Iterator

Origin:

GoF 95

Reason:

To sequentially access all the objects of a collection without exposing the collection's interface and/or representation.

Synopsis:

Define an interface with methods to produce a sequence of objects. Make the interface independent of the object's container.

Example:

An InventoryBrowser displays InventoryItems encapsulated in an InventoryCollection. The InventoryBrowser does not access the InventoryCollection, but an object that implements the InventoryIterator interface.

Solution:

Collection	Class that encapsulates a collection of objects.
IteratorIF	Interface that defines the methods to sequentially access the objects in a Collection.
Iterator	Implementation of IteratorIF.
CollectionIF	Common interface to Collections. Provides method(s) to create Iterators.