Future in WebApp (Java)

Short description about Future and CompletableFuture

1. Future in WebApp Kengo TODA
2. Agenda • What is Future • What is CompletableFuture • Common usage in WebApp
3. What is Future? • Proxy interface to get result of async operation • Similar with JavaScript’s Promise
4. Ask, and it will be given to you
5. How to implement method which returns Future instance? • Asynchronous Method Invocation (Java EE 6) • Creating Asynchronous Methods (Spring Framework)
6. What is CompletableFuture • New class from Java8, implements Future interface • Similar with ListenableFuture in Guava and Spring Framework
7. Apply result to Function,
8. or combine them.
9. Merit: connect result of Async I/O seamlessly auth add new post load timeline START END
11. When we use them? • When call async I/O • Datastore • Message Queue • Cache • RESTful API
12. Example: When we use them? • If you are service provider, • Public service API (interface for user) should return CompletableFuture instance if it may use I/O internally. • Then during I/O is running, your user can use current thread for other usage.
13. Keywords to google • Promise, Future • CompletableFuture • ListenableFuture (Guava & Spring Framework) • Function composition