PHP Interfaces & Polymorphism - Interfaces Explained - Full PHP 8 Tutorial

[@ronniefaithparalejas7678]

Am i the only one who notice these videos are better than any PHP premium or paid tutorial videos out there? Thanks for these great videos!

[@ProgramWithGio]

Thank you 🙏💙

[@DAG_r8]

One thing for sure it is always concise and precise, I would recommend this to many php developer, we are all apprentice.

[@KIKOmanasijev]

Yep, I have bought many courses and none of the matches the quality of Gio's content. Still can't believe this is free and Gio doesn't have more engagement on this channel 🤯

[@Cronay]

100% true. So many tutors bring their character and with that unnecessary fluff into their content. Gio is different. It's just straight and dense knowledge and has just the right amount of his personal opinion in the video(barely any).

[@paul.bitoana]

I just canceled the subscription because of these videos.

[@JohnnyBigodes]

That independent debt collector made my day ;). It is again a great video... Thank you

[@ProgramWithGio]

:D thank you, happy to hear that

[@JoseManuelCornelio]

These videos are so dense that I really have to take some time to digest the content before moving on to the next one. This is better than any paid course out there so far.

[@ProgramWithGio]

Thank you, appreciate it 🙏. Taking some time & digesting it before moving on is proper way to consume content & learn. Binge watching doesn't work for a lot, may work for some but for me personally never worked, if I binge watch a course I forget it very fast, so I like to take my time with each episode when learning something new

[@federicobau8651]

Best php oop with interfaces and polymorphism tutorial, bettern than paid bootcamps

[@wesammohammed1819]

"Your guidance means a lot, my teacher Gio. Thank you for helping me grow every day!"

[@ProgramWithGio]

You're welcome

[@codedigitally9236]

The way instructor has describe the OOPS concepts with realtime examples and cases is really awesome.

[@ProgramWithGio]

Glad it was helpful, thank you 💙

[@neozes]

Dude! This was amazing! The fact, that you have covered the topic from all angels was just spectacular. I just came here from another video, that just explained how to implement interfaces, without any context, especially... what damn problem is this utility solving. Thank you!

[@ProgramWithGio]

That's great to hear, thank you 🙌

[@dajanradovic5341]

great teacher, great examples and way of teaching. thank you for clearing up all these concepts

[@ProgramWithGio]

Thank you 🙌

[@affordablecustomehr4845]

After watching this video many times, I have finally got an opportunity to use it in one of my projects. I recognized the situation I was about to go into needed an interface to keep the system flexible for the future. I needed to build multiple types of XML requests. Using and interface, I only need one gateway class to pass the different XML request to. Thanks Gio!!

[@ProgramWithGio]

Awesome, that's great that you were able to apply this to a real world scenario. Good job

[@emredikmen276]

you are the best at explaining , thanks Gio

[@ProgramWithGio]

Thank you 💙

[@mwaas]

Aside from php, anyone who wants to understand oop should watch this section of the course more than great

[@ProgramWithGio]

💙💙

[@sergeisurin2963]

A really good course, one that doesn't just go over the basics, what I've always hoped to see.

[@ProgramWithGio]

Thank you, happy to hear that

[@sergeisurin2963]

@@ProgramWithGio No, thank you! 👍

[@asadmughal469]

i was always confused about polymorphism that how will it take place and why the hell we needed this to be added in oop basics and today rocky rocked on my polymorphism concept.

[@ProgramWithGio]

Rocky is the best

[@leoortega5420]

You explained interfaces and their use-cases better than my university professor.

[@ProgramWithGio]

hehe, happy to hear it was helpful, thank you

[@OmarFaruk-ku9fv]

You just cleared my doubts and concepts of these topics , which i spent a lot of time searching . Your videos are to the point , with a lot necessary information and with examples . This blew my mind . Kudos to you .

[@ProgramWithGio]

Glad it was helpful, thank you

[@techatival]

Really liked the polymorphism example. Thank you!

