diff --git a/akka-actor/src/main/scala/akka/actor/Deployer.scala b/akka-actor/src/main/scala/akka/actor/Deployer.scala
index 3f5e2b1785..dd3e88dcda 100644
--- a/akka-actor/src/main/scala/akka/actor/Deployer.scala
+++ b/akka-actor/src/main/scala/akka/actor/Deployer.scala
@@ -105,8 +105,6 @@ case object NoScopeGiven extends NoScopeGiven {
/**
* Deployer maps actor paths to actor deployments.
- *
- * @author Jonas Bonér
*/
private[akka] class Deployer(val settings: ActorSystem.Settings, val dynamicAccess: DynamicAccess) {
diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
index 0695180ac2..8d87f3fe53 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
@@ -32,7 +32,41 @@ object ClusterEvent {
unreachable: Set[Member] = Set.empty,
convergence: Boolean = false,
seenBy: Set[Address] = Set.empty,
- leader: Option[Address] = None) extends ClusterDomainEvent
+ leader: Option[Address] = None) extends ClusterDomainEvent {
+
+ /**
+ * Java API
+ * Read only
+ */
+ def getMembers: java.lang.Iterable[Member] = {
+ import scala.collection.JavaConverters._
+ members.asJava
+ }
+
+ /**
+ * Java API
+ * Read only
+ */
+ def getUnreachable: java.util.Set[Member] = {
+ import scala.collection.JavaConverters._
+ unreachable.asJava
+ }
+
+ /**
+ * Java API
+ * Read only
+ */
+ def getSeenBy: java.util.Set[Address] = {
+ import scala.collection.JavaConverters._
+ seenBy.asJava
+ }
+
+ /**
+ * Java API
+ * @return address of current leader, or null if none
+ */
+ def getLeader: Address = leader orNull
+ }
/**
* Marker interface for member related events.
@@ -88,11 +122,6 @@ object ClusterEvent {
if (member.status != Removed) throw new IllegalArgumentException("Expected Removed status, got: " + member)
}
- /**
- * Current snapshot of cluster member metrics. Published to subscribers.
- */
- case class ClusterMetricsChanged(nodes: Set[NodeMetrics]) extends ClusterDomainEvent
-
/**
* Cluster convergence state changed.
*/
@@ -101,7 +130,20 @@ object ClusterEvent {
/**
* Leader of the cluster members changed. Only published after convergence.
*/
- case class LeaderChanged(leader: Option[Address]) extends ClusterDomainEvent
+ case class LeaderChanged(leader: Option[Address]) extends ClusterDomainEvent {
+ /**
+ * Java API
+ * @return address of current leader, or null if none
+ */
+ def getLeader: Address = leader orNull
+ }
+
+ /**
+ * INTERNAL API
+ *
+ * Current snapshot of cluster member metrics. Published to subscribers.
+ */
+ case class ClusterMetricsChanged(nodes: Set[NodeMetrics]) extends ClusterDomainEvent
/**
* INTERNAL API
diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterMetricsCollector.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterMetricsCollector.scala
index ba086b600c..87bb15450b 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterMetricsCollector.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterMetricsCollector.scala
@@ -22,6 +22,8 @@ import java.lang.reflect.Method
import java.lang.System.{ currentTimeMillis ⇒ newTimestamp }
/**
+ * INTERNAL API.
+ *
* This strategy is primarily for load-balancing of nodes. It controls metrics sampling
* at a regular frequency, prepares highly variable data for further analysis by other entities,
* and publishes the latest cluster metrics data around the node ring to assist in determining
@@ -31,10 +33,6 @@ import java.lang.System.{ currentTimeMillis ⇒ newTimestamp }
*
* Calculation of statistical data for each monitored process is delegated to the
* [[akka.cluster.DataStream]] for exponential smoothing, with additional decay factor.
- *
- * INTERNAL API.
- *
- * @author Helena Edelson
*/
private[cluster] class ClusterMetricsCollector(publisher: ActorRef) extends Actor with ActorLogging {
@@ -119,8 +117,6 @@ private[cluster] class ClusterMetricsCollector(publisher: ActorRef) extends Acto
* Samples the latest metrics for the node, updates metrics statistics in
* [[akka.cluster.MetricsGossip]], and publishes the change to the event bus.
*
- * INTERNAL API
- *
* @see [[akka.cluster.ClusterMetricsCollector.collect( )]]
*/
def collect(): Unit = {
@@ -164,7 +160,6 @@ private[cluster] class ClusterMetricsCollector(publisher: ActorRef) extends Acto
* INTERNAL API
*
* @param nodes metrics per node
- * @author Helena Edelson
*/
private[cluster] case class MetricsGossip(rateOfDecay: Int, nodes: Set[NodeMetrics] = Set.empty) {
@@ -220,8 +215,8 @@ private[cluster] case class MetricsGossip(rateOfDecay: Int, nodes: Set[NodeMetri
}
/**
- * Envelope adding a sender address to the gossip.
* INTERNAL API
+ * Envelope adding a sender address to the gossip.
*/
private[cluster] case class MetricsGossipEnvelope(from: Address, gossip: MetricsGossip) extends ClusterMessage
@@ -245,8 +240,6 @@ private[cluster] case class MetricsGossipEnvelope(from: Address, gossip: Metrics
* @param timestamp the most recent time of sampling
*
* @param startTime the time of initial sampling for this data stream
- *
- * @author Helena Edelson
*/
private[cluster] case class DataStream(decay: Int, ewma: ScalaNumber, startTime: Long, timestamp: Long)
extends ClusterMessage with MetricNumericConverter {
@@ -277,9 +270,9 @@ private[cluster] case class DataStream(decay: Int, ewma: ScalaNumber, startTime:
}
/**
- * Companion object of DataStream class.
+ * INTERNAL API
*
- * @author Helena Edelson
+ * Companion object of DataStream class.
*/
private[cluster] object DataStream {
@@ -297,8 +290,6 @@ private[cluster] object DataStream {
*
* @param average the data stream of the metric value, for trending over time. Metrics that are already
* averages (e.g. system load average) or finite (e.g. as total cores), are not trended.
- *
- * @author Helena Edelson
*/
private[cluster] case class Metric(name: String, value: Option[ScalaNumber], average: Option[DataStream])
extends ClusterMessage with MetricNumericConverter {
@@ -348,9 +339,9 @@ private[cluster] case class Metric(name: String, value: Option[ScalaNumber], ave
}
/**
- * Companion object of Metric class.
+ * INTERNAL API
*
- * @author Helena Edelson
+ * Companion object of Metric class.
*/
private[cluster] object Metric extends MetricNumericConverter {
@@ -372,6 +363,8 @@ private[cluster] object Metric extends MetricNumericConverter {
}
/**
+ * INTERNAL API
+ *
* The snapshot of current sampled health metrics for any monitored process.
* Collected and gossipped at regular intervals for dynamic cluster management strategies.
*
@@ -386,8 +379,6 @@ private[cluster] object Metric extends MetricNumericConverter {
* @param timestamp the time of sampling
*
* @param metrics the array of sampled [[akka.actor.Metric]]
- *
- * @author Helena Edelson
*/
private[cluster] case class NodeMetrics(address: Address, timestamp: Long, metrics: Set[Metric] = Set.empty[Metric]) extends ClusterMessage {
@@ -409,12 +400,10 @@ private[cluster] case class NodeMetrics(address: Address, timestamp: Long, metri
}
/**
- * Encapsulates evaluation of validity of metric values, conversion of an actual metric value to
- * a [[akka.cluster.Metric]] for consumption by subscribed cluster entities.
