there ist a composition of 2 Christophers at 16:09 ^^
@sshanzel4 жыл бұрын
Chris: Jump at 16:03 Me: Subscribe (just kidding, ive been subs since ep 1)
@pacoraby5323 ай бұрын
I love how he confuses himself with all the open and close tags; man, that was pure gold. It just goes to show it happens to the best of us. This is the best pedagogical series on design patterns, hands down, and it's kind of funny on top of it. Thank you, Christopher.
@ChristopherOkhravi3 ай бұрын
😊😊😊
@jriseup72016 жыл бұрын
The best design patterns video tutorial series i've seen until now on youtube!
@amiramohammed1568 Жыл бұрын
we are in 2023 and you are the best one out there teaching design patterns ! THANK YOU
@prateeksharma93216 жыл бұрын
I wish my university had teachers like you. Thank you!
@arthurfedotiew36092 жыл бұрын
“Removing this stuff” at 16:10 is the only thing you are better at than being the best OOP patterns teacher on KZfaq! For real, that was fookin epic!
@shankar74356 ай бұрын
You mean is he not good at explaining patterns.
@dp-bhatt6 жыл бұрын
One of the best tutorials I have ever watched on Composite design pattern. Thank you very much.
@ChristopherOkhravi6 жыл бұрын
Thanks :) I’m glad to hear :) Thanks for watching and for commenting.
@dannievasileva90692 ай бұрын
Thank you so much for this series, it has been immensely helpful. Please never stop teaching!
@ChristopherOkhravi6 жыл бұрын
This video got demonetized :( Anyone have an idea of why the algorithm flagged the video? Maybe the "correction boxes" that I put over my face when I said the wrong word looked like censoring bad language? I requested a manual review but have to wait for it :/
@ChristopherOkhravi6 жыл бұрын
It was quickly remonetized after a surprisingly quick manual review (thank you KZfaq). Unfortunately I don't know why it originally was demonetized and I guess we won't get to know since (unless I remember incorrectly) the algorithm is neural network based :D But I would really guess it was the text-over mouth-boxes. That "pattern" ought to be common in videos with heavy use of foul language :) Makes sense right? Ps. thank you very much for the concern :) :) :)
@JohnReloaded6 жыл бұрын
Many others are experiencing the same issue for no reason, probably the algorithm still needs to "learn"
@BrutusPalmeira5 жыл бұрын
Because you satisfied some NoAdvertise Pattern. If some ad shows advertising some other book, it is a fallacy ad principle.
@lucad44724 жыл бұрын
Hi Christopher, I'm Italian, I'm studying Computer science at university. I'd like to thank you for this amazing playlist (GoF strategy patterns). I successfully passed the "Software engineering subject" with 30/30. Whiteout your video I would have never been able to do this. THANK YOU SO MUCH. I hope you will read this! I wish you the best. Sorry for any English mistakes.
@Koriyi3 жыл бұрын
This tutorial series is great! Right now I am watching all of them to study for my masters CS degree and I love your way of explaining things in a simple but entertaining way. Just wanted to say it is the best tutorial series on this topic i have found. Thank you so much!
@segafrompk4 жыл бұрын
Hey Chris! Love your videos and I'm learning so much from you! Thank you for making these, I really appreciate it! I'm sad that you are not uploading anymore, but that's life, I know it's hard to make a living on KZfaq. Hope you would make some CS course on udemy or a similar platform, you are a great teacher and you are great at making others pay attention even during these long videos. Cheers!
@EuanFR6 жыл бұрын
I was asked during an interview to design code that compute the price of boxes containing items. Assuming that each item inside the box has a price, and that the box itself has a price. I responded with a recursive code, including a "if" statement. When the interviewer asked about the composite pattern, which would have been another way of doing it, I didn't know... I somehow had the job. But now, I could talk about composite pattern (thanks :) ).
@martijn2973 Жыл бұрын
Holy shit, I've never had someone explain abstract concepts so clearly. Every single time I was thinking "but if he says this, how does this scenario work?", and like 3 seconds later, he would further explain exactly what I was doubting.
@machi9923 жыл бұрын
I must say this channel is my discovery of the week.
@henriquedesouza4123 жыл бұрын
Thank u SO MUCH ! with 15 minutes of this content I could understand the composite design patter Greatings from Brazil !
@ianauandrei4 жыл бұрын
PING. All the explanations you are saying make a lot of sense and they really do make us (at least in my case) understand better and question our knowledge as WHY we do a certain thing. You are a good educator.
