spring-fu
kotlinx.coroutines
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spring-fu | kotlinx.coroutines | |
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12 | 59 | |
1,664 | 12,701 | |
0.2% | 0.6% | |
0.0 | 8.9 | |
9 months ago | 2 days ago | |
Java | Kotlin | |
Apache License 2.0 | Apache License 2.0 |
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For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
spring-fu
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What's New in Spring Framework 6.1
The point isn't that one should reinvent the way that Tomcat is started, but that Spring Boot (by default) is using action at a distance and runtime reflection which have serious downsides if you want to understand what's actually going on because you're a) new to the technology, or b) have to debug some weird edge case.
The alternative is using explicit, reflection-less code - which you can do even with Spring, although it's experimental: https://github.com/spring-projects-experimental/spring-fu
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What are some of the biggest problems you personally face in Java?
Bean Definition -> Still needed although experimental projects like Spring Fu might remove their need in the future. Technically, there is nothing to stop you from registering beans functionally right now but the verbosity is likely to make that approach less optimal.
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Hexagonal Architecture and Domain Driven Design
Most of these things can be done with higher-order functions too.
I think that if Java had had lambdas earlier, Spring and other such frameworks might look very different. You can see that already, Spring is adding (experimental?) support for more declarative styles of configuration instead of the rather slow and hard-to-debug reflection magic: https://github.com/spring-projects-experimental/spring-fu
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I hate Spring (the Java framework)
Quarkus just moves the problem IMHO. I find it similarly convoluted to use as normal Spring. I had to deal with that a few months ago on a project. Honestly, it actually feels a lot like spring used to be; and not in a good way. Lots of annotation magic all over the place.
I use Spring Boot by default. But I aggressively limit the use of annotation magic. I've never liked the byte code hacks people do to make annotations inject magical behavior. Hard to debug and painful when it does not work as expected.
I don't think either of these frameworks have an edge over each other. You end up using a lot of the same underlying library ecosystem.
I do like the annotation less direction that Spring has been taking since they started adding Kotlin support 4-5 years ago. If you want to, you can get rid of most annotations for things like dependency injection, defining controllers, transactions etc.
Especially with Kotlin, this makes a lot of sense. With Java, dealing with builders is just a lot more painful without kotlin's DSL support. You basically end up with a lot of verbosity, method chaining, etc. But it's possible if you want to. It's a big reason, I prefer using Kotlin with Spring Boot. Makes the whole thing feel like a modern framework. The hard part with Spring Boot is being able to tell apart all the legacy and backwards compatible stuff from the actual current and proper way of doing things.
There's a project that they've been pushing to get rid of all annotations: https://github.com/spring-projects-experimental/spring-fu/tr.... I suspect a lot of that stuff might be part of spring boot 3.x later this year. And quite a bit of it is actually already part of the current version of Spring.
This makes spring boot very similar to what you'd do with ktor. All you do is call kotlin functions. No annotations. No reflection. No magic. Very little verbosity. It's all declarative. And a nice side effect is also that it makes things like spring-native easier, which they started supporting recently.
It's very similar to using ktor with koin (for dependency injection). That combination is worth a try if you are looking for something lightweight and easy to use. Spring Boot has more features and complexity but it can be as simple to use as that if you know what you are doing.
Mostly, keeping things simple is a good thing with Spring. Also, I don't tend to do everything the spring way. Spring integration is a bit of a double edged sword for example. It offers a subset of the features of the libraries that it integrates. If you want the full feature set, you end up working around that. IMHO, you should do that by default. I've removed spring integration from several projects.
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Scala at Scale at Databricks
> And that is a problem how? Stick to one style.
Switching an API from "a result or nothing" to "a result or an error message" happens all the time, and switching in the other direction is only slightly less frequent. And of course most programs have some APIs where one is appropriate and some where the other is. So consistency is valuable.
> https://github.com/spring-projects-experimental/spring-fu/tr...
Still reflection-based.
> There's nothing magical about it.
It's magical to anyone thinking in the language - it breaks the rules of the language, so you can't reason about what it does.
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A new way to construct objects in Java
SpringFu (from Spring team): https://github.com/spring-projects-experimental/spring-fu/tree/main/jafu
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Annotation-free Spring
It's mentioned in the article, even though the examples are written in Kotlin spring-fu supports a java-based dsl.
