The Only Time You Should Use Polymorphism
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- Опубликовано: 19 май 2024
- The only time you should use subtype polymorphism is when you have behavioural variation in the subtypes. I teach two university courses on object oriented programming and I see this problem a lot. Let me explain. RECOMMENDED READING:
🛠️ geni.us/k8KhT3 (Refactoring)
⭐️ geni.us/zzlx (Dependency Injection: Principles, Practices, and Patterns)
💎 geni.us/hNDE (Elegant Objects)
🏛️ geni.us/IBhtLnh (Clean Architecture)
🧩 geni.us/nlbA6 (Head First: Design Patterns)
Read my FREE book on Object Oriented Programming:
🚀 theobjectorientedway.com
Watch next:
• Always Use Interfaces
CONTENTS:
00:00 Thesis
01:16 Example 1
03:28 Example 2
06:25 Example 3
13:26 Summary
Finally he remembered his password
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called it!! 😂
Where you were?, will you make video contunue now@@ChristopherOkhravi
This must have been some variation in data.
He randomly came back after three years! Tak! Good to see you again.
Yessssss I'm glad he is back man, I've learned so many things important on my career because of his videos
Love him, jest super
OMG I can't believe this, I asked him last week on Twitter when he is coming back..and here he is. 🐐
What are the chances he’ll stay with us for some time now 😅
@@DerRabeKirilldepends if project manager leaves him alone
I like to think, that you got so annoyed by someone at work using subtype polymorphism the wrong way, that it brought you back here ;)
I teach at a university so I read a lot of student code 😉
in which university do you teach I need to attend there, you're a CS legend
@@ChristopherOkhravi
I wish more people in your team do things in wrong way that you make more videos to teach others 😂
Man, your notification popping up is the best thing happened in months❤, please don't disappear again :)
literally just watched your design patten playlist, thinking why hasn't he posted for 3 years. perfect timing
Have been watching your Design Patterns series and the code walks videos and was always thinking if I ever wanted to have a youtube channel it would have been of this style. If only he was back. Wish granted, welcome back, so happy to see notifications from you! :DDDD
I came to the comments section to share my excitement about your return.
But, wow, I didn't expect there to be so many of us!
Welcome back! Got a huge amount of value out of this channel in my early days of becoming a dev
I've never been more engaged with software engineering RUclips content. Your presentation skills are excellent.
I've been watching your playlists whilst working on my project over the last year, and this video is so relevant to what I'm currently working on, and exactly what I've been asking myself while working on my current systems. Being self taught I don't know the theory very well, so I would had never known that I was dealing with 'sub-type polymorphism'. Good to know I've been going down the right path, and also to know what it's called!
Great to see you again Christopher. Miss your videos of design patterns and discussions about principles. Welcome Back!!
Suddenly you appeared out of thin air, please be consistent. Love your content.
No one told you to wait
we aint entitled to his time
He can post whenever he feels like posting. How entitled are you. Anyway thanks for the content ignore comment like above
Last month i was discussing with my friend about Design patterns and in that discussion i recommended him your channel. While discussing i said to him that don't know why you aren't posting any content. I was little bit worried about you. Now i am very glad to see you back. 🥳🥳🎉🎉❤❤❤
Oh my god. I used to watch your videos when I started learning programming in 2021. Right now, I have an interview with Google scheduled next week. You don't know how happy I am to see you back. Thanks for coming and welcome back :)
Glad to hear 😊 Best of luck on your interview!
Welcome baaaaack!!!!!!!!! Happy to see you around after so much time! Hope you'll stay for a while, your content and way of explaining things are precious.
Best notification from RUclips in ages. I hope you've got more for us. 100% my favourite videos covering software development!
Whoa, seeing you in my sub box is not something i expected today. Long time viewer of the channel, since the ramda days! Good to see you back.
Your channel helped me get into functional programming, and now i'm absolutely obsessed. Do you have any plans for more FP related videos?
please continue have been rewatching your old stuff so glad to see this
I started watching him on thursday, fell in love in his way of teaching, and was thrilled when saw that last video was posted 3 years ago. And now he appears out of nowhere 😂 If you were giving lectures on my Uni, i wouldnt miss a single one
Awesome to see you back Chris! I’ve learned a lot from your videos, and have always enjoyed hearing your perspective on things. 😎👍
WHOA! i started watching your pattern videos like a week ago, binging them while at the gym, while taking walks, etc. i was like "eh it's been a long time since hes posted...he was a good teacher" and then here you are!!
