Bukkit

Think of a way to deal with items reward when a player's inventory is full.

Keep in mind that the message part can contains messages that inform about giving rewards.
Perhaps create a pending reward on player's metadata and store it on database too.

A way:
inventory is full -> store items on player's metadata and database if he quit

on open inventory event look if player has a pending metadata and slots free to give items

on join check if database contains pending items and store them on player's metadata

For the moment items that can't be stored in player inventory will be drop front of him.