common/thermalexpansion/api/item/IChargeableItem.java

package thermalexpansion.api.item;

import net.minecraft.item.ItemStack;

/**
 * Implement this interface on Item classes that support external manipulation of their internal
 * energy storages. This interface does not provide methods for the underlying internal energy
 * usage.
 */

public interface IChargeableItem {

    /**
     * Adds energy to an item. Returns the quantity of energy that was accepted. This should always
     * return 0 if the item cannot be externally charged.
     * 
     * @param theItem
     *            ItemStack to be charged.
     * @param energy
     *            Maximum amount of energy to be sent into the item.
     * @param doReceive
     *            If false, the charge will only be simulated.
     * @return Amount of energy that was accepted by the item.
     */
    public float receiveEnergy(ItemStack theItem, float energy, boolean doReceive);

    /**
     * Removes energy from an item. Returns the quantity of energy that was removed. This should
     * always return 0 if the item cannot be externally discharged.
     * 
     * @param theItem
     *            ItemStack to be discharged.
     * @param energy
     *            Maximum amount of energy to be removed from the item.
     * @param doTransfer
     *            If false, the discharge will only be simulated.
     * @return Amount of energy that was removed from the item.
     */
    public float transferEnergy(ItemStack theItem, float energy, boolean doTransfer);

    /**
     * Get the amount of energy currently stored in the item.
     */
    public float getEnergyStored(ItemStack theItem);

    /**
     * Get the max amount of energy that can be stored in the item.
     */
    public float getMaxEnergyStored(ItemStack theItem);

}