;
			for(Map.Entry<City, Integer> entry : this.cityList.entrySet())
			{
				String cityID = externalID + "#city_" + i;
				nbt = entry.getKey().writeToNBT(nbt, cityID);
				nbt.setInteger(cityID + "_length", entry.getValue());
				
				i++;
			}
		}
		
		return nbt;
	}

 

[powerLineDayDreams]

1 minute ago, diesieben07 said:

Well, I don't get why you insist on stuffing everything into one NBT compound. Empire::writeToNbt should generate it's own, standalone NBTTagCompound, without any kind of "external ID". Then whoever manages the Empire class (the WorldSavedData in your case) manages that tag compound returned from Empire::writeToNbt, in your case it would probably go into a list (NBTTagList).

Ahh yes, I did that because someEmpire might include someOtherEmpire as its vassal.  Is there a better way to handle this case?  Would it be possible to include a NBTTagList of each vassal within my someEmpire NBTTagCompound (if so, should I be doing this with my resources, territory, etc. Maps as well)?  Or should I try to implement some sort of getEmpireByID method (not really sure how I'd go about doing this) and then just store the empireID for each vassal? Thanks for all of the help so far

[powerLineDayDreams]

They'd each be an instance of Empire, so yeah, they would also be stored on their own in the WorldSavedData EmpireList.  When you refer to a 

Quote

global "all empires" map

are you saying that I should/could have a Map somewhere containing Empires and their empireIDs?  If so, where would I store this?  It seems like this might simplify a lot of this stuff, especially if I could do the same with cities, tiles, resources, etc.

[powerLineDayDreams]

Okay, cool...  Now I'm wondering how I would go about implementing a findEmpireByID method to grab the vassal when I read from the NBT.

[powerLineDayDreams]

Quote

Make a Map<UUID, Empire> (or use a String, depends on how you generate the ID for every empire).

Where would I store this map?  And then I'm assuming that every time that I read a new Empire from the EmpireList WorldSavedData that I'll want to add it as an entry in this Map.

[powerLineDayDreams]

Gotcha!  I will try adjusting the code based on this.  Thank you!