The Iterator pattern is a behavioral design pattern that provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation. It separates the traversal behavior of a collection from the collection itself, making it easier to implement and reuse different traversal algorithms.
- Iterator: Interface or abstract class that defines methods for accessing and traversing elements.
- ConcreteIterator: Implements the
Iteratorinterface and is responsible for keeping track of the current position in the traversal. - Aggregate: Interface or abstract class that defines a method to create an iterator object.
- ConcreteAggregate: Implements the
Aggregateinterface and returns an instance of a ConcreteIterator.
Traversal of Complex Data Structures: Use the Iterator pattern to traverse complex data structures like trees, graphs, or composite structures without exposing their internal details.
Unified Interface for Collections: When you need a unified interface to traverse different types of collections (e.g., arrays, lists), the Iterator pattern provides a consistent way to do so.
Custom Traversal Algorithms: If you need custom traversal algorithms (e.g., reverse traversal, skipping elements), you can implement them using the Iterator pattern without modifying the underlying collection.
Encapsulation: The Iterator pattern encapsulates the traversal logic, keeping the internal representation of the collection hidden.
Single Responsibility Principle: The pattern separates the concerns of collection management and traversal, adhering to the Single Responsibility Principle.
Flexibility: You can add new traversal methods or change existing ones without affecting the underlying collection.