Add support for choice states

- Adding choice state construction and
  guard resolving.
- Relates to #262

spring-statemachine-data/jpa/src/test/java/org/springframework/statemachine/data/jpa/JpaRepositoryTests.java

@@ -31,6 +31,8 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
+import org.springframework.messaging.support.MessageBuilder;
+import org.springframework.statemachine.StateContext;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.config.EnableStateMachineFactory;
 import org.springframework.statemachine.config.StateMachineConfigurerAdapter;
@@ -43,9 +45,11 @@ import org.springframework.statemachine.data.RepositoryTransition;
 import org.springframework.statemachine.data.StateRepository;
 import org.springframework.statemachine.data.TransitionRepository;
 import org.springframework.statemachine.data.support.StateMachineJackson2RepositoryPopulatorFactoryBean;
+import org.springframework.statemachine.guard.Guard;
 import org.springframework.statemachine.test.StateMachineTestPlan;
 import org.springframework.statemachine.test.StateMachineTestPlanBuilder;
 import org.springframework.statemachine.transition.TransitionKind;
+import org.springframework.util.ObjectUtils;
 
 public class JpaRepositoryTests extends AbstractJpaRepositoryTests {
 
@@ -281,6 +285,74 @@ public class JpaRepositoryTests extends AbstractJpaRepositoryTests {
 		plan.test();
 	}
 
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testMachine6First() throws Exception {
+		context.register(Config6.class, FactoryConfig.class);
+		context.refresh();
+		StateMachineFactory<String, String> stateMachineFactory = context.getBean(StateMachineFactory.class);
+		StateMachine<String, String> stateMachine = stateMachineFactory.getStateMachine();
+
+		StateMachineTestPlan<String, String> plan =
+				StateMachineTestPlanBuilder.<String, String>builder()
+					.stateMachine(stateMachine)
+					.step().expectStates("SI").and()
+					.step().sendEvent(MessageBuilder.withPayload("E1").setHeader("choice", "s30").build()).expectStates("S30").and()
+					.build();
+		plan.test();
+	}
+
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testMachine6Then1() throws Exception {
+		context.register(Config6.class, FactoryConfig.class);
+		context.refresh();
+		StateMachineFactory<String, String> stateMachineFactory = context.getBean(StateMachineFactory.class);
+		StateMachine<String, String> stateMachine = stateMachineFactory.getStateMachine();
+
+		StateMachineTestPlan<String, String> plan =
+				StateMachineTestPlanBuilder.<String, String>builder()
+					.stateMachine(stateMachine)
+					.step().expectStates("SI").and()
+					.step().sendEvent(MessageBuilder.withPayload("E1").setHeader("choice", "s31").build()).expectStates("S31").and()
+					.build();
+		plan.test();
+	}
+
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testMachine6Then2() throws Exception {
+		context.register(Config6.class, FactoryConfig.class);
+		context.refresh();
+		StateMachineFactory<String, String> stateMachineFactory = context.getBean(StateMachineFactory.class);
+		StateMachine<String, String> stateMachine = stateMachineFactory.getStateMachine();
+
+		StateMachineTestPlan<String, String> plan =
+				StateMachineTestPlanBuilder.<String, String>builder()
+					.stateMachine(stateMachine)
+					.step().expectStates("SI").and()
+					.step().sendEvent(MessageBuilder.withPayload("E1").setHeader("choice", "s32").build()).expectStates("S32").and()
+					.build();
+		plan.test();
+	}
+
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testMachine6Last() throws Exception {
+		context.register(Config6.class, FactoryConfig.class);
+		context.refresh();
+		StateMachineFactory<String, String> stateMachineFactory = context.getBean(StateMachineFactory.class);
+		StateMachine<String, String> stateMachine = stateMachineFactory.getStateMachine();
+
+		StateMachineTestPlan<String, String> plan =
+				StateMachineTestPlanBuilder.<String, String>builder()
+					.stateMachine(stateMachine)
+					.step().expectStates("SI").and()
+					.step().sendEvent(MessageBuilder.withPayload("E1").build()).expectStates("S33").and()
+					.build();
+		plan.test();
+	}
+
 	@Test
 	public void testPopulate1() {
 		context.register(Config2.class);
@@ -365,6 +437,33 @@ public class JpaRepositoryTests extends AbstractJpaRepositoryTests {
 		}
 	}
 
