ImmunologyCapability.java

package dev.krysztal.immunology.capability;

import dev.krysztal.immunology.network.ImmunologyNetworkChannel;
import dev.krysztal.immunology.network.packet.ImmunologyCapabilitySyncPacket;
import dev.krysztal.immunology.util.CapabilitySyncUtil;
import lombok.Getter;
import lombok.Setter;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.nbt.NbtCompound;
import net.minecraft.server.network.ServerPlayerEntity;
import net.minecraftforge.common.util.INBTSerializable;
import net.minecraftforge.network.PacketDistributor;

public class ImmunologyCapability implements INBTSerializable<NbtCompound> {

    @Getter
    @Setter
    private int immunology = 100;

    @Override
    public NbtCompound serializeNBT() {
        var defaultNBT = new NbtCompound();
        defaultNBT.putInt("ImmunologyValue", immunology);
        return defaultNBT;
    }

    @Override
    public void deserializeNBT(NbtCompound nbtCompound) {
        this.immunology = nbtCompound.getInt("ImmunologyValue");
    }

    public void sync(ServerPlayerEntity player) {
        ImmunologyNetworkChannel.INSTANCE.send(
                PacketDistributor.PLAYER.with(() -> player),
                new ImmunologyCapabilitySyncPacket(this.serializeNBT())
        );
    }

}

ImmunologyCapabilityProvider.java

package dev.krysztal.immunology.capability;

import dev.krysztal.immunology.Immunology;
import lombok.extern.log4j.Log4j2;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.nbt.NbtCompound;
import net.minecraft.util.Identifier;
import net.minecraft.util.math.Direction;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.common.capabilities.*;
import net.minecraftforge.common.util.INBTSerializable;
import net.minecraftforge.common.util.LazyOptional;
import net.minecraftforge.event.AttachCapabilitiesEvent;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

@Log4j2
public class ImmunologyCapabilityProvider extends CapabilityProvider<ImmunologyCapabilityProvider> implements INBTSerializable<NbtCompound> {
    public static final Capability<ImmunologyCapability> INSTANCE = CapabilityManager.get(new CapabilityToken<>() {
    });
    private final LazyOptional<ImmunologyCapability> immunologyCapability;
    private static final Identifier IDENTIFIER = Immunology.id("capability");

    protected ImmunologyCapabilityProvider() {
        super(ImmunologyCapabilityProvider.class);
        immunologyCapability = LazyOptional.of(ImmunologyCapability::new);
    }

    @Override
    public NbtCompound serializeNBT() {
        return immunologyCapability.resolve().isPresent() ? immunologyCapability.resolve().get().serializeNBT() : new NbtCompound();
    }

    @Override
    public void deserializeNBT(NbtCompound nbtCompound) {
        immunologyCapability.ifPresent(cap -> cap.deserializeNBT(nbtCompound));
    }

    @NotNull
    @Override
    public <T> LazyOptional<T> getCapability(@NotNull Capability<T> cap, @Nullable Direction side) {
        return INSTANCE.orEmpty(cap, immunologyCapability);
    }

    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    //                                    Process attach capability                                                   //
    ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    private static void onRegisterCapability(final RegisterCapabilitiesEvent event) {
        event.register(ImmunologyCapability.class);
    }

    private static void onAttachCapabilityToPlayer(final AttachCapabilitiesEvent<PlayerEntity> event) {
        if (!event.getObject().getCapability(ImmunologyCapabilityProvider.INSTANCE).isPresent())
            event.addCapability(ImmunologyCapabilityProvider.IDENTIFIER, new ImmunologyCapabilityProvider());
    }

    public static void init() {
        var forgeBus = MinecraftForge.EVENT_BUS;
        var modBus = FMLJavaModLoadingContext.get().getModEventBus();

        forgeBus.addGenericListener(PlayerEntity.class, ImmunologyCapabilityProvider::onAttachCapabilityToPlayer);
        modBus.addListener(ImmunologyCapabilityProvider::onRegisterCapability);
    }

    public static LazyOptional<ImmunologyCapability> getCapability(PlayerEntity player) {
        return player.getCapability(ImmunologyCapabilityProvider.INSTANCE);
    }

}