Improve creation of StateMachineFactory

- Returning factory from StateMachineBuilder.Builder
- Fixes #845

spring-statemachine-core/src/main/java/org/springframework/statemachine/config/StateMachineBuilder.java

@@ -29,10 +29,7 @@ import org.springframework.statemachine.config.builders.StateMachineTransitionBu
 import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer;
 import org.springframework.statemachine.config.common.annotation.AnnotationBuilder;
 import org.springframework.statemachine.config.common.annotation.ObjectPostProcessor;
-import org.springframework.statemachine.config.model.DefaultStateMachineModel;
 import org.springframework.statemachine.config.model.ConfigurationData;
-import org.springframework.statemachine.config.model.StatesData;
-import org.springframework.statemachine.config.model.TransitionsData;
 
 /**
  * {@code StateMachineBuilder} provides a builder pattern for
@@ -112,40 +109,40 @@ public class StateMachineBuilder {
 		}
 
 		/**
-		 * Builds a {@link StateMachine}.
+		 * Creates a {@link StateMachineFactory} from builder
 		 *
-		 * @return the state machine
+		 * @return the factory to create a state machine
 		 */
-		public StateMachine<S, E> build() {
+		public StateMachineFactory<S, E> createFactory() {
 			try {
 				builder.apply(adapter);
-				StateMachineConfig<S, E> stateMachineConfig = builder.getOrBuild();
 
-				TransitionsData<S, E> stateMachineTransitions = stateMachineConfig.getTransitions();
-				StatesData<S, E> stateMachineStates = stateMachineConfig.getStates();
-				ConfigurationData<S, E> stateMachineConfigurationConfig = stateMachineConfig.getStateMachineConfigurationConfig();
-
-				ObjectStateMachineFactory<S, E> stateMachineFactory = null;
-				if (stateMachineConfig.getModel() != null && stateMachineConfig.getModel().getFactory() != null) {
-					stateMachineFactory = new ObjectStateMachineFactory<S, E>(
-							new DefaultStateMachineModel<S, E>(stateMachineConfigurationConfig, null, null),
-							stateMachineConfig.getModel().getFactory());
-				} else {
-					stateMachineFactory = new ObjectStateMachineFactory<S, E>(new DefaultStateMachineModel<S, E>(
-							stateMachineConfigurationConfig, stateMachineStates, stateMachineTransitions), null);
-				}
+				ObjectStateMachineFactory<S, E> stateMachineFactory = StateMachineFactory.create(builder);
+				ConfigurationData<S, E> stateMachineConfigurationConfig = builder.getOrBuild().stateMachineConfigurationConfig;
 
 				stateMachineFactory.setHandleAutostartup(stateMachineConfigurationConfig.isAutoStart());
 
 				if (stateMachineConfigurationConfig.getBeanFactory() != null) {
 					stateMachineFactory.setBeanFactory(stateMachineConfigurationConfig.getBeanFactory());
 				}
-				return stateMachineFactory.getStateMachine();
+				return stateMachineFactory;
+			} catch (Exception e) {
+				throw new StateMachineException("Error creating state machine factory", e);
+			}
+		}
+
+		/**
+		 * Builds a {@link StateMachine}.
+		 *
+		 * @return the state machine
+		 */
+		public StateMachine<S, E> build() {
+			try {
+				return createFactory().getStateMachine();
 			} catch (Exception e) {
 				throw new StateMachineException("Error building state machine", e);
 			}
 		}
-
 	}
 
 	private static class BuilderStateMachineConfigurerAdapter<S extends Object, E extends Object>

spring-statemachine-core/src/main/java/org/springframework/statemachine/config/StateMachineFactory.java

@@ -16,6 +16,11 @@
 package org.springframework.statemachine.config;
 
 import org.springframework.statemachine.StateMachine;
+import org.springframework.statemachine.config.builders.StateMachineConfigBuilder;
+import org.springframework.statemachine.config.model.ConfigurationData;
+import org.springframework.statemachine.config.model.DefaultStateMachineModel;
+import org.springframework.statemachine.config.model.StatesData;
+import org.springframework.statemachine.config.model.TransitionsData;
 
 import java.util.UUID;
 
