That's one heck of a commit you've got there...

I may have got a bit behind with version control. A lot behind, in fact. Maybe I'll go back and split this sometime - then again, I probably won't. But hey, at least it's here!

src/main/java/electroblob/wizardry/tileentity/SlotItemClassList.java

@@ -0,0 +1,40 @@
+package electroblob.wizardry.tileentity;
+
+import net.minecraft.inventory.IInventory;
+import net.minecraft.inventory.Slot;
+import net.minecraft.item.Item;
+import net.minecraft.item.ItemStack;
+
+/**
+ * Simple extension of {@link Slot} which only accepts items from an array of item classes defined in the constructor.
+ * 
+ * @author Electroblob
+ * @since Wizardry 1.0
+ */
+public class SlotItemClassList extends Slot {
+
+	private final Class<? extends Item>[] itemClasses;
+	private int stackLimit;
+
+	@SafeVarargs
+	public SlotItemClassList(IInventory inventory, int index, int x, int y, int stackLimit, Class<? extends Item>... allowedItemClasses){
+		super(inventory, index, x, y);
+		this.itemClasses = allowedItemClasses;
+		this.stackLimit = stackLimit;
+	}
+
+	public int getSlotStackLimit(){
+		return stackLimit;
+	}
+
+	public boolean isItemValid(ItemStack stack){
+
+		for(Class<? extends Item> itemClass : itemClasses){
+			if(itemClass.isAssignableFrom(stack.getItem().getClass())){
+				return true;
+			}
+		}
+
+		return false;
+	}
+}