[@ProgramWithGio]

You're welcome. Glad you liked it 👍

[@Zubbee]

This is another mind opening lesson in my quest to learn PHP. I also think this is the lesson that is now compelling me to go back and look at some of the earlier OOP lessons to really link terms and concepts better. It has certainly started feeling like I'm taking a course in the University. Thanks Gio

[@ProgramWithGio]

Glad to hear that, thank you

[@parinataneja7099]

Another AWESOME tutorial. Thank you for elaborating all these concepts :)

[@ProgramWithGio]

Thank you 🙌

[@Vitalii-m6r]

It's a very clear explanation. Thanks for this lesson again.

[@ProgramWithGio]

Glad you liked it

[@CarolinaQVargas]

GREAT EXPLANATION! Thank you so much!

[@ProgramWithGio]

You're very welcome

[@Zubbee]

Done re-watching. Moving on. Thanks Gio.

[@ProgramWithGio]

Awesome 👍

[@David92031]

10/10 channel my dude you are awesome

[@ProgramWithGio]

Thank you

[@jaywaldluna3158]

Very informative video. Good job for the sample analogy. Keep uploading like this tutorial

[@ProgramWithGio]

Glad you liked it, thank you 💙

[@Armando-px8hi]

Thanks for this interface explanation. It is the best!!!

[@ProgramWithGio]

Glad you like it, you're welcome

[@karam0101]

Another great tutorial. Thank you for sharing all these concepts

[@ProgramWithGio]

You're welcome & thank you 💙

[@GillesBeaulacJoe]

Thanks!

[@ProgramWithGio]

Thank you 💙

[@ינוןאלבז-כ1ז]

Wow! Perfect explanation!!!

[@ProgramWithGio]

Thank you 🙏

[@siyahkedilucifer]

So if a class implement an interface that must implement all methods in the related interface. In the another hand, at 15:20, an abstract class implemented an interface but didn't implement the render method in Renderable interface. So abstract classes are exempted from that rule? Thank you so much for lecture.

[@ProgramWithGio]

Abstract classes don't need to implement it, underlying class that extends that abstract class will have to implement it. If you implement it withim abstract class then child classes don't need to implement it. You can't instantiate an abstract class directly.

[@siyahkedilucifer]

@@ProgramWithGio thanks for this precious info.

[@d_sportello]

Thanks man, really helpful

[@ProgramWithGio]

You're welcome 💙

[@tolebiGamingTime]

Cool course, I'm waiting for the video lesson on microservices)

[@ProgramWithGio]

Thank you

[@Haamome]

you are the best at explaining. I really like your tutorial.

[@ProgramWithGio]

Thank you so much.

[@donmikele07]

I think I've already said but I'll repeat: you are the guru for programming. Masterpeace! I"m 2 years in software engineering and I would like to hear your opinion about learning design patterns in OOP: creational, structural, behavioral. How important they are?

[@ProgramWithGio]

Thank you. Design patterns are important but it depends on project & requirements. For some projects you may never use any design patterns. For some you may already be using design patterns without knowing it or without having the fancy name for it. Many devs try to stick design patterns in places where they don't belong, just because they want to use the cool new design pattern they read about someone's blog. I would advise to not do that because I've done that & its not good in the long run. Best thing to do is to understand your requirements & project fully and see what problems you need to solve.

[@donmikele07]

@@ProgramWithGio Thank you so much! This means a lot to me.

[@udayan285]

Thank you Gio.

[@ProgramWithGio]

You're welcome

[@tahmidziko]

your video is just awesome. a lot of things i learned from you. i owe you. on thing i want to add in php 8.1 there is may be a new feature default methods in interface . (if i am not wrong )

[@ProgramWithGio]

That RFC didnt pass I think if its what you mean (default methods). Maybe you meant constants?

