+cdd #16799 Add Distributed Data module

Previously know as [patriknw/akka-data-replication](https://github.com/patriknw/akka-data-replication),
which was originally inspired by [jboner/akka-crdt](https://github.com/jboner/akka-crdt).

The functionality is very similar to akka-data-replication 0.11.

Here is a list of the most important changes:

* The package name changed to `akka.cluster.ddata`
* The extension was renamed to `DistributedData`
* The keys changed from strings to classes with unique identifiers and type information of the data values,
  e.g. `ORSetKey[Int]("set2")`
* The optional read consistency parameter was removed from the `Update` message. If you need to read from
  other replicas before performing the update you have to first send a `Get` message and then continue with
  the ``Update`` when the ``GetSuccess`` is received.
* `BigInt` is used in `GCounter` and `PNCounter` instead of `Long`
* Improvements of java api
* Better documentation

akka-distributed-data/src/test/scala/akka/cluster/ddata/protobuf/ReplicatedDataSerializerSpec.scala

@@ -0,0 +1,173 @@
+/**
+ * Copyright (C) 2009-2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.cluster.ddata.protobuf
+
+import scala.concurrent.duration._
+import org.scalatest.BeforeAndAfterAll
+import org.scalatest.Matchers
+import org.scalatest.WordSpecLike
+import akka.actor.ActorSystem
+import akka.actor.Address
+import akka.actor.ExtendedActorSystem
+import akka.cluster.ddata.Flag
+import akka.cluster.ddata.GCounter
+import akka.cluster.ddata.GSet
+import akka.cluster.ddata.LWWMap
+import akka.cluster.ddata.LWWRegister
+import akka.cluster.ddata.ORMap
+import akka.cluster.ddata.ORSet
+import akka.cluster.ddata.PNCounter
+import akka.cluster.ddata.PNCounterMap
+import akka.cluster.ddata.Replicator._
+import akka.cluster.ddata.Replicator.Internal._
+import akka.cluster.ddata.VersionVector
+import akka.testkit.TestKit
+import akka.cluster.UniqueAddress
+import com.typesafe.config.ConfigFactory
+
+class ReplicatedDataSerializerSpec extends TestKit(ActorSystem("ReplicatedDataSerializerSpec",
+  ConfigFactory.parseString("""
+    akka.actor.provider=akka.cluster.ClusterActorRefProvider
+    akka.remote.netty.tcp.port=0
+    """))) with WordSpecLike with Matchers with BeforeAndAfterAll {
+
+  val serializer = new ReplicatedDataSerializer(system.asInstanceOf[ExtendedActorSystem])
+
+  val address1 = UniqueAddress(Address("akka.tcp", system.name, "some.host.org", 4711), 1)
+  val address2 = UniqueAddress(Address("akka.tcp", system.name, "other.host.org", 4711), 2)
+  val address3 = UniqueAddress(Address("akka.tcp", system.name, "some.host.org", 4712), 3)
+
+  override def afterAll {
+    shutdown()
+  }
+
+  def checkSerialization(obj: AnyRef): Unit = {
+    val blob = serializer.toBinary(obj)
+    val ref = serializer.fromBinary(blob, serializer.manifest(obj))
+    ref should be(obj)
+  }
+
+  def checkSameContent(a: AnyRef, b: AnyRef): Unit = {
+    a should be(b)
+    val blobA = serializer.toBinary(a)
+    val blobB = serializer.toBinary(b)
+    blobA.toSeq should be(blobB.toSeq)
+  }
+
+  "ReplicatedDataSerializer" must {
+
+    "serialize GSet" in {
+      checkSerialization(GSet())
+      checkSerialization(GSet() + "a")
+      checkSerialization(GSet() + "a" + "b")
+
+      checkSerialization(GSet() + 1 + 2 + 3)
+      checkSerialization(GSet() + address1 + address2)
+
+      checkSerialization(GSet() + 1L + "2" + 3 + address1)
+
+      checkSameContent(GSet() + "a" + "b", GSet() + "a" + "b")
+      checkSameContent(GSet() + "a" + "b", GSet() + "b" + "a")
+      checkSameContent(GSet() + address1 + address2 + address3, GSet() + address2 + address1 + address3)
+      checkSameContent(GSet() + address1 + address2 + address3, GSet() + address3 + address2 + address1)
+    }
+
+    "serialize ORSet" in {
+      checkSerialization(ORSet())
+      checkSerialization(ORSet().add(address1, "a"))
+      checkSerialization(ORSet().add(address1, "a").add(address2, "a"))
+      checkSerialization(ORSet().add(address1, "a").remove(address2, "a"))
