Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

PHP Designing Interfaces in PHP Using Interfaces Code to Multiple Interfaces

Jonathan Healy
Jonathan Healy
21,601 Points

Can someone explain why we construct the RepositoryInterface in the Collection class opposed to implementing it?

I am unclear on the purpose of introducing the Repository Interface, and it's purpose there, inside of the constructor function of the Collection class.

Does this serve a different purpose as opposed to implementing it as we are with the Iterator and Countable interface?

1 Answer

Shoko Ishigaki
Shoko Ishigaki
21,826 Points

In collection class, we have property called repo which is type "RepositoryInterface" (or class implementing RepositoryInterface). Inside constructor, we initialise the repo and then use that repo's function. Hope this helps.

Jonathan Healy
Jonathan Healy
21,601 Points

That makes sense thank you for your assistance!