[@emekatimothyiloba699]

Thank you Gio

[@ProgramWithGio]

You're welcome

[@romankiashko5435]

What to say except - Bravo!

[@ProgramWithGio]

Thank you 🙌

[@samahgad241]

Is it expected that the video takes hours for me to understand it? Thank you very much. You have a fantastic way of explaining

[@ProgramWithGio]

Everyone learns at different pace, so yes it's normal. Just be consistent and practice 👍

[@samahgad241]

@@ProgramWithGio thanks for your support, I wish you a nice day. 💐🙏

[@vkmishra.singer]

Best !!!! I hope you to create other courses in the future.

[@ProgramWithGio]

Thank you 🙏

[@HakanGalip]

Thank's a lo very good and understandable...

[@ProgramWithGio]

Glad you like it 👍

[@RedZambala]

around 8:59 it sort-of works, but on some random numbers I 'm getting Warnings: Deprecated: Implicit conversion from float 368.5 to int loses precision in \CollectionAgency.php on line 15 Collected $545 out of $737

[@ProgramWithGio]

You are probably on PHP 8.1, during this video we used 8.0 I think, we upgrade to 8.1 later in the series. You can read more info on that here php.watch/versions/8.1/deprecate-implicit-conversion-incompatible-float-string It will trigger warnings when float is implicitly converted to int, so you need to add casting (int) or make sure you pass/use integer

[@rxxt-sh1vj]

Bro at 5:25 you said constants Defined in intefaces cannot be overridden by the concrete class that implements that interface but in PHP 8.1.0 we can override the constants...just in case someone tries that out on a Newer Version....:D Loving your videos watching them one by one...Your PHP course is the best one on internet....Even a paid course on UDEMY cannot match the concept and effort you have put in your videos...:D

[@ProgramWithGio]

Yea this lesson was using 8.0. There is a note about it in the description. Thank you 🙌💙

[@rxxt-sh1vj]

@@ProgramWithGio You dont miss even a single thing...:D

[@kajo2546]

Hey, I have a question. In the video you said that constant defined in the interface can not be overwritten in the class however I am able to do that. Did something change ? Inteface: public const MY_CONSTANT = 1; some Class: public const MY_CONSTANT = 2; or whatever other value This does not throw an error for me.

[@ProgramWithGio]

Yes in php 8.1 it is allowed now, prior to 8.1 it resulted in error. When this video was shot we were using php 8.0. We upgraded to 8.1 soon after and there is a video about 8.1 changes

[@rustem6388]

Very useful! Thank you!🤩

[@ProgramWithGio]

You’re welcome 😊

[@carlosortiz5283]

This is a very interesting lesson, thank you

[@ProgramWithGio]

You're welcome 💙

[@eashikanaznineasha]

Best tutorials on PHP so far! Could you please share the code as well?

[@ProgramWithGio]

Some lessons have link to the repo in description. For some lessons there is nothing to share since they are more of theory type lessons

[@AMoktar]

Awesome 👏 thanks

[@ProgramWithGio]

You're welcome

[@bevedel]

Thank you so much!

[@ProgramWithGio]

You're welcome

[@kooroshmoshrefi3377]

Nicely explained. Thank you.

[@ahmedmubarak8642]

Thank you so much.

[@ProgramWithGio]

You're welcome 🙌

[@ilya_123__]

thank you!

[@ProgramWithGio]

you're welcome

[@RamonaAtkinson]

Genius!!!!!!!

[@ProgramWithGio]

🤯🤯

[@memack101]

Thank you.

[@ProgramWithGio]

💙

[@agahozoclaire9605]

In previously videos you say inheritance cannot inherit multiple inheritance but in course of abstraction you , class field inherit text and boolean and boolean inherit checkbox and radio? before using abstract

[@agahozoclaire9605]

sorry multiple class*

[@ProgramWithGio]

@@agahozoclaire9605 PHP doesn't have multiple inheritance support. You can extend a class that extends another class but that's not really multiple inheritance, multiple inheritance would be something like ClassA extends ClassB, ClassC

[@agahozoclaire9605]

@@ProgramWithGio thanks🙏

[@dangnhattrinh5500]

So if I understand, every time I have the Dependency Injection, that dependency should be an Interface, because if it is a concrete class, that violate to the Liskov principal. Am I correct?

