Observer Pattern - Design Patterns (ep 2)

Video series on Design Patterns for Object Oriented Languages. This time we look at Observer Pattern.
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[@lec446]

Because of the good content, I subscribed and clicked the bell to become an observer of your channel. Now whenever you post a new video, i'll be notified! Thank you for this series!

[@bbcszone1]

hahahaha best com!

[@h4hashir]

Sir I too am now an Observer. Usually I go to Udemy for my design pattern refreshers but this time I thought hey why not give the KZbin algorithm a chance since it's so good with providing me with physics and nature learning videos. But as a programmer I never used youtube as my go to for learning. Usually it's just stackoverflow or Udemy. But seeing this channel just blew me away. It's like Christopher is speaking to my ADHD soul and saying ..."hey, I got you bro". Well thank you sir! OK NOW, can we make this a thing -where if you're simply amazed by the effort Christopher is taking to explain this to us as if we're his own... to at least semi reciprocate -Isn't the least we can do is become an observer to his channel?!! - IF YOU CLICKED ON THE BELL TO BECOME AN OBSERVER THEN LIKE AND REPLY TO THIS COMMENT! thank you. Peace, my fellow homo sapiens. Stay true.

[@devincedric4068]

Instablaster.

[@doumkatekz]

@@h4hashir My ADHD soul got distracted by the comments sections, but I am loving his channel and am also an observer

[@anshulrao2373]

good one xD

[@nicka3203]

that's how teachers are supposed to teach, such that the listener get it at an intuitive level. Great Job.

[@JoramVanhaerens]

Kind of reminds me of a dad driving with the kids in the back repeatedly asking "Are we there yet?". Dad would be more happy if they stay quiet and he just updates the kids upon arrival or pit stops along the route.

[@abhisheksingh-np8yi]

damn nice analogy😂

[@ruddha2]

This is like Vsauce for programmers. Great explanations!

[@gabrielsantos-bn1di]

Perfect! kkkkkk

[@MohamedMagdy-wj3ec]

you are a very good Instructor , good job :)

[@ChristopherOkhravi]

mohamed magdy thank you for the kind words!

[@4848kim]

mohamed magdy z

[@iam1213]

agreed!

[@adriencastella4992]

Yes, I think so too! Much better than my uni Professor. I actually enjoy listening to these videos

[@angeldeveloper]

we are coming from 2024 (6 yrs ago) hahaha! it's one of the best playlist, tech bean instructor I don't know why, but I slowly fell in love with his teaching style thanks tech bean

[@vivek5562]

I'm just putting a comment here to encourage you to make more videos :) Keep up the good work.

[@ChristopherOkhravi]

+VIVEK VERMA appreciated. Thanks for taking the time and thanks for watching :)

[@shivz732]

man if my school had teachers like this, I would never ever skip a class. So fun and interesting to watch

[@EdwardFacundo]

2020 and still one of those best explanations about design patterns. Great work!

[@arthurfedotiew3609]

2021 same :)

[@doumkatekz]

@@arthurfedotiew3609 2022 also same.

[@sharkman4448]

2023 baby

[@ardinhelios5677]

@@sharkman4448 Still the same

[@gauravjindal007]

2023 same

[@NomadicFreediver]

Probably the most frustrating thing about learning something online (either from KZbin or through MOOC) is the fact a given content is explained once and in one way only. If you can't ask, if as a student you cannot ask questions for clarification about a given detail, most of the time you get stuck and you need to find the information elsewhere. Your video is a great example of how repetition and rephrasing can solve this problem. Thanks a lot.

[@sk8erbyern]

yep, I also really liked the carefully chosen words. Words have meaning (duh!) and tech industry (from schools to books to companies) is extremely lenient when it comes to those meanings. Subject can mean the data inside the observeable, therefore it is not a good choice for observeable.

[@Oxygen.O2]

Never did I understood a concept so easily, the rythm, the cuts, the words, the real life example, everything was perfect! THANK YOU!

[@leondaz]

This seems like the most underrated youtube channel ever

[@callmeartae]

It certainly shows that you have a lot of passion for the subject. That's what makes a good teacher - being energetic and excited about certain topics makes your students energized and excited as well. Great job!

[@ruantristancarlinsky3851]

Absolutely fantastic video! People like you are what gets us through Computer Science. You have my utmost gratitude!

[@raulcubila5877]

Dude your explanations are super clear and understandable. This design course is better than a lot of pay courses Online. Thanks a lot!!!!!

