[1.15] Get capibily from player as interface

[KidKoderMod033109]

Hi again,

I was working on my capibily and found a casting error, it read:

Caused by: java.lang.ClassCastException: net.minecraftforge.common.util.LazyOptional cannot be cast to net.kidkoder.allergies.capability.allergies.IAllergies

so, I found the line and it reads:

IAllergies allergies = (IAllergies) player.getCapability(AllergiesProvider.ALLERGIES_CAP);

and I don't know how to properly cast to the coreect type. The IAllergies is the inferfaced used in my capabily. If threre is a way to cast it how?

Thanks in advance,

Kid Koder

[ChampionAsh5357]

Do not cast from LazyOptional<IAllergies> to IAllergies. LazyOptional is quite similar to Optional found in standard java. If you want to do it your way, you should first check if the value is present in the optional (LazyOptional#isPresent) and then get the value (LazyOptional#getValue). You can also use (LazyOptional#ifPresent) instead.

[KidKoderMod033109]

Ok, great! But I saw on the file that I could use Capability.orEmpty(Capability, LazyOptional) to cast it. Or am understading it wrong?

Also, LazyOptional#getValue does not seem to exist? I need help finding the method. Also, would this be what you meant?

 

 

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Spoiler

        LazyOptional<IAllergies> allergiesLazyOptional = player.getCapability(AllergiesProvider.ALLERGIES_CAP);
        IAllergies allergies;
        if(allergiesLazyOptional.isPresent()) {
            allergies = allergiesLazyOptional.getValue();
        }

 

Thanks once again,

Kid Koder

[ChampionAsh5357]

Apologies, I just glanced at the code. LazyOptional#getValue is private. You need to use either orElse, orElseGet, orElseThrow to get the desired result. And yes, something like that would work. Either one will work since you already check if its present. Just make sure you put a valid instance as the parameter. I usually prefer LazyOptional#orElseThrow because I don't want to a null default if it fails.

Edited April 16, 2020 by ChampionAsh5357

[KidKoderMod033109]

Great! But the methods need a NonNullSupplier, so how do I get an instance?

 

Unrealated, but how do you get the code look for the methods?

[ChampionAsh5357]

The first method needs a defaulted instance, the second method needs a defaulted instance passed through a Supplier, and the third method uses a supplier of an exception. Suppliers can be easily made using:

() -> value

 

As for how to look for code, in Eclipse I just ctrl + left click and it opens the source for me. If it doesn't exist, I look for a javadoc on the internet.

[KidKoderMod033109]

2 minutes ago, ChampionAsh5357 said:

() -> value

 

Is an is an example possible, as I don't really get that.

 

Also, for my previous question I meant the gray backround and monospace font look.

[ChampionAsh5357]

IAllergies allergies = player.getCapability(AllergiesProvider.ALLERGIES_CAP).orElseThrow(() -> new RuntimeException("This capability does not exist"));

 

There's a button called TeleType and it looks like tt.

[KidKoderMod033109]

1 minute ago, ChampionAsh5357 said:

IAllergies allergies = player.getCapability(AllergiesProvider.ALLERGIES_CAP).orElseThrow(() -> new RuntimeException("This capability does not exist"));

 

There's a button called TeleType and it looks like tt.

??. I'm using IntelliJ IDEA, where could I find this.

[ChampionAsh5357]

It's in the forge message system for the website? Or am I understanding your question wrong again?

[KidKoderMod033109]

Great would this code work?

 

 

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Spoiler

LazyOptional<IAllergies> allergiesLazyOptional = player.getCapability(AllergiesProvider.ALLERGIES_CAP);
        IAllergies allergies;
        if(allergiesLazyOptional.isPresent()) {
             allergies = player.getCapability(AllergiesProvider.ALLERGIES_CAP).orElseThrow(() -> new RuntimeException("This capability does not exist"));
        } else {
            allergies = new CapabilityAllergies();
        }

 

Thank you

Kid Koder

[Draco18s]

Or you can use ifPresent.

player.getCapability(AllergiesProvider.ALLERGIES_CAP).ifPresent(allergies -> {
	//your code here
});

 

[Alpvax]

You can simplify it, you are checking whether it is present twice:

//Either
IAllergies allergies = allergiesLazyOptional.orElseGet(CapabilityAllergies::new);
//Or
IAllergies allergies = allergiesLazyOptional.orElse(new CapabilityAllergies());

The whole point of the "orElse" methods is to do something else if it is not present.

