Add distibuted action

- New module spring-statemachine-cluster which is
  based on spring-cloud-cluster to provide leader
  election.
- Ensemble now has a concept of a leader if implementation
  supports it.
- New DistributedLeaderAction can use leader info to execute
  action only on a leader.
- Tweak web sample with these new concepts.
- Fixes #176

spring-statemachine-samples/web/src/main/java/demo/web/StateMachineConfig.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,10 +22,14 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.framework.CuratorFrameworkFactory;
 import org.apache.curator.retry.ExponentialBackoffRetry;
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.messaging.simp.SimpMessagingTemplate;
 import org.springframework.statemachine.StateContext;
 import org.springframework.statemachine.action.Action;
+import org.springframework.statemachine.action.DistributedLeaderAction;
+import org.springframework.statemachine.cluster.LeaderZookeeperStateMachineEnsemble;
 import org.springframework.statemachine.config.EnableStateMachine;
 import org.springframework.statemachine.config.EnumStateMachineConfigurerAdapter;
 import org.springframework.statemachine.config.builders.StateMachineConfigurationConfigurer;
@@ -33,7 +37,6 @@ import org.springframework.statemachine.config.builders.StateMachineStateConfigu
 import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer;
 import org.springframework.statemachine.ensemble.StateMachineEnsemble;
 import org.springframework.statemachine.guard.Guard;
-import org.springframework.statemachine.zookeeper.ZookeeperStateMachineEnsemble;
 
 @Configuration
 public class StateMachineConfig {
@@ -45,8 +48,12 @@ public class StateMachineConfig {
 	static class Config
 			extends EnumStateMachineConfigurerAdapter<States, Events> {
 
+		@Autowired
+		private SimpMessagingTemplate simpMessagingTemplate;
+
 		@Override
-		public void configure(StateMachineConfigurationConfigurer<States, Events> config) throws Exception {
+		public void configure(StateMachineConfigurationConfigurer<States, Events> config)
+				throws Exception {
 			config
 				.withDistributed()
 					.ensemble(stateMachineEnsemble())
@@ -72,7 +79,7 @@ public class StateMachineConfig {
 							.parent(States.S1)
 							.initial(States.S11)
 							.state(States.S11)
-							.state(States.S12)
+							.state(States.S12, distAction(), null)
 							.and()
 					.withStates()
 						.parent(States.S0)
@@ -178,9 +185,14 @@ public class StateMachineConfig {
 			return new SetVariableAction();
 		}
 
+		@Bean
+		public DistributedLeaderAction<States, Events> distAction() throws Exception {
+			return new DistributedLeaderAction<>(new HelloAction(simpMessagingTemplate), stateMachineEnsemble());
+		}
+
 		@Bean
 		public StateMachineEnsemble<States, Events> stateMachineEnsemble() throws Exception {
-			return new ZookeeperStateMachineEnsemble<States, Events>(curatorClient(), "/foo");
+			return new LeaderZookeeperStateMachineEnsemble<States, Events>(curatorClient(), "/foo");
 		}
 
 		@Bean
@@ -193,7 +205,6 @@ public class StateMachineConfig {
 			client.start();
 			return client;
 		}
-
 	}
 
 	public enum States {
@@ -247,7 +258,22 @@ public class StateMachineConfig {
 				context.getExtendedState().getVariables().put("testVariable", testVariable);
 			}
 		}
-
 	}
 
+	private static class HelloAction implements Action<States, Events> {
+
+		SimpMessagingTemplate simpMessagingTemplate;
+
+		public HelloAction(SimpMessagingTemplate simpMessagingTemplate) {
+			this.simpMessagingTemplate = simpMessagingTemplate;
+		}
+
+		@Override
+		public void execute(StateContext<States, Events> context) {
+			log.info("Hello");
+			StateMachineMessage message = new StateMachineMessage();
+			message.setMessage("Hello action");
+			simpMessagingTemplate.convertAndSend("/topic/sm.message", message);
+		}
+	}
 }

spring-statemachine-samples/web/src/main/java/demo/web/StateMachineController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,6 +34,8 @@ import org.springframework.messaging.simp.annotation.SubscribeMapping;
 import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.StateMachineException;
+import org.springframework.statemachine.ensemble.EnsembleListenerAdapter;
+import org.springframework.statemachine.ensemble.StateMachineEnsemble;
 import org.springframework.statemachine.listener.StateMachineListenerAdapter;
 import org.springframework.statemachine.state.State;
 import org.springframework.statemachine.transition.Transition;
@@ -59,6 +61,9 @@ public class StateMachineController {
 	@Autowired
 	private StateMachine<States, Events> stateMachine;
 
