Java 8 Interop

interop-implicits.scala

package com.batanga.eng.interop

import java.util.function.{BiFunction, BiPredicate, Function => JFunction, Predicate => JPredicate}
import java.util.stream.{Stream => JStream}

import scala.collection.JavaConverters._

/** Interoperability with java functional interfaces and stream api.
 * Created by f on 10/30/14.
 */
object Implicits {


  //usage example: `i: Int ⇒ 42`
  implicit def toJavaFunction[A, B](f: (A) => B): JFunction[A, B] = new JFunction[A, B] {
    override def apply(a: A): B = f(a)
  }

  implicit def toJavaBiFunction[A, B, C](f: (A, B) => C): BiFunction[A, B, C] = new BiFunction[A, B, C] {
    override def apply(a: A, b: B): C = f(a,b)
  }

  //usage example: `i: Int ⇒ true`
  implicit def toJavaPredicate[A](f: (A) => Boolean): JPredicate[A]  = new JPredicate[A] {
    override def test(a: A): Boolean = f(a)
  }

  //usage example: `(i: Int, s: String) ⇒ true`
  implicit def toJavaBiPredicate[A, B](predicate: (A, B) => Boolean): BiPredicate[A, B] =
    new BiPredicate[A, B] {
      def test(a: A, b: B) = predicate(a, b)
    }


  implicit def iteratorFromJavaStream[T](s: JStream[T]): Iterator[T] =
    s.iterator().asScala

}