Dependency Injection with PHP 8.4’s Lazy Objects

PHP 8.4 is out now for approximately 2 month and there are a lot of new features. One significant new feature is “Lazy Objects”, which is described as follows:

A lazy object is an object whose initialization is deferred until its state is observed or modified.

The past few weeks, I read a couple of blogs addressing Lazy Objects in the context of Dependency Injection and how it works together to boost up performance. I would like to discuss a few confusions and clarify some terminology.

This topic will also be published as a video on my YouTube channel: https://www.youtube.com/@doganoo

I will go into the topic in more detail there. So don’t forget to follow so you don’t miss anything!

Abstract Dependency Injection

Brief Recap: What is Dependency Injection

Dependency Injection (DI) is a design pattern that promotes loose coupling between components in software systems. Instead of a class creating its own dependencies, these are injected from an external source. This means a class simply declares what it needs, and another part of the application (e.g., a Dependency Injection container) provides those dependencies.

By separating the creation of dependencies from their usage, DI offers several advantages:

• Improved Testability: Dependencies can be easily mocked or replaced during unit testing.
• Flexibility: Dependencies can be swapped out or configured differently without modifying the class itself.
• Maintainability: Changes in dependency implementation don’t require changes in dependent classes.

There are several ways to implement DI:

1. Constructor Injection: Dependencies are passed into a class via its constructor.
2. Setter Injection: Dependencies are assigned using setter methods.
3. Method Injection: Dependencies are passed directly to methods that require them.

Lazy Loading vs. Lazy Initialization: Similar Terms, Different Concepts

While lazy loading and lazy initialization are often mentioned together, they refer to distinct…