Bukkit

The configuration file is created on first startup in DiveCraft/config.yml but can be prepared beforehand. The default configuration is as follows:

# item = itemID of the helmet. Must be something the player can put in the helmet slot.
# usage = the amount of fuel this helmet requires to refill the air bar.
helmets:
    - item  : 86  # Pumpkin
      usage : 1
    - item  : 302 # Chain Helmet
      usage : 2
    - item  : 310 # Diamond Helmet
      usage : 3
    - item  : 314 # Gold Helmet
      usage : 5
    - item  : 306 # Iron Helmet
      usage : 8
    - item  : 298 # Leather Cap
      usage : 13
fuel: 338 # Sugar Cane'''

You can see that when a player is diving while wearing a Leather Cap, he needs 13 fuel to have a full refill of his air bar. The fuel used in this case is Sugar Cane but can be any item.

The helmet section needs to be a list of maps with the item and usage keys. The item key must be an itemID and the usage must be a positive nonzero integer. The fuel section takes a single numeric value as the itemID.