How to implement paging in both directions in GAE-J with cursors

I'm trying to implement paging in my GAE-J/GWT app. Paging forward with a cursor is straight-forward, but I'm wondering if there's some best-p开发者_Python百科ractice for paging both forward and backward with cursors.

Thanks!

---

If you are talking about datastore cursor you can`t; The only way to do it is to store previous cursors in memcache with page numbers (cursros are just strings) and when you go back to extract the cursor/result for the page from the cache.