 

`CapabilityAllergies::new` is the same as `() -> new CapabilityAllergies()`: A method which takes no arguments and returns an instance of CapabilityAllergies.

Edited April 16, 2020 by Alpvax
Fixed error in code

[KidKoderMod033109]

3 hours ago, Alpvax said:

You can simplify it, you are checking whether it is present twice:

IAllergies allergies = allergiesLazyOptional.orElse(CapabilityAllergies::new);

The whole point of the "orElse" methods is to do something else if it is not present.

 

`CapabilityAllergies::new` is the same as `() -> new CapabilityAllergies()`: A method which takes no arguments and returns an instance of CapabilityAllergies.

I used this line, but for CapabilityAllergies::new  IntelliJ said that IAllergies was a functional interface.

Edited April 16, 2020 by KidKoderMod033109

[Alpvax]

6 minutes ago, KidKoderMod033109 said:

I used this line, but for CapabilityAllergies::new  IntelliJ said that IAllergies was a functional interface.

My mistake, I didn't have access to the code at the time.

It should be either .orElseGet(CapabilityAllergies::new) or .orElse(new CapabilityAllergies()).

The difference is that the first option will not create a new instance unless it is required, whereas the second will regardless. (Which you use will probably only result in a minor performance difference).

Edited April 16, 2020 by Alpvax
More information

[KidKoderMod033109]

I got a java.lang.NullPointerException for this class:

 

 

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Spoiler

/*
 * Koded by Kid Koder :)
 *
 *  % : ° ° : %
 *       O
 */

package net.kidkoder.allergies.system;

import net.kidkoder.allergies.capability.allergies.AllergiesProvider;
import net.kidkoder.allergies.capability.allergies.CapabilityAllergies;
import net.kidkoder.allergies.capability.allergies.IAllergies;
import net.kidkoder.allergies.system.allergy.Allergen;
import net.kidkoder.allergies.system.allergy.PlayerAllergies;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.util.text.StringTextComponent;
import net.minecraftforge.common.util.LazyOptional;
import net.minecraftforge.event.entity.player.PlayerEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.common.Mod;


@Mod.EventBusSubscriber(bus=Mod.EventBusSubscriber.Bus.FORGE)
public class Events {

    static SystemAssignment assignment = new SystemAssignment();

    @SubscribeEvent
    public static void newPlayerJoinWorld(PlayerEvent.PlayerLoggedInEvent event) {
        PlayerEntity player = event.getPlayer();

        StringTextComponent textWorked = new StringTextComponent("In the event");
        player.sendMessage(textWorked);

        LazyOptional<IAllergies> allergiesLazyOptional = player.getCapability(AllergiesProvider.ALLERGIES_CAP);
        IAllergies allergies = allergiesLazyOptional.orElseGet(CapabilityAllergies::new);

        if(allergies.rolled()) {
            StringTextComponent textLoad = new StringTextComponent("Loaded allergies");
            player.sendMessage(textLoad);
        } if(!allergies.rolled()) {
            assignment.roll(player, player.getEntityWorld());
            StringTextComponent textRoll = new StringTextComponent("Allergies rolled");
            player.sendMessage(textRoll);
            allergies.setRolled();
            PlayerAllergies playerAllergies = player.getCapability(AllergiesProvider.ALLERGIES_CAP).orElse(new CapabilityAllergies()).getAllergens();
            StringTextComponent allergiesListGold = new StringTextComponent("You are allergic to gold: " + playerAllergies.hasAllergen(Allergen.GOLD));
            player.sendMessage(allergiesListGold);
            StringTextComponent allergiesListWheat = new StringTextComponent("You are allergic to wheat: " + playerAllergies.hasAllergen(Allergen.WHEAT));
            player.sendMessage(allergiesListWheat);
            StringTextComponent allergiesListEggs = new StringTextComponent("You are allergic to eggs: " + playerAllergies.hasAllergen(Allergen.EGGS));
            player.sendMessage(allergiesListEggs);
            StringTextComponent allergiesListMilk = new StringTextComponent("You are allergic to gold: " + playerAllergies.hasAllergen(Allergen.MILK));
            player.sendMessage(allergiesListMilk);
        }