[@ProgramWithGio]

You don't have to have interface all the time. Its better yes to inject any implementation rather than a concrete class, but you also don't want to overdo it. It depends on the app & the type of class you are injecting.

[@josephjohn4810]

can you create a donation link? these videos worth more than diamonds 😁 thumbs up

[@ProgramWithGio]

Thank you. I have Patreon (link in description) and there is also Super Thanks feature on KZbin under each video 💙

[@ousssika5359]

thanks man

[@ProgramWithGio]

No problem

[@johongirrahimov2343]

So it's Composition then right? In Composition we can use the same methods in 2 ore more unrelated classes?

[@ProgramWithGio]

Kind of, we'll cover composition in more detail in 3rd section

[@dhirendrasinghnegi7948]

how are you running your code in editor terminal pls explain

[@ProgramWithGio]

It's phpstorm terminal within the IDE, you just need to connect to your docker container and run commands there. I showed that in Docker lesson beginning of section 2.

[@dhirendrasinghnegi7948]

@@ProgramWithGio thanks Gio you are very kind

[@ProgramWithGio]

@@dhirendrasinghnegi7948 you're welcome 🙌

[@dotsad]

and my mind started melting again, also do you think is a good idea to start learning laravel before learning advanced php?

[@ProgramWithGio]

It's ok, some of these concepts are not easy to get on first try, it took me some time as well when I was first learning so don't worry if you don't get it right away. You can learn Laravel in parallel, some of the topics in advanced series will help you understand how Laravel works behind the scenes

[@brangja4815]

I don't understand why the property passed into the method should be specific? Can't we just leave it as $collector?

[@ProgramWithGio]

You don't have to, but its good to type hint everything, at least in my opinion. It prevents future bugs. You will notice I use strict types in most of my videos & type hint everything. Typehinting to specific class/interface gives you autocomplete features in IDE as well as assurance that no other type is allowed.

[@gullyCZ]

this video is missing subtitles. would it be possible to supplement them?

[@ProgramWithGio]

KZbin sometimes removes them or doesnt add them automatically unfortunately. I don't add them manually

[@ahmedyasser571]

when the abstract class implemented the interface it didn't give an error that the class must declare the interface methods. why this happened?

[@ProgramWithGio]

Because its an abstract class, if you dont define the method in abstract class, you would have to define it in the class that extends that abstract class. You can't instantiate the abstract classes directly

[@ahmedyasser571]

@@ProgramWithGio excuse me can you elaborate more

[@ProgramWithGio]

@@ahmedyasser571 In abstract classes you don't have to define the interface methods because its an abstract class, you can't create a new object directly from abstract class, you typically create a new object of some other class that extends your abstract class. That child class that extends your abstract class will need to define the interface methods if its not defined in your abstract class.

[@ahmedyasser571]

@@ProgramWithGio thank you

[@BehzodSabirov]

Aaah...Now I get it

[@ProgramWithGio]

Awesome

[@dawid_dahl]

My mind makes me think of the Strategy pattern when I listen to this. Interfaces sounds perfect when implementing that pattern, am I wrong?

[@ProgramWithGio]

Nope you are not wrong. That's pretty much how strategy pattern is implemented

[@rxxt-sh1vj]

Bro on some methods I have seen the return type as name of the Interface...What does that mean...how can a return type be an interface ??

[@ProgramWithGio]

It's the same way as accepting arguments as interface. You are returning some implementation of interface. You can return concrete classes as long it implements that interface.

[@rxxt-sh1vj]

You mean to say any class that implements that interface is returned..Is that what it means ?

