Fix empty @OnTransition

- Fix so that bean method will be called with
  plain @OnTransition having no source or target
  defined.
- Fixes #128

docs/src/reference/asciidoc/sm.adoc

@@ -668,7 +668,8 @@ into your beans.
 === Annotation Support
 _@WithStateMachine_ annotation can be used to associate a state
 machine with a existing bean. Within this annotation a property's
-_source_ and _target_ can be used to qualify a transition 
+_source_ and _target_ can be used to qualify a transition. If
+_source_ and _target_ is left empty then any transition is matched.
 
 [source,java,indent=0]
 ----

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

@@ -23,8 +23,8 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.UUID;
 import java.util.Map.Entry;
+import java.util.UUID;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -36,10 +36,10 @@ import org.springframework.messaging.Message;
 import org.springframework.messaging.MessageHeaders;
 import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.statemachine.ExtendedState;
+import org.springframework.statemachine.ExtendedState.ExtendedStateChangeListener;
 import org.springframework.statemachine.StateContext;
 import org.springframework.statemachine.StateMachine;
 import org.springframework.statemachine.StateMachineContext;
-import org.springframework.statemachine.ExtendedState.ExtendedStateChangeListener;
 import org.springframework.statemachine.access.StateMachineAccess;
 import org.springframework.statemachine.access.StateMachineAccessor;
 import org.springframework.statemachine.access.StateMachineFunction;
@@ -907,7 +907,7 @@ public abstract class AbstractStateMachine<S, E> extends StateMachineObjectSuppo
 			WithStateMachine withStateMachine = AnnotationUtils.findAnnotation(entry.getValue().getBeanClass(), WithStateMachine.class);
 			if (withStateMachine == null || !ObjectUtils.nullSafeEquals(withStateMachine.name(), getBeanName())) {
 				continue;
-			}			
+			}
 			OnTransition metaAnnotation = entry.getValue().getMetaAnnotation();
 			Annotation annotation = entry.getValue().getAnnotation();
 			if (transitionHandlerMatch(metaAnnotation, annotation, sourceState, targetState)) {
@@ -959,6 +959,8 @@ public abstract class AbstractStateMachine<S, E> extends StateMachineObjectSuppo
 							StateMachineUtils.toStringCollection(targetState.getIds()))) {
 				handle = true;
 			}
+		} else if (scoll.isEmpty() && tcoll.isEmpty()) {
+			handle = true;
 		}
 
 		return handle;

spring-statemachine-core/src/test/java/org/springframework/statemachine/annotation/MethodAnnotationTests.java

@@ -30,8 +30,8 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.messaging.support.MessageBuilder;
 import org.springframework.statemachine.AbstractStateMachineTests;
-import org.springframework.statemachine.ObjectStateMachine;
 import org.springframework.statemachine.ExtendedState;
+import org.springframework.statemachine.ObjectStateMachine;
 import org.springframework.statemachine.StateMachineSystemConstants;
 import org.springframework.statemachine.config.EnableStateMachine;
 import org.springframework.statemachine.config.EnumStateMachineConfigurerAdapter;
@@ -48,15 +48,23 @@ public class MethodAnnotationTests extends AbstractStateMachineTests {
 		ObjectStateMachine<TestStates,TestEvents> machine =
 				context.getBean(StateMachineSystemConstants.DEFAULT_ID_STATEMACHINE, ObjectStateMachine.class);
 		assertThat(context.containsBean("fooMachine"), is(true));
+		Bean1 bean1 = context.getBean(Bean1.class);
 		machine.start();
 
-		Bean1 bean1 = context.getBean(Bean1.class);
+		assertThat(bean1.onMethod1Latch.await(2, TimeUnit.SECONDS), is(false));
+		assertThat(bean1.onOnTransitionLatch.await(2, TimeUnit.SECONDS), is(true));
+		assertThat(bean1.onMethod1Count, is(0));
+		assertThat(bean1.onOnTransitionCount, is(1));
+
+		bean1.reset(1, 1);
 
 		// this event should cause 'method1' to get called
 		machine.sendEvent(MessageBuilder.withPayload(TestEvents.E1).build());
 
 		assertThat(bean1.onMethod1Latch.await(2, TimeUnit.SECONDS), is(true));
-		assertThat(bean1.onOnTransitionFromS2ToS3Latch.await(2, TimeUnit.SECONDS), is(false));
+		assertThat(bean1.onOnTransitionLatch.await(2, TimeUnit.SECONDS), is(true));
+		assertThat(bean1.onMethod1Count, is(1));
+		assertThat(bean1.onOnTransitionCount, is(1));
 
 		context.close();
 	}
@@ -93,16 +101,27 @@ public class MethodAnnotationTests extends AbstractStateMachineTests {
 	static class Bean1 {
 
 		CountDownLatch onMethod1Latch = new CountDownLatch(1);
-		CountDownLatch onOnTransitionFromS2ToS3Latch = new CountDownLatch(1);
+		CountDownLatch onOnTransitionLatch = new CountDownLatch(1);
+		int onMethod1Count;
+		int onOnTransitionCount;
 
 		@OnTransition(source = "S1", target = "S2")
 		public void method1() {
+			onMethod1Count++;
 			onMethod1Latch.countDown();
 		}
 
 		@OnTransition
-		public void onTransitionFromS2ToS3() {
-			onOnTransitionFromS2ToS3Latch.countDown();
+		public void onTransition() {
+			onOnTransitionCount++;
+			onOnTransitionLatch.countDown();
+		}
+
+		public void reset(int a1, int a2) {
+			onMethod1Latch = new CountDownLatch(a1);
+			onOnTransitionLatch = new CountDownLatch(a2);
+			onMethod1Count = 0;
+			onOnTransitionCount = 0;
 		}
 
 	}

spring-statemachine-core/src/test/java/org/springframework/statemachine/docs/DocsConfigurationSampleTests.java

@@ -415,6 +415,10 @@ public class DocsConfigurationSampleTests extends AbstractStateMachineTests {
 		@OnTransition(source = "S1", target = "S2")
 		public void fromS1ToS2() {
 		}
+
+		@OnTransition
+		public void anyTransition() {
+		}
 	}
 // end::snippetI[]