Decorator Pattern - Design Patterns (ep 3)

[@bot-bot]

Hey Christopher, when you mention you use the Decorator pattern when trying to deprecate the usage of some class, wouldn't an Adapter/Facade pattern be better for that? I'm new to design patterns so I'm just trying to analyze it a bit :) BTW, when is the next pattern coming out?

[@ChristopherOkhravi]

Excellent question! While filming, this question struck me as well. It's really quite hairy. They are deviously similar and I keep forgetting the nuances :) TLDR; I agree with you. But, let's define the concepts... 1) The adapter adapter pattern changes the interface but does not change the implementation. 2) The proxy pattern changes the implementation but does not change the interface. 3) The decorator pattern changes the implementation but does not change the interface. 4) The facade pattern is a high-level level abstraction over low-level components, where the interface is changed. So, I guess it boils down to proxy vs decorator. The deprecation example I gave could, depending on the scenario, probably be technically considered decorator pattern. But then again, it's a too simplistic example that doesn't really take advantage of the true power of decorator pattern. So I agree with your comment. Further, my example becomes even more silly if we look at it in a statically typed language (I usually work in dynamically typed languages and was thinking of that when I blurted out the example). In the decorator pattern we have the two interfaces Component and Decorator. The old class we want to deprecate is a Component, but if we were to use Decorator Pattern to deprecate it then the new concrete class would have to be a Decorator which in turn is a Component. From an abstraction point of view, this is actually a good thing because the abstract Decorator could then make sure to delegate all method calls to the decorated Component, which leaves the concrete Decorator with the job of only implementing the few methods it wants to change. But then again... this is probably massive overkill, and you'd be better off just throwing in a proxy where the proxied object is dependency injected into the proxy. Interesting excursion :) Thank you for the comment. I need to think my examples through a bit better before rocking it :) Ps. I've got an older video on Adapter vs Facade vs Proxy here: kzbin.info/www/bejne/noWmZKWjh6d8rtU

[@bot-bot]

Thank you for a very detailed and educational answer :) I still haven't touched the Proxy pattern which I'll do next and that is probably the reason why Adapter and Facade were the first that came to mind. For now it makes sense why and how to use the Decorator for deprecation even if it is an overkill. It's good to have these examples in your videos because they give us the opportunity to think about them and ask when unclear, so keep it up, it's all good :) I enjoy the Code Walks as well, especially liked the one about VR/AR and moving coding away from the monitor+keyboard environment!

[@theesunnlightt2268]

Christopher Okhravi, Thank you very much for these amazing videos.

[@shanmugamsekar4044]

In this case , i think proxy pattern makes sense. Awesome video Chris .

[@borjagomez1663]

BEST saxo ever

[@FlipYourLearning]

This series is becoming one of my favorite coding tutorial series here on KZbin, as a combination of the delivery and the value. Every video keeps me engaged from beginning to end, and each has all I need to start applying the concept to my own projects. Thanks for making them.

[@Anonymous-vd1pb]

noob

[@serkangoktancelik5081]

This man's explanation is so much better than any prof I have in uni and all other KZbinrs. Thank you.

[@rizvinazish]

One of the best explanation in KZbin pattern videos, classic!

[@ChristopherOkhravi]

One of the best comments on KZbin :) :) ;)

[@smilerelax5265]

execuse me this is the best not one of the best. believe me i went trought them all.

[@harshtalwar9615]

@@ChristopherOkhravi (One of the best comm......) 😁 yes, it is true.

[@sshanzel]

Not one of the best. But actually THE BEST OF EM ALL

[@fordsim7]

I love how the cat wanted to learn about the Decorator pattern at the end. Love the videos by the way

[@kareemjeiroudi1964]

You asked us in the video if you should change anything. Please don't change anything. Your videos are goddamn awesome! Just keep making more videos. The community needs people like you who have the knack to explain things the way you do. Man, you are 100 times more valuable than all my university professors put together. World's best CS instructor!

[@shanm4629]

More than KZbin supporting you, its actually you are helping youtube to provide such a quality content to public. Thanks for sharing this.