- *
* INTERNAL API
*
- * @author Helena Edelson
+ * Encapsulates evaluation of validity of metric values, conversion of an actual metric value to
+ * a [[akka.cluster.Metric]] for consumption by subscribed cluster entities.
*/
private[cluster] trait MetricNumericConverter {
@@ -439,18 +428,16 @@ private[cluster] trait MetricNumericConverter {
}
/**
+ * INTERNAL API
+ *
* Loads JVM metrics through JMX monitoring beans. If Hyperic SIGAR is on the classpath, this
* loads wider and more accurate range of metrics in combination with SIGAR's native OS library.
*
* FIXME switch to Scala reflection
*
- * INTERNAL API
- *
* @param sigar the optional org.hyperic.Sigar instance
*
* @param address The [[akka.actor.Address]] of the node being sampled
- *
- * @author Helena Edelson
*/
private[cluster] class MetricsCollector private (private val sigar: Option[AnyRef], address: Address) extends MetricNumericConverter {
@@ -562,9 +549,8 @@ private[cluster] class MetricsCollector private (private val sigar: Option[AnyRe
}
/**
+ * INTERNAL API
* Companion object of MetricsCollector class.
- *
- * @author Helena Edelson
*/
private[cluster] object MetricsCollector {
def apply(address: Address, log: LoggingAdapter, dynamicAccess: DynamicAccess): MetricsCollector =
diff --git a/akka-cluster/src/main/scala/akka/cluster/Member.scala b/akka-cluster/src/main/scala/akka/cluster/Member.scala
index e806b0a933..f8a064977d 100644
--- a/akka-cluster/src/main/scala/akka/cluster/Member.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/Member.scala
@@ -87,7 +87,7 @@ object Member {
*
* Can be one of: Joining, Up, Leaving, Exiting and Down.
*/
-sealed trait MemberStatus extends ClusterMessage {
+abstract class MemberStatus extends ClusterMessage {
/**
* Using the same notion for 'unavailable' as 'non-convergence': DOWN
@@ -102,4 +102,34 @@ object MemberStatus {
case object Exiting extends MemberStatus
case object Down extends MemberStatus
case object Removed extends MemberStatus
+
+ /**
+ * JAVA API
+ */
+ def joining: MemberStatus = Joining
+
+ /**
+ * JAVA API
+ */
+ def up: MemberStatus = Up
+
+ /**
+ * JAVA API
+ */
+ def leaving: MemberStatus = Leaving
+
+ /**
+ * JAVA API
+ */
+ def exiting: MemberStatus = Exiting
+
+ /**
+ * JAVA API
+ */
+ def down: MemberStatus = Down
+
+ /**
+ * JAVA API
+ */
+ def removed: MemberStatus = Removed
}
\ No newline at end of file
diff --git a/akka-docs/rst/cluster/cluster-usage-java.rst b/akka-docs/rst/cluster/cluster-usage-java.rst
new file mode 100644
index 0000000000..c8e2d791b4
--- /dev/null
+++ b/akka-docs/rst/cluster/cluster-usage-java.rst
@@ -0,0 +1,496 @@
+
+.. _cluster_usage_java:
+
+######################
+ Cluster Usage (Java)
+######################
+
+.. note:: This module is :ref:`experimental `. This document describes how to use the features implemented so far. More features are coming in Akka Coltrane. Track progress of the Coltrane milestone in `Assembla `_ and the `Roadmap `_.
+
+For introduction to the Akka Cluster concepts please see :ref:`cluster`.
+
+Preparing Your Project for Clustering
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The Akka cluster is a separate jar file. Make sure that you have the following dependency in your project::
+
+
+ com.typesafe.akka
+ akka-cluster-experimental_@binVersion@
+ @version@
+
+
+If you are using the latest nightly build you should pick a timestamped Akka
+version from
+``_.
+We recommend against using ``SNAPSHOT`` in order to obtain stable builds.
+
+A Simple Cluster Example
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+The following small program together with its configuration starts an ``ActorSystem``
+with the Cluster extension enabled. It joins the cluster and logs some membership events.
+
+Try it out:
+
+1. Add the following ``application.conf`` in your project, place it in ``src/main/resources``:
+
+
+.. literalinclude:: ../../../akka-samples/akka-sample-cluster/src/main/resources/application.conf
+ :language: none
+
+To enable cluster capabilities in your Akka project you should, at a minimum, add the :ref:`remoting-java`
+settings, but with ``akka.cluster.ClusterActorRefProvider``.
+The ``akka.cluster.seed-nodes`` and cluster extension should normally also be added to your
+``application.conf`` file.
+
+The seed nodes are configured contact points for initial, automatic, join of the cluster.
+
+Note that if you are going to start the nodes on different machines you need to specify the
+ip-addresses or host names of the machines in ``application.conf`` instead of ``127.0.0.1``
+
+2. Add the following main program to your project, place it in ``src/main/java``:
+
+.. literalinclude:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterApp.java
+ :language: java
+
+
+3. Start the first seed node. Open a sbt session in one terminal window and run::
+
+ run-main sample.cluster.simple.japi.SimpleClusterApp 2551
+
+2551 corresponds to the port of the first seed-nodes element in the configuration.
+In the log output you see that the cluster node has been started and changed status to 'Up'.
+
+4. Start the second seed node. Open a sbt session in another terminal window and run::
+
+ run-main sample.cluster.simple.japi.SimpleClusterApp 2552
+
+
+2552 corresponds to the port of the second seed-nodes element in the configuration.
+In the log output you see that the cluster node has been started and joins the other seed node
+and becomes a member of the cluster. It's status changed to 'Up'.
+
+Switch over to the first terminal window and see in the log output that the member joined.
+
+5. Start another node. Open a sbt session in yet another terminal window and run::
+
+ run-main sample.cluster.simple.japi.SimpleClusterApp
+
+Now you don't need to specify the port number, and it will use a random available port.
+It joins one of the configured seed nodes. Look at the log output in the different terminal
+windows.
+
+Start even more nodes in the same way, if you like.
+
+6. Shut down one of the nodes by pressing 'ctrl-c' in one of the terminal windows.
+The other nodes will detect the failure after a while, which you can see in the log
+output in the other terminals.
+
+Look at the source code of the program again. What it does is to create an actor
+and register it as subscriber of certain cluster events. It gets notified with
+an snapshot event, ``CurrentClusterState`` that holds full state information of
+the cluster. After that it receives events for changes that happen in the cluster.
+
+Automatic vs. Manual Joining
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+You may decide if joining to the cluster should be done automatically or manually.
+By default it is automatic and you need to define the seed nodes in configuration
+so that a new node has an initial contact point. When a new node is started it
+sends a message to all seed nodes and then sends join command to the one that
+answers first. If no one of the seed nodes replied (might not be started yet)
+it retries this procedure until successful or shutdown.
+
+There is one thing to be aware of regarding the seed node configured as the
+first element in the ``seed-nodes`` configuration list.
+The seed nodes can be started in any order and it is not necessary to have all
+seed nodes running, but the first seed node must be started when initially
+starting a cluster, otherwise the other seed-nodes will not become initialized
+and no other node can join the cluster. Once more than two seed nodes have been
+started it is no problem to shut down the first seed node. If it goes down it
+must be manually joined to the cluster again.
+Automatic joining of the first seed node is not possible, it would only join
+itself. It is only the first seed node that has this restriction.
+
+You can disable automatic joining with configuration::
+
+ akka.cluster.auto-join = off
+
+Then you need to join manually, using :ref:`cluster_jmx_java` or :ref:`cluster_command_line_java`.
+You can join to any node in the cluster. It doesn't have to be configured as
+seed node. If you are not using auto-join there is no need to configure
+seed nodes at all.
