KotlinConf 2018 - Exploring Coroutines in Kotlin by Venkat Subramaniam
Ғылым және технология
Recording brought to you by American Express americanexpress.io/kotlin-jobs
Coroutines have intrigued programmers for a long time. Some languages of the past implemented coroutines, but programmers using the mainstream languages of recent decades largely did not get much exposure to this programming construct. There's a resurgence of interest for coroutines and some serious work has been done in Kotlin to implement it. We'll take an example oriented approach to learning about the benefits of coroutines and along the way explore this feature of Kotlin.
About the Presenter:
Dr. Venkat Subramaniam is an award-winning author, founder of Agile Developer, Inc., creator of agilelearner.com, and an instructional professor at the University of Houston. He has trained and mentored thousands of software developers in the US, Canada, Europe, and Asia, and is a regularly-invited speaker at several international conferences. Venkat helps his clients effectively apply and succeed with sustainable agile practices on their software projects. Venkat is a (co)author of multiple technical books, including the 2007 Jolt Productivity award winning book Practices of an Agile Developer. You can find a list of his books at agiledeveloper.com. You can reach him by email at venkats@agiledeveloper.com or on twitter at @venkat_s.
Пікірлер: 123
Great, It really helped to understand coroutines. BTW, It's very impressive that he could keep talking without a break while he writes several lines of codes and runs it. There must have been coroutines running in his brain.
This guy is who made me start kotlin, greet to see him in the Kotlin Conf
@navsingh7934
5 жыл бұрын
same here man
@akashkroy
3 жыл бұрын
I read his programming kotlin
I've not seen anyone explaining the internals of coroutines better than Venkat Subramaniam.
@ViperCinema4D
5 жыл бұрын
kzread.info/dash/bejne/i6amt6WMmZqYdZs.html
@navsingh7934
5 жыл бұрын
he is the best speaker I have seen so far.
@aprofromuk
3 жыл бұрын
no 1 can do that :)
That's some introduction. I like how he explained the "Why?" part of the changes.
I'm a simple man. I see Venkat Subramariam in a video title, I click.
@chukzydee
5 жыл бұрын
Venkat and/or Florina on the title is enough to make me suspend all I'm doing and click on the video.
@salvatoreshiggerino6810
5 жыл бұрын
To click is to do the needful
@j-r-hill
5 жыл бұрын
It's so true
@AmarPoonia
4 жыл бұрын
Same here.. even if I've watched it before, it's so satisfying
@gleb.ignatev
2 жыл бұрын
@@chukzydee suspend, you're saying, I see what you did here...
What a god damn pro, sometimes I need to pause to think about what he said
@0xmg
4 жыл бұрын
The buffering does that for me
This well co-ordinated explanation along with live coding demonstration is simply brilliant. He makes it look simple, but let me tell you, as some one who makes tutorials on KZread, this requires exceptional skills. Not just coding but presence of mind.
I refer to Venkat's lectures whenever I get to the mood of seeking out wisdom 😌
I love Venkat voice, it is so calming.
One of the best talks I've watched in a long time.
Great presentation. I really appreciated the use of bare bone editors and the love coding. I wish he slowed down a bit around the crucial points but understand it's a lot to cover in the given time. Impressive how he kept going confidently despite the inevitable typos, etc. I still have some questions about coroutines but this talk really gave me some good examples to think about.
What a legend. Solved so many queries I had about coroutines with such simple but precise and amazing explanations.
Amazing talk. Impressed by his coding and explanation going hand in hand.
He explains it so well and so simply. A very bright man.
really like a way he explains stuff, his talk about DSLs also nice
This guys speech is so captivating!
Good examples. the multitasking while presentation using vim is incredible. !! Also the sound of claps at end of video says it all.
Every the venkat's videos make me to want to be a better developer 💪🏿. Great explanation!
Excellent stuff, Venkat. Great explanations and witty humor.
Amazing talk, thanks for the content!
He is really awesome. He is totally different from any other devs. It's like an entertainer or magician.
This talk was great. Thanks Venkat!
the best speaker ever ) java versions are bumping, new langs come and go. but Venkat is a guy who always was with us )
Just loved it. Thanks for this simple explanation
This was so captivating. i didn't even felt for a minute that am staring at my screen for 44 minutes. amazing presentation. Anyone reading this comment in 2021 : How to access the launch{} function in coroutines 1.5?
That last example of step by step conversion from sequential -> suspend -> async did the trick for me :)
I've never seen anyone program in VI before. It felt a bit like black magic.
Great explanation. Must have been took months to find/create an example code which is this simple but very informative and covers almost everything. Great job.
@JetBrainsTV
4 жыл бұрын
Glad you liked it
What a great explanation! You know he is an absolute professional when he shows how suspend functions are sending the rest of the code (Continuation) of the function as a parameter 28:24 . Everything including async block explanation was just great. He taught me things he wasn't even trying(possibly) to cover in this conf. Thanks!
this was fantastic.
amazing and so engaging.