I didnt even fully read the title, I just saw the thumbnail and clicked. Welcome back good sir.
From last week I started watching your Design Pattern playlist and thinking why Chris stopped posting videos for last 3 years. To my surprise there was a notification😮. Your teaching is so great and natural, not everyone gets so easily. Keep up the Great work!
I did not expect you coming back, loved your design patterns, glad to see you're doing well!
Man, I was so happy to see your face in my feed again. Glad to have you back, your videos always helped me understand these concepts so much better.
Hey @Chris, it's great to see you after such a long time! I've always been a fan of the way you present content with crisp editing.
happy to see you are back! keep the content coming! learning a lot.|
love the whiteboard, the editing and the why you teach :)
Glad to see you're back uploading videos! Your series on design patterns were instrumental in taking another step in my career!
Love to see you again, I look forward to rewatching as much of your videos as possible !
I didn't learn anything, but the way you described the information in the video *clarified* what I'd already known -if that makes sense.
You are excellent at explaining things in very clear terms, and I appreciate that. Subbed.
I'm very happy to hear that. Also, thank you for the sub. Welcome 😊
Welcome back Christopher. Good to see you back 😊 Keep up the good work and make learning fun and easy. All power and good wishes ❤
Glad RUclips was smart enough to recommend your video. Glad to see you posting. Always top notch stuff.
Welcome back Chris. Have learnt a lot from your design pattern series!
Your Design pattern playlist is the best I have ever seen on any channel/courses. It was about a year ago I started and completed the DP videos, but was disappointed to see no more , and randomly today this video pops up on my feed, very happy to see you again hopefully you will complete the rest of the patterns too 😊. I tried connecting you on LinkedIn too but it was restricted I think 😅.
Finally you are back!
I enjoyed so much your design patterns playlist.
Welcome back! Your videos helped me a ton while getting my degree - good to see you're still at it!
Your teaching is the greatest and simpler....❤
So happy to see you back. You're the sole educator whose RUclips videos I choose to view at regular speed, even when they extend to an hour.
Welcome back! Please upload more videos on system design and LLD. We appreciate your effort!
I watch your videos and you are the first teacher whoes course i can buy without thinking about money.
Welcome back, I have missed your content, it is great. Your analysis has been vital to my programming evolution, if only I'd have had teachers with your energy.
I missed your tutorials man, good to have you back!
The man, the legend, welcome back
Happy to see you upload after 3 years love the way you teach..
This is the first video I watch from you. It makes complete sense, no idea why I never though of it like this. Looking forward to more videos!!
I'm very happy to hear. Welcome 😊
Glad that see you again, hope I can see another series also before I die. But high quality takes times, I'm really enjoying when watching your videos.
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I don't have words to describe how happy I am to see you back.. Love your style of teaching
Legend is backkk!!! Good to see you, your system design videos are epic!! MASSIVE THANKS
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omg great to see u again! Ur videos has helped me tremendously during my time at chalmers, and im actually now TEACHING the same course i used ur videos to pass years before! Will recommend ur channel to all my students!
Thank you 🙏😊 And congratulations
I didn't realise you hadn't posted for three years! I've been taking a break from coding but had to watch this video! Please keep posting!
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I like this format. My ADD was trying its best to block the info, but this guy just kept going :)
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Kul att se att du är tillbaka igen! Dina förklaringar av designmönster hjälpte mig enormt under skoltiden. 👍
Man önskade att fler lärare var såhär pedagogiska.
Tack så mycket!
Welcome back! So excited to see you back! huge fan of your videos. Thank you!
I just remebered your design patterns series from years ago and was looking what you were up to. Great timing.
😊😊
Thanks for checking in again 😊
Previously, thank you for the knowledge, and welcome back.
What I get from the explanation is:
We should/must prefer to be implicit about a specific type of data that has the same structure and behavior, instead of being explicit (where we define it based on the actual concept or domain) about that type (CMIW).
Welcome back ! , good decision to come back , your content is wonderful
you did really well with this video, i was able to flip into it and out of it, while just listening and you never lost me. i now know what you put into this video and thats always nice!
Welcome back! Thank you for this! The cliffhanger in the end...oh man, please don't let us hanging for too long
Gotta leave some loops open 😊😊
It's so good to have you back. Thank you 😊
Thanks for all of these and welcome back!
