This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
4.6 Interoperating with Java
If you get a Java map from calling a Java method, you may want to convert it to a Scala map so that you can use the pleasant Scala map API.
Simply add an import statement:
import scala.jdk.CollectionConverters.*
Then use the asScala method to turn the Java map into a Scala map:
val ids = java.time.ZoneId.SHORT_IDS.asScala // Yields a scala.collection.mutable.Map[String, String]
In addition, you can get a conversion from java.util.Properties to a Map[String, String]:
val props = System.getProperties.asScala // Yields a Map[String, String], not a Map[Object, Object]
Conversely, to pass a Scala map to a method that expects a Java map, provide the opposite conversion. For example:
import java.awt.font.TextAttribute.* // Import keys for map below val attrs = Map(FAMILY -> "Serif", SIZE -> 12) // A Scala map val font = java.awt.Font(attrs.asJava) // Expects a Java map