The one and only. We meet again.
Great presentation, great teacher!
Loved it
Topics: 1. Parallel vs Asynchronous 0:50 (Java, Kotlin ahead of Java at least 5-years, Microservices, sequential vs parallel) coroutines make it easy to write asynchronous code. 2. Concurrency vs non-blocking 1:50 (Java example and comparison) 3. Let's examine parallel just a bit, in Java 2:30 (Java example and comparison) Parallel Stream: Structure of [functional] sequential code is the same as parallel code Coroutine: Structure of [Imperative] Synchronous code is the same as asynchronous code 4. Why not be happy with that? 5:20 5. Functional style is awesome 5:20 6. But, handling exceptions is a mess 5:44 7. Coroutines are asynchronous 6:25 launch { //launch () method } 8. From synchronous to asynchronous 9:00 Non-blocking GUI's 9. Blocking to non-blocking 10:12 10. How do coroutines work? 10:12 11. A sequential code 17:14 12. Using suspend 23:20, 24:30 Parallel Stream: Structure of [functional] sequential code is the same as parallel code Coroutine: Structure of [Imperative] Synchronous code is the same as asynchronous code 13. Doing asyn 33:00
@andromadusnaruto1544
Жыл бұрын
Awesome. Much appreciated...👍🏾
Great stuff!
excellent excellent excellent
Venkat Superman
thanks sir ,best lecture on coroutine
Отличная информация, спасибо большое!
Live coding! Awesome!
I finally know what to do when someone asks me to put the status bar below the phone and the system back actions on top of the screen! Run for the exit!!!!!
Instead of suspend measureTime you could have made it inline, i think it would work with await 😀 really nice talk btw, finally understood coroutines
@hhhapz
5 жыл бұрын
I think the goal of the talk was to show how suspend functions make a difference, and allow thread blocking versus non-suspension functions.
Amazing presentation
@JetBrainsTV
3 жыл бұрын
Thank you! Cheers!
Amazing talk, but I am curious what the setup is being used for interactive Kotlin/Java coding in vi/vim
Extraodinarly goed presentation! Explaining everything from how we got here, why apply coroutines and the way to do that in Kotlin with great examples. I especially loved that last example where we can see how small changes in the code can make it asynchronous using coroutines. The yield example was really a great step in getting there to explain that. It really helped me to make it even more clear to me what coroutines actualy are, what they can do and where to use them.
Great great presentation. 🙌
@JetBrainsTV
3 жыл бұрын
Thank you kindly!
Great talk! I like that it was very concise, but I could offer one piece of feedback is to have longer pauses /paragraph breaks. It feels a little bit like a giant paragraph would read. There are sentences, but it there is no place to rest, its just one big big paragraph.
@methodsignature
5 жыл бұрын
Yea, it felt a bit like catching a wave. If I didn't have much coroutine experience, I'm not sure I could have followed very well. Some of that was probably the time constraint of the setting.
A very good explanation, thank you!
Just so you know, there is an error in explanation of "suspend" modifier. Explanation by Roman Elizarov could be found here: medium.com/@elizarov/blocking-threads-suspending-coroutines-d33e11bf4761
If getting Google's stock price took "2 seconds" and Amzn's stock price took 1 second... Then for the last example Amazon's stock price would show up earlier right ?
Frankly, found it quite convoluted
3:10 HOLY MAMA! WATTA HELL IS GOIN' ON? (Nice talk, by the way. Good job!)
yes
@37:53 So this all is really just syntactic sugar for Thread pools and ComplteableFutures?
Venkat is such an awesome teacher
"suspend modifier to a function makes it either asynchronous or non-blocking. " is not true according to the Roman Elizarov's article. medium.com/@elizarov/blocking-threads-suspending-coroutines-d33e11bf4761
Venkat is God of programming
I think I get coroutines now, but I'm not really sure why in the last part of the video, everything still needs to be in a launch {} block. Doesn't the suspend / async / await mechanism already make it asynchronous?
@vyli1
5 жыл бұрын
async {} can only be called from within a coroutine or a suspending function. In fact in the last example, the async call was not made from launch {} function, rather it was made from the lambda, that was passed as argument to the measure function. Since async {} can only be called from coroutine or a suspending function, he had to mark the lambda parameter from measure function as suspending. launch {} function is a coroutine builder. It hides lot of nontrivial code that you would have to write manually, if you wanted to write a coroutine.
@HermanBovens
5 жыл бұрын
@@vyli1 so the call to launch() is indeed unnecessary?
