Java-Scala interoperability - April 2016

Java-Scala interoperability
Portland Java User Group
April 19, 2016

Transcript

1. Java-Scala interoperability Sean Sullivan April 19, 2016 Portland Java User Group
2. • software engineer • 20 years Java • 5 years at Gilt • back office systems @ Gilt About me
3. • Scala @ Gilt.com • Scala on the Java VM • code examples Agenda
4. www.gilt.com
5. https://www.gilt.com/checkout
7. “The Scala 2.11.x series targets Java 6" http://www.scala-lang.org/news/2.11.0/
8. http://scala-lang.org/news/2.12-roadmap/ “The official Scala 2.12 distribution will be built for Java 8 (and thus require it)”
9. Scala case classes and JSP’s
10. case class Thing( name: String, color: String)
11. thing.jsp <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <html> <body> <c:out value=“${myThing.name}”/> </body> </html>
12. JSP expression language expects a JavaBean with “getter” methods
13. import scala.reflect.BeanProperty case class Thing( @BeanProperty name: String, @BeanProperty color: String) @BeanProperty annotation
14. Collections
16. • convert java.util.List to Scala collection • convert java.util.Set to Scala collection • convert java.util.Map to Scala collection • convert Scala List to java.util.List Common scenarios
17. import scala.collection.JavaConverters._
18. import java.util.{ArrayList => JArrayList}
 import scala.collection.JavaConverters._
 
 val jArrayList = new JArrayList[String]
 jArrayList.add("a")
 jArrayList.add("b")
 jArrayList.add("c")
 
 val scalaList = jArrayList.asScala
 
 scalaList should be (List("a", "b", "c"))

19. Google Guava library
20. • com.google.common.base.Optional • com.google.common.util.concurrent.ListenableFuture
21. Guava @ Gilt
22. Guava Optional -> Scala Option Scala Option -> Guava Optional
23. import com.gilt.gfc.guava.GuavaConverters._
24. Guava Future -> Scala Future Scala Future -> Guava Future
25. import com.gilt.gfc.guava.future.FutureConverters._
26. Java 8
27. https://github.com/scala/scala-java8-compat
28. import scala.compat.java8.FutureConverters._ Java 8 Future to Scala Future
29. import scala.compat.java8.OptionConverters._ java.util.Optional to scala.Option
30. https://github.com/sullis/java-scala-interop-examples
31. The end