Scala Collection in JSF

This code is based on ScalaElResolver by Werner Punz. I have stripped it down, so it just handles the conversion from a Scala Iterable to a java.lang.Iterable:

class SimpleScalaElResolver extends ELResolver { override def getValue(elContext: ELContext, base: AnyRef, prop: AnyRef): AnyRef = { println(s"SimpleElResolver: getValue: Entering: $base.$prop") if (base == null) { null } else { val method = base.getClass.getDeclaredMethod(prop.toString) if (method != null) { val res = method.invoke(base) if (res.isInstanceOf[Iterable[_]]) { val iter = res.asInstanceOf[Iterable[_]] println("getValue: Wrapping as Java iterable") elContext.setPropertyResolved(true) JavaConversions.asJavaIterable(iter) } else { null } } else { null } } } 

This is sufficient to get it running using sbt and its web plugin (which uses jetty under the hood), even if all other methods remained "not yet implemented", like this:

override def getCommonPropertyType(elContext: ELContext, o: AnyRef): Class[_] = { ??? } 

The other methods were not called in my case.

I've tested it only from within a .jspx; as far as I know this should work with JSF as well.

Example: If you have a class

class Model(val list: List[Int]) 

and in your controller

val model = new Model(List(1)) httpRequest.setAttribute("model", model) 

you can access the instance in EL

 <ul> <c:forEach var="i" items="${ model.list }"> <li> <c:out value="${ i }"/> </li> </c:forEach> </ul> 

so the property name in EL exactly matches the name of the val in your model class. Otherwise you get a java.lang.NoSuchMethodException.