+      checkSerialization(ORSet().add(address1, "a").add(address2, "b").remove(address1, "a"))
+      checkSerialization(ORSet().add(address1, 1).add(address2, 2))
+      checkSerialization(ORSet().add(address1, 1L).add(address2, 2L))
+      checkSerialization(ORSet().add(address1, "a").add(address2, 2).add(address3, 3L).add(address3, address3))
+
+      val s1 = ORSet().add(address1, "a").add(address2, "b")
+      val s2 = ORSet().add(address2, "b").add(address1, "a")
+      checkSameContent(s1.merge(s2), s2.merge(s1))
+
+      val s3 = ORSet().add(address1, "a").add(address2, 17).remove(address3, 17)
+      val s4 = ORSet().add(address2, 17).remove(address3, 17).add(address1, "a")
+      checkSameContent(s3.merge(s4), s4.merge(s3))
+    }
+
+    "serialize Flag" in {
+      checkSerialization(Flag())
+      checkSerialization(Flag().switchOn)
+    }
+
+    "serialize LWWRegister" in {
+      checkSerialization(LWWRegister(address1, "value1", LWWRegister.defaultClock))
+      checkSerialization(LWWRegister(address1, "value2", LWWRegister.defaultClock[String])
+        .withValue(address2, "value3", LWWRegister.defaultClock[String]))
+    }
+
+    "serialize GCounter" in {
+      checkSerialization(GCounter())
+      checkSerialization(GCounter().increment(address1, 3))
+      checkSerialization(GCounter().increment(address1, 2).increment(address2, 5))
+
+      checkSameContent(
+        GCounter().increment(address1, 2).increment(address2, 5),
+        GCounter().increment(address2, 5).increment(address1, 1).increment(address1, 1))
+      checkSameContent(
+        GCounter().increment(address1, 2).increment(address3, 5),
+        GCounter().increment(address3, 5).increment(address1, 2))
+    }
+
+    "serialize PNCounter" in {
+      checkSerialization(PNCounter())
+      checkSerialization(PNCounter().increment(address1, 3))
+      checkSerialization(PNCounter().increment(address1, 3).decrement(address1, 1))
+      checkSerialization(PNCounter().increment(address1, 2).increment(address2, 5))
+      checkSerialization(PNCounter().increment(address1, 2).increment(address2, 5).decrement(address1, 1))
+
+      checkSameContent(
+        PNCounter().increment(address1, 2).increment(address2, 5),
+        PNCounter().increment(address2, 5).increment(address1, 1).increment(address1, 1))
+      checkSameContent(
+        PNCounter().increment(address1, 2).increment(address3, 5),
+        PNCounter().increment(address3, 5).increment(address1, 2))
+      checkSameContent(
+        PNCounter().increment(address1, 2).decrement(address1, 1).increment(address3, 5),
+        PNCounter().increment(address3, 5).increment(address1, 2).decrement(address1, 1))
+    }
+
+    "serialize ORMap" in {
+      checkSerialization(ORMap())
+      checkSerialization(ORMap().put(address1, "a", GSet() + "A"))
+      checkSerialization(ORMap().put(address1, "a", GSet() + "A").put(address2, "b", GSet() + "B"))
+    }
+
+    "serialize LWWMap" in {
+      checkSerialization(LWWMap())
+      checkSerialization(LWWMap().put(address1, "a", "value1", LWWRegister.defaultClock[Any]))
+      checkSerialization(LWWMap().put(address1, "a", "value1", LWWRegister.defaultClock[Any])
+        .put(address2, "b", 17, LWWRegister.defaultClock[Any]))
+    }
+
+    "serialize PNCounterMap" in {
+      checkSerialization(PNCounterMap())
+      checkSerialization(PNCounterMap().increment(address1, "a", 3))
+      checkSerialization(PNCounterMap().increment(address1, "a", 3).decrement(address2, "a", 2).
+        increment(address2, "b", 5))
+    }
+
+    "serialize DeletedData" in {
+      checkSerialization(DeletedData)
+    }
+
+    "serialize VersionVector" in {
+      checkSerialization(VersionVector())
+      checkSerialization(VersionVector().increment(address1))
+      checkSerialization(VersionVector().increment(address1).increment(address2))
+
+      val v1 = VersionVector().increment(address1).increment(address1)
+      val v2 = VersionVector().increment(address2)
+      checkSameContent(v1.merge(v2), v2.merge(v1))
+    }
+
+  }
+}
+