MinecraftForge/MinecraftForge — pull request #1019 by chibill (2014-03-30 04:33:00+00:00)
Title: Added DispenseEvents.

This PR adds two events that allow you to tell when a Dispenser or Dropper out puts an Item let it be in to the air or in to an inventory.

The first event fires right before the block does anything with the item.
It also lets you change that item before it is fired.

The second event fires after the block is all done dispensing.