+
+Joining can also be performed programatically with ``Cluster.get(system).join(address)``.
+
+
+Automatic vs. Manual Downing
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+When a member is considered by the failure detector to be unreachable the
+leader is not allowed to perform its duties, such as changing status of
+new joining members to 'Up'. The status of the unreachable member must be
+changed to 'Down'. This can be performed automatically or manually. By
+default it must be done manually, using using :ref:`cluster_jmx_java` or
+:ref:`cluster_command_line_java`.
+
+It can also be performed programatically with ``Cluster.get(system).down(address)``.
+
+You can enable automatic downing with configuration::
+
+ akka.cluster.auto-down = on
+
+Be aware of that using auto-down implies that two separate clusters will
+automatically be formed in case of network partition. That might be
+desired by some applications but not by others.
+
+.. _cluster_subscriber_java:
+
+Subscribe to Cluster Events
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+You can subscribe to change notifications of the cluster membership by using
+``Cluster.get(system).subscribe(subscriber, to)``. A snapshot of the full state,
+``akka.cluster.ClusterEvent.CurrentClusterState``, is sent to the subscriber
+as the first event, followed by events for incremental updates.
+
+There are several types of change events, consult the API documentation
+of classes that extends ``akka.cluster.ClusterEvent.ClusterDomainEvent``
+for details about the events.
+
+Worker Dial-in Example
+----------------------
+
+Let's take a look at an example that illustrates how workers, here named *backend*,
+can detect and register to new master nodes, here named *frontend*.
+
+The example application provides a service to transform text. When some text
+is sent to one of the frontend services, it will be delegated to one of the
+backend workers, which performs the transformation job, and sends the result back to
+the original client. New backend nodes, as well as new frontend nodes, can be
+added or removed to the cluster dynamically.
+
+In this example the following imports are used:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackend.java#imports
+
+Messages:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationMessages.java#messages
+
+The backend worker that performs the transformation job:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackend.java#backend
+
+Note that the ``TransformationBackend`` actor subscribes to cluster events to detect new,
+potential, frontend nodes, and send them a registration message so that they know
+that they can use the backend worker.
+
+The frontend that receives user jobs and delegates to one of the registered backend workers:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontend.java#frontend
+
+Note that the ``TransformationFrontend`` actor watch the registered backend
+to be able to remove it from its list of availble backend workers.
+Death watch uses the cluster failure detector for nodes in the cluster, i.e. it detects
+network failures and JVM crashes, in addition to graceful termination of watched
+actor.
+
+This example is included in ``akka-samples/akka-sample-cluster``
+and you can try by starting nodes in different terminal windows. For example, starting 2
+frontend nodes and 3 backend nodes::
+
+ sbt
+
+ project akka-sample-cluster-experimental
+
+ run-main sample.cluster.transformation.japi.TransformationFrontendMain 2551
+
+ run-main sample.cluster.transformation.japi.TransformationBackendMain 2552
+
+ run-main sample.cluster.transformation.japi.TransformationBackendMain
+
+ run-main sample.cluster.transformation.japi.TransformationBackendMain
+
+ run-main sample.cluster.transformation.japi.TransformationFrontendMain
+
+
+.. note:: The above example should probably be designed as two separate, frontend/backend, clusters, when there is a `cluster client for decoupling clusters `_.
+
+Failure Detector
+^^^^^^^^^^^^^^^^
+
+The nodes in the cluster monitor each other by sending heartbeats to detect if a node is
+unreachable from the rest of the cluster. The heartbeat arrival times is interpreted
+by an implementation of
+`The Phi Accrual Failure Detector `_.
+
+The suspicion level of failure is given by a value called *phi*.
+The basic idea of the phi failure detector is to express the value of *phi* on a scale that
+is dynamically adjusted to reflect current network conditions.
+
+The value of *phi* is calculated as::
+
+ phi = -log10(1 - F(timeSinceLastHeartbeat))
+
+where F is the cumulative distribution function of a normal distribution with mean
+and standard deviation estimated from historical heartbeat inter-arrival times.
+
+In the :ref:`cluster_configuration_java` you can adjust the ``akka.cluster.failure-detector.threshold``
+to define when a *phi* value is considered to be a failure.
+
+A low ``threshold`` is prone to generate many false positives but ensures
+a quick detection in the event of a real crash. Conversely, a high ``threshold``
+generates fewer mistakes but needs more time to detect actual crashes. The
+default ``threshold`` is 8 and is appropriate for most situations. However in
+cloud environments, such as Amazon EC2, the value could be increased to 12 in
+order to account for network issues that sometimes occur on such platforms.
+
+The following chart illustrates how *phi* increase with increasing time since the
+previous heartbeat.
+
+.. image:: images/phi1.png
+
+Phi is calculated from the mean and standard deviation of historical
+inter arrival times. The previous chart is an example for standard deviation
+of 200 ms. If the heartbeats arrive with less deviation the curve becomes steeper,
+i.e. it's possible to determine failure more quickly. The curve looks like this for
+a standard deviation of 100 ms.
+
+.. image:: images/phi2.png
+
+To be able to survive sudden abnormalities, such as garbage collection pauses and
+transient network failures the failure detector is configured with a margin,
+``akka.cluster.failure-detector.acceptable-heartbeat-pause``. You may want to
+adjust the :ref:`cluster_configuration_java` of this depending on you environment.
+This is how the curve looks like for ``acceptable-heartbeat-pause`` configured to
+3 seconds.
+
+.. image:: images/phi3.png
+
+Cluster Aware Routers
+^^^^^^^^^^^^^^^^^^^^^
+
+All :ref:`routers ` can be made aware of member nodes in the cluster, i.e.
+deploying new routees or looking up routees on nodes in the cluster.
+When a node becomes unavailble or leaves the cluster the routees of that node are
+automatically unregistered from the router. When new nodes join the cluster additional
+routees are added to the router, according to the configuration.
+
+When using a router with routees looked up on the cluster member nodes, i.e. the routees
+are already running, the configuration for a router looks like this:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSpec.scala#router-lookup-config
+
+It's the relative actor path defined in ``routees-path`` that identify what actor to lookup.
+
+``nr-of-instances`` defines total number of routees in the cluster, but there will not be
+more than one per node. Setting ``nr-of-instances`` to a high value will result in new routees
+added to the router when nodes join the cluster.
+
+The same type of router could also have been defined in code:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java#router-lookup-in-code
+
+When using a router with routees created and deployed on the cluster member nodes
+the configuration for a router looks like this:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSingleMasterSpec.scala#router-deploy-config
+
+
+``nr-of-instances`` defines total number of routees in the cluster, but the number of routees
+per node, ``max-nr-of-instances-per-node``, will not be exceeded. Setting ``nr-of-instances``
+to a high value will result in creating and deploying additional routees when new nodes join
+the cluster.
+
+The same type of router could also have been defined in code:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java#router-deploy-in-code
+
+See :ref:`cluster_configuration_java` section for further descriptions of the settings.
+
+
+Router Example
+--------------
+
+Let's take a look at how to use cluster aware routers.
+
+The example application provides a service to calculate statistics for a text.
+When some text is sent to the service it splits it into words, and delegates the task
+to count number of characters in each word to a separate worker, a routee of a router.
+The character count for each word is sent back to an aggregator that calculates
+the average number of characters per word when all results have been collected.
+
+In this example we use the following imports:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java#imports
+
+Messages:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsMessages.java#messages
+
+The worker that counts number of characters in each word:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsWorker.java#worker
+
+The service that receives text from users and splits it up into words, delegates to workers and aggregates:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java#service
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsAggregator.java#aggregator
+
+
+Note, nothing cluster specific so far, just plain actors.
