Bugfix/task scheduler lifecycle

spring-statemachine-build-tests/src/test/java/org/springframework/statemachine/buildtests/TimerSmokeTests.java

@@ -16,7 +16,10 @@
 package org.springframework.statemachine.buildtests;
 
 import org.junit.Test;
+import org.springframework.core.task.SyncTaskExecutor;
+import org.springframework.core.task.TaskExecutor;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.config.StateMachineBuilder;
 import org.springframework.statemachine.test.StateMachineTestPlan;
@@ -25,8 +28,10 @@
 public class TimerSmokeTests {
 
 	private static ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
+	private static ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
 	{
 		taskExecutor.initialize();
+		taskScheduler.initialize();
 	}
 
 	private StateMachine<String, String> buildMachine() throws Exception {
@@ -35,7 +40,8 @@ private StateMachine<String, String> buildMachine() throws Exception {
 
 		builder.configureConfiguration()
 			.withConfiguration()
-				.taskExecutor(taskExecutor);
+				.taskExecutor(taskExecutor)
+					.taskScheduler(taskScheduler);
 
 		builder.configureStates()
 			.withStates()

spring-statemachine-core/src/main/java/org/springframework/statemachine/StateMachineSystemConstants.java

@@ -38,4 +38,7 @@ public abstract class StateMachineSystemConstants {
 	/** Bean name for task executor */
 	public static final String TASK_EXECUTOR_BEAN_NAME = "stateMachineTaskExecutor";
 
+	/** Task scheduler threads prefix **/
+	public static final String TASK_SCHEDULER_THREAD_PREFIX = "spring-state-machine-task-scheduler-";
+
 }

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

@@ -16,9 +16,10 @@
 package org.springframework.statemachine.config;
 
 import org.springframework.core.task.SyncTaskExecutor;
-import org.springframework.scheduling.concurrent.ConcurrentTaskScheduler;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.StateMachineException;
+import org.springframework.statemachine.StateMachineSystemConstants;
 import org.springframework.statemachine.config.builders.StateMachineConfigBuilder;
 import org.springframework.statemachine.config.builders.StateMachineConfigurationBuilder;
 import org.springframework.statemachine.config.builders.StateMachineConfigurationConfigurer;
@@ -35,6 +36,11 @@
 import org.springframework.statemachine.config.model.ConfigurationData;
 import org.springframework.statemachine.config.model.StatesData;
 import org.springframework.statemachine.config.model.TransitionsData;
+import org.springframework.statemachine.listener.StateMachineListener;
+import org.springframework.statemachine.listener.StateMachineListenerAdapter;
+
+import java.util.ArrayList;
+import java.util.Collection;
 
 /**
  * {@code StateMachineBuilder} provides a builder pattern for
@@ -147,12 +153,35 @@ public StateMachine<S, E> build() {
 				} else {
 					stateMachineFactory.setTaskExecutor(new SyncTaskExecutor());
 				}
+
+				final Collection<StateMachineListener<S, E>> resourceManagementListeners = new ArrayList<>();
 				if (stateMachineConfigurationConfig.getTaskScheduler() != null) {
 					stateMachineFactory.setTaskScheduler(stateMachineConfigurationConfig.getTaskScheduler());
 				} else {
-					stateMachineFactory.setTaskScheduler(new ConcurrentTaskScheduler());
+					final ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
+					taskScheduler.setThreadNamePrefix(StateMachineSystemConstants.TASK_SCHEDULER_THREAD_PREFIX);
+					taskScheduler.setPoolSize(1);
+					taskScheduler.setWaitForTasksToCompleteOnShutdown(true);
+					taskScheduler.setAwaitTerminationSeconds(10);
+					taskScheduler.afterPropertiesSet();
+					stateMachineFactory.setTaskScheduler(taskScheduler);
+					resourceManagementListeners.add(new StateMachineListenerAdapter<S, E>() {
+						@Override
+						public void stateMachineStarted(final StateMachine<S, E> stateMachine) {
+							taskScheduler.afterPropertiesSet();
+						}
+
+						@Override
+						public void stateMachineStopped(final StateMachine<S, E> stateMachine) {
+							taskScheduler.destroy();
+						}
+					});
+				}
+				final StateMachine<S, E> stateMachine = stateMachineFactory.getStateMachine();
+				for (final StateMachineListener<S, E> listener : resourceManagementListeners) {
+					stateMachine.addStateListener(listener);
 				}
-				return stateMachineFactory.getStateMachine();
+				return stateMachine;
 			} catch (Exception e) {
 				throw new StateMachineException("Error building state machine", e);
 			}

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

@@ -20,7 +20,7 @@
 import org.springframework.core.task.SyncTaskExecutor;
 import org.springframework.core.task.TaskExecutor;
 import org.springframework.scheduling.TaskScheduler;
-import org.springframework.scheduling.concurrent.ConcurrentTaskScheduler;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 import org.springframework.statemachine.StateMachineSystemConstants;
 
 /**
@@ -39,7 +39,7 @@ public TaskExecutor taskExecutor() {
 
 	@Bean
 	public TaskScheduler taskScheduler() {
-		return new ConcurrentTaskScheduler();
+		return new ThreadPoolTaskScheduler();
 	}
 
 	@Bean(name = StateMachineHandlerApplicationListener.BEAN_NAME)