    }

    @SubscribeEvent
    public static void playerClone(PlayerEvent.Clone event) {
        /*
       Transfer Capability
         */
        PlayerEntity newPlayer = event.getPlayer();
        IAllergies allergies = newPlayer.getCapability(AllergiesProvider.ALLERGIES_CAP).orElse(new CapabilityAllergies());
        IAllergies oldAllergies = newPlayer.getCapability(AllergiesProvider.ALLERGIES_CAP).orElse(new CapabilityAllergies());

        allergies.setAllergens(oldAllergies.getAllergens());

    }


}

 

 

[Alpvax]

1 minute ago, diesieben07 said:

If the capability isnt attached here it is most likely an error. orElseThrow should be used.

Probably true, but as the initial code created a new capability if there wasn't an existing one, I repeated that functionality.

[KidKoderMod033109]

Here is the log:

 

 

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 Advanced issue found

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Spoiler

---- Minecraft Crash Report ---- // Surprise! Haha. Well, this is awkward. Time: 4/16/20 11:27 AM Description: Ticking memory connection java.lang.NullPointerException: Ticking memory connection at net.kidkoder.allergies.system.Events.newPlayerJoinWorld(Events.java:47) ~[main/:?] {re:classloading} at net.minecraftforge.eventbus.ASMEventHandler_1_Events_newPlayerJoinWorld_PlayerLoggedInEvent.invoke(.dynamic) ~[?:?] {} at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) ~[eventbus-2.0.0-milestone.1-service.jar:?] {} at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) ~[eventbus-2.0.0-milestone.1-service.jar:?] {} at net.minecraftforge.fml.hooks.BasicEventHooks.firePlayerLoggedIn(BasicEventHooks.java:43) ~[?:?] {re:classloading} at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:209) ~[?:?] {re:classloading} at net.minecraft.network.login.ServerLoginNetHandler.tryAcceptPlayer(ServerLoginNetHandler.java:116) ~[?:?] {re:classloading} at net.minecraft.network.login.ServerLoginNetHandler.tick(ServerLoginNetHandler.java:63) ~[?:?] {re:classloading} at net.minecraft.network.NetworkManager.tick(NetworkManager.java:224) ~[?:?] {re:classloading} at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:135) ~[?:?] {re:classloading} at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:864) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:782) ~[?:?] {re:classloading,pl:accesstransformer:B} at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:114) ~[?:?] {re:classloading,pl:runtimedistcleaner:A} at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:635) [?:?] {re:classloading,pl:accesstransformer:B} at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181] {} A detailed walkthrough of the error, its code path and all known details is as follows: --------------------------------------------------------------------------------------- -- Head -- Thread: Server thread Stacktrace: at net.kidkoder.allergies.system.Events.newPlayerJoinWorld(Events.java:47) at net.minecraftforge.eventbus.ASMEventHandler_1_Events_newPlayerJoinWorld_PlayerLoggedInEvent.invoke(.dynamic) at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80) at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258) at net.minecraftforge.fml.hooks.BasicEventHooks.firePlayerLoggedIn(BasicEventHooks.java:43) at net.minecraft.server.management.PlayerList.initializeConnectionToPlayer(PlayerList.java:209) at net.minecraft.network.login.ServerLoginNetHandler.tryAcceptPlayer(ServerLoginNetHandler.java:116) at net.minecraft.network.login.ServerLoginNetHandler.tick(ServerLoginNetHandler.java:63) at net.minecraft.network.NetworkManager.tick(NetworkManager.java:224) -- Ticking connection -- Details: Connection: net.minecraft.network.NetworkManager@51453f24 Stacktrace: at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:135) at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:864) at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:782) at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:114) at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:635) at java.lang.Thread.run(Thread.java:748) -- System Details -- Details: Minecraft Version: 1.15.2 Minecraft Version ID: 1.15.2 Operating System: Windows 10 (amd64) version 10.0 Java Version: 1.8.0_181, Oracle Corporation Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation Memory: 670124008 bytes (639 MB) / 1954021376 bytes (1863 MB) up to 3817865216 bytes (3641 MB) CPUs: 4 JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx4096m ModLauncher: 5.0.0-milestone.4+67+b1a340b ModLauncher launch target: fmluserdevclient ModLauncher naming: mcp ModLauncher services: /eventbus-2.0.0-milestone.1-service.jar eventbus PLUGINSERVICE /forge-1.15.2-31.1.9_mapped_stable_60-1.15-launcher.jar object_holder_definalize PLUGINSERVICE /forge-1.15.2-31.1.9_mapped_stable_60-1.15-launcher.jar runtime_enum_extender PLUGINSERVICE /accesstransformers-2.0.0-milestone.1-shadowed.jar accesstransformer PLUGINSERVICE /forge-1.15.2-31.1.9_mapped_stable_60-1.15-launcher.jar capability_inject_definalize PLUGINSERVICE /forge-1.15.2-31.1.9_mapped_stable_60-1.15-launcher.jar runtimedistcleaner PLUGINSERVICE /forge-1.15.2-31.1.9_mapped_stable_60-1.15-launcher.jar fml TRANSFORMATIONSERVICE FML: 31.1 Forge: net.minecraftforge:31.1.9 FML Language Providers: [email protected] minecraft@1 Mod List: client-extra.jar Minecraft {[email protected] DONE} main Allergies & Athsma Mod {allergies@PRIVATE-ALPHA DONE} forge-1.15.2-31.1.9_mapped_stable_60-1.15-recomp.jar Forge {[email protected] DONE} Player Count: 1 / 8; [ServerPlayerEntity['Dev'/228, l='World', x=11.72, y=70.00, z=-23.23]] Data Packs: vanilla, mod:allergies (incompatible), mod:forge (incompatible) Type: Integrated Server (map_client.txt) Is Modded: Definitely; Client brand changed to 'forge'

