ContainerTileEntityPurifier *Changed Energy*

public class ContainerTileEntityPurifier extends Container {
    private TileEntityPurifier te;

    private int progress;
    private int currentProgress;
    private int storedPower;

    public ContainerTileEntityPurifier(IInventory playerInv, TileEntityPurifier te) {
        this.te = te;

        // Tile Entity, Slot 1, Slot ID 1
        this.addSlotToContainer(new SlotPurifierSand(te.getInventory(), 0, 58, 40));
        this.addSlotToContainer(new SlotPurifierOutput(te.getInventory(), 1, 102, 40));

        // Player Inventory, Slot 9-35, Slot IDs 9-35
        for (int y = 0; y < 3; ++y) {
            for (int x = 0; x < 9; ++x) {
                this.addSlotToContainer(new Slot(playerInv, x + y * 9 + 9, 8 + x * 18, 84 + y * 18));
            }
        }

        // Player Inventory, Slot 0-8, Slot IDs 36-44
        for (int x = 0; x < 9; ++x) {
            this.addSlotToContainer(new Slot(playerInv, x, 8 + x * 18, 142));
        }
    }

    /**
     * Looks for changes made in the container, sends them to every listener.
     */
    @Override
    public void detectAndSendChanges() {
        super.detectAndSendChanges();

        for(IContainerListener listener : listeners) {
            if (progress != te.getField(0)) {
                if (listener instanceof EntityPlayerMP) {
                    ModPacketHandler.INSTANCE.sendTo(new PurifierMessage(progress, currentProgress, storedPower, this.windowId), (EntityPlayerMP) listener);
                }
            }

            if (currentProgress != te.getField(1)) {
                if (listener instanceof EntityPlayerMP) {
                    ModPacketHandler.INSTANCE.sendTo(new PurifierMessage(progress, currentProgress, storedPower, this.windowId), (EntityPlayerMP) listener);
                }
            }

            if (storedPower != te.getField(2)) {
                if (listener instanceof EntityPlayerMP) {
                    int change = te.getField(2) - storedPower;

                    ModPacketHandler.INSTANCE.sendTo(new PurifierMessage(progress, currentProgress, change, this.windowId), (EntityPlayerMP) listener);
                }
            }
        }

        this.progress = this.te.getField(0);
        this.currentProgress = this.te.getField(1);
        this.storedPower = this.te.getField(2);
    }

    @SideOnly(Side.CLIENT)
    @Override
    public void updateProgressBar(int id, int data) {
        this.te.setField(id, data);
    }

    @Override
    public boolean canInteractWith(EntityPlayer playerIn) {
        return true;
    }
}