@user-ss2rj4wz5s4 жыл бұрын
The best discussion about this pattern I'd found on youtube. That's what I was looking for after reading the book's chapter. Thank you!
@yoruwamatahajimaru Жыл бұрын
Hi! I am a newbie, I have been watching these videos in the playlist order, starting with the first one. In the beginning, I barely understood the abstract part and had to look up examples of patterns in the language I am studying to at least barely understand how they work. In this video, I finally understood the abstract pattern just from your explanation (and it took only a week and a half). Thank you.
@JitendraSarswat6 жыл бұрын
Yeah... I would love to see a discussion over recursion. Can you do that?
@ChristopherOkhravi6 жыл бұрын
Thanks for the ping :) :) I’m planning an algorithms series and this video will probably go into that series. Need to think a bit about how to approach it. Maybe I should just e.g. do a series where I compare non-recursive solutions to recursive solutions. Or something along those lines :) Thanks again for the ping and for watching :)
@josipmareljic90925 жыл бұрын
@@ChristopherOkhravi What ever approach you prefer, it doesn't matter, just do it. U R great
@prashantsomvanshi5744 жыл бұрын
@@ChristopherOkhravi algorithm series please
@denispronin24175 жыл бұрын
You should go on the stage with such a proficient mimic and wonderful performances in front of the camera :) thank you for these series, I have got addicted to them
@nandukishore8445 жыл бұрын
at around 27:00 min in the video you have mentioned "interface segregation principle" and you said leaves should not be forced to have add() and/remove() methods but what I think is leaves are not permanently leaves in this scenario .We can see leaves as children or teenagers who might become parents at some point of their life-cycle .
@swellbot57386 жыл бұрын
Had an exam 2 weeks ago, used all your videos for study and this one came up - was so gutted you hadn't made it sooner. Either way, here I am watching it because the quality of your videos are great. props. Keep on doing what you're doing.
@ChristopherOkhravi6 жыл бұрын
I'm sorry to hear and terribly sorry I wasn't able to upload sooner :( It takes an outrageous amount of time to edit these videos :D Either way, I hope you do get a chance for a re-exam :) and I hope you nail it :D Thanks for watching and for the encouragement :)
@swellbot57386 жыл бұрын
Christopher Okhravi oh mate don't worry in the slightest. I just had to look elsewhere for this one, got it in the end, you just articulate and explain it so nicely you became a 'one stop shop'. I was hoping the strategy pattern would come up so I could wow them with your quote from sandi metz about inheritance haha :D Rock on, keep it up, look forward to your future videos
@raghuhuchchannavar61842 жыл бұрын
The best design patterns video tutorial series i have seen until now . Superb
@georgebadza Жыл бұрын
Great lessons, very easy-to-understand complex topics, even though the lessons are long. The type of aggregation arrows are necessary for UML diagrams sometimes, and they are not vague if you'll think about it. The aggregation arrows are of two types in UML, has one and has many, the one, used in this tutorial is - has many. So it means, that the particular component has many parent components.
@josephtuk38343 жыл бұрын
You have a clear voice, you explained well. You're good. Thank you.
@shraddheshbhandari87406 жыл бұрын
Great video. The ToDoList example nailed the principles of the pattern. Practical examples perfectly highlight the need and use of design patterns. The point you were trying to convey with the mutability discussion regarding whether a mutated object is the same object as before or a new one is actually a programmatic case of the famous paradox called Theseus's paradox.
@Defiguss Жыл бұрын
Thank you so much! You can't imagine how helpful these videos are. At least for me, this seems like the best way to explain design patterns.
@Tall-Cool-Drink6 жыл бұрын
Christopher, you have a way of making everything interesting.......lol....so discuss away, I'll be watching and listening.
@ashishgarwal41033 жыл бұрын
Super thumbs up, Christopher. You explained in a very simplified way.
@salsaSamuel6 жыл бұрын
That design patterns book is the required text for my Uni class, but I couldn't understand it. Thank you so much, these videos facilitate real learning!
@Messier_-826 жыл бұрын
Great explanation as always! And yes, i'd like to see a video from you about recursion :)
@anonymousmask42242 жыл бұрын
It's 2021 and still best explanation on the internet.
@DhrumilShahDOTin4 жыл бұрын
he specified so many times about books ... finally, I bought it on kindle ...
@ChristopherOkhravi4 жыл бұрын
😊😊😊
@baja_taco3564 Жыл бұрын
You have a tremendous teaching gift bro I visit your videos still to this day. You can dice a complex concept into an understandable form for your listeners. I hope you are doing well bro!
