Added reply methods to Actor trait + fixed race-condition in Actor.spawn

akka-core/src/main/scala/actor/Actor.scala

@@ -228,12 +228,11 @@ object Actor extends Logging {
   def spawn(body: => Unit): Unit = {
     case object Spawn
     actorOf(new Actor() {
-      self.start
-      self ! Spawn
       def receive = {
         case Spawn => body; self.stop
       }
-    })
+    }).start ! Spawn
+    
   }
 }
 
@@ -413,6 +412,22 @@ trait Actor extends Logging {
    */
   def initTransactionalState {}
 
+  /**
+   * Use <code>reply(..)</code> to reply with a message to the original sender of the message currently
+   * being processed.
+   * <p/>
+   * Throws an IllegalStateException if unable to determine what to reply to.
+   */
+  def reply(message: Any) = self.reply(message)
+
+  /**
+   * Use <code>reply_?(..)</code> to reply with a message to the original sender of the message currently
+   * being processed.
+   * <p/>
+   * Returns true if reply was sent, and false if unable to determine what to reply to.
+   */
+  def reply_?(message: Any): Boolean = self.reply_?(message)
+
   // =========================================
   // ==== INTERNAL IMPLEMENTATION DETAILS ====
   // =========================================

akka-core/src/main/scala/dispatch/MessageHandling.scala

@@ -7,7 +7,7 @@ package se.scalablesolutions.akka.dispatch
 import java.util.List
 
 import se.scalablesolutions.akka.util.{HashCode, Logging}
-import se.scalablesolutions.akka.actor.{Actor, ActorRef}
+import se.scalablesolutions.akka.actor.{Actor, ActorRef, ActorInitializationException}
 
 import java.util.concurrent.ConcurrentHashMap
 
@@ -23,7 +23,12 @@ final class MessageInvocation(val receiver: ActorRef,
                               val transactionSet: Option[CountDownCommitBarrier]) {
   if (receiver eq null) throw new IllegalArgumentException("receiver is null")
 
-  def invoke = receiver.invoke(this)
+  def invoke = try { 
+    receiver.invoke(this)
+  } catch {
+    case e: NullPointerException => throw new ActorInitializationException(
+      "Don't call 'self ! message' in the Actor's constructor (e.g. body of the class).")
+  }
 
   def send = receiver.dispatcher.dispatch(this)