cap

cap_event.java

package loordgek.extragenarators.api.cap;

import net.minecraft.entity.Entity;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.event.AttachCapabilitiesEvent;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;

public class event {
    @SubscribeEvent
    public void onAttachCapabilities(AttachCapabilitiesEvent<Entity> event) {
        if (event.getObject() instanceof EntityPlayer){
            event.addCapability( new ResourceLocation(yourmodid and a name), new yourcap((EntityPlayer)event.getObject()));
        }
    }
}

cap_yourcap.java

package loordgek.extragenarators.api.cap;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.EnumFacing;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.ICapabilityProvider;

import javax.annotation.Nullable;

public class yourcap implements ICapabilityProvider {
    private final EntityPlayer player;

    public yourcap(EntityPlayer player) {
        this.player = player;
    }

    @Override
    public boolean hasCapability(Capability<?> capability, @Nullable EnumFacing facing) {
        return false;
    }

    @Override
    public <T> T getCapability(Capability<T> capability, @Nullable EnumFacing facing) {
        return null;
    }
}