Hi mrsato, congratulations on your upcoming cruise! There are refrigerators in the room. The cabin steward will fill the ice bucket twice a day. There are glasses on the counter and in the restroom. If you need more ice than that, just ask your cabin steward, they'll be happy to oblige.
Hope your cruise on the Diamond is fantastic. We've not yet sailed on her, but every Princess ship we've sailed on has been great. They're our favorite line, so far.