It's possible to remove it anyway, provided you accept to use APIs considered experimental. The solution is Spring Fu, with "Fu" standing for functional. It's available in two flavors, one for Java and one for Kotlin, respectively named JaFu and KoFu.
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Kotlin Team AMA #3: Ask Us Anything
There is already a very close collaboration between Kotlin and Spring teams. I think leveraging more multiplatform capabilities and more DSL à la KoFu from https://github.com/spring-projects-experimental/spring-fu could increase Koltin usage on server side long term.
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The Modern Java Platform
There's a next stage after annotations. The current thinking is to replace annotations with function calls. It makes more sense if you use Kotlin because Java is a bit verbose when you do this and in Kotlin you get to create nice DSLs. This cuts down on use of reflection and AOP magic that spring relies on and also enables native compilation. It also makes it easier to debug and it makes it much easier to understand what is going on at the price of surprisingly little verbosity. Kofu and Jafu are basically still experimental but work quite nicely https://github.com/spring-projects-experimental/spring-fu/tr...
Another trend is native compilation. Spring native just went into beta (uses the Graal compiler). That still relies on reflection but they re-engineered the internals to be more native friendly.
Spring Boot basically added the notion of autoconfiguring libraries that simply by being on the classpath self configure in a sane way. It's one of those things that makes the experience a bit more ruby on rails like. Stuff just works with minimal coding and you customise it as needed (or not, which is perfectly valid).
Compared to XML configuration, Spring has come a long way. Separating code and configuration is still a good idea with Spring but indeed not strictly enforced. @Configuration classes can take the place of XML and if you use the bean dsl, that's basically the equivalent of using XML. Only it's type checked at compile time and a bit more readable.
kotlinx.coroutines
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Gradle: from Newbie to Strong fundamentals
Now, let's consider an example. For instance, let's create a Kotlin/JVM project with kotlinx.coroutines library as a dependency.
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Add `statefulMap` and `statefulTransform` operator to Kotlin coroutines' Flow
Greetings community, I just submited a PR to Kotlin coroutines with two additional operators :
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Should I choose Kotlin over Java for a new project (backend)?
The harder parts of Kotlin are going to be things like kotlinx.coroutines, but that's just a library, not a core part of the language. It's about as hard to learn as a comparable library in another language, like the Task Parallel Library in .NET.
- kotlinx.coroutines 1.7.0 released
- Is it ok to have global scopes when the coroutine I'm starting has *nothing* to do with showing UI, nor do I care about its result?
- Release 1.7.0-Beta · Kotlin/kotlinx.coroutines
- Does the documentation of async{} and launch{} apply to each other? (Aside from the difference that async {} returned a Deferred)
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Reactive Backend Applications with Spring Boot, Kotlin and Coroutines (Part 2)
Kotlin has coroutines that are supported by the language and implemented by a library (the implementation remains platform-dependent): kotlinx.coroutines and a sandbox environment is available here to try it out.
- Kotlinx Coroutines for Kotlin 1.7.x
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Get value from coroutine function
That said, since it seems like you're doing UI stuff (Android?), you're best off doing all of the UI code in coroutines, using Dispatchers.Main as a context (as provided by one of the platform-specific coroutine libraries), since this will guarantee that your UI code will be safely run in the UI thread.
What are some alternatives?
koin - Koin - a pragmatic lightweight dependency injection framework for Kotlin & Kotlin Multiplatform
kotlin-coroutines - Examples for coroutines design in Kotlin
compose-multiplatform - Compose Multiplatform, a modern UI framework for Kotlin that makes building performant and beautiful user interfaces easy and enjoyable.
kotlin - The Kotlin Programming Language.
teavm - Compiles Java bytecode to JavaScript, WebAssembly and C
kotlinx-datetime - KotlinX multiplatform date/time library
okio - A modern I/O library for Android, Java, and Kotlin Multiplatform.
kotlinx.html - Kotlin DSL for HTML
korim - Korim: Kotlin cORoutines IMaging, Bitmap and Vector graphics for Multiplatform Kotlin
javalin - A simple and modern Java and Kotlin web framework [Moved to: https://github.com/javalin/javalin]
korio - Korio: Kotlin cORoutines I/O : Virtual File System + Async/Sync Streams + Async TCP Client/Server + WebSockets for Multiplatform Kotlin 1.3