Disarm timers

- Trying to handle scenario where TimerTrigger keeps firing
  even if machine is stopped or has moved away from its
  hosting state.
- Explicitely handle trigger starts/stops in
  DefaultStateMachineExecutor when executor itself
  is started/stopped.
- Backport #321
- Relates to #307

spring-statemachine-core/src/main/java/org/springframework/statemachine/support/DefaultStateMachineExecutor.java

@@ -150,11 +150,13 @@ public class DefaultStateMachineExecutor<S, E> extends LifecycleObjectSupport im
 	@Override
 	protected void doStart() {
 		super.doStart();
+		startTriggers();
 		execute();
 	}
 
 	@Override
 	protected void doStop() {
+		stopTriggers();
 		super.doStop();
 		initialHandled.set(false);
 	}
@@ -461,12 +463,25 @@ public class DefaultStateMachineExecutor<S, E> extends LifecycleObjectSupport im
 					}
 				});
 			}
+		}
+	}
+
+	private void startTriggers() {
+		for (final Trigger<S, E> trigger : triggerToTransitionMap.keySet()) {
 			if (trigger instanceof Lifecycle) {
 				((Lifecycle) trigger).start();
 			}
 		}
 	}
 
+	private void stopTriggers() {
+		for (final Trigger<S, E> trigger : triggerToTransitionMap.keySet()) {
+			if (trigger instanceof Lifecycle) {
+				((Lifecycle) trigger).stop();
+			}
+		}
+	}
+
 	private class TriggerQueueItem {
 		Trigger<S, E> trigger;
 		Message<E> message;

spring-statemachine-core/src/test/java/org/springframework/statemachine/trigger/CleanTimerTests.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.statemachine.trigger;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.junit.Assert.assertThat;
+
+import java.util.Queue;
+import java.util.concurrent.CountDownLatch;
+
+import org.junit.Test;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.statemachine.AbstractStateMachineTests;
+import org.springframework.statemachine.StateContext;
+import org.springframework.statemachine.StateMachine;
+import org.springframework.statemachine.TestUtils;
+import org.springframework.statemachine.action.Action;
+import org.springframework.statemachine.config.EnableStateMachine;
+import org.springframework.statemachine.config.EnumStateMachineConfigurerAdapter;
+import org.springframework.statemachine.config.builders.StateMachineStateConfigurer;
+import org.springframework.statemachine.config.builders.StateMachineTransitionConfigurer;
+
+public class CleanTimerTests extends AbstractStateMachineTests {
+
+	@Override
+	protected AnnotationConfigApplicationContext buildContext() {
+		return new AnnotationConfigApplicationContext();
+	}
+
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testMachineStopStopsTriggering() throws Exception {
+		context.register(BaseConfig.class, Config1.class);
+		context.refresh();
+		StateMachine<TestStates, TestEvents> machine = context.getBean(StateMachine.class);
+		TestTimerAction action = context.getBean("testTimerAction", TestTimerAction.class);
+
+		Object stateMachineExecutor = TestUtils.readField("stateMachineExecutor", machine);
+		Queue<?> triggerQueue = TestUtils.readField("triggerQueue", stateMachineExecutor);
+
+		machine.start();
+		assertThat(machine.getState().getIds(), containsInAnyOrder(TestStates.S1));
+		machine.sendEvent(TestEvents.E1);
+
+		Thread.sleep(100);
+		machine.stop();
+
+		int tqize1 = triggerQueue.size();
+		Thread.sleep(100);
+		int tqsize2 = triggerQueue.size();
+		assertThat(tqsize2, is(tqize1));
+
+		int asize1 = action.count;
+		Thread.sleep(100);
+		int asize2 = action.count;
+		assertThat(asize2, is(asize1));
+	}
+
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testMoveToOtherStateStopsTriggering() throws Exception {
+		context.register(BaseConfig.class, Config1.class);
+		context.refresh();
+		StateMachine<TestStates, TestEvents> machine = context.getBean(StateMachine.class);
+		TestTimerAction action = context.getBean("testTimerAction", TestTimerAction.class);
+
+		Object stateMachineExecutor = TestUtils.readField("stateMachineExecutor", machine);
+		Queue<?> triggerQueue = TestUtils.readField("triggerQueue", stateMachineExecutor);
+
+		machine.start();
+		assertThat(machine.getState().getIds(), containsInAnyOrder(TestStates.S1));
+
+		machine.sendEvent(TestEvents.E1);
+
+		Thread.sleep(100);
+		machine.sendEvent(TestEvents.E2);
+		Thread.sleep(100);
+
+		int tqize1 = triggerQueue.size();
+		Thread.sleep(100);
+		int tqsize2 = triggerQueue.size();
+		assertThat(tqsize2, is(tqize1));
+
+		int asize1 = action.count;
+		Thread.sleep(100);
+		int asize2 = action.count;
+		assertThat(asize2, is(asize1));
+	}
+
+	@Configuration
+	@EnableStateMachine
+	static class Config1 extends EnumStateMachineConfigurerAdapter<TestStates, TestEvents> {
+
+		@Override
+		public void configure(StateMachineStateConfigurer<TestStates, TestEvents> states) throws Exception {
+			states
+				.withStates()
+					.initial(TestStates.S1)
+					.state(TestStates.S2)
+					.state(TestStates.S3);
+		}
+
+		@Override
+		public void configure(StateMachineTransitionConfigurer<TestStates, TestEvents> transitions) throws Exception {
+			transitions
+				.withExternal()
+					.source(TestStates.S1)
+					.target(TestStates.S2)
+					.event(TestEvents.E1)
+					.and()
+				.withInternal()
+					.source(TestStates.S2)
+					.action(testTimerAction())
+					.timer(10)
+					.and()
+				.withExternal()
+					.source(TestStates.S2)
+					.target(TestStates.S3)
+					.event(TestEvents.E2);
+		}
+
+		@Bean
+		public TestTimerAction testTimerAction() {
+			return new TestTimerAction();
+		}
+
+	}
+
+	private static class TestTimerAction implements Action<TestStates, TestEvents> {
+
+		int count = 0;
+		volatile CountDownLatch latch = new CountDownLatch(1);
+
+		@Override
+		public void execute(StateContext<TestStates, TestEvents> context) {
+			count++;
+			latch.countDown();
+		}
+	}
+}