[@ProgramWithGio]

@@rxxt-sh1vj Yes. It works the same way as in arguments. It's polymorphism, you are returning an instance of an interface, so you know that this method call will return some type of instance of that interface without being too specific. Has the same benefits as using polymorphism in arguments.

[@rxxt-sh1vj]

@@ProgramWithGio Would request you to make a video on interface type hinting that also cover return type of Interface...Thanks for taking the time to reply...I am confused..:D Returning an instance of interface means any class that implements the interface... that class object will be returned..hope that I am correct..:D

[@ProgramWithGio]

@@rxxt-sh1vj Watch this lesson again from 10:00 mark, its the same idea with returns. For example: interface MyInterface {} ClassA implements MyInterface {} ClassB implements MyInterface {} ClassC { public function someFunction(): MyInterface { // this function can now return any implementation of that interface, it can return new ClassA(); // or it can return ClassB return new ClassB(); } }

[@abduabdu7404]

i didn't quite understand the psr interfaces, can someone explain it to me

[@ProgramWithGio]

Do you have any specific questions?

[@abduabdu7404]

@@ProgramWithGio i didn't understand why i i would use it

[@ProgramWithGio]

When you may have multiple implementations of the same contract. For example, if you are implementing a payment processing & want to accept payments. You might want to use Stripe as your processor/gateway. If you code it to an interface and have PaymentProcessor or PaymentGateway interface and implement it inside Stripe class then later if you decide to switch to another provider you could easily create that other class, implement the PaymentGateway interface & most of your other code would continue to function assuming that you coded it right & they are using the interface instead of concrete class.

[@abduabdu7404]

@@ProgramWithGio Thanks you so much for your efforts , this course has been gold you deserve more recognition man, much love from Saudi Arabia

[@amoskim5813]

wow~

[@ProgramWithGio]

💙

[@saugmaddox349]

Hello sir, here is my question abstract class x { protected function x: void protected function y: array protected function z: string private function a: void private function x: void } How can i make an interface for an abstract method..it has no public methods.Assume that abstract class x will be inherited by another class Y which will not be abstract...Can we make an interface for such an abstract class X that has no public methods and only contains protected and private methods??

[@ProgramWithGio]

Hello. That's one of the differences between abstract class and interface. You can't have private/protected methods in an interface, only public.

[@rxxt-sh1vj]

Bro I have one more ques...Is it necessary that an interface must be used whenever there is polymorphism...I have a class that has 15 public methods with 4-5 private methods...For better organisation of the code and readability of the implemented methods in the class... I want to make an interface and define 15 public methods signature in the interface. Is that a good practice or bad practice according to you..??

[@ProgramWithGio]

Don't overuse the interface. If all those 15 methods are related then yea you can extract them in an interface, however, if some of those methods are not really related then you might want to extract them into multiple interfaces. Also, do you plan on implementing this interface in other classes as well?

[@rxxt-sh1vj]

@@ProgramWithGio I will not implement any of the interface in other classes...Only one class will implement a single interface in my case...:D Whats your suggestion bro..:D

[@ProgramWithGio]

@@rxxt-sh1vj It's up to you, I personally would not create an interface unless I saw the need to implement it in multiple classes or the need to have polymorphism. No need to overcomplicate things. Also the main deciding factor is if the methods you are planning on putting in an interface are actually related, like if one method processes transaction & other method sends an email then these two are not really related & should not be part of the same interface, you would have two interfaces one called ProcessableInvoice & Mailable interface

[@rxxt-sh1vj]

@@ProgramWithGio Bro all methods in my interface are interdependent....like I built an orm that has methods like table ...select...where....getSQL(); when all methods are chained it produces a statement like...... select * from users where id = ?. I am building a PHP framework from absolute scratch that will outperform laravel in terms of sheer speed with lowest possible size...It will be under 1 MB in size with less than 150 files and will work with single library developed by me ...the project will not need any other external dependency. My ORM can inject 10,000 records in my sql database in mere 1.64 seconds. If you will compare laravel it has 6700 files approx on just fresh installation. File size is around 32MB which cripples performance on the production server....according to my calculations as the project becomes complex..:D

