Iterator

• Also known as: Cursor
• Sequentially access the elements of a collection
• Provide a way to access the elements of an aggregate object sequentially without exposing its underlying representation

Iterator

• Defines an interface for accessing and traversing elements.

ConcreteIterator

• Implements the Iterator interface.
• Keeps track of the current position in the traversal of the aggregate.

Aggregate

• Defines an interface for creating an Iterator object.

ConcreteAggregate

• Implements the Iterator creation interface to return an instance of the proper ConcreteIterator.