Modularize configuration. See #1361

* Split config reference to one for each module/extension.
* Adjusted signature of registerExtension to avoid race of extension init
* Moved Duration.dilated to testkit
* TestKitExtension
* RemoteExtension
* SerializationExtension
* Durable mailboxes extensions
* Fixed broken serialization bindings and added test
* Updated configuration documentation
* System properties akka.remote.hostname akka.remote.port replaced with akka.remote.server.hostname and akka.remote.server.port
* Adjustments of ActorSystem initialization. Still don't like the two-phase constructor/init flow. Very fragile for changes.

Review fixes. SerializationExtension

akka-remote/src/main/scala/akka/remote/RemoteExtension.scala

@@ -0,0 +1,110 @@
+/**
+ * Copyright (C) 2009-2011 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.remote
+
+import akka.actor.ActorSystem
+import akka.actor.ExtensionKey
+import akka.actor.Extension
+import akka.actor.ActorSystemImpl
+import com.typesafe.config.Config
+import com.typesafe.config.ConfigFactory
+import com.typesafe.config.ConfigParseOptions
+import com.typesafe.config.ConfigRoot
+import akka.util.Duration
+import java.util.concurrent.TimeUnit.MILLISECONDS
+import java.net.InetAddress
+import akka.config.ConfigurationException
+import com.eaio.uuid.UUID
+
+object RemoteExtensionKey extends ExtensionKey[RemoteExtension]
+
+object RemoteExtension {
+  def apply(system: ActorSystem): RemoteExtension = {
+    if (!system.hasExtension(RemoteExtensionKey)) {
+      system.registerExtension(new RemoteExtension)
+    }
+    system.extension(RemoteExtensionKey)
+  }
+
+  class Settings(cfg: Config) {
+    private def referenceConfig: Config =
+      ConfigFactory.parseResource(classOf[ActorSystem], "/akka-remote-reference.conf",
+        ConfigParseOptions.defaults.setAllowMissing(false))
+    val config: ConfigRoot = ConfigFactory.emptyRoot("akka-remote").withFallback(cfg).withFallback(referenceConfig).resolve()
+
+    import config._
+
+    val RemoteTransport = getString("akka.remote.layer")
+    val FailureDetectorThreshold = getInt("akka.remote.failure-detector.threshold")
+    val FailureDetectorMaxSampleSize = getInt("akka.remote.failure-detector.max-sample-size")
+    val ShouldCompressData = config.getBoolean("akka.remote.use-compression")
+    val RemoteSystemDaemonAckTimeout = Duration(config.getMilliseconds("akka.remote.remote-daemon-ack-timeout"), MILLISECONDS)
+
+    // TODO cluster config will go into akka-cluster-reference.conf when we enable that module
+    val ClusterName = getString("akka.cluster.name")
+
+    val NodeName: String = config.getString("akka.cluster.nodename") match {
+      case ""    ⇒ new UUID().toString
+      case value ⇒ value
+    }
+
+    val serverSettings = new RemoteServerSettings
+    val clientSettings = new RemoteClientSettings
+
+    class RemoteClientSettings {
+      val SecureCookie: Option[String] = config.getString("akka.remote.secure-cookie") match {
+        case ""     ⇒ None
+        case cookie ⇒ Some(cookie)
+      }
+
+      val ReconnectionTimeWindow = Duration(config.getMilliseconds("akka.remote.client.reconnection-time-window"), MILLISECONDS)
+      val ReadTimeout = Duration(config.getMilliseconds("akka.remote.client.read-timeout"), MILLISECONDS)
+      val ReconnectDelay = Duration(config.getMilliseconds("akka.remote.client.reconnect-delay"), MILLISECONDS)
+      val MessageFrameSize = config.getInt("akka.remote.client.message-frame-size")
+    }
+
+    class RemoteServerSettings {
+      import scala.collection.JavaConverters._
+      val MessageFrameSize = config.getInt("akka.remote.server.message-frame-size")
+      val SecureCookie: Option[String] = config.getString("akka.remote.secure-cookie") match {
+        case ""     ⇒ None
+        case cookie ⇒ Some(cookie)
+      }
+      val RequireCookie = {
+        val requireCookie = config.getBoolean("akka.remote.server.require-cookie")
+        if (requireCookie && SecureCookie.isEmpty) throw new ConfigurationException(
+          "Configuration option 'akka.remote.server.require-cookie' is turned on but no secure cookie is defined in 'akka.remote.secure-cookie'.")
+        requireCookie
+      }
+
+      val UsePassiveConnections = config.getBoolean("akka.remote.use-passive-connections")
+
+      val UntrustedMode = config.getBoolean("akka.remote.server.untrusted-mode")
+      val Hostname = config.getString("akka.remote.server.hostname") match {
+        case ""    ⇒ InetAddress.getLocalHost.getHostAddress
+        case value ⇒ value
+      }
+      val Port = config.getInt("akka.remote.server.port")
+      val ConnectionTimeout = Duration(config.getMilliseconds("akka.remote.server.connection-timeout"), MILLISECONDS)
+
+      val Backlog = config.getInt("akka.remote.server.backlog")
+    }
+
+  }
+}
+
+class RemoteExtension extends Extension[RemoteExtension] {
+  import RemoteExtension._
+  @volatile
+  private var _settings: Settings = _
+
+  def key = RemoteExtensionKey
+
+  def init(system: ActorSystemImpl) {
+    _settings = new Settings(system.applicationConfig)
+  }
+
+  def settings: Settings = _settings
+
+}