Welcome Back, Great to see you after 3 years :D
Good to see you after 3 years. I love the way you teach.
Welcome back, sir. Happy to know you are still creating content.
Holy shit. You're back. And the beard is ever so magnificent. Don't you dare disappear for such a long time again.
We've been waiting for you to come back! - so WELCOME BACK ^^!
Thanks for sharing your valuable knowledge again. Your videos about design patterns helped me a lot when I landed my first job as a software developer. I hope 🤞 you don’t give a break anymore 😊
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Welcome back! Good to watch your video again!
Your knowledge is actually so precious. I love the fact that you just use concepts with whiteboard. Thank You for coming back to us, You can make a lot of us promote with your videos!
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Word to mother....ur design patterns videos helped me nail an interview in 2017 🤣🤣🤣. Now I'm a Lead software engineer. Thanks
Your teaching is simpler and also in depth, good to see you back on youtube. Please create more good quality content !!
I would add a point that "variations in behavior" can also come from _outside_ the class - a class can just be a data type, without being responsible for all the ways the data will be used. Imagine an Attack subtype, EnergyAttack, which has an additional property EnergyType. Now Scratch is a base Attack instance, and Thunderbolt is an EnergyAttack (with EnergyType = Lightning). Looking at just the class definitions, you could say this is a data-only variation, but it makes sense because the change is in the data structure (an additional property), not just values. These subclasses may or may not implement variations in behavior themselves, but _allow for_ external variations by being different types: We may have many general functions that work with the Attack type, as well as some functions that accept EnergyAttack specifically and work with the EnergyType property.
Happy to hear your new lectures! You're the best! When me and my friends discussing some youtube channels which we used to watch I am always pointing out that there is a guy: Okhravi, he explains the in a best possible way and it is quite unlikely that someone can do better. And they say. "yes, we know him" :), after agreeing with me.
🙏🙏🙏
He's alive!!! Glad to have you back!
Hej, you are back. I have mist your videos, they have helped me so very much. Thank you for another interesting and great video.
Great to see you again! Love your content, the way you explain complicated things is simple and approachable, love the mustaches also 🙂
Loved this video. Thank you so much for the bite-size CS training. Love your style, heart, and expertise.
bro scared me with that jump in the frame haha welcome back! Thanks for the Design Patterns series which helped me a lot!
Wow man, so glad to see u again, you are an amazing teacher, please keep the quality content😊
Welcome back! Good to see you!
Hey Chris, It's been a while!
Nice to see you back with goood content
Welcome back Chris. loved this one.🙏
Good to see you again! Welcome back!
I was literally googling for your name yesterday to know what are you up to these days and suddenly your new video pops up after 3 years. Thank you for sharing knowledge with us. You’re an amazing teacher!
Damn you're back! Thank you very much for the content!
Welcome back, 🙏. I loved your style of teaching, sub for ramdajs series.
Once again, you enlightened me about something that might seen implicitly known and simple but in reality a truly good software engineer needs to be absolute aware of.
WB Christopher,
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I have a very curious question:
6:55: YES, why?
7:35: You MUST have had a way simpler example at first, where you still used "IAttack"; which is sort of revealed by you forgetting to delete "Stun".
I personally believe that you might have overthought the lesson a bit here. Despite how rational you try to justify the new super type and broader scope.
As I see it, you could easily still have stuck to: "IAttack". The third example would then showcase e.g. "Attack" and "Stun". The latter could implement e.g. a timer for the duration of the stun. That would now also be accounted for as an introduction of a new behavior and the whole thing would be fairly straight forward to understand, at least in my book 🙂
Instead, I feel like, with the current approach (creating a broader super type) students could then easily start wondering - when is enough - enough?
You could then arguably keep pushing the goalpost, higher and higher in responsibility, instead of keeping the example grounded where it all began...
I guess this also leaves the solution vulnerable to potential constant refactor, just as the slightest requirements change regarding the architecture...
I think you somewhat try to clarify for this yourself around 9:55...
Maybe I'm just too caught up in the semantics or too curious...
Let me know, if I misunderstood something very vital 🙂
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Thanks!
I'm extremely happy you are back. Thank you.
Thank you bro for coming back
The king of Design patterns is back🔥
I was waiting for this quality content again, thank you so much !!!!
First time I've seen the use case for polymorphism clearly delineated. Great job. Very useful.
Thank you Christopher for your design pattern series. That is one of the reason I got promoted 🙏🙏🙏
Congratulations! 🎊😊