KeyHandler.java

public class KeyHandler
{
	private static Map<KeyBinding, List<IKeyReceiver>> callbacks = new HashMap<KeyBinding, List<IKeyReceiver>>();
	
	public static void registerKeybindForNotification(KeyBinding keyBinding, IKeyReceiver callbackReceiver)
	{
		if(!callbacks.containsKey(keyBinding))
		{
			List<IKeyReceiver> receivers = new ArrayList<IKeyReceiver>();
			receivers.add(callbackReceiver);
			callbacks.put(keyBinding, receivers);
		}
		else
		{
			List<IKeyReceiver> receivers = callbacks.get(keyBinding);
			receivers.add(callbackReceiver);
			callbacks.put(keyBinding, receivers);
		}
	}
	
	@SubscribeEvent
	public void clientKeyListener(TickEvent.PlayerTickEvent event)
	{
		if(event.side == Side.CLIENT && event.phase == TickEvent.Phase.START)
		{
			for(KeyBinding k : Minecraft.getMinecraft().gameSettings.keyBindings)
			{
				if(callbacks.containsKey(k) && k.isKeyDown())
				{
					List<IKeyReceiver> receivers = callbacks.get(k);
					for(IKeyReceiver receiver : receivers)
					{
						receiver.onKeypress(event.player, k);
					}
				}
			}
		}
	}
}