@@ -53,4 +58,23 @@ public interface StateMachineFactory<S, E> {
 	 * @return a new state machine instance.
 	 */
 	StateMachine<S, E> getStateMachine(UUID uuid);
+
+	static <S, E> ObjectStateMachineFactory<S, E> create(StateMachineConfigBuilder<S, E> builder) {
+		StateMachineConfig<S, E> stateMachineConfig = builder.getOrBuild();
+
+		TransitionsData<S, E> stateMachineTransitions = stateMachineConfig.getTransitions();
+		StatesData<S, E> stateMachineStates = stateMachineConfig.getStates();
+		ConfigurationData<S, E> stateMachineConfigurationConfig = stateMachineConfig.getStateMachineConfigurationConfig();
+
+		ObjectStateMachineFactory<S, E> stateMachineFactory = null;
+		if (stateMachineConfig.getModel() != null && stateMachineConfig.getModel().getFactory() != null) {
+			stateMachineFactory = new ObjectStateMachineFactory<S, E>(
+					new DefaultStateMachineModel<S, E>(stateMachineConfigurationConfig, null, null),
+					stateMachineConfig.getModel().getFactory());
+		} else {
+			stateMachineFactory = new ObjectStateMachineFactory<S, E>(new DefaultStateMachineModel<S, E>(
+					stateMachineConfigurationConfig, stateMachineStates, stateMachineTransitions), null);
+		}
+		return stateMachineFactory;
+	}
 }

spring-statemachine-core/src/main/java/org/springframework/statemachine/config/configuration/StateMachineConfiguration.java

@@ -38,14 +38,11 @@ import org.springframework.statemachine.config.EnableStateMachine;
 import org.springframework.statemachine.config.ObjectStateMachineFactory;
 import org.springframework.statemachine.config.StateMachineConfig;
 import org.springframework.statemachine.config.StateMachineConfigurerAdapter;
+import org.springframework.statemachine.config.StateMachineFactory;
 import org.springframework.statemachine.config.builders.StateMachineConfigBuilder;
 import org.springframework.statemachine.config.builders.StateMachineConfigurer;
 import org.springframework.statemachine.config.common.annotation.AbstractImportingAnnotationConfiguration;
 import org.springframework.statemachine.config.common.annotation.AnnotationConfigurer;
-import org.springframework.statemachine.config.model.ConfigurationData;
-import org.springframework.statemachine.config.model.DefaultStateMachineModel;
-import org.springframework.statemachine.config.model.StatesData;
-import org.springframework.statemachine.config.model.TransitionsData;
 import org.springframework.statemachine.monitor.StateMachineMonitor;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -165,27 +162,15 @@ public class StateMachineConfiguration<S, E> extends
 			AnnotationConfigurer<StateMachineConfig<S, E>, StateMachineConfigBuilder<S, E>> configurer =
 					(AnnotationConfigurer<StateMachineConfig<S, E>, StateMachineConfigBuilder<S, E>>) getBeanFactory()
 						.getBean(ClassUtils.forName(clazzName, classLoader));
-			getBuilder().apply(configurer);
+			StateMachineConfigBuilder<S, E> builder = getBuilder();
+			builder.apply(configurer);
 
-			StateMachineConfig<S, E> stateMachineConfig = getBuilder().getOrBuild();
-			TransitionsData<S, E> stateMachineTransitions = stateMachineConfig.getTransitions();
-			StatesData<S, E> stateMachineStates = stateMachineConfig.getStates();
-			ConfigurationData<S, E> stateMachineConfigurationConfig = stateMachineConfig.getStateMachineConfigurationConfig();
-
-			ObjectStateMachineFactory<S, E> stateMachineFactory = null;
-			if (stateMachineConfig.getModel() != null && stateMachineConfig.getModel().getFactory() != null) {
-				stateMachineFactory = new ObjectStateMachineFactory<S, E>(
-						new DefaultStateMachineModel<S, E>(stateMachineConfigurationConfig, null, null),
-						stateMachineConfig.getModel().getFactory());
-			} else {
-				stateMachineFactory = new ObjectStateMachineFactory<S, E>(new DefaultStateMachineModel<S, E>(
-						stateMachineConfigurationConfig, stateMachineStates, stateMachineTransitions), null);
-			}
+			ObjectStateMachineFactory<S, E> stateMachineFactory = StateMachineFactory.create(builder);
 
 			stateMachineFactory.setBeanFactory(getBeanFactory());
 			stateMachineFactory.setContextEventsEnabled(contextEvents);
 			stateMachineFactory.setBeanName(beanName);
-			stateMachineFactory.setHandleAutostartup(stateMachineConfigurationConfig.isAutoStart());
+			stateMachineFactory.setHandleAutostartup(builder.getOrBuild().stateMachineConfigurationConfig.isAutoStart());
 			if (stateMachineMonitor != null) {
 				stateMachineFactory.setStateMachineMonitor(stateMachineMonitor);
 			}

spring-statemachine-core/src/main/java/org/springframework/statemachine/config/configuration/StateMachineFactoryConfiguration.java

