Making Players Pick Only 1 Item

So i need to make a player only pick up 1 item at a time, for example, if there was a stack of diamonds on the ground, i want them to only have 1 diamond when they pick it up.

 

Just check if a player has more than 1 diamond in his inventory and if not delete the amount.

 

Figured it out, here's the code for anyone who needs it, and thanks @BurnerDiamond for replying

Code:

@EventHandler
    public void onPick(PlayerPickupItemEvent e) {
       
        if(e.getItem().getItemStack().getAmount() > 1) {
            e.setCancelled(true);
           
            ItemStack d = new ItemStack(e.getItem().getItemStack());
            d.setAmount(1);
           
            e.getPlayer().getInventory().addItem(d);
            e.getItem().remove();
        }
       
    }