+
+We can use these actors with two different types of router setup. Either with lookup of routees,
+or with create and deploy of routees. Remember, routees are the workers in this case.
+
+We start with the router setup with lookup of routees. All nodes start ``StatsService`` and
+``StatsWorker`` actors and the router is configured with ``routees-path``:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleMain.java#start-router-lookup
+
+This means that user requests can be sent to ``StatsService`` on any node and it will use
+``StatsWorker`` on all nodes. There can only be one worker per node, but that worker could easily
+fan out to local children if more parallelism is needed.
+
+This example is included in ``akka-samples/akka-sample-cluster``
+and you can try by starting nodes in different terminal windows. For example, starting 3
+service nodes and 1 client::
+
+ sbt
+
+ project akka-sample-cluster-experimental
+
+ run-main sample.cluster.stats.japi.StatsSampleMain 2551
+
+ run-main sample.cluster.stats.japi.StatsSampleMain 2552
+
+ run-main sample.cluster.stats.japi.StatsSampleClientMain
+
+ run-main sample.cluster.stats.japi.StatsSampleMain
+
+The above setup is nice for this example, but we will also take a look at how to use
+a single master node that creates and deploys workers. To keep track of a single
+master we need one additional actor:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsFacade.java#facade
+
+The ``StatsFacade`` receives text from users and delegates to the current ``StatsService``, the single
+master. It listens to cluster events to create or lookup the ``StatsService`` depending on if
+it is on the same same node or on another node. We run the master on the same node as the leader of
+the cluster members, which is nothing more than the address currently sorted first in the member ring,
+i.e. it can change when new nodes join or when current leader leaves.
+
+All nodes start ``StatsFacade`` and the router is now configured like this:
+
+.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterMain.java#start-router-deploy
+
+
+This example is included in ``akka-samples/akka-sample-cluster``
+and you can try by starting nodes in different terminal windows. For example, starting 3
+service nodes and 1 client::
+
+ sbt
+
+ project akka-sample-cluster-experimental
+
+ run-main sample.cluster.stats.japi.StatsSampleOneMasterMain 2551
+
+ run-main sample.cluster.stats.japi.StatsSampleOneMasterMain 2552
+
+ run-main sample.cluster.stats.japi.StatsSampleOneMasterClientMain
+
+ run-main sample.cluster.stats.japi.StatsSampleOneMasterMain
+
+.. note:: The above example, especially the last part, will be simplified when the cluster handles automatic actor partitioning.
+
+
+.. _cluster_jmx_java:
+
+JMX
+^^^
+
+Information and management of the cluster is available as JMX MBeans with the root name ``akka.Cluster``.
+The JMX information can be displayed with an ordinary JMX console such as JConsole or JVisualVM.
+
+From JMX you can:
+
+* see what members that are part of the cluster
+* see status of this node
+* join this node to another node in cluster
+* mark any node in the cluster as down
+* tell any node in the cluster to leave
+
+Member nodes are identified with their address, in format `akka://actor-system-name@hostname:port`.
+
+.. _cluster_command_line_java:
+
+Command Line Management
+^^^^^^^^^^^^^^^^^^^^^^^
+
+The cluster can be managed with the script `bin/akka-cluster` provided in the
+Akka distribution.
+
+Run it without parameters to see instructions about how to use the script::
+
+ Usage: bin/akka-cluster ...
+
+ Supported commands are:
+ join - Sends request a JOIN node with the specified URL
+ leave - Sends a request for node with URL to LEAVE the cluster
+ down - Sends a request for marking node with URL as DOWN
+ member-status - Asks the member node for its current status
+ cluster-status - Asks the cluster for its current status (member ring,
+ unavailable nodes, meta data etc.)
+ leader - Asks the cluster who the current leader is
+ is-singleton - Checks if the cluster is a singleton cluster (single
+ node cluster)
+ is-available - Checks if the member node is available
+ is-running - Checks if the member node is running
+ has-convergence - Checks if there is a cluster convergence
+ Where the should be on the format of 'akka://actor-system-name@hostname:port'
+
+ Examples: bin/akka-cluster localhost:9999 is-available
+ bin/akka-cluster localhost:9999 join akka://MySystem@darkstar:2552
+ bin/akka-cluster localhost:9999 cluster-status
+
+
+To be able to use the script you must enable remote monitoring and management when starting the JVMs of the cluster nodes,
+as described in `Monitoring and Management Using JMX Technology `_
+
+Example of system properties to enable remote monitoring and management::
+
+ java -Dcom.sun.management.jmxremote.port=9999 \
+ -Dcom.sun.management.jmxremote.authenticate=false \
+ -Dcom.sun.management.jmxremote.ssl=false
+
+.. _cluster_configuration_java:
+
+Configuration
+^^^^^^^^^^^^^
+
+There are several configuration properties for the cluster. We refer to the following
+reference file for more information:
+
+
+.. literalinclude:: ../../../akka-cluster/src/main/resources/reference.conf
+ :language: none
+
+Cluster Scheduler
+-----------------
+
+It is recommended that you change the ``tick-duration`` to 33 ms or less
+of the default scheduler when using cluster, if you don't need to have it
+configured to a longer duration for other reasons. If you don't do this
+a dedicated scheduler will be used for periodic tasks of the cluster, which
+introduce the extra overhead of another thread.
+
+::
+
+ # shorter tick-duration of default scheduler when using cluster
+ akka.scheduler.tick-duration.tick-duration = 33ms
+
+
+
diff --git a/akka-docs/rst/cluster/cluster-usage.rst b/akka-docs/rst/cluster/cluster-usage-scala.rst
similarity index 95%
rename from akka-docs/rst/cluster/cluster-usage.rst
rename to akka-docs/rst/cluster/cluster-usage-scala.rst
index 6b8f3fa6a7..31ce7e7191 100644
--- a/akka-docs/rst/cluster/cluster-usage.rst
+++ b/akka-docs/rst/cluster/cluster-usage-scala.rst
@@ -1,9 +1,9 @@
-.. _cluster_usage:
+.. _cluster_usage_scala:
-###############
- Cluster Usage
-###############
+#######################
+ Cluster Usage (Scala)
+#######################
.. note:: This module is :ref:`experimental `. This document describes how to use the features implemented so far. More features are coming in Akka Coltrane. Track progress of the Coltrane milestone in `Assembla `_ and the `Roadmap `_.
@@ -12,11 +12,9 @@ For introduction to the Akka Cluster concepts please see :ref:`cluster`.
Preparing Your Project for Clustering
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-The Akka cluster is a separate jar file. Make sure that you have the following dependency in your project:
+The Akka cluster is a separate jar file. Make sure that you have the following dependency in your project::
-.. parsed-literal::
-
- "com.typesafe.akka" %% "akka-cluster" % "@version@" @crossString@
+ "com.typesafe.akka" %% "akka-cluster-experimental" % "@version@" @crossString@
If you are using the latest nightly build you should pick a timestamped Akka
version from
@@ -115,7 +113,7 @@ You can disable automatic joining with configuration::
akka.cluster.auto-join = off
-Then you need to join manually, using :ref:`cluster_jmx` or :ref:`cluster_command_line`.
+Then you need to join manually, using :ref:`cluster_jmx_scala` or :ref:`cluster_command_line_scala`.
You can join to any node in the cluster. It doesn't have to be configured as
seed node. If you are not using auto-join there is no need to configure
seed nodes at all.
@@ -130,8 +128,8 @@ When a member is considered by the failure detector to be unreachable the
leader is not allowed to perform its duties, such as changing status of
new joining members to 'Up'. The status of the unreachable member must be
changed to 'Down'. This can be performed automatically or manually. By
-default it must be done manually, using using :ref:`cluster_jmx` or
-:ref:`cluster_command_line`.
