Are you struggling to create a non-blocking REST application or a reactive micro-services? Spring WebFlux, a new module introduced by Spring 5 may help. This new module introduces: - Fully non-blocking - Supports Reactive Streams back pressure - Runs on such servers as Netty, Undertow, and Servlet 3.1+ containers - Its support for the reactive programming model In our next Scrum Breakfast, we will discuss Spring WebFlux, its benefit and how we implement it. Our workshop will be including the following: - What is reactive programming - Introduction to Spring Webflux - Tea break - The details in Spring Webflux - Reactive stack demonstration - Q&A

1. Flamingo+ Team
Reactive
programming
By Spring WebFlux

2. ► What is reactive programming?
► Introduction to Spring WebFlux.
► Features of Spring WebFlux.
► Reactive stack demo.
► Q&A.
Agenda

3. What is reactive programming?
- Reactive Programming is a programming paradigm.
- Meets today’s demands.
- Lays the foundation of Reactive Systems.
- Makes systems more flexible, scalable.

4. What is reactive programming?
- Four key attributes:
1. Responsive.
2. Resilient.
3. Elastic.
4. Message Driven.
more related to
the architecture choices

5. What is reactive programming?
- Message Driven
1. Failures as Messages.
2. Back Pressure.
3. Non-Blocking.

6. What is reactive programming?
- Use cases
1. External Service Calls.
2. Highly Concurrent Message Consumers.
3. Spreadsheets.
4. ...

7. Introduction to Spring WebFlux
- New framework of Spring 5.
- A part of Reactive stack.
- Embraces Reactive Streams and Reactor.

8. Introduction to Spring WebFlux
+ A standard and specification for Stream-oriented libraries.
+ Consists of four API components:
- Reactive Streams.
1. Publisher.
2. Subscriber.
3. Subscription.
4. Processor.
public interface Publisher<T> {
public void subscribe(Subscriber<? Super T> s);
}
public interface Subscriber<T> {
public void onSubscribe(Subscription s);
public void onNext(T t);
public void onError(Throwable t);
public void onComplete();
}
public interface Subscription<T> {
public void request(long n);
public void cancel();
}
public interface Processor<T, R> extends Subscriber<T>, Publisher<R> {
}
Publisher Subscriber
On Subscribe:
Request N items
Pushes N items
End
Publisher
End
Subscriber
Request
N items
Pushes
N items
Processor
(Subscriber
+
Publisher)
Request
N items
Pushes
N items

9. Introduction to Spring WebFlux
- Uses Reactor internally.
+ A Reactive Streams implementation.
+ A fully non-blocking foundation.

10. Features of Spring WebFlux
- Comparison:
Spring MVC Spring WebFlux
Annotations
Reactive client support
Blocking API support
Runtime server
Base HTTP API
Servlet container Servlet 3.1+ & non-servlet
Servlet / Filter classes Servlet 3.1+ API & HTTP
abstractions

11. Features of Spring WebFlux
- Comparison:
Spring MVC Spring WebFlux
Asynchronous web API
Non-blocking web API
Functional endpoints
Reactive web client
Reactive streams
No built-in Built-in
No built-in Built-in
No built-in
No built-in
No built-in
Built-in
Built-in
Built-in

12. Features of Spring WebFlux
- Comparison:
Spring MVC Spring WebFlux
Concurrency model
Thread usage
Memory usage
Processing time
At large scale
Slightly less Slightly more (less in parallel)
Quickly much degraded
performance
Slightly degraded performance
More blocked & slow request
process threads
Bigger data queues
Blocking
More non-blocking & fast
request process threads
Smaller data queues
Event-based loop workers

13. Features of Spring WebFlux
- Supports two distinct programming models:
+ Annotation-based.
+ Functional, Java 8 lambda style.

14. Reactive stack demo
- Stack:
Let's vote

15. Q&A
Spring
WebFlux

16. THANK YOU!