Add autostart flag for top-level machine

- Fixes #82
- Now have configure method ConfigurationConfigurer.autoStart(boolean)
  which can be used to enable autostart feature for top-level state machine.
  We keep this feature disabled as default because most of the cases it is
  easier to enable it than disable it.

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

@@ -188,6 +188,11 @@ public abstract class AbstractStateMachineFactory<S, E> extends LifecycleObjectS
 			stateStack.push(stateData);
 		}
 
+		// setup autostart for top-level machine
+		if (machine instanceof LifecycleObjectSupport) {
+			((LifecycleObjectSupport)machine).setAutoStartup(stateMachineConfigurationConfig.isAutoStart());
+		}
+
 		// set top-level machine as relay
 		final StateMachine<S, E> fmachine = machine;
 		fmachine.getStateMachineAccessor().doWithAllRegions(new StateMachineFunction<StateMachineAccess<S, E>>() {

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

@@ -42,6 +42,7 @@ public class StateMachineConfigurationBuilder<S, E>
 	private BeanFactory beanFactory;
 	private TaskExecutor taskExecutor;
 	private TaskScheduler taskScheculer;
+	private boolean autoStart = false;
 	private StateMachineEnsemble<S, E> ensemble;
 
 	/**
@@ -83,7 +84,7 @@ public class StateMachineConfigurationBuilder<S, E>
 
 	@Override
 	protected StateMachineConfigurationConfig<S, E> performBuild() throws Exception {
-		return new StateMachineConfigurationConfig<>(beanFactory, taskExecutor, taskScheculer, ensemble);
+		return new StateMachineConfigurationConfig<>(beanFactory, taskExecutor, taskScheculer, autoStart, ensemble);
 	}
 
 	/**
@@ -122,4 +123,13 @@ public class StateMachineConfigurationBuilder<S, E>
 		this.ensemble = ensemble;
 	}
 
+	/**
+	 * Sets the auto start.
+	 *
+	 * @param autoStart the new autostart flag
+	 */
+	public void setAutoStart(boolean autoStart) {
+		this.autoStart = autoStart;
+	}
+
 }

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

@@ -33,6 +33,7 @@ public class StateMachineConfigurationConfig<S, E> {
 	private final BeanFactory beanFactory;
 	private final TaskExecutor taskExecutor;
 	private final TaskScheduler taskScheduler;
+	private final boolean autoStart;
 	private final StateMachineEnsemble<S, E> ensemble;
 
 	/**
@@ -41,13 +42,15 @@ public class StateMachineConfigurationConfig<S, E> {
 	 * @param beanFactory the bean factory
 	 * @param taskExecutor the task executor
 	 * @param taskScheduler the task scheduler
+	 * @param autoStart the autostart flag
 	 * @param ensemble the state machine ensemble
 	 */
 	public StateMachineConfigurationConfig(BeanFactory beanFactory, TaskExecutor taskExecutor,
-			TaskScheduler taskScheduler, StateMachineEnsemble<S, E> ensemble) {
+			TaskScheduler taskScheduler, boolean autoStart, StateMachineEnsemble<S, E> ensemble) {
 		this.beanFactory = beanFactory;
 		this.taskExecutor = taskExecutor;
 		this.taskScheduler = taskScheduler;
+		this.autoStart = autoStart;
 		this.ensemble = ensemble;
 	}
 
@@ -87,4 +90,12 @@ public class StateMachineConfigurationConfig<S, E> {
 		return ensemble;
 	}
 
+	/**
+	 * Returns autostart flag.
+	 *
+	 * @return true, if is autostart is enabled.
+	 */
+	public boolean isAutoStart() {
+		return autoStart;
+	}
 }

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

@@ -56,4 +56,13 @@ public interface ConfigurationConfigurer<S, E> extends
 	 */
 	ConfigurationConfigurer<S, E> taskScheduler(TaskScheduler taskScheduler);
 
+	/**
+	 * Specify if state machine should be started automatically.
+	 * On default state machine is not started automatically.
+	 *
+	 * @param autoStart the autostart flag
+	 * @return configurer for chaining
+	 */
+	ConfigurationConfigurer<S, E> autoStart(boolean autoStart);
+
 }

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

@@ -38,12 +38,14 @@ public class DefaultConfigurationConfigurer<S, E>
 	private BeanFactory beanFactory;
 	private TaskExecutor taskExecutor;
 	private TaskScheduler taskScheculer;
+	private boolean autoStart = false;
 
 	@Override
 	public void configure(StateMachineConfigurationBuilder<S, E> builder) throws Exception {
 		builder.setBeanFactory(beanFactory);
 		builder.setTaskExecutor(taskExecutor);
 		builder.setTaskScheculer(taskScheculer);
+		builder.setAutoStart(autoStart);
 	}
 
 	@Override
@@ -64,4 +66,10 @@ public class DefaultConfigurationConfigurer<S, E>
 		return this;
 	}
 
+	@Override
+	public ConfigurationConfigurer<S, E> autoStart(boolean autoStart) {
+		this.autoStart = autoStart;
+		return this;
+	}
+
 }

spring-statemachine-core/src/test/java/org/springframework/statemachine/config/ConfigurationTests.java

@@ -16,6 +16,7 @@
 package org.springframework.statemachine.config;
 
 import static org.hamcrest.Matchers.notNullValue;
+import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
 
@@ -34,6 +35,7 @@ import org.springframework.statemachine.AbstractStateMachineTests;
 import org.springframework.statemachine.ObjectStateMachine;
 import org.springframework.statemachine.StateMachineSystemConstants;
 import org.springframework.statemachine.action.Action;
+import org.springframework.statemachine.config.builders.StateMachineConfigurationConfigurer;
 import org.springframework.statemachine.config.builders.StateMachineStateConfigurer;
 import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer;
 
@@ -109,6 +111,16 @@ public class ConfigurationTests extends AbstractStateMachineTests {
 		assertThat(machine, notNullValue());
 	}
 
+	@SuppressWarnings({ "unchecked" })
+	@Test
+	public void testAutoStartFlagOn() throws Exception {
+		context.register(Config9.class);
+		context.refresh();
+		ObjectStateMachine<TestStates,TestEvents> machine =
+				context.getBean(StateMachineSystemConstants.DEFAULT_ID_STATEMACHINE, ObjectStateMachine.class);
+		assertThat(machine.isAutoStartup(), is(true));
+	}
+
 	@Configuration
 	@EnableStateMachine
 	public static class Config1 extends EnumStateMachineConfigurerAdapter<TestStates, TestEvents> {
@@ -430,4 +442,25 @@ public class ConfigurationTests extends AbstractStateMachineTests {
 
 	}
 
+	@Configuration
+	@EnableStateMachine
+	public static class Config9 extends EnumStateMachineConfigurerAdapter<TestStates, TestEvents> {
+
+		@Override
+		public void configure(StateMachineConfigurationConfigurer<TestStates, TestEvents> config) throws Exception {
+			config
+				.withConfiguration()
+					.autoStart(true);
+		}
+
+		@Override
+		public void configure(StateMachineStateConfigurer<TestStates, TestEvents> states) throws Exception {
+			states
+				.withStates()
+					.initial(TestStates.S1)
+					.states(EnumSet.allOf(TestStates.class));
+		}
+
+	}
+
 }