+default it must be done manually, using using :ref:`cluster_jmx_scala` or
+:ref:`cluster_command_line_scala`.
It can also be performed programatically with ``Cluster(system).down(address)``.
@@ -143,7 +141,7 @@ Be aware of that using auto-down implies that two separate clusters will
automatically be formed in case of network partition. That might be
desired by some applications but not by others.
-.. _cluster_subscriber:
+.. _cluster_subscriber_scala:
Subscribe to Cluster Events
^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -230,12 +228,12 @@ is dynamically adjusted to reflect current network conditions.
The value of *phi* is calculated as::
- phi = -log10(1 - F(timeSinceLastHeartbeat)
+ phi = -log10(1 - F(timeSinceLastHeartbeat))
where F is the cumulative distribution function of a normal distribution with mean
and standard deviation estimated from historical heartbeat inter-arrival times.
-In the :ref:`cluster_configuration` you can adjust the ``akka.cluster.failure-detector.threshold``
+In the :ref:`cluster_configuration_scala` you can adjust the ``akka.cluster.failure-detector.threshold``
to define when a *phi* value is considered to be a failure.
A low ``threshold`` is prone to generate many false positives but ensures
@@ -261,7 +259,7 @@ a standard deviation of 100 ms.
To be able to survive sudden abnormalities, such as garbage collection pauses and
transient network failures the failure detector is configured with a margin,
``akka.cluster.failure-detector.acceptable-heartbeat-pause``. You may want to
-adjust the :ref:`cluster_configuration` of this depending on you environment.
+adjust the :ref:`cluster_configuration_scala` of this depending on you environment.
This is how the curve looks like for ``acceptable-heartbeat-pause`` configured to
3 seconds.
@@ -306,7 +304,7 @@ The same type of router could also have been defined in code:
.. includecode:: ../../../akka-samples/akka-sample-cluster/src/main/scala/sample/cluster/stats/StatsSample.scala#router-deploy-in-code
-See :ref:`cluster_configuration` section for further descriptions of the settings.
+See :ref:`cluster_configuration_scala` section for further descriptions of the settings.
Router Example
@@ -355,6 +353,10 @@ This example is included in ``akka-samples/akka-sample-cluster``
and you can try by starting nodes in different terminal windows. For example, starting 3
service nodes and 1 client::
+ sbt
+
+ project akka-sample-cluster-experimental
+
run-main sample.cluster.stats.StatsSample 2551
run-main sample.cluster.stats.StatsSample 2552
@@ -404,7 +406,7 @@ Set up your project according to the instructions in :ref:`multi-node-testing` a
add the ``sbt-multi-jvm`` plugin and the dependency to ``akka-remote-tests-experimental``.
First, as described in :ref:`multi-node-testing`, we need some scaffolding to configure the ``MultiNodeSpec``.
-Define the participating roles and their :ref:`cluster_configuration` in an object extending ``MultiNodeConfig``:
+Define the participating roles and their :ref:`cluster_configuration_scala` in an object extending ``MultiNodeConfig``:
.. includecode:: ../../../akka-samples/akka-sample-cluster/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSpec.scala
:include: MultiNodeConfig
@@ -434,7 +436,7 @@ From the test you interact with the cluster using the ``Cluster`` extension, e.g
.. includecode:: ../../../akka-samples/akka-sample-cluster/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSpec.scala#join
-Notice how the `testActor` from :ref:`testkit ` is added as :ref:`subscriber `
+Notice how the `testActor` from :ref:`testkit ` is added as :ref:`subscriber `
to cluster changes and then waiting for certain events, such as in this case all members becoming 'Up'.
The above code was running for all roles (JVMs). ``runOn`` is a convenient utility to declare that a certain block
@@ -451,7 +453,7 @@ the actor system for a specific role. This can also be used to grab the ``akka.a
.. includecode:: ../../../akka-samples/akka-sample-cluster/src/multi-jvm/scala/sample/cluster/stats/StatsSampleSpec.scala#addresses
-.. _cluster_jmx:
+.. _cluster_jmx_scala:
JMX
^^^
@@ -469,7 +471,7 @@ From JMX you can:
Member nodes are identified with their address, in format `akka://actor-system-name@hostname:port`.
-.. _cluster_command_line:
+.. _cluster_command_line_scala:
Command Line Management
^^^^^^^^^^^^^^^^^^^^^^^
@@ -510,7 +512,7 @@ Example of system properties to enable remote monitoring and management::
-Dcom.sun.management.jmxremote.authenticate=false \
-Dcom.sun.management.jmxremote.ssl=false
-.. _cluster_configuration:
+.. _cluster_configuration_scala:
Configuration
^^^^^^^^^^^^^
diff --git a/akka-docs/rst/cluster/index.rst b/akka-docs/rst/cluster/index.rst
index dac3a558d9..e44e8ab2e6 100644
--- a/akka-docs/rst/cluster/index.rst
+++ b/akka-docs/rst/cluster/index.rst
@@ -5,4 +5,5 @@ Cluster
:maxdepth: 2
cluster
- cluster-usage
+ cluster-usage-java
+ cluster-usage-scala
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterApp.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterApp.java
new file mode 100644
index 0000000000..b216e174fa
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterApp.java
@@ -0,0 +1,28 @@
+package sample.cluster.simple.japi;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.cluster.Cluster;
+import akka.cluster.ClusterEvent.ClusterDomainEvent;
+
+public class SimpleClusterApp {
+
+ public static void main(String[] args) {
+ // Override the configuration of the port
+ // when specified as program argument
+ if (args.length > 0)
+ System.setProperty("akka.remote.netty.port", args[0]);
+
+ // Create an Akka system
+ ActorSystem system = ActorSystem.create("ClusterSystem");
+
+ // Create an actor that handles cluster domain events
+ ActorRef clusterListener = system.actorOf(new Props(
+ SimpleClusterListener.class), "clusterListener");
+
+ // Add subscription of cluster events
+ Cluster.get(system).subscribe(clusterListener,
+ ClusterDomainEvent.class);
+ }
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterListener.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterListener.java
new file mode 100644
index 0000000000..24770318c1
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/simple/japi/SimpleClusterListener.java
@@ -0,0 +1,41 @@
+package sample.cluster.simple.japi;
+
+import akka.actor.UntypedActor;
+import akka.cluster.ClusterEvent.ClusterDomainEvent;
+import akka.cluster.ClusterEvent.CurrentClusterState;
+import akka.cluster.ClusterEvent.MemberJoined;
+import akka.cluster.ClusterEvent.MemberUnreachable;
+import akka.cluster.ClusterEvent.MemberUp;
+import akka.event.Logging;
+import akka.event.LoggingAdapter;
+
+public class SimpleClusterListener extends UntypedActor {
+ LoggingAdapter log = Logging.getLogger(getContext().system(), this);
+
+ @Override
+ public void onReceive(Object message) {
+ if (message instanceof CurrentClusterState) {
+ CurrentClusterState state = (CurrentClusterState) message;
+ log.info("Current members: {}", state.members());
+
+ } else if (message instanceof MemberJoined) {
+ MemberJoined mJoined = (MemberJoined) message;
+ log.info("Member joined: {}", mJoined);
+
+ } else if (message instanceof MemberUp) {
+ MemberUp mUp = (MemberUp) message;
+ log.info("Member is Up: {}", mUp.member());
+
+ } else if (message instanceof MemberUnreachable) {
+ MemberUnreachable mUnreachable = (MemberUnreachable) message;
+ log.info("Member detected as unreachable: {}", mUnreachable.member());