 

[KidKoderMod033109]

Opps not everything was pasted

Here is the PasteBin: https://pastebin.com/TustzfFp

[Draco18s]

Quote

Stacktrace:

    at net.kidkoder.allergies.system.Events.newPlayerJoinWorld(Events.java:47)

2 hours ago, diesieben07 said:

And line 47 is...?

Line 47 of your code is...?

[KidKoderMod033109]

Oh... 

            StringTextComponent allergiesListGold = new StringTextComponent("You are allergic to gold: " + playerAllergies.hasAllergen(Allergen.GOLD));

ya. Here 

[KidKoderMod033109]

11 minutes ago, diesieben07 said:

getAllergens returned null.

And that orElse is still nonsensicle.

Ok, ya true, so how can I fix that?

Also, that line I sent a minute ago was line 48, this is line 47:

            PlayerAllergies playerAllergies = player.getCapability(AllergiesProvider.ALLERGIES_CAP).orElse(new CapabilityAllergies()).getAllergens();

 

[KidKoderMod033109]

25 minutes ago, diesieben07 said:

This is why you post your code as a Git repo!

 

I did. It is located here: https://github.com/KidKoder09923/Allergies-Mod

25 minutes ago, diesieben07 said:

If that is line 47 then that means that your ICapabilityProvider returned a LazyOptional with a null inside (that should log a warning "Supplier should not return null value").

Also, back the orginial question, how would I convert the LazyOptional to an IAllergies. I still geting a java.lang.NullPointerExeption

[Animefan8888]

16 minutes ago, KidKoderMod033109 said:

I did. It is located here: https://github.com/KidKoder09923/Allergies-Mod

You never linked it how were we supposed to know or have access to it.
 

Quote

@SubscribeEvent

public void attachCapability(AttachCapabilitiesEvent event) {

event.addCapability(ALLERGIES_LOC, new AllergiesProvider());

}

You need to specify what you are attaching it to IE AttachCapabilitiesEvent<Entity>

then to only attach it to player do if (event.getObject() instanceof PlayerEntity)

then add the Capability.

Quote

@Nonnull

@Override

public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, @Nullable Direction side) {

return null;

}

@Nonnull

@Override

public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap) {

return null;

}

Here's your NullPointerException an issue...

 

Did you forget to update your git repo?

Edited April 17, 2020 by Animefan8888

[KidKoderMod033109]

42 minutes ago, diesieben07 said:

This would throw a RuntimeException for attached capabilities (see CapabilityDispatcher#getCapability).

I don't follow...