[@ChristopherOkhravi]

Thank you for the very kind words. Humbling. 🙏🙏

[@zmonkey111]

I am self teaching myself to try and break into the tech industry. Having you almost feels like I have a professor to lecture the material to supplement my reading and practice. Thank you for doing this. On to the Decorator chapter!

[@anasfcb]

Hey Christopher, First, thanks a lot for the valuable information but also for your natural and nice way to breaking down abstract notions to make them more concrete. Being an intermerdiate Architect/developper, I find your "code walks" very "friendly" too, answering many of daily dilemmas, and helping to think in a larger and better way. The design patterns videos are quiete long, but EVERY minute is worth watching! Please keep inlightening us (y)

[@ChristopherOkhravi]

anasfcb thank you very much for the utterly kind words. I'm very glad that the content is useful. I consider myself intermediate as well but tend to talk a lot about what I think about :) :)

[@SSn0wx]

Dude I swear to god this is one of the best channels I've encountered in a while. Fucking godly content

[@kolobamanacas]

Christopher, you are the master of explanation! Your editing style with cutting all redundant pauses, etc. is superb! The way you explain things is also very nice. Please continue your project, it's very useful!

[@charg1nmalaz0r51]

Theres just something better watching someone talk through stuff than reading from a book

[@NikhilSharad]

By far the most effective lessons on design pattern, I am going through your entire series. Thank you!

[@airor4]

This guy is so organized that his books are organized by color. Great video!

[@taylorsmith6961]

Dude these are SO GOOD. Thank you for this content. Currently studying for upcoming FAANG interviews and I like to cap off my study sessions with a video or two of yours because they are just so good and entertaining that I can still pay attention and soak in that much more. Cheers!

[@positive-mind-miracle]

Hi, How was the interview experience ? Did you get in ? Me on the same path. 😑

[@satishgopaldas4040]

2023 and still one of those best explanations about design patterns.Thank you Christopher ❤

[@shoaibahmad6910]

TINGGGG! You've got an Observer You've kinda injected it into my mind. Amazing stuff.

[@kvaditya4011]

Having just started my career as a programmer ( ~ 6 months ) , This playlist is a god-send to me, Thank you so much for crystal clear explanations and examples. You're a legend.

[@codycoker7176]

These videos are incredible. Thank you so much for making them. I really do feel like I understand these design patterns in a way that I didn't before.

[@ChristopherOkhravi]

James Coker fantastic! I'm so glad. Thanks for letting me know :)

[@miguelcerne1150]

The first Design Patterns Series that really simplifies and doesn't overcomplicates the basics! You're the best, keep up with the channel please!

[@Sapphiamur]

you're the best, seriously :dd.

[@ShobhaMahadev-x5y]

I never ever thought that design patterns are this much easy to understand. All concepts are explained so well in this series. Thank you so much. Best regards.

[@worldown]

Cool, I like it. Your energetical didn't give me to sleep otherwise wen I read this book and watch other videos it was boring , Thank you bro =)

[@ChristopherOkhravi]

Thanks! I'm glad :) Thanks for the comment.

[@kumarpallav8156]

Your Channel is really Observable And Today I have become it's Observer.😍😍

[@StelaTasheva]

Real life Poll example: Toddler asking every ms "Mommy, can I have a chocolate" ...

[@ChristopherOkhravi]

🤣🤣🤣

[@Studywithsalma]

I swear this is the best video on the internet explain Observers

[@trailblazer_nomad]

Awesome job, Chris! Saves time to read 50 pages :) I've watched your other pattern videos and they are also great! Thank you, Chris :)

[@rahulyavvari]

Until you reached the pseudo code I was not 100% sure about the pattern, and then "boom!!", it's crystal clear. You are crazy good at explaining! Subscribed!!!!!!!!

[@taianilange1500]

You make learning so much fun! Thank you! Absolutely love these videos.

[@ChristopherOkhravi]

Thank you! That makes me very glad to hear. I appreciate you taking the time to share it :D Thanks for watching :)

[@sohypemadainy7948]

@@ChristopherOkhravi you are so good instructor, thank you for these free tutorials

[@venkateshrajendran2362]

Thanks, @Christopher Okhravi. The more I watch your series the more I fall in love with the Design patterns.

[@sachinkainth9508]

Here's a couple of improvements I would make to this. In order to satisfy the Single Responsibility Principle, I would create a WeatherStationObservable class that implements IObservable and use composition to have an instance of WeatherStationObservable inside the WeatherStation class. This way, WeatherStation will only have the responsibility of dealing with temperatures, pressures and other weather related things. The second thing I would do is make WeatherStation implement an interface IWeatherStation, this way I can inject an IWeatherStation into PhoneDisplay so that it doesn't rely on the concretion WeatherStation.