+
+ } else if (message instanceof ClusterDomainEvent) {
+ // ignore
+
+ } else {
+ unhandled(message);
+ }
+
+ }
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsAggregator.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsAggregator.java
new file mode 100644
index 0000000000..469a443131
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsAggregator.java
@@ -0,0 +1,56 @@
+package sample.cluster.stats.japi;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+
+import sample.cluster.stats.japi.StatsMessages.JobFailed;
+import sample.cluster.stats.japi.StatsMessages.StatsResult;
+import scala.concurrent.util.Duration;
+import akka.actor.ActorRef;
+import akka.actor.ReceiveTimeout;
+import akka.actor.UntypedActor;
+
+//#aggregator
+public class StatsAggregator extends UntypedActor {
+
+ final int expectedResults;
+ final ActorRef replyTo;
+ final List results = new ArrayList();
+
+ public StatsAggregator(int expectedResults, ActorRef replyTo) {
+ this.expectedResults = expectedResults;
+ this.replyTo = replyTo;
+ }
+
+ @Override
+ public void preStart() {
+ getContext().setReceiveTimeout(Duration.create(10, TimeUnit.SECONDS));
+ }
+
+ @Override
+ public void onReceive(Object message) {
+ if (message instanceof Integer) {
+ Integer wordCount = (Integer) message;
+ results.add(wordCount);
+ if (results.size() == expectedResults) {
+ int sum = 0;
+ for (int c : results)
+ sum += c;
+ double meanWordLength = ((double) sum) / results.size();
+ replyTo.tell(new StatsResult(meanWordLength), getSelf());
+ getContext().stop(getSelf());
+ }
+
+ } else if (message == ReceiveTimeout.getInstance()) {
+ replyTo.tell(new JobFailed("Service unavailable, try again later"),
+ getSelf());
+ getContext().stop(getSelf());
+
+ } else {
+ unhandled(message);
+ }
+ }
+
+}
+//#aggregator
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsFacade.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsFacade.java
new file mode 100644
index 0000000000..25366c8064
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsFacade.java
@@ -0,0 +1,84 @@
+package sample.cluster.stats.japi;
+
+import sample.cluster.stats.japi.StatsMessages.JobFailed;
+import sample.cluster.stats.japi.StatsMessages.StatsJob;
+import akka.actor.ActorRef;
+import akka.actor.Address;
+import akka.actor.Props;
+import akka.actor.UntypedActor;
+import akka.cluster.Cluster;
+import akka.cluster.ClusterEvent.CurrentClusterState;
+import akka.cluster.ClusterEvent.LeaderChanged;
+import akka.cluster.ClusterEvent.MemberEvent;
+import akka.event.Logging;
+import akka.event.LoggingAdapter;
+
+//#facade
+public class StatsFacade extends UntypedActor {
+
+ LoggingAdapter log = Logging.getLogger(getContext().system(), this);
+ Cluster cluster = Cluster.get(getContext().system());
+
+ ActorRef currentMaster = null;
+ boolean currentMasterCreatedByMe = false;
+
+ //subscribe to cluster changes, MemberEvent
+ @Override
+ public void preStart() {
+ cluster.subscribe(getSelf(), LeaderChanged.class);
+ }
+
+ //re-subscribe when restart
+ @Override
+ public void postStop() {
+ cluster.unsubscribe(getSelf());
+ }
+
+ @Override
+ public void onReceive(Object message) {
+ if (message instanceof StatsJob && currentMaster == null) {
+ getSender()
+ .tell(new JobFailed("Service unavailable, try again later"),
+ getSelf());
+
+ } else if (message instanceof StatsJob) {
+ StatsJob job = (StatsJob) message;
+ currentMaster.forward(job, getContext());
+
+ } else if (message instanceof CurrentClusterState) {
+ CurrentClusterState state = (CurrentClusterState) message;
+ updateCurrentMaster(state.getLeader());
+
+ } else if (message instanceof LeaderChanged) {
+ LeaderChanged leaderChanged = (LeaderChanged) message;
+ updateCurrentMaster(leaderChanged.getLeader());
+
+ } else {
+ unhandled(message);
+ }
+ }
+
+ void updateCurrentMaster(Address leaderAddress) {
+ if (leaderAddress == null)
+ return;
+
+ if (leaderAddress.equals(cluster.selfAddress())) {
+ if (!currentMasterCreatedByMe) {
+ log.info("Creating new statsService master at [{}]", leaderAddress);
+ currentMaster = getContext().actorOf(
+ new Props(StatsService.class), "statsService");
+ currentMasterCreatedByMe = true;
+ }
+ } else {
+ if (currentMasterCreatedByMe) {
+ getContext().stop(currentMaster);
+ }
+ log.info("Using statsService master at [{}]", leaderAddress);
+ currentMaster = getContext().actorFor(
+ getSelf().path().toStringWithAddress(leaderAddress)
+ + "/statsService");
+ currentMasterCreatedByMe = false;
+ }
+ }
+}
+//#facade
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsMessages.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsMessages.java
new file mode 100644
index 0000000000..538024efa6
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsMessages.java
@@ -0,0 +1,55 @@
+package sample.cluster.stats.japi;
+
+import java.io.Serializable;
+
+//#messages
+public interface StatsMessages {
+
+ public static class StatsJob implements Serializable {
+ private final String text;
+
+ public StatsJob(String text) {
+ this.text = text;
+ }
+
+ public String getText() {
+ return text;
+ }
+ }
+
+ public static class StatsResult implements Serializable {
+ private final double meanWordLength;
+
+ public StatsResult(double meanWordLength) {
+ this.meanWordLength = meanWordLength;
+ }
+
+ public double getMeanWordLength() {
+ return meanWordLength;
+ }
+
+ @Override
+ public String toString() {
+ return "meanWordLength: " + meanWordLength;
+ }
+ }
+
+ public static class JobFailed implements Serializable {
+ private final String reason;
+
+ public JobFailed(String reason) {
+ this.reason = reason;
+ }
+
+ public String getReason() {
+ return reason;
+ }
+
+ @Override
+ public String toString() {
+ return "JobFailed(" + reason + ")";
+ }
+ }
+
+}
+//#messages
\ No newline at end of file
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleClient.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleClient.java
new file mode 100644
index 0000000000..3350fed61a
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleClient.java
@@ -0,0 +1,98 @@
+package sample.cluster.stats.japi;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.TimeUnit;
+
+import sample.cluster.stats.japi.StatsMessages.JobFailed;
+import sample.cluster.stats.japi.StatsMessages.StatsJob;
+import sample.cluster.stats.japi.StatsMessages.StatsResult;
+import scala.concurrent.forkjoin.ThreadLocalRandom;
+import scala.concurrent.util.Duration;
+import scala.concurrent.util.FiniteDuration;
+import akka.actor.ActorRef;
+import akka.actor.Address;
+import akka.actor.Cancellable;
+import akka.actor.UntypedActor;
+import akka.cluster.Cluster;
+import akka.cluster.ClusterEvent.CurrentClusterState;
+import akka.cluster.ClusterEvent.MemberEvent;
+import akka.cluster.ClusterEvent.MemberUp;
+import akka.cluster.Member;
+import akka.cluster.MemberStatus;
+
+public class StatsSampleClient extends UntypedActor {
+
+ final String servicePath;
+ final Cancellable tickTask;
+ final Set nodes = new HashSet();
+
+ Cluster cluster = Cluster.get(getContext().system());
+
+ public StatsSampleClient(String servicePath) {
+ this.servicePath = servicePath;
+ FiniteDuration interval = Duration.create(2, TimeUnit.SECONDS);
+ tickTask = getContext()
+ .system()
+ .scheduler()
+ .schedule(interval, interval, getSelf(), "tick",
+ getContext().dispatcher());
+ }
+
+ //subscribe to cluster changes, MemberEvent
+ @Override
+ public void preStart() {
+ cluster.subscribe(getSelf(), MemberEvent.class);