@@ -41,10 +41,6 @@ import org.springframework.statemachine.config.StateMachineFactory;
 import org.springframework.statemachine.config.builders.StateMachineConfigBuilder;
 import org.springframework.statemachine.config.common.annotation.AbstractImportingAnnotationConfiguration;
 import org.springframework.statemachine.config.common.annotation.AnnotationConfigurer;
-import org.springframework.statemachine.config.model.ConfigurationData;
-import org.springframework.statemachine.config.model.DefaultStateMachineModel;
-import org.springframework.statemachine.config.model.StatesData;
-import org.springframework.statemachine.config.model.TransitionsData;
 import org.springframework.util.ClassUtils;
 
 /**
@@ -156,21 +152,7 @@ public class StateMachineFactoryConfiguration<S, E> extends
 						.getBean(ClassUtils.forName(clazzName, classLoader));
 		    builder.apply(configurer);
 
-			StateMachineConfig<S, E> stateMachineConfig = builder.getOrBuild();
-			TransitionsData<S, E> stateMachineTransitions = stateMachineConfig.getTransitions();
-			StatesData<S, E> stateMachineStates = stateMachineConfig.getStates();
-			ConfigurationData<S, E> stateMachineConfigurationConfig = stateMachineConfig
-					.getStateMachineConfigurationConfig();
-
-			ObjectStateMachineFactory<S, E> objectStateMachineFactory = null;
-			if (stateMachineConfig.getModel() != null && stateMachineConfig.getModel().getFactory() != null) {
-				objectStateMachineFactory = new ObjectStateMachineFactory<S, E>(
-						new DefaultStateMachineModel<S, E>(stateMachineConfigurationConfig, null, null),
-						stateMachineConfig.getModel().getFactory());
-			} else {
-				objectStateMachineFactory = new ObjectStateMachineFactory<S, E>(new DefaultStateMachineModel<S, E>(
-						stateMachineConfigurationConfig, stateMachineStates, stateMachineTransitions), null);
-			}
+			ObjectStateMachineFactory<S, E> objectStateMachineFactory =	StateMachineFactory.create(builder);
 
 			objectStateMachineFactory.setBeanFactory(beanFactory);
 			objectStateMachineFactory.setContextEventsEnabled(contextEvents);

spring-statemachine-core/src/test/java/org/springframework/statemachine/StateMachineFactoryTests.java

@@ -18,6 +18,7 @@ package org.springframework.statemachine;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
 import static org.springframework.statemachine.TestUtils.doSendEventAndConsumeAll;
 import static org.springframework.statemachine.TestUtils.doStartAndAssert;
 import static org.springframework.statemachine.TestUtils.resolveFactory;
@@ -33,6 +34,7 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.statemachine.config.EnableStateMachineFactory;
 import org.springframework.statemachine.config.EnumStateMachineConfigurerAdapter;
 import org.springframework.statemachine.config.StateMachineFactory;
+import org.springframework.statemachine.config.builders.StateMachineConfigBuilder;
 import org.springframework.statemachine.config.builders.StateMachineConfigurationConfigurer;
 import org.springframework.statemachine.config.builders.StateMachineStateConfigurer;
 import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer;
@@ -46,6 +48,23 @@ public class StateMachineFactoryTests extends AbstractStateMachineTests {
 		return new AnnotationConfigApplicationContext();
 	}
 
+	/**
+	 * {@link org.springframework.statemachine.config.ManualBuilderTests#testManualBuildConcept()}
+	 */
+	@Test
+	public void testCreate() throws Exception{
+		StateMachineConfigBuilder<TestStates, TestEvents> builder = new StateMachineConfigBuilder<>();
+		Config1 config = new Config1();
+		builder.apply(config);
+
+		StateMachineFactory<TestStates,TestEvents> factory = StateMachineFactory.create(builder);
+		StateMachine<TestStates,TestEvents> machine = factory.getStateMachine();
+		doStartAndAssert(machine);
+
+		assertThat(machine, notNullValue());
+		assertThat(machine.getState().getId(), is(TestStates.S1));
+	}
+
 	@Test
 	public void testMachineFromFactory() {
 		context.register(Config1.class);