Add stop logic to DefaultStateMachineService

- Now implementing DisposableBean and clearing/stopping
  machines if service is destroyed.
- Relates to #432

spring-statemachine-core/src/main/java/org/springframework/statemachine/service/DefaultStateMachineService.java

@@ -15,12 +15,14 @@
  */
 package org.springframework.statemachine.service;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.CountDownLatch;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.beans.factory.DisposableBean;
 import org.springframework.context.Lifecycle;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.StateMachineContext;
@@ -40,7 +42,7 @@ import org.springframework.util.Assert;
  * @param <S> the type of state
  * @param <E> the type of event
  */
-public class DefaultStateMachineService<S, E> implements StateMachineService<S, E> {
+public class DefaultStateMachineService<S, E> implements StateMachineService<S, E>, DisposableBean {
 
 	private final static Log log = LogFactory.getLog(DefaultStateMachineService.class);
 	private final StateMachineFactory<S, E> stateMachineFactory;
@@ -69,6 +71,11 @@ public class DefaultStateMachineService<S, E> implements StateMachineService<S,
 		this.stateMachinePersist = stateMachinePersist;
 	}
 
+	@Override
+	public final void destroy() throws Exception {
+		doStop();
+	}
+
 	@Override
 	public StateMachine<S, E> acquireStateMachine(String machineId) {
 		return acquireStateMachine(machineId, true);
@@ -130,6 +137,16 @@ public class DefaultStateMachineService<S, E> implements StateMachineService<S,
 		this.stateMachinePersist = stateMachinePersist;
 	}
 
+	protected void doStop() {
+		log.info("Entering stop sequence, stopping all managed machines");
+		synchronized (machines) {
+			ArrayList<String> machineIds = new ArrayList<>(machines.keySet());
+			for (String machineId : machineIds) {
+				releaseStateMachine(machineId, true);
+			}
+		}
+	}
+
 	protected StateMachine<S, E> restoreStateMachine(StateMachine<S, E> stateMachine, final StateMachineContext<S, E> stateMachineContext) {
 		if (stateMachineContext == null) {
 			return stateMachine;

spring-statemachine-core/src/test/java/org/springframework/statemachine/service/DefaultStateMachineServiceTests.java

@@ -18,6 +18,8 @@ package org.springframework.statemachine.service;
 import static org.hamcrest.CoreMatchers.is;
 import static org.junit.Assert.assertThat;
 
+import java.util.Map;
+
 import org.junit.Test;
 import org.springframework.context.Lifecycle;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
@@ -28,6 +30,7 @@ import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
 import org.springframework.statemachine.AbstractStateMachineTests;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.StateMachineSystemConstants;
+import org.springframework.statemachine.TestUtils;
 import org.springframework.statemachine.config.EnableStateMachineFactory;
 import org.springframework.statemachine.config.EnumStateMachineConfigurerAdapter;
 import org.springframework.statemachine.config.StateMachineFactory;
@@ -153,6 +156,24 @@ public class DefaultStateMachineServiceTests extends AbstractStateMachineTests {
 		assertThat(((Lifecycle)machine1).isRunning(), is(true));
 	}
 
+	@Test
+	public void testServiceStop() throws Exception {
+		context.register(Config1.class);
+		context.refresh();
+		StateMachineFactory<TestStates, TestEvents> stateMachineFactory =
+				context.getBean(StateMachineSystemConstants.DEFAULT_ID_STATEMACHINEFACTORY, StateMachineFactory.class);
+
+		DefaultStateMachineService<TestStates, TestEvents> service = new DefaultStateMachineService<>(stateMachineFactory);
+		StateMachine<TestStates,TestEvents> machine1 = service.acquireStateMachine("m1", false);
+		StateMachine<TestStates,TestEvents> machine2 = service.acquireStateMachine("m2", false);
+		assertThat(((Lifecycle)machine1).isRunning(), is(false));
+		assertThat(((Lifecycle)machine2).isRunning(), is(false));
+		Map<?, ?> machines = TestUtils.readField("machines", service);
+		assertThat(machines.size(), is(2));
+		service.destroy();
+		assertThat(machines.size(), is(0));
+	}
+
 	@Configuration
 	@EnableStateMachineFactory
 	static class Config1 extends EnumStateMachineConfigurerAdapter<TestStates, TestEvents> {