+act #3873 Adding Props.create method with manifested type

The generated classes for Java 8 lambdas doesn't carry the type information that we need, so we need to pass in the return type of the Creator.

akka-actor-tests/src/test/java/akka/actor/ActorCreationTest.java

@@ -55,6 +55,25 @@ public class ActorCreationTest {
     }
   }
 
+
+  static class G implements Creator {
+    public Object create() {
+      return null;
+    }
+  }
+
+  @Test
+  @SuppressWarnings("unchecked")
+  public void testErasedCreator() {
+    try {
+      Props.create(new G());
+      assert false;
+    } catch(IllegalArgumentException e) {
+      assertEquals("erased Creator types are unsupported, use Props.create(actorClass, creator) instead", e.getMessage());
+    }
+    Props.create(UntypedActor.class, new G());
+  }
+
   @Test
   public void testRightCreator() {
     final Props p = Props.create(new C());

akka-actor-tests/src/test/java/akka/actor/JavaAPI.java

@@ -57,12 +57,27 @@ public class JavaAPI {
     });
   }
 
+  @SuppressWarnings("unchecked")
+  public static Props mkErasedProps() {
+    return Props.create(JavaAPITestActor.class, new Creator() {
+      public Object create() {
+        return new JavaAPITestActor();
+      }
+    });
+  }
+
   @Test
   public void mustBeAbleToCreateActorRefFromFactory() {
     ActorRef ref = system.actorOf(mkProps());
     assertNotNull(ref);
   }
 
+  @Test
+  public void mustBeAbleToCreateActorRefFromErasedFactory() {
+    ActorRef ref = system.actorOf(mkErasedProps());
+    assertNotNull(ref);
+  }
+
   @Test
   public void mustBeAbleToCreateActorWIthConstructorParams() {
     ActorRef ref = system.actorOf(Props.create(ActorWithConstructorParams.class, "a", "b", new Integer(17), 18));

akka-actor/src/main/scala/akka/actor/Props.scala

@@ -100,12 +100,19 @@ object Props {
 
   /**
    * Create new Props from the given [[akka.japi.Creator]].
+   *
+   * You can not use a Java 8 lambda with this method since the generated classes
+   * don't carry enough type information.
+   *
+   * Use the Props.create(actorClass, creator) instead.
    */
   def create[T <: Actor](creator: Creator[T]): Props = {
-    if ((creator.getClass.getEnclosingClass ne null) && (creator.getClass.getModifiers & Modifier.STATIC) == 0)
+    val cc = creator.getClass
+    if ((cc.getEnclosingClass ne null) && (cc.getModifiers & Modifier.STATIC) == 0)
       throw new IllegalArgumentException("cannot use non-static local Creator to create actors; make it static (e.g. local to a static method) or top-level")
     val ac = classOf[Actor]
-    val actorClass = Reflect.findMarker(creator.getClass, classOf[Creator[_]]) match {
+    val coc = classOf[Creator[_]]
+    val actorClass = Reflect.findMarker(cc, coc) match {
       case t: ParameterizedType ⇒
         t.getActualTypeArguments.head match {
           case c: Class[_] ⇒ c // since T <: Actor
@@ -113,9 +120,18 @@ object Props {
             v.getBounds collectFirst { case c: Class[_] if ac.isAssignableFrom(c) && c != ac ⇒ c } getOrElse ac
           case x ⇒ throw new IllegalArgumentException(s"unsupported type found in Creator argument [$x]")
         }
+      case c: Class[_] if (c == coc) ⇒
+        throw new IllegalArgumentException(s"erased Creator types are unsupported, use Props.create(actorClass, creator) instead")
     }
     apply(defaultDeploy, classOf[CreatorConsumer], actorClass :: creator :: Nil)
   }
+
+  /**
+   * Create new Props from the given [[akka.japi.Creator]] with the type set to the given actorClass.
+   */
+  def create[T <: Actor](actorClass: Class[T], creator: Creator[T]): Props = {
+    apply(defaultDeploy, classOf[CreatorConsumer], actorClass :: creator :: Nil)
+  }
 }
 
 /**