+	@Autowired
+	private StateMachineEnsemble<States, Events> stateMachineEnsemble;
+
 	@PostConstruct
 	public void setup() {
 
@@ -102,6 +107,28 @@ public class StateMachineController {
 			}
 
 		});
+
+		stateMachineEnsemble.addEnsembleListener(new EnsembleListenerAdapter<States, Events>() {
+
+			@Override
+			public void ensembleLeaderGranted(StateMachine<States, Events> stateMachine) {
+				StateMachineMessage message = new StateMachineMessage();
+				message.setMessage("Leader granted " + stateMachine.getUuid().toString());
+				simpMessagingTemplate.convertAndSend("/topic/sm.message", message);
+			}
+
+			@Override
+			public void ensembleLeaderRevoked(StateMachine<States, Events> stateMachine) {
+				StateMachineMessage message = new StateMachineMessage();
+				message.setMessage("Leader revoked " + stateMachine.getUuid().toString());
+				simpMessagingTemplate.convertAndSend("/topic/sm.message", message);
+			}
+		});
+	}
+
+	@SubscribeMapping("/sm.uuid")
+	public String retrieveUuid() {
+		return stateMachine.getUuid().toString();
 	}
 
 	@SubscribeMapping("/sm.states")
@@ -123,12 +150,24 @@ public class StateMachineController {
 	public void sendEvent(@RequestParam(value = "id") Events id,
 			@RequestParam(value = "testVariable", required = false) String testVariable) {
 		log.info("Got request to send event " + id + " testVariable " + testVariable);
-	    Message<Events> message = MessageBuilder
-	            .withPayload(id)
-	            .setHeader("testVariable", testVariable)
-	            .build();
-	    stateMachine.sendEvent(message);
-    }
+		Message<Events> message = MessageBuilder
+				.withPayload(id)
+				.setHeader("testVariable", testVariable)
+				.build();
+		stateMachine.sendEvent(message);
+	}
+
+	@RequestMapping("/join")
+	@ResponseStatus(HttpStatus.OK)
+	public void joinEnsemble() {
+		stateMachineEnsemble.join(stateMachine);
+	}
+
+	@RequestMapping("/leave")
+	@ResponseStatus(HttpStatus.OK)
+	public void leaveEnsemble() {
+		stateMachineEnsemble.leave(stateMachine);
+	}
 
 	@RequestMapping(value = "/states", method = RequestMethod.GET, produces="application/json")
 	@ResponseBody

