Minecraft Forge 1.14.4 ~ LevelHearts Capability

IMoreHealth.java

package com.firecontroller1847.levelhearts.capabilities;

public interface IMoreHealth {
	
	byte getHeartContainers();
	byte getDefaultHealth();
	double getModifier();
	short getLevelRampPosition();
	
	void setHeartContainers(byte heartContainers);
	void setDefaultHealth(byte defaultHealth);
	void setModifier(double modifier);
	void setLevelRampPosition(short levelRampPosition);

}

LevelHearts.java

package com.firecontroller1847.levelhearts;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.firecontroller1847.levelhearts.capabilities.IMoreHealth;
import com.firecontroller1847.levelhearts.capabilities.MoreHealth;
import com.firecontroller1847.levelhearts.capabilities.MoreHealthProvider;
import com.firecontroller1847.levelhearts.capabilities.MoreHealthStorage;

import net.minecraft.entity.Entity;
import net.minecraft.entity.player.PlayerEntity;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.common.capabilities.CapabilityManager;
import net.minecraftforge.event.AttachCapabilitiesEvent;
import net.minecraftforge.eventbus.api.SubscribeEvent;
import net.minecraftforge.fml.ModLoadingContext;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.config.ModConfig;
import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;

@Mod(LevelHearts.MOD_ID)
@Mod.EventBusSubscriber(modid = LevelHearts.MOD_ID)
public class LevelHearts {

	public static final String MOD_ID = "levelhearts";
	public static final String MOD_NAME = "LevelHearts";
	public static final String MOD_VERSION = "2.0.0";
	public static Logger logger = LogManager.getLogger(LevelHearts.MOD_ID);

	public LevelHearts() {
		ModLoadingContext.get().registerConfig(ModConfig.Type.COMMON, LevelHeartsConfig.COMMON, "levelhearts.toml");
		FMLJavaModLoadingContext.get().getModEventBus().addListener(LevelHearts::onCommonSetup);
	}
	
	@SubscribeEvent
	public static void onCommonSetup(FMLCommonSetupEvent event) {
		CapabilityManager.INSTANCE.register(IMoreHealth.class, new MoreHealthStorage(), MoreHealth::new);
	}

	@SubscribeEvent
	public static void onAttachCapabilities(AttachCapabilitiesEvent<Entity> event) {
		if (event.getObject() instanceof PlayerEntity) {
			event.addCapability(new ResourceLocation(LevelHearts.MOD_ID, "morehealth"), new MoreHealthProvider());
		}
	}

	public static void debug(String message) {
		if (LevelHeartsConfig.GENERAL.debug.get()) {
			logger.info(message);
		}
	}

}

MoreHealth.java

package com.firecontroller1847.levelhearts.capabilities;

import com.firecontroller1847.levelhearts.LevelHeartsConfig;

import net.minecraft.entity.SharedMonsterAttributes;

public class MoreHealth implements IMoreHealth {

	private byte heartContainers;
	private byte defaultHealth;
	private double modifier;
	private short levelRampPosition;
	
	public MoreHealth() {
		this.heartContainers = 0;
		this.defaultHealth = LevelHeartsConfig.HEALTH.defHealth.get().byteValue();
		this.modifier = this.defaultHealth - SharedMonsterAttributes.MAX_HEALTH.getDefaultValue();
		this.levelRampPosition = 0;
	}

	@Override
	public byte getHeartContainers() {
		return this.heartContainers;
	}

	@Override
	public byte getDefaultHealth() {
		return this.defaultHealth;
	}

	@Override
	public double getModifier() {
		return this.modifier;
	}

	@Override
	public short getLevelRampPosition() {
		return this.levelRampPosition;
	}

	@Override
	public void setHeartContainers(byte heartContainers) {
		this.heartContainers = heartContainers;
	}

	@Override
	public void setDefaultHealth(byte defaultHealth) {
		this.defaultHealth = defaultHealth;
	}

	@Override
	public void setModifier(double modifier) {
		this.modifier = modifier;
	}

	@Override
	public void setLevelRampPosition(short levelRampPosition) {
		this.levelRampPosition = levelRampPosition;
	}

}

MoreHealthProvider.java

package com.firecontroller1847.levelhearts.capabilities;

import net.minecraft.nbt.INBT;
import net.minecraft.util.Direction;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.CapabilityInject;
import net.minecraftforge.common.capabilities.ICapabilitySerializable;
import net.minecraftforge.common.util.LazyOptional;

public class MoreHealthProvider implements ICapabilitySerializable<INBT> {

	@CapabilityInject(IMoreHealth.class)
	public static final Capability<IMoreHealth> MORE_HEALTH_CAPABILITY = null;

	private LazyOptional<IMoreHealth> instance = LazyOptional.of(MORE_HEALTH_CAPABILITY::getDefaultInstance);

	@Override
	public <T> LazyOptional<T> getCapability(Capability<T> cap, Direction side) {
		return cap == MORE_HEALTH_CAPABILITY ? instance.cast() : LazyOptional.empty();
	}

	@Override
	public INBT serializeNBT() {
		// @formatter:off
		return MORE_HEALTH_CAPABILITY.getStorage().writeNBT(MORE_HEALTH_CAPABILITY, this.instance.orElseThrow(() -> new IllegalArgumentException("LazyOptional must not be empty!")), null);
		// @formatter:on
	}

	@Override
	public void deserializeNBT(INBT nbt) {
		// @formatter:off
		MORE_HEALTH_CAPABILITY.getStorage().readNBT(MORE_HEALTH_CAPABILITY, this.instance.orElseThrow(() -> new IllegalArgumentException("LazyOptional must not be empty!")), null, nbt);
		// @formatter:on
	}

}

MoreHealthStorage.java

package com.firecontroller1847.levelhearts.capabilities;

import net.minecraft.nbt.CompoundNBT;
import net.minecraft.nbt.INBT;
import net.minecraft.util.Direction;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.Capability.IStorage;

public class MoreHealthStorage implements IStorage<IMoreHealth> {

	@Override
	public INBT writeNBT(Capability<IMoreHealth> capability, IMoreHealth instance, Direction side) {
		CompoundNBT tag = new CompoundNBT();
		tag.putByte("heartContainers", instance.getHeartContainers());
		tag.putByte("minHealth", instance.getDefaultHealth());
		tag.putDouble("modifier", instance.getModifier());
		tag.putShort("levelRampPosition", instance.getLevelRampPosition());
		return tag;
	}

	@Override
	public void readNBT(Capability<IMoreHealth> capability, IMoreHealth instance, Direction side, INBT nbt) {
		CompoundNBT tag = (CompoundNBT) nbt;
		instance.setHeartContainers(tag.getByte("heartContainers"));
		instance.setDefaultHealth(tag.getByte("minHealth"));
		instance.setModifier(tag.getDouble("modifier"));
		instance.setLevelRampPosition(tag.getShort("levelRampPosition"));
	}

}

Thanks for putting this on GitHub, this is really helping me understand capabilities better. Forges documents on this kinda suck.

Thanks for putting this on GitHub, this is really helping me understand capabilities better. Forges documents on this kinda suck.

Glad I was able to be of help. Forge documentation relies heavily on a "trial-and-error" and a "figure it out" mentality which, in my opinion, is a terrible way to go about things. I'm very much so more of a "learn by example" type of guy, and so I wanted to share this so that there'd be at least one public example of capabilities working for 1.14. They've changed a little in 1.17 but not by much, so hopefully this example is still helpful