[@heroChaddi]

why do you need extra WeatherStationObservable class, why cant WeatherStation class implement IObservable and IWeatherStation and this will be injected to PhoneDisplay so that it only worries abt getTemp instead of having access to registry.

[@AidenElliott-ff2vt]

Single Responsibility Principle: A class should only serve one purpose in your code. By breaking it up, your code becomes more modular, reusable, and less likely to break during later refactoring.

[@a.yashwanth]

There is no point in creating extra IWeatherStation interface and using it in phonedisplay. You are still coupling WeatherStation to phone display because IWeatherStation will only be implemented by WeatherStation.

[@srinivaspitani1326]

I'm so grateful for your ability to simplify complex topics. You're a true master of explanation!

[@RZato]

Great job man! I would like to suggest that one inconvenient of passing the Observable reference in the Observer constructor is when an object is Observer from more than one Observable. In the example, imagine that the display needs to show not only data from the WeatherStation, but also from a RealtimeClock. One solution can be to include the reference in the Update() function.

[@FAOZIAISLAM]

The best explanation I've found so far. I mean yes I need to hear the same thing for a lot of time to catch in my memory regardless the duration of the video. Enjoying the learning!

[@herediadev]

Hello Christopher, very interesting and very clear how you explained the observer pattern. I just subscribed to your channel because I am interesting in this design pattern series. By the way, Robert Martin (Uncle Bob) talks about the Single Responsibility Principle violation in the observer pattern, but if i remember correctly, it is part of the trade off you have in order to use the pattern, on the other Hand, remember that the SOLID principles are more like guidelines than some kind of laws, some of them bend, some of them can be broken.

[@ChristopherOkhravi]

Rafael Heredia Bastidas Thanks for the comment! I'm glad it's useful. And thanks for bringing the words of Bob Martin into the conversation! Makes sense.

[@nirmalakumari8971]

I subscribed your channel and register myself as an observer, now it’s observable(your) responsibility to get me(observer) notified if any change happens on observable(any good content posted), so that I(observer) can pull(watch) changes. Great work, appreciated

[@silviupanait8861]

every programming tutorial should be done like this :)

[@Generally2310]

honestly I mostly don't comment but I need to emphasize how good this content is thanks Chris!

[@scorepro5059]

All devs should know these patterns. Great work! Better than watching someone type ;) Just a quick note, this could of been a lot shorter. Laboured the point some times. Appreciate your enthusiasm and effort though 👍🏻

[@ChristopherOkhravi]

+Adrian Collins Thank you for the detailed feedback. Much appreciated. It's super easy to accidentally get repetitive but point well taken and I'll try harder! Thanks for watching and for sharing :)

[@reneschindhelm4482]

Well, as a dev I know the patterns but having to deal with legacy code bases, getting into what's going on in there (because developer's didn't document, the 2nd/3rd generation of developers is on the project, ...) and with very little time on my hands there's simply no way I could apply all of them. No one pays me for heavy refactorings. If you have the time to design a new program, design it well and DOCUMENT it :)

[@kardaschow6482]

I find it hard to focus on things like this, so i appreciate the repetition

[@arvind31459]

@@ChristopherOkhravi I like the repetition. It basically reinforces our understanding without having to seek the video multiple times and losing the momentum.

[@thefattysplace]

I have watched two of your videos so far, and i must say that you are an excellent teacher! 10/10.

[@rsdntevl]

Really great explanations

[@ChristopherOkhravi]

Thanks. I'm glad to hear it works :) Thank you for watching :)

[@alamaralaa]

Headfirst design patterns is a great book! I've recommended it to dozens of people I've worked with and people I've interviewed who had never heard of design patterns. Years ago, I read one of the original books on design patterns and understood the ideas, but I didn't get the why of it all. Years later, I picked up Headfirst, and suddenly, it all made sense. My favorite design pattern is the state machine. I've found so many places in my designs where it simplified what would otherwise end up being hundreds of lines of nested case and if/then/else statements into small, trivially testable, pieces of code. Much of it containing no control statements at all. I could not recommend this book more!!!

[@ChristopherOkhravi]

Thanks for sharing this. I think you are very right in that it is a tremendously useful book for introducing the topic of patterns in an approachable manner. Thanks for watching 😊

[@avahome5285]

NOTES: An observable has many observers. Push model/Broadcasting/chatting system can be implemented using observer pattern. Chatroom is an observable, user is observer.

[@LucidFabrics]

I usually don't subscribe to any channels. I'll make an exception here. I crave for more. Thank you for being a great teacher!

