[URGENT] Can't block crafting recipes

I am making a custom plugin that prevents players on the server from crafting TNT, but still letting them buy it. If anyone knows how to make someting like an onCraft method for TNT plz post it. Srry im kinda new to the bukkit api :/

Thx in advance
-LazerMan47

 

Code:java

public void onEnable(){
        getServer().getPluginManager().registerEvents(new Mylistener(), this);//register the listener
    }
 
public final class Mylistener implements Listener {//define a listener
 
@EventHandler
public void tnt(CraftItemEvent event){ //are they crafting?
            ItemStack is = new ItemStack(Material.TNT);//define what we're looking for
            if(event.getResult().equals(is)){//is what their crafting going to be tnt?
                event.setCancelled(true);//stop them from crafting it
            }
        }
}