+ }
+
+ //re-subscribe when restart
+ @Override
+ public void postStop() {
+ cluster.unsubscribe(getSelf());
+ tickTask.cancel();
+ }
+
+ @Override
+ public void onReceive(Object message) {
+ if (message.equals("tick") && !nodes.isEmpty()) {
+ // just pick any one
+ List nodesList = new ArrayList(nodes);
+ Address address = nodesList.get(ThreadLocalRandom.current().nextInt(
+ nodesList.size()));
+ ActorRef service = getContext().actorFor(address + servicePath);
+ service.tell(new StatsJob("this is the text that will be analyzed"),
+ getSelf());
+
+ } else if (message instanceof StatsResult) {
+ StatsResult result = (StatsResult) message;
+ System.out.println(result);
+
+ } else if (message instanceof JobFailed) {
+ JobFailed failed = (JobFailed) message;
+ System.out.println(failed);
+
+ } else if (message instanceof CurrentClusterState) {
+ CurrentClusterState state = (CurrentClusterState) message;
+ nodes.clear();
+ for (Member member : state.getMembers()) {
+ if (member.status().equals(MemberStatus.up())) {
+ nodes.add(member.address());
+ }
+ }
+
+ } else if (message instanceof MemberUp) {
+ MemberUp mUp = (MemberUp) message;
+ nodes.add(mUp.member().address());
+
+ } else if (message instanceof MemberEvent) {
+ MemberEvent other = (MemberEvent) message;
+ nodes.remove(other.member().address());
+
+ } else {
+ unhandled(message);
+ }
+ }
+
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleClientMain.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleClientMain.java
new file mode 100644
index 0000000000..191a8f264c
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleClientMain.java
@@ -0,0 +1,20 @@
+package sample.cluster.stats.japi;
+
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.actor.UntypedActor;
+import akka.actor.UntypedActorFactory;
+
+public class StatsSampleClientMain {
+
+ public static void main(String[] args) throws Exception {
+ ActorSystem system = ActorSystem.create("ClusterSystem");
+ system.actorOf(new Props(new UntypedActorFactory() {
+ @Override
+ public UntypedActor create() {
+ return new StatsSampleClient("/user/statsService");
+ }
+ }), "client");
+
+ }
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleMain.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleMain.java
new file mode 100644
index 0000000000..cf7387b6fd
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleMain.java
@@ -0,0 +1,37 @@
+package sample.cluster.stats.japi;
+
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+
+import com.typesafe.config.ConfigFactory;
+
+public class StatsSampleMain {
+
+ public static void main(String[] args) throws Exception {
+ // Override the configuration of the port
+ // when specified as program argument
+ if (args.length > 0)
+ System.setProperty("akka.remote.netty.port", args[0]);
+
+ //#start-router-lookup
+ ActorSystem system = ActorSystem.create("ClusterSystem",
+ ConfigFactory.parseString(
+ "akka.actor.deployment { \n" +
+ " /statsService/workerRouter { \n" +
+ " router = consistent-hashing \n" +
+ " nr-of-instances = 100 \n" +
+ " cluster { \n" +
+ " enabled = on \n" +
+ " routees-path = \"/user/statsWorker\" \n" +
+ " allow-local-routees = on \n" +
+ " } \n" +
+ " } \n" +
+ "} \n")
+ .withFallback(ConfigFactory.load()));
+
+ system.actorOf(new Props(StatsWorker.class), "statsWorker");
+ system.actorOf(new Props(StatsService.class), "statsService");
+ //#start-router-lookup
+
+ }
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterClientMain.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterClientMain.java
new file mode 100644
index 0000000000..7971d357d8
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterClientMain.java
@@ -0,0 +1,21 @@
+package sample.cluster.stats.japi;
+
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.actor.UntypedActor;
+import akka.actor.UntypedActorFactory;
+
+public class StatsSampleOneMasterClientMain {
+
+ public static void main(String[] args) throws Exception {
+ ActorSystem system = ActorSystem.create("ClusterSystem");
+ system.actorOf(new Props(new UntypedActorFactory() {
+ @Override
+ public UntypedActor create() {
+ return new StatsSampleClient("/user/statsFacade");
+ }
+ }), "client");
+
+ }
+
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterMain.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterMain.java
new file mode 100644
index 0000000000..9a85c58cb5
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsSampleOneMasterMain.java
@@ -0,0 +1,37 @@
+package sample.cluster.stats.japi;
+
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+
+import com.typesafe.config.ConfigFactory;
+
+public class StatsSampleOneMasterMain {
+
+ public static void main(String[] args) throws Exception {
+ // Override the configuration of the port
+ // when specified as program argument
+ if (args.length > 0)
+ System.setProperty("akka.remote.netty.port", args[0]);
+
+ //#start-router-deploy
+ ActorSystem system = ActorSystem.create("ClusterSystem",
+ ConfigFactory.parseString(
+ "akka.actor.deployment { \n" +
+ " /statsFacade/statsService/workerRouter { \n" +
+ " router = consistent-hashing \n" +
+ " nr-of-instances = 100 \n" +
+ " cluster { \n" +
+ " enabled = on \n" +
+ " max-nr-of-instances-per-node = 3 \n" +
+ " allow-local-routees = off \n" +
+ " } \n" +
+ " } \n" +
+ "} \n")
+ .withFallback(ConfigFactory.load()));
+
+ system.actorOf(new Props(StatsFacade.class), "statsFacade");
+ //#start-router-deploy
+
+ }
+
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java
new file mode 100644
index 0000000000..6a3c2ca44d
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsService.java
@@ -0,0 +1,83 @@
+package sample.cluster.stats.japi;
+
+import sample.cluster.stats.japi.StatsMessages.StatsJob;
+//#imports
+import akka.actor.ActorRef;
+import akka.actor.Props;
+import akka.actor.UntypedActor;
+import akka.actor.UntypedActorFactory;
+import akka.cluster.routing.ClusterRouterConfig;
+import akka.cluster.routing.ClusterRouterSettings;
+import akka.routing.ConsistentHashingRouter;
+import akka.routing.ConsistentHashingRouter.ConsistentHashableEnvelope;
+import akka.routing.FromConfig;
+//#imports
+
+//#service
+public class StatsService extends UntypedActor {
+
+ ActorRef workerRouter = getContext().actorOf(
+ new Props(StatsWorker.class).withRouter(FromConfig.getInstance()),
+ "workerRouter");
+
+ @Override
+ public void onReceive(Object message) {
+ if (message instanceof StatsJob) {
+ StatsJob job = (StatsJob) message;
+ if (job.getText().equals("")) {
+ unhandled(message);
+ } else {
+ final String[] words = job.getText().split(" ");
+ final ActorRef replyTo = getSender();
+
+ // create actor that collects replies from workers
+ ActorRef aggregator = getContext().actorOf(
+ new Props(new UntypedActorFactory() {
+ @Override
+ public UntypedActor create() {
+ return new StatsAggregator(words.length, replyTo);
+ }
+ }));
+
+ // send each word to a worker
+ for (String word : words) {
+ workerRouter.tell(new ConsistentHashableEnvelope(word, word),
+ aggregator);
+ }
+ }
+
+ } else {
+ unhandled(message);
+ }
+ }
+}
+
+//#service
+
+//not used, only for documentation
+abstract class StatsService2 extends UntypedActor {
+ //#router-lookup-in-code
+ int totalInstances = 100;
+ String routeesPath = "/user/statsWorker";
+ boolean allowLocalRoutees = true;
+ ActorRef workerRouter = getContext().actorOf(
+ new Props(StatsWorker.class).withRouter(new ClusterRouterConfig(
+ new ConsistentHashingRouter(0), new ClusterRouterSettings(
