Move all doc examples out of the akka-package to avoid use of private APIs. See #2092

akka-docs/scala/code/docs/extension/ExtensionDocSpec.scala

@@ -0,0 +1,91 @@
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+package docs.extension
+
+import java.util.concurrent.atomic.AtomicLong
+import akka.actor.Actor
+import akka.testkit.AkkaSpec
+
+//#extension
+import akka.actor.Extension
+
+class CountExtensionImpl extends Extension {
+  //Since this Extension is a shared instance
+  // per ActorSystem we need to be threadsafe
+  private val counter = new AtomicLong(0)
+
+  //This is the operation this Extension provides
+  def increment() = counter.incrementAndGet()
+}
+//#extension
+
+//#extensionid
+import akka.actor.ExtensionId
+import akka.actor.ExtensionIdProvider
+import akka.actor.ExtendedActorSystem
+
+object CountExtension
+  extends ExtensionId[CountExtensionImpl]
+  with ExtensionIdProvider {
+  //The lookup method is required by ExtensionIdProvider,
+  // so we return ourselves here, this allows us
+  // to configure our extension to be loaded when
+  // the ActorSystem starts up
+  override def lookup = CountExtension
+
+  //This method will be called by Akka
+  // to instantiate our Extension
+  override def createExtension(system: ExtendedActorSystem) = new CountExtensionImpl
+}
+//#extensionid
+
+object ExtensionDocSpec {
+
+  val config = """
+    //#config
+    akka {
+      extensions = ["docs.extension.CountExtension$"]
+    }
+    //#config
+    """
+
+  //#extension-usage-actor
+
+  class MyActor extends Actor {
+    def receive = {
+      case someMessage ⇒
+        CountExtension(context.system).increment()
+    }
+  }
+  //#extension-usage-actor
+
+  //#extension-usage-actor-trait
+
+  trait Counting { self: Actor ⇒
+    def increment() = CountExtension(context.system).increment()
+  }
+  class MyCounterActor extends Actor with Counting {
+    def receive = {
+      case someMessage ⇒ increment()
+    }
+  }
+  //#extension-usage-actor-trait
+}
+
+class ExtensionDocSpec extends AkkaSpec(ExtensionDocSpec.config) {
+  import ExtensionDocSpec._
+
+  "demonstrate how to create an extension in Scala" in {
+    //#extension-usage
+    CountExtension(system).increment
+    //#extension-usage
+  }
+
+  "demonstrate how to lookup a configured extension in Scala" in {
+    //#extension-lookup
+    system.extension(CountExtension)
+    //#extension-lookup
+  }
+
+}