[1.8]Anvil Recipies

Hey I was trying to make anvil recipies and so i saw the AnvilUpdateEvent so i tired to create one using that. Unfortunately it doesn't seem to be working.

@SubscribeEvent

public void AnvilRecipies(AnvilUpdateEvent event) {

    if(event.right == new ItemStack(Items.apple) && event.left == new ItemStack(Items.apple)){

    event.cost = 2;

    event.output = new ItemStack(Items.apple);

    return;

    }

  }