@ShyamSharma-pg1zu3 жыл бұрын
Awesome . Listening you is like doing meditation . Its not easy to get out of focus
@JohnReloaded6 жыл бұрын
Yes, a video about recursion, in particular about backtracking, would be great!
@anydobre17963 жыл бұрын
Absolutely. I would love to have recursion explained by Mr Christopher. Did he post anything like that, does anyone know?
@sia-yx3wd Жыл бұрын
You're so good at explaining!!! Thank you so much for these videos they're very helpful!!!!!!
@elisedappollone86433 жыл бұрын
Love these videos! I would be interested in seeing a further discussion about handling the add()/remove() scenarios with mutability vs. immutability. Did another video ever get made to go over how that would work?
@hanscesa56782 жыл бұрын
Hi, have you got your answer already? Mind if you share it? I'm currently looking for it too
@kartikmangal32182 жыл бұрын
Hey Chris, I really love while watching your videos coz you make it so interesting and easy to understand. I am very glad to have your DP series to learn from. I was wondering if you could please put a series on DSA as well coz I have been finding it difficult to make a proper decision in what way to start grasping them and what is the right resource for me but after watching your DP series I was wondering if you could please take out your precious time for a DSA series. Thanks and a lot of support
@ta-cvig3 жыл бұрын
Thanks for this series man. I learned a lot just from 2 videos thus far.
@jamalbutt78646 жыл бұрын
Chris! You are going to heaven. I wish I could meet you, and thank you in person! Best wishes from Pakistan!
@ChristopherOkhravi6 жыл бұрын
Thank you for the blessing 😀 And thanks for watching :)
@shayaxelrod76913 жыл бұрын
"So what do we need to do, to do a todo list?" 🤯
@delulu69692 жыл бұрын
Just to add, you don't necessarily need a heading tag inside li. Headings are for hierarchal structure of a sectioning element of the document like section, header, footer, etc (as opposed to of a flow content ie ul). You might need the first heading to make a new subsection for your list in relation to the section it's in, but not necessarily inside of them
@suyashpatel26525 жыл бұрын
Thanks for making such awesome videos. I have one doubt. Why you put the logic of wrapping "ToDo" text inside in "Project" class. Shouldn't it be responsibility of "ToDo::GetHTML()" method?
@vinokanthvelu26605 жыл бұрын
@Christopher Okhravi Please do the algorithm series if you have time. Will be very useful :)
@nijuyonkadesu4 ай бұрын
the pattern itself is so sophisticated, and now that I think about how to initialize this... ahhhh breaks my poor head
@ChristopherOkhravi4 ай бұрын
You got this! Hang in there! 💪
@VoyagerJourneys2 жыл бұрын
Hey man. I like your videos. I watch your video after I read one chapter of book. It is so helful for me.
@hfontanez985 жыл бұрын
One could say that a Composite Pattern is useful when a node (object) could have two distinct roles (i.e. Parent or Child, Component or Container), depending if the point of reference or a given node is root or not.
@finestHQ Жыл бұрын
I 100% agree on your statement regarding immutability, but in case of a tree structure, which could have many different nodes copying is quite expensive. Wondering what you would choose in such a scenario?
