[1.14.4] arraylist capability

[andGarrett]

I've got and arraylist of objects. the objects contain a string and a double. the purpose of this list is to contain monetary value for every item in the game. it's basically the Energy-Matter Currency (EMC) from "Equivalent Exchange." I started writing a capability to store the array. I'm not sure how to write the storage class for this capability. specifically the read and write methods. I tried returning a compoundNBT in the read method, but I don't yet understand compoundNBT, and I'm not even sure that's what I should be returning.

 

package com.Garrett.backtobasics.capabilities.itemValues;

import com.Garrett.backtobasics.capabilities.blockPopulation.IBlockPopulation;
import net.minecraft.nbt.CompoundNBT;
import net.minecraft.nbt.INBT;
import net.minecraft.nbt.IntNBT;
import net.minecraft.util.Direction;
import net.minecraftforge.common.capabilities.Capability;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import javax.annotation.Nullable;

public class ItemValuesStorage implements Capability.IStorage<ItemValues> {

    @Nullable
    @Override
    public CompoundNBT writeNBT(Capability<ItemValues> capability, ItemValues instance, Direction side) {
        return new CompoundNBT(instance.getValueList());
    }

    @Override
    public void readNBT(Capability<ItemValues> capability, ItemValues instance, Direction side, INBT nbt) {
    }
}

 

[Animefan8888]

19 minutes ago, andGarrett said:

and I'm not even sure that's what I should be returning.

If you're just saving an array list that stores two values you should store a ListNBT or a TagListNBT. I'm not sure what it was changed to recently. But that tag list needs to store a CompoundNBT in which you will call CompoundNBT#putDouble(ID, double) and CompoundNBT#putString(ID, string)

 

[andGarrett]

13 hours ago, Animefan8888 said:

If you're just saving an array list that stores two values you should store a ListNBT or a TagListNBT. I'm not sure what it was changed to recently. But that tag list needs to store a CompoundNBT in which you will call CompoundNBT#putDouble(ID, double) and CompoundNBT#putString(ID, string)

 

for now what I did is pointless, as I don't need to change any data in the capability yet, but I was able to learn how to work with ListNBT and CompoundNBT. what if I never need to change any data? how might I code the write method in such a case?

 

 

here's what I did:

    @Nullable
    @Override
    public ListNBT writeNBT(Capability<ItemValues> capability, ItemValues instance, Direction side) {
        ListNBT itemValueListNBT = new ListNBT();
        int index = 0;
        for (TradeItem tradeItem:instance.getItemValueList()) {
            CompoundNBT compoundNBT = new CompoundNBT();
            compoundNBT.putString("item", tradeItem.getItemRegistryName());
            compoundNBT.putDouble("value", tradeItem.getMonetaryValue());
            itemValueListNBT.add(index, compoundNBT);
            index++;
        }
        return itemValueListNBT;
    }

 

Edited September 8, 2019 by andGarrett

[eatthenight]

15 minutes ago, andGarrett said:

for now what I did is pointless, as I don't to change any data in the capability yet, but I was able to learn how to work with ListNBT and CompoundNBT. what if I never need to change any data? how might I code the write method in such a case?

 

 

here's what I did:

    @Nullable
    @Override
    public ListNBT writeNBT(Capability<ItemValues> capability, ItemValues instance, Direction side) {
        ListNBT itemValueListNBT = new ListNBT();
        int index = 0;
        for (TradeItem tradeItem:instance.getItemValueList()) {
            CompoundNBT compoundNBT = new CompoundNBT();
            compoundNBT.putString("item", tradeItem.getItemRegistryName());
            compoundNBT.putDouble("value", tradeItem.getMonetaryValue());
            itemValueListNBT.add(index, compoundNBT);
            index++;
        }
        return itemValueListNBT;
    }

 

you change the data with the methods in your capability class. 

Edited September 8, 2019 by eatthenight

[Animefan8888]

1 hour ago, andGarrett said:

what if I never need to change any data?

Then you dont ever need to save it. You could just compute it at startup. And store it in a static variable. And if it is customizable/world dependent sync it from the server to the client.

[andGarrett]

35 minutes ago, Animefan8888 said:

store it in a static variable

where would I put this static variable, and how would I access it? I know I wouldn't want to put it in a block class as it would need to compute the list every time a such a block was created.

[Animefan8888]

3 minutes ago, andGarrett said:

where would I put this static variable, and how would I access it?

You'd put it anywhere. Static variables only exist once.

 

3 minutes ago, andGarrett said:

it would need to compute the list every time a such a block was created.

No it would only compute it where you told it to compute it. I would need more information on what would affect the values to determine where it should be computed.

[andGarrett]

2 hours ago, diesieben07 said:

I don't think you understand how static works.

hmm, I thought I did, but after double checking, there were some key aspects of the static keyword that I had either forgotten or never learnt.  I could just create a static method  essentially anywhere that would return the list. I feel silly for not remembering this is possible in java. Sorry to bring a java issue to a forge form