An IContainer is an item container that is able to hold several itemStacks such as a chest.

• container.containerSize returns the container size as int
• container.getStack(int index) returns the IItemStack at the given index.
• container.setStack(int index, IItemStack stack) sets the IItemStack at the given index.
• container.asString() container as string executes toString on the container object.

An IContainer is an Iterable<IItemStack>.
This means that you can use a for-loop on the container to iterate over its IItemStacks.