@vyli1
5 жыл бұрын
@@HermanBovens I'm sorry, I gave you a little bit misleading information. But first to answer your question, call to launch {} IS necessary. Originally I said, that async {} can only be called from coroutine or suspend function. This is not true, it can be called from wherever. However, .await() can only be called from coroutine or suspending function. Since in the code in the presentation we call .await() on result of async {} operation within lambda parameter, that lambda parameter MUST BE suspending lambda. (.await() can only be called from within a coroutine or suspending function). Since we've turned the lambda into a suspending function and we want to invoke the lambda from within measure function, we want to basically invoke a suspending function inside a nonsuspending function. That's not possible. Suspending functions can only be invoked from other suspending functions, or coroutines. Therefore, the measure function itself must be suspending. As I said before, suspend functions can only be called from within coroutines or another suspending functions. And we want to call the measure function. But measure function is suspending. Therefore we need to create a coroutine, from which we can call the measure function. That's why we do the call to launch {}. launch {} is a coroutine builder. It will build all the coroutine boilerplate code for us. So when we invoke our suspending function measure from within launch, our code will be executed within a coroutine, so the compiler will finally let us compile this code. There are other coroutine builders than launch, for example runBlocking {}, but in this case we didn't want to block the main thread, so that's why launch {} coroutine builder was chosen. When I said .await() can only be called from coroutine or another suspending function, what I mean is, compiler won't let you compile a code, where you'd want to invoke suspending function outside of a coroutine or a suspending function.
the " A sequential code" part is hard to understand :(
Which IDE is he using to show the demo?
isnt this all wrong?slapping suspend on a blocking call doesnt not make it async, its just synchronous within dispatcher thread from launch
One of the best talk on coroutines (Y)
VERY GOOD EXPLANATION...
How is he auto-filling sentences ?
Wow that was really good!! 😱😱 👏👏 just really wanna show my appreciation here 👏👏
There are issues with this presentation, glossing over or missing key concepts. I would skip it if you are learning about coroutines. This was exploring, kinda, but really only the last 10 minutes are useful. The presenters book is decent, but this was not a good exploring talk. It appears I will be in the minority here. There are so few good coroutine talks, check out the Coroutines catch them all, best talk and maybe the only one.
You have the last name of Venkat spelled wrong in the title
@JetBrainsTV
4 жыл бұрын
Thank you. Fixed.
👍
Which editor does he use?
@akashpatra19
5 жыл бұрын
TextMate.
This guy literally looks like my maths professor.
Meu Deus, pare 1 segundo pra respirar!!!
What do Coroutines offer that RxJava does not?
@RobertGolusinski
5 жыл бұрын
proandroiddev.com/kotlin-coroutines-vs-rxjava-an-initial-performance-test-68160cfc6723
@robchr
5 жыл бұрын
It doesn't offer anything that RxJava cannot do. Coroutines can easily represent RxJava's Single and Maybe contexts but does not handle Observable streams without additional boilerplate. For some use cases where there would be a large number of concurrent requests like a server that has 100k+ concurrent connections, coroutines could be more memory efficient since it requrires less intermediate objects (lambdas). Coroutines represent a single chain in a single object that acts like a state machine.
@igorg.8624
5 жыл бұрын
... although I must say - sequence continuations in Coroutines are super simple to reason about and much easier to teach to a newbie than RxJava
@GK-rl5du
5 жыл бұрын
It doesn't offer anything new as compared with RxJava or even any callback+eventloop models. The main promise of coroutines is that one can write syncrhonous looking code which the runtime executes concurrently. On the other hand, consider Rx... one has to be familiar with the core Rx interfaces like Observable... although this approach was much better than callback hell.. esp considering exception handling.. there's still a learning curve. Coroutines on the other hand will bring concurrency to where you are.
@vlastos
4 жыл бұрын
I love rx, but flatmapping singles is stupid and you need to always return tuples everywhere like an idiot
is this man from pragimtech.com ?
@JetBrainsTV
5 жыл бұрын
No, we don't believe so. Dr. Venkat Subramaniam is the founder of Agile Developer, Inc. agiledeveloper.com
what a killer mustache
Bm -16:58
He need pauses.
What is that, well, IDE?
@meribold
5 жыл бұрын
That's a text editor. Probably TextMate.
@jakubgwozdz2780
5 жыл бұрын
I like the way it displays output at cursor.
@akashpatra19
5 жыл бұрын
@@jakubgwozdz2780 Yes, you have to configure. Long back after I saw his talk on Java Streams, I also configured like that. :)
He changed camps, first Scala, now this lol
TBH, Very hard to follow. Keep the sentences simple and the example simpler.
He is coding and explaining at the same time. He is so async.
27:00 Only moment, I can laugh.
@jayasome199
2 жыл бұрын
28:30 suspend bytecode -> Continuation
this guy is too fast
@RameshK-dy6yb
4 жыл бұрын
for simple basics kzread.info/dash/bejne/qmaFsdydmJOsodY.html
Sir, with due respect u have very nice knowledge but ur are speaking very fast, and hard to catch you and i lost my interest.
Not his best talk. Surprised and disappointed that he didn't compare coroutines to using threads directly and Futures. He didn't really say what co-routines add that we can't do since Java 5
If you have such a thick accent, consider SLOWING DOWN A LOT.
his talking style is very...... weird