spring-statemachine-samples/web/src/main/resources/statechartmodel.txt

@@ -1,44 +1,44 @@
-+----------------------------------------------------------------------------------------------+
-|                                                S0                                            |
-+----------------------------------------------------------------------------------------------+
-|  entry/                                                                                      |
-|  exit/                                                                                       |
-|  H/[foo.equals(0)];                                                                          |
-|                                                                                              |
-|            +-------------------------+      +--------------------------------------------+   |
-|        *-->|            S1           |      |                     S2                     |   |
-|            +-------------------------+      +--------------------------------------------+   |
-|            | entry/                  |  C   | entry/                                     |   |
-|      D     | exit/                   |----->| exit/                                      |   |
-|<-----------| H/                      |      | H/[foo.equals(1)];                         |   |
-|            |                         |      |                                            |   |
-|            |     +---------------+   |  K   |      +------------------------------+      |   |
-|            | *-->|      S11      |   |<-----|  *-->|             S21              |      |   |
-|            |     +---------------+   |      |      +------------------------------+      |   |
-|            |     | entry/        |   |  F   |      | entry/                       |      |   |
-|            |     | exit/         |<---------|      | exit/                        |      |   |
-|            |     |               |   |      |      |       +--------------+       |      |   |
-|            |  B  |               |   |      |      |   *-->|     s211     |       |      |   |
-|            |---->|       J       |   |      |   F  |       +--------------+   G   |      |   |
-|            |     |   +-------+   |   |-------------------->| entry/       |----------------->|
-|            |  +--|   |       |   |   |      |   G  |       | exit/        |       |      |   |
-|            |  |  |   |       v   |------------------------>|              |       |  E   |   |
-|            |  |  +---------------+   |      |      |   B   |              |<-----------------|
-|            |  |                      |      |      |------>|              |       |      |   |
-|            |  |  +---------------+   |      |      |       |              |   D   |      |   |
-|            | I|  |      S12      |   |      |      |    +--|              |------>|      |   |
-|            |  |  +---------------+   |      |      |    |  +--------------+       |      |   |
-|            |  |  | entry/        |   |      |      |    |                         |      |   |
-|            |  |  | exit/         |   |      |      |   I|  +--------------+       |      |   |
-|            |  |  |               |   |      |      |    |  |     s212     |       |      |   |
-|            |  +->|               |   |      |      |    |  +--------------+       |      |   |
-|         +--|     |               |   |      |      |    +->| entry/       |       |      |   |
-|         |  |     |               |   |  I   |      |       | exit/        |       |      |   |
-|         |  |     |               |------------------------>|              |       |      |   |
-|        A|  |     |               |   |      |      |       +--------------+       |      |   |
-|         |  |     |               |   |      |      |                              |      |   |
-|         |  |     +---------------+   |      |      +------------------------------+      |   |
-|         +->|                         |      |                                            |   |
-|            +-------------------------+      +--------------------------------------------+   |
-| A[foo.equals(1)];                                                                            |
-+----------------------------------------------------------------------------------------------+
++-----------------------------------------------------------------------------------------------+
+|                                                 S0                                            |
++-----------------------------------------------------------------------------------------------+
+|  entry/                                                                                       |
+|  exit/                                                                                        |
+|  H/[foo.equals(0)];                                                                           |
+|                                                                                               |
+|            +--------------------------+      +--------------------------------------------+   |
+|        *-->|            S1            |      |                     S2                     |   |
+|            +--------------------------+      +--------------------------------------------+   |
+|            | entry/                   |  C   | entry/                                     |   |
+|      D     | exit/                    |----->| exit/                                      |   |
+|<-----------| H/                       |      | H/[foo.equals(1)];                         |   |
+|            |                          |      |                                            |   |
+|            |     +----------------+   |  K   |      +------------------------------+      |   |
+|            | *-->|      S11       |   |<-----|  *-->|             S21              |      |   |
+|            |     +----------------+   |      |      +------------------------------+      |   |
+|            |     | entry/         |   |  F   |      | entry/                       |      |   |
+|            |     | exit/          |<---------|      | exit/                        |      |   |
+|            |     |                |   |      |      |       +--------------+       |      |   |
+|            |  B  |                |   |      |      |   *-->|     s211     |       |      |   |
+|            |---->|       J        |   |      |   F  |       +--------------+   G   |      |   |
+|            |     |   +-------+    |   |-------------------->| entry/       |----------------->|
+|            |  +--|   |       |    |   |      |   G  |       | exit/        |       |      |   |
+|            |  |  |   |       v    |------------------------>|              |       |  E   |   |
+|            |  |  +----------------+   |      |      |   B   |              |<-----------------|
+|            |  |                       |      |      |------>|              |       |      |   |
+|            |  |  +----------------+   |      |      |       |              |   D   |      |   |
+|            | I|  |      S12       |   |      |      |    +--|              |------>|      |   |
+|            |  |  +----------------+   |      |      |    |  +--------------+       |      |   |
+|            |  |  | entry/         |   |      |      |    |                         |      |   |
+|            |  |  |   distAction() |   |      |      |   I|  +--------------+       |      |   |
+|            |  |  | exit/          |   |      |      |    |  |     s212     |       |      |   |
+|            |  +->|                |   |      |      |    |  +--------------+       |      |   |
+|         +--|     |                |   |      |      |    +->| entry/       |       |      |   |
+|         |  |     |                |   |  I   |      |       | exit/        |       |      |   |
+|         |  |     |                |------------------------>|              |       |      |   |
+|        A|  |     |                |   |      |      |       +--------------+       |      |   |
+|         |  |     |                |   |      |      |                              |      |   |
+|         |  |     +----------------+   |      |      +------------------------------+      |   |
+|         +->|                          |      |                                            |   |
+|            +--------------------------+      +--------------------------------------------+   |
+| A[foo.equals(1)];                                                                             |
++-----------------------------------------------------------------------------------------------+