[@Gobberfisch]

the way you are teaching is genius, I watch one video and get it all, no need to look anything up afterwards

[@ryancederoth727]

@2:38 Wow... I spent, like, 3 days a couple months ago researching Abstract classes and didn't manage to gain, like, a lick of insight. This guy sums it in a TOTALLY understandable way in all of a minute.. and this tutorial isn't even about abstract classes!!

[@8uddishh]

I cleared three interviews back to back ... coz of this man... keep it up...

[@abdulquadiransari7476]

The best part of this video series that Christopher Okhravi is teaching from a book. At first these vidio series were not making any sense to me. But after I read the chapter from the book and came back to this video I understood the concept even better. Thanks Christopher for making videos on KZbin. I wonder where have you gone since 6 years now !!!!

[@406owner]

by far, you are the best. your teaching and explaining methods are simple and easy ( and in the world of programming, that is priceless ) waiting for the next episode.

[@ChristopherOkhravi]

Osama Tamimi Thanks for taking the time to write this comment. I appreciate it. I'm glad the video is useful :)

[@chrishopkins652]

I absolutely love these explanations. Thanks so much for them. I found it confusing to think of Caramel/Chocolate as types of beverages. It helped me to think of the Abstract Beverage class as a 'Product' instead. Both Espresso and Caramel are Products that the coffee shop sells, but Espresso is the base Product. Caramel is an addon but also still a Product.

[@88ylli]

It's funny because before watching your videos I was getting information about patterns on different sources, and it seemed to me that all different sources were saying different things on the same pattern. Then after watching your videos I realized that all these sources were saying the same thing. Definitely the simplest explanation ever. Thank you!

[@yussufclark9390]

This is really good stuff. Please don't stop making these videos, unless you've already exhausted all the information of course. You're a really good teacher and you're easy to follow.

[@panosgr7228]

When reading the book I kept on asking myself why we were calling the toppings (Soy, Mocha, Whip, etc) beverages and even using an "IS-A" relationship when they clearly aren't beverages lol. So those two key pieces of information at the end really helped me understand this pattern. 1. You should look for alternatives if the Decorators you are using aren't actually of the type of component which you are initially wrapping. 2. You shouldn't use Decorator Pattern when the only variation between Decorators is a couple of properties. I feel like watching your explanations really complements the information in the book and will continue to watch the rest of the series. Thanks for this!

[@fayazmohammad8545]

I love your teaching pattern. And I want to learn all these patterns from this playlist.

[@JeremyMoritz1]

Outstanding! Thank you so much for all of the quick cuts throughout the video. This shows great respect for your audience's time and makes the content much more interesting, digestible, and entertaining!

[@rob876]

I've never heard a better explanation of the decorator design pattern. Thank you.

[@BooSgu]

I love your method of teaching. Ez than reading than the books.

[@jawharomeryaba8696]

I love the way this guy is moving

[@kserra9112]

Still the best video ever about explaining the decorator pattern.

[@roman_mf]

I've just started to dip my toes into design patterns and boy am I glad I found this video. Excellent explanation. Heard about the book but now I'm more motivated to start reading it. I'm sure it will go super well together with your videos. Thank you!

[@pcccmn]

Came here after reading and leaving Head First's Decorator chapter confused. This video makes everything super clear! Thank you.

[@msaifii]

I do not have patience to watch long explanation. But I confess that I watched the first three videos in one seat with out getting bored. Congratulation for the excellent explanation!

[@typsy1981]

You really feel and understand very clear what you are saying about. Good job Chris! Great explanation!

[@bernong1]

This the the This video I have watched. This is amazing. Clear, concise, hits home on all the points to clarify the design and how it is implemented. I have not been able to get this clarify for years by reading books. Past 2 days of watching your videos was time well spent.

[@firuzafynchina9208]

What a cool tutorial. thanks for a comprehensive tutorial and charisma. 50 mins passed so fast!

[@tutanchacon]

One of the best explanations I've ever seen. You are a great teacher

[@heraldo623]

51 min to explain decorator, I never seen so long explanation of a pattern. That's excellent

[@RajVadla]

You are a savior. Thanks for your time and care about community 💐

[@imsoanju]

I absolutely love listening to you. Not only you explain everything in a great and understandable way but you also have such an awesome vibe going on. Love it.