@nesreenmosimi99256 жыл бұрын
very useful and clear , thank you alot :)
@ChristopherOkhravi6 жыл бұрын
Thank you. And thanks for watching 🙂🙂
@_frank785 жыл бұрын
First of all, I really must congratulate you for this series of videos. It is in absolute the best that I've ever seen on the design patterns. It's exhaustive and you succeed in explaining the design pattern having a good time. What I mostly appreciate, it is not the technical realization of the pattern itself, but the explanation of problem that is intended to be resolved, by adopting a specific pattern. (the "mind set" of the pattern). I have a question about the composite pattern: Is there really need of leaf class? I'm working on a project started by a very experienced software developer. He adopted the composite pattern but without using the leaf class; he simply uses just one class: the composite class. If a COMPOSITE instance has children, it is "considered" a "Complex-composite", if it has no children it is as a "Simple-composite" (a leaf in the original pattern, but in our case IT'S JUST A COMPOSITE CLASS INSTANCE WITH NO CHILDREN). When a component is added to a "Simple-composite", that one "becomes" automatically a "Complex-composite" (it was already an instance of composite class, but now it has children, and this is the only difference from its previous state). This involve the discussion about mutation (in our scenario, the mutation is a specific design request, and we cannot create a new tree, every time the data structure changes): In our scenario it is requested that the user can add to the system an "object of the real world" that it is, for instance a "car" and, at that specific time, the user has no information or doesn't want to insert them, about what a car is (at that point a "car" IS JUST A NAME, or a bunch of properties, and then it is a simple component, "a leaf" in the original pattern). In a second time, the user can or wants to specify what a car is: he specify that a car have four wheels (at this point a "wheel" IS just a name, or a bunch of properties, and then it is a simple component, a leaf, always in the original pattern), a shell (idem: a leaf) and an engine (again a leaf). In a third time, the user wants to define better what an engine is; so, it adds to the engine four cylinders (just names), a crankshaft (just a name), and so on... but by doing this the COMPOSITE CLASS INSTANCE "engine" becomes a "Complex-composite". Each time the user adds a new "real world object" to an existing simple component, the new "real world object" it's a leaf (or better a "Simple-composite") and its parent from a leaf, becomes a "Complex-composite". I repeat for clarity: I call them "Simple-composite" and "Complex-composite", but the class is just one: the Component. And finally, the question is: it is really needed to have two distinct objects: composite and leaf? (A father isn't just a PERSON with one or more children? and a child isn't just a PERSON without any children? (both of them are just a PERSON)) To me this approach (that is not type checking) has the big advantage to add semplicity to data structure and permits to manage all the objects in the same way. What do you think about it? Thank you very much
@_frank785 жыл бұрын
Sorry, i've made a mistake: "I repeat for clarity: I call them "Simple-composite" and "Complex-composite", but the class is just one: the ** COMPOSITE **".
@uniumuniu11765 жыл бұрын
In the video 'leaf' class exists to provide different implementation for 'getHtml()' method. Obviously you can use only one class but if implementation of some method differs depending on being 'simple' or 'complex' then you have to use conditional statement in that method (and that's what in some cases people tries to avoid by using good class structure). In your scenario (with mutation being part of your design) you don't really want to use 'leaf like class' because there is no way to assign further children to it. It sounds OK to me.
@linux_lectures226 Жыл бұрын
had to watch 3 times now i understand thanks man
@leszektarnawski94606 жыл бұрын
Great video and the whole series. And since I am here - isn't folders structure an example of composite pattern? It is a mutable tree and any node could be either a folder or a file (leaf) but we don't want to care about it when doing operations on them - add, delete, etc. I can't think of any other way of doing folders structure.
@ArtcodEAscetik2 жыл бұрын
I've made some PHP HTMLElement with this D.P.. Works fine !
@samanehmonemirad37233 жыл бұрын
may I ask you for preparing a new section for "Chain of Responsibility Design Pattern"?
@felixjost82062 жыл бұрын
The best explanations!
@maximkuzminsky6 жыл бұрын
hi Why can't we just omit Leaf class from the picture? Couldn't we simply use Project with empty todos instead?
@shanmukhchandrayama85083 жыл бұрын
we need a base condition right ,so for that we are using leaf class
@jvsnyc2 жыл бұрын
Great video. There are some minor focus issues around 59:00 which had my eyes going googly while trying to read the updated code in the bottom right, but, great video.
@joannalai71472 жыл бұрын
Please cover the Visitor and Builder pattern if you plan to continue this series 🙏🏼
@alecc82314 жыл бұрын
Chris, another wonderful example and explanation of the pattern! Though I think, the interface name should've been like "TodoItem" instead of "TodoList". Then simple leaf implementation will be SingleItem: TodoItem. and ProjectItem: TodoItem. Does it make sense? Name "ToDoList" as an interface is confusing because it's implying a list of items already. Thanks, Christopher!
@codingwithgraceandtruth24562 жыл бұрын
really enjoying your hard work. Thanks a lot!!!
@TubeOutside5 жыл бұрын
regarding the discussion about where to put add/remove(), what if there's no separate classes for leaf vs composite. What if all you got is just "component" concrete class, so logically if it doesn't contain any other component, then it should be treated as leaf, otherwise composite, then there's no need to discuss where to put the add/remove method and yet still have a "composite pattern".
@MrEnsiferum775 жыл бұрын
So what's the difference between composite pattern and n-ary tree? For example implementation In Javascript, the Node hold array as reference to all childs down the tree.
