[OT] Shopping cart best practices - Cookie, HttpSession or DB

[Brian McSweeney]

Hi all,
 
Quick question. I want to implement a shopping cart. I know this has 
been done a million times in a million open source projects however I 
have a few questions, and seeing as everyone in here seems so
knowledgeable.
 
What I'd like:
 
1) User can add to shopping cart without having to check in. (checkout
requires login).
 
2) User can leave the site and un-checked out shopping cart data will
remain.
 
The options I have to implement the shopping cart:
 
a)       Cookies -  satisfies 1 and 2, but assumes user doesn't turn off
cookies
 
b)       HttpSession object - satisfies 1, but not 2
 
c)       Database shopping cart object - satisfies 2, but not 1.
 
I'd like to know,
 
a)       am I basically correct with these assumptions.
b)       What would people recommend based on their experience.
c)   any struts open source project that might have this?
 
Thanks very much,
Brian