[@andreiflorea5070]

I'm supposed to learn for a microeconomics exam that's in two days from now but this stuff is way too captivating lol

[@ChristopherOkhravi]

+Andrei Florea hahaha :D Well, at least you're procrastinating with something that might have a high payback still :) Best of luck on the exam and thanks for watching!

[@maximus1172]

Holy crap, the best explanation in the history of the universe

[@JacklapottTv]

if only it was possible to click like more than once, great vidéo (y)

[@ChristopherOkhravi]

You having commented on multiple videos is perhaps even better :) But I'm humbled, and I thank you :) If you know someone who might be interested in the video, do feel free to share it with them.

[@ChristopherOkhravi]

Also the (y) has to count for something right? Qualitative thumbs instead of quantitative :)

[@altinuku6766]

You are the Man of Design Pattern! damn it, even after 3-4 years this video are awasome. Great job and thanks for sharing with us this job Christopher

[@AbdAllahBoda]

mmmm, I still don't like the idea of passing the observable to the observers as parameter into the constructor of the observers. feels like you are giving the observers more than they need to know the data! I think it would be better to send the updated data via update(newData) method.. - consider the following use case:- * At the same concrete class "weather station", they are more than one senser.. for wind speed, another for humidity, and of course the one for temprture.. * Now Imagin that there're some observers which are interested only in the humidity, and others in wind speed only.. we can do an observer pattern for each piece of data by itself, with the update method signature changed based on the wanted data.. * so we can have update (Humidity newHumidityData), update (WindSpeed newWindSpeed), etc .. each one into its own observer interface of course.. * what I'm saying is, you observe pieces of data, not the whole object :) .. that way I prefer passing the new data via update :) .. I really like your vids, don't stop, keep moving forward :) ---------------------------------------------- Edit: I wrote my comment before finishing the vid :D , my bad there.. I liked that you touched on the subject at the end :)

[@ChristopherOkhravi]

I agree 100% with your comment. Great example. Thanks for sharing it! :D

[@FeroChau]

I also have the same concern. Instead of creating interfaces for different signatures of update method, we should create a generic interface that has void Update(T value) and IObservable with void Add(IObservable observer).

[@ChristopherOkhravi]

+1 Excellent idea! Can't see why I didn't think of that :) :) Thanks for sharing!!

[@andylinkOFFICIAL]

.NET has their own battle tested APIs for this that takes generics. Pretty sweet! msdn.microsoft.com/en-us/library/dd990377(v=vs.110).aspx

[@BraBo]

Makes more sense to send the instance and/or data in the update() method itself, as said at the end...

[@atintandon9624]

21:00 you literally flip the whiteboard! these video are edited for perfect comedic timing... cracks me up!

[@2perspektiva]

42:15 left down corner :)

[@ChristopherOkhravi]

Hah! I had not seen it :D

[@gigajoules6636]

kzbin.info/www/bejne/gZypaWCsnbuAlZI

[@younesizeria4375]

What is a great explanation ... I was looking all over the web about some1 that explains this things. Well I watched many videos on youtube but with no result. My mistake is I was looking for desing pattern in C# but it doesnt even matter which language as it is related to oop . Then i went to search bar i removed the c# and just looked for design pattern in general and then this playlist popped up and it really amazed me. I understand things very well now. Thank you man ! May Allah guide you to the right path and reward you Jannah!

[@ofirfridman3525]

really good tutorial :)

[@ChristopherOkhravi]

Thanks!! :)

[@dorsharoni10]

What fun to watch your videos. You are funny, human, and free. And most importantly know how to explain in the clearest way.

[@牛岱]

I guess you forgot " station.add(this); " in the constructor of the displayer.

[@jihwang9579]

Never have I seen the best explanation of design patterns like this in Korean videos! Your content is better than Korean content to me lol

[@pajeetsingh]

Same. Never seen a Korean video.

[@harshuljain4940]

The guy teaches with so much passion, with so much clarity that you can understand whatever he says in one go. So Good Man! So Good! Once done with design patterns, start with system design too.

[@harshuljain4940]

And I actually like the vibes from the video too. There are a bunch of books kept on the right side, which shows he reads a lot and makes sure what he delivers is correct. In love with your videos. I hate watching videos, even Netflix, but have seen 2 of the videos in an hour so far.

[@kwaku_2023]

This is by far one of the best design patterns playlist i have seen.

[@nifengjujuzhang8429]

THIS IS THE BEST EXPLANATION I HAVE SEEN SO FAR! My lecture in uni just made a ten minutes power point slide to explain this and i understand no shit except using a magical interface called observer can reduce coupling. The explanation you made makes total sense, you have done such a great job on keep repeating and emphasising your points and used some great examples for looking in the insights. Thank you so much :D I have learned a lot and it's fun watching it! Keep on the good work!