[@ProgramWithGio]

@@rxxt-sh1vj Got it, they are then related to each other because it's a QueryBuilder essentially, so you could have QueryBuilder interface and if in future you decide to switch from MySQL to something else, you would simply create another driver class and implement that interface

[@ozorg]

no - playback speed is not set to 1,25 .... ;) ... great info though! thx!

[@ProgramWithGio]

Oops 😬 😅. Thank you 🙌

[@paatuc6457]

Should I just skip these advanced OOP methods, since these feels a bit too complicated and return to these when more advanced ?

[@ProgramWithGio]

Skipping OOP is not ideal because you will need OOP if you want to work with PHP. Which topic/concept is more complicated for you? I would rewatch videos on those topics and also I would read some articles on those topics. If you have specific questions feel free to DM me on Twitter

[@paatuc6457]

@@ProgramWithGio Thanks for reply, you are easily best php or any coding language teacher, I just ate too much information for one day, I need to go slower and actually code these OOP examples to my end as well and I'm starting to get this slowly :D

[@ProgramWithGio]

@@paatuc6457 thank you. That is a good idea, take your time & if you have questions don't hesitate to ask 🙌

[@FGj-xj7rd]

That independent debt collector is all kinds of suspect 😂😂

[@ProgramWithGio]

😂

[@Netpilation]

Rule of interfaces in php

[@ProgramWithGio]

💙

[@أحمدكلش-ض3ع]

lower the speed plz

[@ProgramWithGio]

I improved on that in third section. You can also lower the speed yourself on KZbin. Simply click gear ⚙️ icon and set the desired speed 👍

[@أحمدكلش-ض3ع]

@@ProgramWithGio thanks

[@realchicagophill]

I think the concept of abstract is too abstract for my mind to understand.

[@ProgramWithGio]

Feel free to reach out to me on Twitter & we can discuss any questions you might have about it.

[@mohamedaltahan4875]

thanks so munch, but you speak so fast

[@ProgramWithGio]

Sorry about that. You can slow it down on KZbin by clicking on ⚙️ icon and set the playback speed

[@SamuelNasta]

Editing tip: you don't leave ANY room for breathing Your WHOLE VIDEO looks like one enormous phrase. Yes, you should cut the spaces of breathing WITHIN phrases. But yes, you absolutely should leave some room for the brain to absorb the information you're providing.

[@SamuelNasta]

Try to read the same message like you speak in your videos instead editing tip you don't leave any room for breathing your whole video looks like one enormous phrase yes you should cut the spaces of breathing within phrases but yes you absolutely should leave some room for the brain to absorb the information you're providing

[@ProgramWithGio]

Thank you. I improved on this in later videos a little bit & will keep in mind for future as well. It's not just editing, it's just the way I speak :). Need to slow down a bit. KZbin lets you slow it down also & set the playback speed which should help a bit, but I get what you are saying

[@SamuelNasta]

@@ProgramWithGio Another thing that I found later in the video In the middle parts you talked about many scenarios, wrote the code for it, but just didn't test it. If something is relevant, maybe spend 5 more seconds to run the code to show it makes it much easier to understand. Even if you talked what would be the scenario, if you didn't show it, the brain wouldn't grasp the information like it would SEEING it. It's the same if you give advice to a friend. hehehehe

[@ProgramWithGio]

Thank you, I do try to run it every time to verify that it works, maybe I missed it in few places. Can you give me an example of where I did not run the example code?

[@SamuelNasta]

@@ProgramWithGio 11:43 in the instanceof example

[@omaryahia]

The incredible Gio Course🫡🥰☺

[@ProgramWithGio]

Thank you 💙