[@acupsf]

Greatly explained! Totally agreed w/ your comments towards the end

[@ridakalim6218]

just watched this and my mind is blown u explained it so well its so simple

[@jareeq]

Christopher, your explanations are among the best , multi level references, kept my mind focused and thanks of that i can simply remember more. Thank you.

[@neolopus]

Best explanation about Decorator. after 5 videos, it finally makes sense.

[@puneetsingh6782]

Hey Christopher, thank you! your prodigious energy, and no-beating-the-bushes style of teaching is awesome. You convey your ideas very clearly, and succinctly

[@iamdijki]

Wow.. I didn't sleep in a long lecture? what a miracle!

[@XxxGuitarMadnessxxX]

I'm EXTREMELY happy that I recently found your channel. Been watching your design patterns playlist in order and I've been actually getting pretty excited about implementing them in my code! So far, I've found the talks about Observer and this one about decorators to be suuupperr helpful with a thread-safe logging library I'm making for use in other personal projects where the observer pattern is used in managing multiple loggers and progress indication bars and this decorator pattern is used in the logger sinks and progress bar attributes. Again, Thank You for making easy-to-digest videos as they have been super helpful in grasping new concepts so far!

[@dcngn_]

After listening to 1 hour of how not to implement the coffee shop system I was really wondering what would be the most efficient way instead? Anyway, this video really cleared my mind regarding the decorator pattern, so mission accomplished!

[@shaanmohammed33]

Awesome explanation (Special applause for telling how decorative pattern is more useful in cases of behavioural changes rather than value changes which is a better scenario for using iterator patter). If someone has not gone through iterator pattern, just by that line of yours he/she will get to know everything about the iterator pattern. Great Teacher you are. Keep on doing the good job of educating others.

[@sameer1234ification]

I don't feel of time when watching this series ... Great explanation

[@kopilkaiser8991]

Thank you for taking the time on explaining the Decorator pattern. I've been introduced to it for the first time on this video and it is all thanks to you. I found this resource helpful and useful at the same time, you are very good in being able to illustrate all the different perspective to this subject.

[@陈冰强]

The best video about decorator pattern I have ever seen!

[@msh6783]

best explanation on youtube by far

[@johnconnor9787]

The way you explain the material is awesome!

[@Aslam2012ful]

OMG, this is the very best abstract explanation ever....

[@Stehocke]

Nice video. I am teaching programming and your whiteboard + cut seems to be the key. The pace is perfect. Usually i finish the class with a nice board picture provided in a confuse way or i just need to long to draw and write the illustrations.

[@kareemjeiroudi1964]

I would also argue that for this Coffee example, the decorator pattern is an overkill. I think the suggested solution at 48:30 is a more suitable one. I just wanna say thank you a ton for your hard work. Please keep making more videos 👍.

[@sudhakark91]

Never heard better explanation than this about design patterns.. you are awesome..

[@brtk7]

@Christopher Okhravi You are good teacher. Thank you.

[@kkthatik]

Awesome! After several tries now I understand it better here, the decorator pattern. Thanks.

[@MikhailDangcal]

i like the explanation. programmers who are doing Point of sale System can totally understand your explaination.

[@OmarChida]

I don't usually comment on videos. But this time I have to. Because you completely nailed it man best explanation ever heard! Before I used to think that I understand DP. But after watching your video I relalised that I actually don't.

[@sushmitagoswami7320]

A huge respect and admiration to you for sharing your knowledge in such a lucid way. I would request if you can also include some real life use cases at end of each pattern, it would help us tremendously.

[@yairshahar1560]

hey Christopher, great explanation. You have unique way for explain complicated things to be easy understand, thank you very much ! I am looking forward for the next chapters...

[@ChristopherOkhravi]

Thank you for the kind words. And thanks for watching.

[@alanlai8769]

A clever way of using recursion and polymorphism, great explaination!

[@gvk]

Hands down the best explanation you'll ever find on the Internet! Thank You

[@miracledoh4020]

For those who are looking for the difference of using a decorator and a List, go to 46:30, Christopher talked how the classical example of beverage, or pizza is unsuitable for the decorator pattern and scenarios that make it suitable.