spring-statemachine-samples/web/src/main/resources/static/index.html

@@ -1,15 +1,15 @@
 <!DOCTYPE html>
 <html lang="en" ng-app="springChat">
 	<head>
-	  <meta charset="utf-8" />
-	  <title>Spring Statemachine Zookeeper Demo</title>
-	  <meta name="viewport" content="width=device-width, initial-scale=1.0">
+		<meta charset="utf-8" />
+		<title>Spring Statemachine Zookeeper Demo</title>
+		<meta name="viewport" content="width=device-width, initial-scale=1.0">
 
-	  <link href="lib/flat-ui/dist/css/vendor/bootstrap.min.css" rel="stylesheet">
-	  <link href="lib/flat-ui/dist/css/flat-ui.css" rel="stylesheet">
-	  <link href="lib/angularjs-toaster/toaster.css" rel="stylesheet">
+		<link href="lib/flat-ui/dist/css/vendor/bootstrap.min.css" rel="stylesheet">
+		<link href="lib/flat-ui/dist/css/flat-ui.css" rel="stylesheet">
+		<link href="lib/angularjs-toaster/toaster.css" rel="stylesheet">
 
-	  <link href="css/chat.css" rel="stylesheet">
+		<link href="css/chat.css" rel="stylesheet">
 	</head>
 	<body>
 
@@ -23,18 +23,18 @@
 				</nav>
 			</div>
 			<div class="row">
-	        	<div>
-       				<button ng-click="sendEvent('A')">event A</button>
-       				<button ng-click="sendEvent('B')">event B</button>
-       				<button ng-click="sendEvent('C')">event C</button>
-       				<button ng-click="sendEvent('D')">event D</button>
-       				<button ng-click="sendEvent('E')">event E</button>
-       				<button ng-click="sendEvent('F')">event F</button>
-       				<button ng-click="sendEvent('G')">event G</button>
-       				<button ng-click="sendEvent('H')">event H</button>
-       				<button ng-click="sendEvent('I')">event I</button>
-       				<button ng-click="sendEvent('K')">event K</button>
-       			</div>
+				<div>
+					<button ng-click="sendEvent('A')">event A</button>
+					<button ng-click="sendEvent('B')">event B</button>
+					<button ng-click="sendEvent('C')">event C</button>
+					<button ng-click="sendEvent('D')">event D</button>
+					<button ng-click="sendEvent('E')">event E</button>
+					<button ng-click="sendEvent('F')">event F</button>
+					<button ng-click="sendEvent('G')">event G</button>
+					<button ng-click="sendEvent('H')">event H</button>
+					<button ng-click="sendEvent('I')">event I</button>
+					<button ng-click="sendEvent('K')">event K</button>
+				</div>
 			</div>
 			<div class="row">
 				<div>
@@ -42,44 +42,53 @@
 					<input id="newTestVariable" type="text" ng-model="testVariable" placeholder="New testVariable value..." />
 				</div>
 			</div>
-	        <div class="row">
-        		<div class="col-xs-3">
-        			<h4>States</h4>
-        			<div class="share">
-	        			<ul ng-repeat="participant in participants">
-	        				<li>
-	        					<div>{{participant.message}}</div>
-	        				</li>
-	        			</ul>
-        			</div>
-        		</div>
-        		<div class="col-xs-3">
-        			<h4>Variables</h4>
-        			<div class="share">
-	        			<ul ng-repeat="variable in variables">
-	        				<li>
-	        					<div>{{variable}}</div>
-	        				</li>
-	        			</ul>
-        			</div>
-        		</div>
-        		<div class="col-xs-8 chat-box">
-        			<h4>Messages</h4>
-	        		<div ng-repeat="message in messages">
-	       	 			<small print-message></small>
-	      			</div>
-        		</div>
-        	</div>
-	    </div>
-	    <!-- /.container -->
+			<div class="row">
+				<div>
+					<button ng-click="joinEnsemble()">Join</button>
+					<button ng-click="leaveEnsemble()">Leave</button>
+				</div>
+			</div>
+			<div class="row">
+				<div ng-if="uuid">UUID: {{uuid}}</div>
+			</div>
+			<div class="row">
+				<div class="col-xs-3">
+					<h4>States</h4>
+					<div class="share">
+						<ul ng-repeat="participant in participants">
+							<li>
+								<div>{{participant.message}}</div>
+							</li>
+						</ul>
+					</div>
+				</div>
+				<div class="col-xs-3">
+					<h4>Variables</h4>
+					<div class="share">
+						<ul ng-repeat="variable in variables">
+							<li>
+								<div>{{variable}}</div>
+							</li>
+						</ul>
+					</div>
+				</div>
+				<div class="col-xs-8 chat-box">
+					<h4>Messages</h4>
+					<div ng-repeat="message in messages">
+							<small print-message></small>
+					</div>
+				</div>
+			</div>
+		</div>
+		<!-- /.container -->
 