[@NightKnight252]

This is THE best design pattern tutorial I've ever seen

[@zest9n4ik]

Учу английский и знакомлюсь с паттернами. Благодаря Вам, успеваю делать два дела одновременно. Спасибо большое!

[@shubhamchandra9258]

Respect for the fact that you really want to make sure that we get the concept. A true contributor for the community.

[@zolisawelani9338]

You are fantastic! I have more than 4 years of software development experience but it's only know I understand these things.

[@saurabhkacholiya]

my interest in programming was fading but this video has helped me to get back on the track and understand the code better.

[@tntdogs6910]

Very helpful, rare to find these good teachers. Good because, on subject, concise. And I have to describe it as you kind of re-iterate over every step, you explain the most important thing at the start. Then we are reminded everytime when you reuse that step, becuase you explain it briefly or how it is used this time. Great job bro, honestly

[@abdulmughniabuzainah2561]

your explanation is really beyond description...i'd love to get notified more often of your video...

[@nimeshnelanga8780]

Fact that most of the people came down to put a comment shows that they sincerely appreciate your content. It definitely deserves more views. This channel worth subbing 💜

[@sandoval3265]

This is pure gold, I am not a native English speaker but your videos are very easy to understand. I hope you consider adding the part of the code in an IDE instead of the board, it would be great. Thank you!

[@YigitmK]

Dude that was the cleanest explanation with the most detail. I mean it was too long for me, I am an experienced developer. But I think this video is great for a beginner instead of other cramming videos. So, nice work sir!

[@WinLOL-p1v]

What ia a clean lecture for design pattern.... I'm just engineering students that is not computer science, But I can understand very easily!!! Thanks for making this video!!

[@jaserq]

I love your english! You are giving yourself teaching by emphaty. Brilliant !

[@samuellam7951]

Thank you for the detailed explanation. I like how you go into every single detail and almost always answer the questions that sprang to my mind on the spot. Everything clicks after watching the video. You deserve more subscribers.

[@upchaine1944]

our uni teacher suggested your videos , and it's 100% worth XD you explain better than he does .

[@franco7545]

The clearest explanation about this topic I've ever heard, thank you!

[@AugusSchoolAccount]

this was super helpful! The longer length really drilled home the points you were making. Thank you!

[@Elantry]

Yes please! This is great for all of us who needs to hear things 3 times to get it!

[@gaofan2856]

I've read 2 books , watched several tutorials but so far there is no clearer explanation of patterns. I used to force myself to understand and repeat again and again in order to remember, but your videos made me remember all these patterns subconsciously. Now I won't forget even if I want to :D

[@arastusharma439]

Pure Majic in Explanation !! Didn't realise the time while watching it and it seems like just now started.Thankyou for such good content!

[@CSharpProdigy]

This is indeed like apples of gold, in pictures of silver. Thank you Chris.. good work

[@gauravganna]

I cannot stress how great Teacher you are.

[@abdulmudhir4042]

Man thank the lord I have found your video. You are so freaking amazing making explanation so simple to digest,thank you very much

[@nikitabal]

Very very very good explanation. Now I am the observer of your channel.

[@AntonSamokat]

Very great detailed explanation. No questions must be left from viewers.

[@qweerval]

I am not very good in English, but your explanation allowed me to understand the concept deeply. Thank you!

[@lazymacs2823]

The best tutorial ever, you easily explained the hard stuffs

[@michaelo.agboola7685]

Wow! Awesome! I really appreciate your effort. This is the exact explanation I need. Funny thing is no one is talking about this, it's syntax here and there. Thanks for closing the gap, it a big difference.

[@jodellepg]

i'm pulling an all nighter to recap on design patterns for my exam tomorrow morning, you're my life saver LOL this is helpful because my classes are in french which isn't my mother tongue. The teacher teaches fine it's just that sometimes i can't process some words the same way as in english..

[@YaoZu3DArtist]

OMG, you are magical! Even I'm just in the first year of computer science, I can understand! Thank you sooooo much!

[@davidb5039]

I found your channel yesterday. Lessons are very clear and comprehensible. You spared me of frustration and confusion time. Thank you very much sir!

[@ChristopherOkhravi]

I’m very glad to hear 😊😊 Thank you for watching and for your comment 😊

[@DAS-jk3mw]

A very good instructor then, now an inspiration !!

[@Desheph]

It is 2023 and still it is the best video for design patterns. Thank You.

[@acupsf]

Great explanations, concise yet to the point!