In this series, Object-Oriented PHP Part 3, we'll teach you all about inheritance in PHP, including how that works in classes, abstractions, and interfaces. These concepts are keys to understanding the code you will see in Drupal 8 modules.

Sometimes we need to be able to retrieve the value of a property on an object, but we don't know the name of that property. Instead, we need to dynamically calculate the property name, and then access the value. For example: $row->{$my_property};. This post looks at how the Views module uses this technique and allows for a huge amount of flexibility.

Object-oriented programming (OOP) is way of organizing your code to be more efficient, and it takes advantage of some really nice features in modern versions of PHP. One of the basic concepts of OOP is, not surprisingly, an object. Directly related to working with objects is understanding PHP classes. Drupal 8 is taking big steps to move to an OOP architecture, and so you will get very familiar with both of these as you start to jump into Drupal 8 development.

This tutorial, based on the video Create a Basic PHP Class, will explain what a class is, show you how to set up a class, and look at a PHP object. By the end of this tutorial, you will be able to create a class, an object, add a property to your object, and set the value of the property inside the class.

This week, we continue our Introduction to Object-oriented PHP series, in partnership with KnpUniversity (now SymfonyCasts), with tutorials that mostly focus on working with objects in PHP. You'll also learn how to add a specially formatted comment to your code that will enable code autocomplete functionality in your IDE.

Part of learning Drupal’s API is learning about “what’s in the pantry.” In Drupal 8, that pantry is configured quite a bit differently than before. Instead of getting the whole warehouse of Drupal functions on every page load, functions—well, now methods—are contained in objects which are defined by classes. Most, if not all, of these classes, which exist in their own PHP files, can be extended and many of them are specifically designed to be extended. These extensible classes are the pantries. They contain properties and methods that we can just use in the classes that extend them. When we extend these classes, we need to make sure we peek inside to see what’s available before we go elsewhere for something that might already be in the cupboard.