+	@EnableAutoConfiguration
+	static class Config6 {
+
+		@Bean
+		public StateMachineJackson2RepositoryPopulatorFactoryBean jackson2RepositoryPopulatorFactoryBean() {
+			StateMachineJackson2RepositoryPopulatorFactoryBean factoryBean = new StateMachineJackson2RepositoryPopulatorFactoryBean();
+			factoryBean.setResources(new Resource[]{new ClassPathResource("data6.json")});
+			return factoryBean;
+		}
+
+		@Bean
+		public Guard<String, String> s30Guard() {
+			return new ChoiceGuard("s30");
+		}
+
+		@Bean
+		public Guard<String, String> s31Guard() {
+			return new ChoiceGuard("s31");
+		}
+
+		@Bean
+		public Guard<String, String> s32Guard() {
+			return new ChoiceGuard("s32");
+		}
+
+	}
+
 	@Configuration
 	@EnableStateMachineFactory
 	public static class FactoryConfig extends StateMachineConfigurerAdapter<String, String> {
@@ -388,4 +487,18 @@ public class JpaRepositoryTests extends AbstractJpaRepositoryTests {
 		}
 	}
 
+	private static class ChoiceGuard implements Guard<String, String> {
+
+		private final String match;
+
+		public ChoiceGuard(String match) {
+			this.match = match;
+		}
+
+		@Override
+		public boolean evaluate(StateContext<String, String> context) {
+			return ObjectUtils.nullSafeEquals(match, context.getMessageHeaders().get("choice", String.class));
+		}
+	}
+
 }

spring-statemachine-data/jpa/src/test/resources/data6.json

@@ -0,0 +1,78 @@
+[
+	{
+		"@id": "1",
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryState",
+		"initial": true,
+		"state": "SI"
+	},
+	{
+		"@id": "2",
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryState",
+		"initial": false,
+		"state": "S3",
+		"kind": "CHOICE"
+	},
+	{
+		"@id": "3",
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryState",
+		"initial": false,
+		"state": "S30"
+	},
+	{
+		"@id": "4",
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryState",
+		"initial": false,
+		"state": "S31"
+	},
+	{
+		"@id": "5",
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryState",
+		"initial": false,
+		"state": "S32"
+	},
+	{
+		"@id": "6",
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryState",
+		"initial": false,
+		"state": "S33"
+	},
+	{
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryTransition",
+		"source": "1",
+		"target": "2",
+		"event": "E1",
+		"kind": "EXTERNAL"
+	},
+	{
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryTransition",
+		"source": "2",
+		"target": "3",
+		"guard": {
+			"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryGuard",
+			"name": "s30Guard"
+		}
+	},
+	{
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryTransition",
+		"source": "2",
+		"target": "4",
+		"guard": {
+			"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryGuard",
+			"name": "s31Guard"
+		}
+	},
+	{
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryTransition",
+		"source": "2",
+		"target": "5",
+		"guard": {
+			"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryGuard",
+			"name": "s32Guard"
+		}
+	},
+	{
+		"_class": "org.springframework.statemachine.data.jpa.JpaRepositoryTransition",
+		"source": "2",
+		"target": "6"
+	}
+]

spring-statemachine-data/src/main/java/org/springframework/statemachine/data/RepositoryStateMachineModelFactory.java

@@ -17,6 +17,10 @@ package org.springframework.statemachine.data;
 
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import org.springframework.expression.spel.SpelCompilerMode;
@@ -25,6 +29,7 @@ import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.statemachine.action.Action;
 import org.springframework.statemachine.action.SpelExpressionAction;
 import org.springframework.statemachine.config.model.AbstractStateMachineModelFactory;
+import org.springframework.statemachine.config.model.ChoiceData;
 import org.springframework.statemachine.config.model.ConfigurationData;
 import org.springframework.statemachine.config.model.DefaultStateMachineModel;
 import org.springframework.statemachine.config.model.HistoryData;
@@ -149,6 +154,7 @@ public class RepositoryStateMachineModelFactory extends AbstractStateMachineMode
 		StatesData<String, String> statesData = new StatesData<>(stateDatas);
 		Collection<TransitionData<String, String>> transitionData = new ArrayList<>();
 		Collection<HistoryData<String, String>> historys = new ArrayList<HistoryData<String, String>>();
+		Map<String, LinkedList<ChoiceData<String, String>>> choices = new HashMap<String, LinkedList<ChoiceData<String,String>>>();
 		for (RepositoryTransition t : transitionRepository.findByMachineId(machineId)) {
 
