Allow only one quantity per item and get response

[maxleistner]

Is there any functionality already built in to allow only one quantity per item?
If the user tries to add the item again, i would like to show a message, that that item is already in the cart.

thanks!

[ultrono]

Bespoke functionality as described would be handled by your own application. It is not the job of a generic shopping cart package to handle business specific rules.