Created
May 21, 2015 10:44
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Implicit Scala Option to Java Optional conversion
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/** | |
* Convers any type A to a Java compatible type B if such a conversion exists. | |
* Default they exist for all primitive types. | |
* | |
* Usage: Option(1).asJava[java.lang.Integer] | |
* | |
* The type [B] must be provided because the compiler is aparently not able to determine the wanted java.util.Optional<B> type | |
* since that type is removed due to type erasure. | |
* If you want to keep the type A just do not provide a type B when using ```asJava```. For example for custom Pojos. | |
*/ | |
object ScalaToJava { | |
implicit class OptionToOptional[A](val o: Option[A]) extends AnyVal { | |
import java.util.Optional | |
def asJava[B](implicit conv: A => B): Optional[B] = o map (value => Optional.of(conv(value))) getOrElse Optional.empty() | |
} | |
} | |
/** | |
* This test uses some of our Java types to test the implicit conversion. | |
*/ | |
object ScalaToJavaTest extends App { | |
val b: scala.Boolean = true | |
val f: scala.Float = 1f | |
new LightXY(Optional.of(java.lang.Boolean.valueOf(b)), Optional.of(java.lang.Float.valueOf(f))) | |
val c = Color.fromXY(1,1) | |
import Tmp._ | |
val l1 = new LightXY(None.asJava[java.lang.Boolean], Some(f).asJava[java.lang.Float]) | |
println(l1) | |
val l2 = new LightXY(Some(b).asJava[java.lang.Boolean], Some(f).asJava[java.lang.Float], Some(c).asJava) | |
println(l2) | |
} |
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