@burakkalafat7632 жыл бұрын
Great video. Only the thing is leaves do not have to implement Add and Remove methods if you don't define them at the interface, so this is not violating the interface segregation principle. We can need different methods on a composite node than leaves. It's very typical. I only can't entirely agree with that part. Other than that, it's a great explanation. Regards
@facundorodriguez926 жыл бұрын
Hello Christopher, I would like to know if there is a possibility that you dedicate any video to the concept of TDD. I am beginning to immerse myself in that subject and I would like to know your opinion about it. Thank you very much. Saludos desde Argentina!
@facundorodriguez926 жыл бұрын
Sorry I should have done a search before suggesting. For those interested here speaks of similar concepts: kzfaq.info/get/bejne/sMekltmgs9e3kX0.html
@ChristopherOkhravi6 жыл бұрын
Nice! You were pretty quick to find it though :) :) Lemme know if you find anything specific in the videos that you would like me to explore further in future videos. Also, thank you very much for suggesting topics and thank you very much for following the channel 🙂
@mattgraves37095 жыл бұрын
I absolutely have loved this series so far Chris. I'm in American I'm 40 years old and I don't think that I'm too far out there but I've never heard of Part whole hierarchies... well let me digress I have heard of it, in fact it was another composition design pattern video I was watching in which I heard that term....I just don't know what it means I've never had it to find for me...
@jessecalato4677Ай бұрын
doesn't matter much for this example, but when you talk about mutation you say @24:27 you say that b will be 6, but that's not true, you used the post decrement opperator, the value of a is returned before it is incremented, so b would actually be set to 5, and then a becomes 6.
@pedromedeiros6907 Жыл бұрын
wonderful class
@prolamaamvs6952 Жыл бұрын
deam this dude is going crazy :D love it
@radiagulzan4 жыл бұрын
You're an amazing teacher!
@BangsarRia2 ай бұрын
GoF intends that the Composite Pattern be used in cases that the Client does not have to distinguish between Nodes and Leaves. GoF p167, point 4 expressly addresses the issues of ISP and LSP: "trade-off between safety and transparency". GoF's use of "transparency" here makes me uncomfortable, because I don't think they mean that at all, and the word does not appear in the index, so we don't know what they mean by it. In this context I think they mean "uniformity", or even "abstraction". While we're talking about terminology, GOF was published before Java was revealed. So we see "operation" for "method" throughout. They might have gone with "function" instead of "method" anyway, as not all languages use "method" and "member" etc as terms.
@BrunoOlivera223 жыл бұрын
my man!! great vids n explaining, much appreciated!!
@AshokKumar-uf5nj5 жыл бұрын
Hi @Okhravi, Super likes the series. But I don't see the Builder and Chain of responsibility patterns covered in the playlist. Can you point me to these if you have covered ?
@cyantulip6 жыл бұрын
Hey Chris! Thank you so much for doing these videos. Your explanations are well thought-out and very comprehensive. I find them very helpful. I have a request for you. Could you please do a video about shared libraries, static vs dynamic linkage, implicit vs explicit loading, in a modern OS environment (i.e. how things work now, not how they used to work 20 years ago.) Oh, and I’d be interested in that recursion discussion too. Thanks again, and keep up the good work! :-)
@liorocker16 жыл бұрын
Yes please, hope you can explain recursion as good as you teach design patterns.
@ChristopherOkhravi6 жыл бұрын
Thanks for the feedback :)
@MRarvai5 жыл бұрын
I think at 24:00 b would be equal to 5 because the value of a is incremented after the operation ( Im only speaking for the few languages I know like C++ and C# , there might be some weird languages where this is not the case ) you'd have to use ++a ;)
@MRarvai5 жыл бұрын
oh shoot, didn't see the correction because of the 2X speed, my bad :D :D
@nickbarton31916 жыл бұрын
Another excellent topic would be dependency injection. Trying to persuade my colleagues about the case for this because of the testability of units.
@bsuperbrain6 жыл бұрын
Magic jump what removes stuff from the board. Haha! Anyway, nice to see this new one, long ago waited.
@ChristopherOkhravi6 жыл бұрын
Yeeeeah :) My editing skills are sub-par so it was tricky to figure out how to do it :D Thanks for watching and I hope the video was accommodating :)
@rajsoni7085 Жыл бұрын
thanks for making this video .
@piotrjaga6929 Жыл бұрын
that is awesome! thank you
@shinemperor89505 жыл бұрын
Loving this series. Thank you for this. I during the video you mention something about refactoring, branching logic and polymorphism. Was this video already made? (I haven't gone through all your content yet) Because I find the idea of replacing branching logic with polymorphism absolutely fascinating.
