ms/packages/plugins/docs/MiaoMail.md

private static void injectInventoryAddItemMethod() {
    System.out.println("Injectoring Mail...");
    try {
        ClassPool pool = ClassPool.getDefault();
        String inventoryClassName = Bukkit.getServer().getClass().getPackage().getName() + ".inventory.CraftInventory";
        File classFile = new File(URLDecoder.decode(InventoryDragEvent.class.getProtectionDomain().getCodeSource().getLocation().getPath().split("!")[0], "UTF-8"));
        pool.appendClassPath(classFile.getPath());
        classFile = new File(URLDecoder.decode(MailPlugin.class.getProtectionDomain().getCodeSource().getLocation().getPath().split("!")[0], "UTF-8"));
        pool.appendClassPath(classFile.getPath());
        CtClass inventoryClass = pool.get(inventoryClassName);
        CtMethod addItemMethod = inventoryClass.getDeclaredMethod("addItem");

        addItemMethod.insertAfter(
                "if(this instanceof org.bukkit.inventory.PlayerInventory){"
                + "    final org.bukkit.inventory.PlayerInventory playerInventory = (org.bukkit.inventory.PlayerInventory)this;"
                + "    final org.bukkit.entity.Player player = (org.bukkit.entity.Player)playerInventory.getHolder();"
                + "    if(!$_.values().isEmpty()){"
                + "        org.bukkit.event.inventory.InventoryDragEvent event = new org.bukkit.event.inventory.InventoryDragEvent(player.getOpenInventory(), new org.bukkit.inventory.ItemStack(org.bukkit.Material.AIR), new org.bukkit.inventory.ItemStack(org.bukkit.Material.AIR), true, $_);"
                + "        event.setCancelled(true);"
                + "        event.setResult(org.bukkit.event.Event.Result.DENY);"
                + "        org.bukkit.Bukkit.getPluginManager().callEvent(event);"
                + "    }"
                + "}");
        try {
            inventoryClass.toClass();
            System.out.println("Injected");
        } catch (Exception e) {
            System.out.println("Inject fail, Please restart server");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}