Iterator Pattern

Owned by Computer Science Department
Last updated: Jul 10, 2023
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The Iterator Pattern is a design pattern in Object-Oriented Programming (OOP) that provides a way to access the elements of an aggregate object (like a collection or a list) sequentially without exposing its underlying representation.

The Iterator Design Pattern is a behavioral design pattern that allows sequential traversal through a complex data structure (like collections, lists, arrays etc.) without exposing its internal details. It separates the logic of iteration from business logic.

 

The Iterator Pattern involves two main concepts:

  1. Iterator - This is an interface that provides methods to traverse through a collection, typically with methods like next(), hasNext(), first(), current(), etc. It keeps track of the current position while traversing.

  2. Aggregate (or Collection) - This is the collection of objects that we want to traverse through. It provides an interface to create an iterator.

One of the main benefits of the iterator pattern is that it provides a uniform way to traverse different collections. This makes the client code (the code that uses the iterator) simpler and easier to understand. It also adheres to the principle of single responsibility as it separates the responsibility of iteration from the Collection object.