add a jersey MessageBodyWriter that serializes scala lists to JSON arrays

akka-rest/src/main/resources/META-INF/services/javax.ws.rs.ext.MessageBodyWriter

@@ -0,0 +1 @@
+se.scalablesolutions.akka.rest.ListWriter

akka-rest/src/main/scala/ListWriter.scala

@@ -0,0 +1,38 @@
+/**
+ * Copyright (C) 2009 Scalable Solutions.
+ */
+package se.scalablesolutions.akka.rest
+
+import java.io.OutputStream
+import se.scalablesolutions.akka.serialization.Serializer
+import javax.ws.rs.core.{MultivaluedMap, MediaType}
+import javax.ws.rs.ext.{MessageBodyWriter, Provider}
+import javax.ws.rs.Produces
+
+/**
+ * writes Lists of JSON serializable objects
+ */
+@Provider
+@Produces(Array("application/json"))
+class ListWriter extends MessageBodyWriter[List[_]] {
+
+  def isWriteable(aClass: Class[_], aType: java.lang.reflect.Type, annotations: Array[java.lang.annotation.Annotation], mediaType: MediaType) = {
+    classOf[List[_]].isAssignableFrom(aClass) || aClass == ::.getClass
+  }
+
+  def getSize(list: List[_], aClass: Class[_], aType: java.lang.reflect.Type, annotations: Array[java.lang.annotation.Annotation], mediaType: MediaType) = -1L
+
+  def writeTo(list: List[_],
+              aClass: Class[_],
+              aType: java.lang.reflect.Type,
+              annotations: Array[java.lang.annotation.Annotation],
+              mediaType: MediaType,
+              stringObjectMultivaluedMap: MultivaluedMap[String, Object],
+              outputStream: OutputStream) : Unit = {
+      if (list.isEmpty)
+        outputStream.write(" ".getBytes)
+      else
+        outputStream.write(Serializer.ScalaJSON.out(list))
+  }
+
+}