(PROMISE[JAVA8] => SCALA)

A short 30min talk for Malaga Scala Meetup about why Java8 is not enough.

Transcript

2. ABOUT ME aboutMe map(java) map(scala) What...? •  Java •  Measurements collector •  Gambling industry •  other boring stories… •  Scala •  BigData projects •  Log aggregation •  other interesting stories… @sergiotudela
3. LAMBDA EXPRESSIONS – PART 1 Are you from past?
4. LAMBDA EXPRESSIONS – PART 2 SCALA JAVA
5. LAMBDA EXPRESSIONS – PART 3 Cool! basically there is no difference… wait! SCALA Lambda expressions in Java are syntactic sugar over anonymous classes that have access to the final objects of a context only. But in Scala, they are full-on closures that have the full access to the context.
6. LAMBDA EXPRESSIONS – PART 4 Well, It's not such a big deal anyway. Ok, let’s talk ‘lambda declaration’... SCALA JAVA java: illegal start of type / Are you kidding me?
7. LAMBDA EXPRESSIONS – PART 5 And now, calling to that lambda… SCALA JAVA java: cannot find symbol / Are you kidding me?
8. TRAIT – PART 1 Mixing abstraction and interface SCALA JAVA
9. TRAIT – PART 2 Inherit? Java has an answer for you: java: class Clazz inherits unrelated defaults for draw() from types SayHello and SayGoodbye SCALA OUTPUT Diamond problem? Scala considers the order in which traits are inherited
10. OBJECT Briefly: keyword as creating a singleton object of a class that is defined implicitly. SCALA JAVA
11. CASE CLASS SCALA JAVA
12. TUPLES SCALA Tuples have “equals” and “hashcode” already correctly implemented, so…
13. PATTERN MATCHING – PART 1 SCALA – TRADITIONAL
14. PATTERN MATCHING – PART 2 SCALA – TYPED
15. PATTERN MATCHING – PART 3 SCALA – FUNCTIONAL (TAILREC)
16. PATTERN MATCHING – PART 4 SCALA – COLLECTION HELP ME!
17. PATTERN MATCHING – PART 5 SCALA – CASE CLASS
18. STREAM SCALA JAVA
19. DEFAULT/NAMED PARAMETERS SCALA JAVA TRICK … Varargs, Nulls, Optional class, Builder pattern, Maps,…
20. IMPLICITS – PART 1 SCALA A method with implicit parameters can be applied to arguments just like a normal method. In this case the implicit label has no effect. However, if such a method misses arguments for its implicit parameters, such arguments will be automatically provided.
21. IMPLICITS – PART 2 SCALA Or… enriched!
22. MORE, MORE AND MORE… •  “For” comprehension •  Lazy variables (not so easy to implement in Java…) •  Most complex yet most powerful type system in any language I know of •  Type inference •  Let’s not forget pass by name arguments and the ability to construct a DSL •  Much better and more elegant futures / promises •  Macros! •  …
23. LIBRARIES TO THE RESCUE Modular extensions for Java8 •  https://github.com/aol/cyclops More control, less code. Functional component library for java8 •  http://javaslang.com/ Functional Java is an open source library facilitating functional programming in Java •  http://www.functionaljava.org/ Backport of Java 8's lambda expressions to Java 7, 6 and 5 •  https://github.com/orfjackal/retrolambda
24. (QUESTION => OPTION[ANSWER])