[@parhamzolfaghari7394]

mid-way through the video, but had to tell you you're teaching is top-notch!

[@keaman]

Great description! Read that book about 10 years ago but never understood the pattern as much as I do now having seen your video.

[@ChristopherOkhravi]

That's awesome! I'm glad to hear the videos complement the contents of the book. Thank you very much for sharing and for watching :)

[@sergioshev]

Thank you for so nice work you are doing! Was a honor to view your teaching. Very useful.

[@MahmoudRKeshk]

That was awesome! A detailed neat explanation ... Now I got how the linq operators work under the hood ! This pattern with method chaining in C# will be absolutely great. Thank you !

[@Adi-mj3cb]

Your way of repeating things over and over again is absolutely brilliant, keep doing this. Well done. I thank you. Also, the very last part where you showed how to actually implement it - that is very important as well! I was wondering if that would show up at it thankfully did. Absolutely wonderful job all around.

[@TheIdan2108]

Hi, I just wanted to say that you explain this material very well. Thank you!!

[@thunderkiss007]

Explained very well and please continue for all Design patterns which are explained in book.

[@ChristopherOkhravi]

Fikret thanks! Will do :)

[@dynamic_pointer_cast]

Indeed, the Coffee/Condiments example is quite roundabout since we can just represent a combinations of condiments as a string (each character represents a condiment) and have this string analyzed to get the final cost. This is even more flexible since we can manage rare situations where we want certain combinations produce an entirely different cost (or even Description).

[@naturalsmen1]

Clear and comprehensive. Thank you for your sharing!

[@piegoesboom]

I wish more college professors could explain topics this well and with this much enthusiasm

[@shishirkakhandki9230]

Thank you so much for explaining in such detail. Respect from India! :)

[@DBakars]

Hi Christopher, I by mistake came across your channel and am wonderstruck with your style of telling the things. I already had the book but everything never meant much sense until I started watching your videos.Thanks for making things simple. Eagerly waiting for your next videos. Please keep us posted. :)

[@ChristopherOkhravi]

Thank you for the kind words :) :)

[@ОлегТокмачев-в9ц]

I never seen any better explanations of anything! Thanks a lot!

[@demonspawn5967]

Hi Christopher, thank you very much for this informative video! I was quite frustrated with the material that my teacher handed out, because I didn't understand what exactly the pattern is and how it's used, but now I do :)

[@jonp9511]

Christopher, thank you so much. I finally came across your channel today when searching for info on the decorator design pattern(liked and subscribed). It is exactly what I have been looking for. I go to school online and sadly there is little to no actual "face-to-face" instruction. By that I mean, we have assignments, and are essentially left to own to figure out how to work through them. In fact the class I am taking now does not even have an accompanying textbook. I don't learn well by relying on slow email correspondence ( I am a busy man) to drive some complex principles home. Sometimes I need to have things broken down into very simple terms and viewed from several different angles to finally sink in, so that I can actually use it in practice and not just theory. Your approach here is exactly what the Dr ordered. Again, thank you very much.

[@sarahmostafa3984]

Thank you for the amazing explanation, I finally understood the decorator pattern

[@ananyakes936]

Hey Crishtopher, When are you planning to post the next chapter. Your explanations are really helpful for my studies as Design Pattern is part of my course and sorry to say our professor taught us 5 design patterns (the 1st 5 chapters) in 45 minutes :(. so eagerly waiting for your next video.

[@ChristopherOkhravi]

Thanks! I'm very glad they're making sense. That sounds like a very tough job for your professor :) I've been covered in work which is the reason for the delay but I'll get to it as soon as possible.

[@callmeartae]

Awesome job, as always! Just one teeny tiny point - in teaching, repetition is good. It's more than good - it's crucial. I can't stress enough how crucial it is. But keep in mind that repetition of a concept does not necessarily mean explaining it multiple times. Explain it thoroughly once or twice and then repeat, repeat, repeat but only the gist of the concept or even just the name of it. I'm talking about the HAS-A/IS-A part in your video - it's sufficient to explain it once or twice and then to remind your audience: "remember: IS-A/HAS-A" so they immediately think about "decorator pattern" when they hear "IS-A/HAS-A" or vice versa. Just a quick tip from a methodological point of view, I hope you don't mind my babbling. Anyway thanks for the video, can't wait to see more!