+ totalInstances, routeesPath, allowLocalRoutees))),
+ "workerRouter2");
+ //#router-lookup-in-code
+}
+
+//not used, only for documentation
+abstract class StatsService3 extends UntypedActor {
+ //#router-deploy-in-code
+ int totalInstances = 100;
+ int maxInstancesPerNode = 3;
+ boolean allowLocalRoutees = false;
+ ActorRef workerRouter = getContext().actorOf(
+ new Props(StatsWorker.class).withRouter(new ClusterRouterConfig(
+ new ConsistentHashingRouter(0), new ClusterRouterSettings(
+ totalInstances, maxInstancesPerNode, allowLocalRoutees))),
+ "workerRouter3");
+ //#router-deploy-in-code
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsWorker.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsWorker.java
new file mode 100644
index 0000000000..ca0af86af6
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/stats/japi/StatsWorker.java
@@ -0,0 +1,30 @@
+package sample.cluster.stats.japi;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import akka.actor.UntypedActor;
+
+//#worker
+public class StatsWorker extends UntypedActor {
+
+ Map cache = new HashMap();
+
+ @Override
+ public void onReceive(Object message) {
+ if (message instanceof String) {
+ String word = (String) message;
+ Integer length = cache.get(word);
+ if (length == null) {
+ length = word.length();
+ cache.put(word, length);
+ }
+ getSender().tell(length, getSelf());
+
+ } else {
+ unhandled(message);
+ }
+ }
+
+}
+//#worker
\ No newline at end of file
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackend.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackend.java
new file mode 100644
index 0000000000..a81d9db39d
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackend.java
@@ -0,0 +1,65 @@
+package sample.cluster.transformation.japi;
+
+import static sample.cluster.transformation.japi.TransformationMessages.BACKEND_REGISTRATION;
+import sample.cluster.transformation.japi.TransformationMessages.TransformationJob;
+import sample.cluster.transformation.japi.TransformationMessages.TransformationResult;
+//#imports
+import akka.actor.UntypedActor;
+import akka.cluster.Cluster;
+import akka.cluster.ClusterEvent.CurrentClusterState;
+import akka.cluster.ClusterEvent.MemberEvent;
+import akka.cluster.ClusterEvent.MemberUp;
+import akka.cluster.Member;
+import akka.cluster.MemberStatus;
+//#imports
+
+//#backend
+public class TransformationBackend extends UntypedActor {
+
+ Cluster cluster = Cluster.get(getContext().system());
+
+ //subscribe to cluster changes, MemberEvent
+ @Override
+ public void preStart() {
+ cluster.subscribe(getSelf(), MemberEvent.class);
+ }
+
+ //re-subscribe when restart
+ @Override
+ public void postStop() {
+ cluster.unsubscribe(getSelf());
+ }
+
+ @Override
+ public void onReceive(Object message) {
+ if (message instanceof TransformationJob) {
+ TransformationJob job = (TransformationJob) message;
+ getSender()
+ .tell(new TransformationResult(job.getText().toUpperCase()),
+ getSelf());
+
+ } else if (message instanceof CurrentClusterState) {
+ CurrentClusterState state = (CurrentClusterState) message;
+ for (Member member : state.getMembers()) {
+ if (member.status().equals(MemberStatus.up())) {
+ register(member);
+ }
+ }
+
+ } else if (message instanceof MemberUp) {
+ MemberUp mUp = (MemberUp) message;
+ register(mUp.member());
+
+ } else {
+ unhandled(message);
+ }
+ }
+
+ //try to register to all nodes, even though there
+ // might not be any frontend on all nodes
+ void register(Member member) {
+ getContext().actorFor(member.address() + "/user/frontend").tell(
+ BACKEND_REGISTRATION, getSelf());
+ }
+}
+//#backend
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackendMain.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackendMain.java
new file mode 100644
index 0000000000..42fa8e6c80
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationBackendMain.java
@@ -0,0 +1,20 @@
+package sample.cluster.transformation.japi;
+
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+
+public class TransformationBackendMain {
+
+ public static void main(String[] args) throws Exception {
+ // Override the configuration of the port
+ // when specified as program argument
+ if (args.length > 0)
+ System.setProperty("akka.remote.netty.port", args[0]);
+
+ ActorSystem system = ActorSystem.create("ClusterSystem");
+
+ system.actorOf(new Props(TransformationBackend.class), "backend");
+
+ }
+
+}
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontend.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontend.java
new file mode 100644
index 0000000000..c1fe0f9038
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontend.java
@@ -0,0 +1,48 @@
+package sample.cluster.transformation.japi;
+
+import static sample.cluster.transformation.japi.TransformationMessages.BACKEND_REGISTRATION;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import sample.cluster.transformation.japi.TransformationMessages.JobFailed;
+import sample.cluster.transformation.japi.TransformationMessages.TransformationJob;
+import akka.actor.ActorRef;
+import akka.actor.Terminated;
+import akka.actor.UntypedActor;
+
+//#frontend
+public class TransformationFrontend extends UntypedActor {
+
+ List backends = new ArrayList();
+ int jobCounter = 0;
+
+ @Override
+ public void onReceive(Object message) {
+ if ((message instanceof TransformationJob) && backends.isEmpty()) {
+ TransformationJob job = (TransformationJob) message;
+ getSender().tell(
+ new JobFailed("Service unavailable, try again later", job),
+ getSender());
+
+ } else if (message instanceof TransformationJob) {
+ TransformationJob job = (TransformationJob) message;
+ jobCounter++;
+ backends.get(jobCounter % backends.size())
+ .forward(job, getContext());
+
+ } else if (message.equals(BACKEND_REGISTRATION)) {
+ getContext().watch(getSender());
+ backends.add(getSender());
+
+ } else if (message instanceof Terminated) {
+ Terminated terminated = (Terminated) message;
+ backends.remove(terminated.getActor());
+
+ } else {
+ unhandled(message);
+ }
+ }
+
+}
+//#frontend
diff --git a/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontendMain.java b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontendMain.java
new file mode 100644
index 0000000000..2793494b3d
--- /dev/null
+++ b/akka-samples/akka-sample-cluster/src/main/java/sample/cluster/transformation/japi/TransformationFrontendMain.java
@@ -0,0 +1,45 @@
+package sample.cluster.transformation.japi;
+
+import java.util.concurrent.TimeUnit;
+
+import sample.cluster.transformation.japi.TransformationMessages.TransformationJob;
+import scala.concurrent.ExecutionContext;
+import scala.concurrent.util.Duration;
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.dispatch.OnSuccess;
+import akka.util.Timeout;
+import static akka.pattern.Patterns.ask;
+
+public class TransformationFrontendMain {
+
+ public static void main(String[] args) throws Exception {
+ // Override the configuration of the port
+ // when specified as program argument
+ if (args.length > 0)
+ System.setProperty("akka.remote.netty.port", args[0]);
+
+ ActorSystem system = ActorSystem.create("ClusterSystem");
+
+ ActorRef frontend = system.actorOf(new Props(
+ TransformationFrontend.class), "frontend");
+ Timeout timeout = new Timeout(Duration.create(5, TimeUnit.SECONDS));
+ final ExecutionContext ec = system.dispatcher();
+ for (int n = 1; n <= 120; n++) {
+ ask(frontend, new TransformationJob("hello-" + n), timeout)
+ .onSuccess(new OnSuccess