Reactor training

Spring Reactor hands-on training (3 days)

Day 1: Introduction

• What is reactive programming
• Crash course to CompletableFuture and thread pools
• Introducing Reactor
• How to create a stream?
  • just(), generate(), create(), fromCallable(), fromStream()
• Laziness
  • Hot vs. cold
• Basic operators
  • map(), filter(), filterWhen() flatMap(), handle(), take(), skip()
  • doOn*() operators
  • window(), buffer(), distinct()
  • cast(), ofType(), index()
  • timestamp(), elapsed()
  • zip(), merge()
• Error handling
  • timeout(), retry*(), retryBackoff()
  • onError*()
• Blocking and reactive, back and forth
• Concurrency with blocking code and thread pools
  • subscribeOn(), parallel()
• Unit testing

Day 2: Reactor advanced

• Concurrency with non-blocking code
• Advanced error handling and retries
• transform() vs. compose()
• Advanced operators
  • groupBy(), window()
  • reduce(), scan()
  • expand*()
• Backpressure
  • onBackpressure*()
• Processor API
  • Unicast, Emitter, Replay
• Advanced testing with virtual time
• Context
• Speculative execution example
• RxJava interoperability

Day 3: Practical

• Comparison to blocking and asynchronous servlets
• Refactoring existing application to Reactor
• Spring Boot
  • Reactive database access
  • Reactive controllers
  • WebFilter
  • Global error handling
  • Payload validation
  • Web sockets
• Streaming data in and out
• Troubleshooting and debugging
  • checkpoint(), onOperatorDebug(), doOn*()

Reference materials

1. Reactor 3 Reference Guide
2. Web on Reactive Stack in Spring Framework Documentation
3. The "Spring WebFlux Framework" in Spring Boot Reference Guide