 			Collection<Action<String, String>> actions = new ArrayList<Action<String, String>>();
@@ -172,28 +178,51 @@ public class RepositoryStateMachineModelFactory extends AbstractStateMachineMode
 
 			TransitionKind kind = t.getKind();
 
-			Guard<String, String> guard = null;
-			RepositoryGuard repositoryGuard = t.getGuard();
-			if (repositoryGuard != null) {
-				if (StringUtils.hasText(repositoryGuard.getName())) {
-					guard = resolveGuard(repositoryGuard.getName());
-				} else if (StringUtils.hasText(repositoryGuard.getSpel())) {
-					SpelExpressionParser parser = new SpelExpressionParser(
-							new SpelParserConfiguration(SpelCompilerMode.MIXED, null));
-					guard = new SpelExpressionGuard<>(parser.parseExpression(repositoryGuard.getSpel()));
-				}
-			}
+			Guard<String, String> guard = resolveGuard(t);
 			transitionData.add(new TransitionData<>(t.getSource().getState(), t.getTarget().getState(), t.getEvent(), actions, guard, kind != null ? kind : TransitionKind.EXTERNAL));
 
-			if (t.getSource().getKind() == PseudoStateKind.HISTORY_SHALLOW) {
+			if (t.getSource().getKind() == PseudoStateKind.CHOICE) {
+				LinkedList<ChoiceData<String, String>> list = choices.get(t.getSource().getState());
+				if (list == null) {
+					list = new LinkedList<ChoiceData<String, String>>();
+					choices.put(t.getSource().getState(), list);
+				}
+				guard = resolveGuard(t);
+				// we want null guards to be at the end
+				if (guard == null) {
+					list.addLast(new ChoiceData<String, String>(t.getSource().getState(), t.getTarget().getState(), guard));
+				} else {
+					list.addFirst(new ChoiceData<String, String>(t.getSource().getState(), t.getTarget().getState(), guard));
+				}
+
+			} else if (t.getSource().getKind() == PseudoStateKind.HISTORY_SHALLOW) {
 				historys.add(new HistoryData<String, String>(t.getSource().getState(), t.getTarget().getState()));
 			} else if (t.getSource().getKind() == PseudoStateKind.HISTORY_DEEP) {
 				historys.add(new HistoryData<String, String>(t.getSource().getState(), t.getTarget().getState()));
 			}
 		}
-		TransitionsData<String, String> transitionsData = new TransitionsData<>(transitionData, null, null, null, null, null, null, historys);
+
+		HashMap<String, List<ChoiceData<String, String>>> choicesCopy = new HashMap<String, List<ChoiceData<String, String>>>();
+		choicesCopy.putAll(choices);
+
+		TransitionsData<String, String> transitionsData = new TransitionsData<>(transitionData, choicesCopy, null, null, null, null, null, historys);
 
 		StateMachineModel<String, String> stateMachineModel = new DefaultStateMachineModel<>(configurationData, statesData, transitionsData);
 		return stateMachineModel;
 	}
+
+	private Guard<String, String> resolveGuard(RepositoryTransition t) {
+		Guard<String, String> guard = null;
+		RepositoryGuard repositoryGuard = t.getGuard();
+		if (repositoryGuard != null) {
+			if (StringUtils.hasText(repositoryGuard.getName())) {
+				guard = resolveGuard(repositoryGuard.getName());
+			} else if (StringUtils.hasText(repositoryGuard.getSpel())) {
+				SpelExpressionParser parser = new SpelExpressionParser(
+						new SpelParserConfiguration(SpelCompilerMode.MIXED, null));
+				guard = new SpelExpressionGuard<>(parser.parseExpression(repositoryGuard.getSpel()));
+			}
+		}
+		return guard;
+	}
 }