 		<!-- 3rd party -->
 		<script src="lib/angular/angular.min.js"></script>
-	    <script src="lib/angular-animate/angular-animate.min.js"></script>
-	    <script src="lib/angularjs-toaster/toaster.js"></script>
-	    <script src="lib/angularjs-scroll-glue/src/scrollglue.js"></script>
-	    <script src="lib/sockjs/sockjs.min.js"></script>
-	    <script src="lib/stomp/lib/stomp.min.js"></script>
+			<script src="lib/angular-animate/angular-animate.min.js"></script>
+			<script src="lib/angularjs-toaster/toaster.js"></script>
+			<script src="lib/angularjs-scroll-glue/src/scrollglue.js"></script>
+			<script src="lib/sockjs/sockjs.min.js"></script>
+			<script src="lib/stomp/lib/stomp.min.js"></script>
 
 		<!-- App -->
 		<script src="js/app.js"></script>

spring-statemachine-samples/web/src/main/resources/static/js/controllers.js

@@ -7,10 +7,11 @@ angular.module('springChat.controllers', ['toaster'])
 
 		var typing = undefined;
 
+		$scope.uuid = '';
 		$scope.participants = [];
 		$scope.variables = [];
-		$scope.messages     = [];
-		$scope.newMessage   = '';
+		$scope.messages = [];
+		$scope.newMessage = '';
 
 		$scope.sendEvent = function(event) {
 			$http.post('/event', null, {params:{"id": event}}).
@@ -24,11 +25,27 @@ angular.module('springChat.controllers', ['toaster'])
 				});
 		};
 
+		$scope.joinEnsemble = function(event) {
+			$http.post('/join', null, {}).
+				success(function(data) {
+				});
+		};
+
+		$scope.leaveEnsemble = function(event) {
+			$http.post('/leave', null, {}).
+				success(function(data) {
+				});
+		};
+
 		var initStompClient = function() {
 			chatSocket.init('/ws');
 
 			chatSocket.connect(function(frame) {
 
+				chatSocket.subscribe("/app/sm.uuid", function(message) {
+					$scope.uuid = message.body;
+				});
+
 				chatSocket.subscribe("/app/sm.states", function(message) {
 					$scope.participants = JSON.parse(message.body);
 				});
@@ -55,16 +72,16 @@ angular.module('springChat.controllers', ['toaster'])
 
 				chatSocket.subscribe("/topic/sm.message", function(message) {
 					$scope.messages.unshift(JSON.parse(message.body));
-		        });
+						});
 
 				chatSocket.subscribe("/user/queue/errors", function(message) {
 					toaster.pop('error', "Error", message.body);
-		        });
+						});
 
 			}, function(error) {
 				toaster.pop('error', 'Error', 'Connection error ' + error);
 
-		    });
+				});
 		};
 
 		initStompClient();