[@SwethaSaseendran]

I would recommend this channel to all my collages who wants to learn about design patterns. You are doing an amazing job Christopher. Thanks a lot. :D

[@benwho1549]

Really awesome playlist, I can easily understand the patterns even though I’m not a native speaker.

[@amrhansari]

I love your videos, You are the best teacher. I never get tired.

[@sivar4300]

I like the way you visualise it like a recursion and linked list

[@rosscarlson3701]

Perhaps the coffee example could become more appropriate for the decorator pattern if you think about the possibility that each coffee add-on could change not only properties (cost) but also behavior by adding a make() method. Now, the way the coffee is made changes with each decoration. It doesn't change only the price.

[@shanmukhchandrayama8508]

dude, your explanation is extraordinary, hatsoff for your effort to make us understand. Thank you bro for making these videos on design patterns

[@kimhamaidi3124]

Best explanation i ever saw thanks alot

[@ilovepandaypoe6056]

my third video of the day. its very engaging. I just wish you have the same pattern for all. Meaning as always you start with the definition , then problem and the possible solution using the pattern. Overall it was really very educational. Thanks heaps for your efforts.

[@Brunoenribeiro]

Love how "coffee" starts to lose its meaning and becomes just a data thing during this video 😂 just kidding. Love your content, the best I found in yt

[@renarsdilevka6573]

From refactoring.guru "Decorator and Proxy have similar structures, but very different intents. Both patterns are built on the composition principle, where one object is supposed to delegate some of the work to another. The difference is that a Proxy usually manages the life cycle of its service object on its own, whereas the composition of Decorators is always controlled by the client."

[@metehanmutlu9187]

Nice video! Nice explanation! Thanks. I think there is a slight difference between class diagram and pseudo code which might not matter much but i wanted to mention anyway. On the class diagram abstract decorator class has 'Has A' and 'Is a' relationship but on pseudo code doesn't have a Beverage property(so there is not a 'Has a' relationship), instead concrete decorator class(caramel or soy) has.

[@Venezuelangel]

HOOOOlLLLLLYYYY CRAP, I was recommended your videos by the YT Algorithm and I was like, "nah, I'm just a Junior Dev, I ain't gonna need Design Patterns for another year"... WRONG! So glad the algorithm found you again. Subscribed.

[@nemanjastankovic941]

Very very very good explanation. I'm impressed. It is obvious that you're getting better with every video. Video is a little bit long, but you've managed to keep my attention. Great job. Regards from Serbia.

[@jhpadilha]

Thanks for your explanation. So clear and easy.

[@k.safonov]

You should take money for such lessons. You have teaching talent.

[@embalyst]

Another great instructional video! I feel like I understand how to make and use the decorator pattern. If I'm still a bit fuzzy on anything, it is why or when to use this pattern. Maybe extra examples might have helped.

[@gisela6704]

Thank you for talking about why we might use an abstract class instead of an interface. That was a helpful aside. (at 7:53)

[@rickmonarch4552]

Ur way better than my old uni teacher.

[@mireazma]

You could get rid of the need for a base case by simply making the abstract class have an object of itself (be the decorator). This makes it possible: 1. In our case, have just caramel. 2. Doesn't enforce an order (anchor the decorator chain on decaf or espresso at the bottom).

[@TheDanielBarcellos]

"Is it a and is has a", by Christopher Okhravi. That's awesome!

[@benjamin_fdw]

You are doing an amazing job! Great content, well explained. You seem to master these topics but you stay very humble and you ask people their opinion about your explanation and implementation/illustration. Plus I like your ability to talk so fast and stay understandable at the same time. That's mind-blowing

[@milachekua]

Fantastic! - always saving out time by editing the video - mention a lot of importent things (even those that not always related) - your emotions that helps to understand and remember much better Thank you so much for creating such useful videos.

[@serkangoktancelik5081]

This man's explanation is so much better than any prof I have in uni and all other KZbinrs. Thank you.