@danielkapitanov18166 жыл бұрын
you're a life saver
@professorfontanez2 жыл бұрын
Java Swing is built on this Design Pattern, where you have Container and Component. And really, that's how Composite Pattern should be designed. There is no need for a distinct "Leaf" class. A "Leaf" is simply a "Component" that has no sub-components. At any given point, a "Leaf" should accept new components and become a "Composite". Long story short, it is more effective to remove "Leaf" from the design and deal only with Containers and Components the way Java Swing have done it. Components containing zero sub-components are in essence leaves. However, you can transform this leaf into a composite simply by adding components to it. So, the best UML diagram for Composite Pattern is what is illustrated at 27:36 without the class "Leaf" in it.
@deathangel9086 жыл бұрын
26:50 I feel very confused now, `no client should be forced to depend on methods it does not use`, a client = `has a`, not `is a`. In your scenario, it breaks Linskov's Substitution principle, as a Component can't be replaced with a Leaf. Please correct me if I'm wrong.
@ribaker8225 жыл бұрын
Hey Christopher, thanks again for this video. On your point on Interface Segregation Principle, while I agree with you, I thought that Leaf was not a client of Component, but actually is a component. Or maybe it's me not fully understanding the ISP?
@MrZnSstr2 жыл бұрын
In the book it was very confusing, this pattern it mixes my weakest skills in programming. Trees and recursion, I know conceptually what they are, but regarding trees I never used them for a solution and I can't visualize much their ideas and recursion I used it at some point with basic programs like fibonacci algorithm, but its not like I am experienced with it. I hope your video will make more sense. Edit: Oh shit, I went checking on trees again and I ended up watching the MIT classes.. quite a rabbithole and I am back.
@khoinguyen-ft2ys3 жыл бұрын
Thanks!
@feosys76955 жыл бұрын
man, its awesome channel, thank u
@tarike98082 жыл бұрын
God bless you man
@nawakoff25812 жыл бұрын
I understand it is all about mutability, but wouldn't it be more flexible to create just one class and determine whether it a leaf or a composite based on whether it contains subitems or not at all? Of course, it would force us to use a conditional, but it seems to be more like a composition over inheritance
@nawakoff25812 жыл бұрын
But yes, I guess it depends on the specific case, whether we need to wrap composites into new ones without altering the first ones, or we will know the entire structure and just use constructor, or we need to extend different nodes dynamically
@pushpendrapratap31163 жыл бұрын
"I don't wanna talk about recursion if u r not familiar with recursion." 😆
@princekm59025 жыл бұрын
Hi Christopher, I have seen your video about strategic pattern.In that you discuss about the rubber duck and IFlyBehaviour interface.Similarly Can't I make an interface "IAddBehaviour" for Component and define add() into it and create two more interfaces from IAddBehaviour.Let's say AddNotSupportedBehaviour and AddSupportedBehaviour for leaf and composite respectively.Doesn't that make sense?Shouldn't we be doing that?
@Tall-Cool-Drink6 жыл бұрын
lol.....I glad I'm not the only one confused by "part-whole"......I'm confused by many phrases like this throughout software coding methods.....
@moathnaji85055 жыл бұрын
thanks for the big effort its really clear, but i need to ask where the TodoList come from ?
@rizwansabir2448 Жыл бұрын
thanks
@davidspencer37264 жыл бұрын
Immutability's an odd idea. That you can't change an object, but must recreate it. Logically therefore, what contains that object also cannot be modified; it too must be recreated. So ultimately you end up having to recreate zillions of gigabytes of stuff just to increment an integer. Could you explain how this isn't the dumbest idea computer science has ever come up with?
@SoferPeOZN3 жыл бұрын
16:07 Didn't see that coming
@TheAd0214 жыл бұрын
Hi, your videos are really helpful and I absolutely love this series, learning a lot from it. I know, this is an old video, but I'd be happy, if you replied. This example got me confused - I understand how GetHTML() method works, and the relations between classes and interfaces here. But what I don't understand is how would one construct such a structure. I mean, you get rid of conditional expressions for rendering html, but you'd have to use them for construction - somehow you need to know, what instance you want to create (is it going to be "new Todo()" or "new Project()"). Say, you fetch the whole TO DO list from a database, and then you have to populate it to the structure from your example in memory. What would be the right way to approach this task? My thoughts are that you start with one empty root component and use add() methods, adding components one by one. But then you'd have to implement add() for the Todo class.