transitions with no targets

spring-webflow/src/main/java/org/springframework/webflow/engine/Flow.java

@@ -531,15 +531,15 @@ public class Flow extends AnnotatedObject implements FlowDefinition {
 	 * Handle the last event that occurred against an active session of this flow.
 	 * @param context the flow execution control context
 	 */
-	public void handleEvent(RequestControlContext context) {
+	public boolean handleEvent(RequestControlContext context) {
 		TransitionableState currentState = getCurrentTransitionableState(context);
 		try {
-			currentState.handleEvent(context);
+			return currentState.handleEvent(context);
 		} catch (NoMatchingTransitionException e) {
 			// try the flow level transition set for a match
 			Transition transition = globalTransitionSet.getTransition(context);
 			if (transition != null) {
-				transition.execute(currentState, context);
+				return transition.execute(currentState, context);
 			} else {
 				// no matching global transition => let the original exception
 				// propagate

spring-webflow/src/main/java/org/springframework/webflow/engine/RequestControlContext.java

@@ -85,11 +85,12 @@ public interface RequestControlContext extends RequestContext {
 	 * should be called by clients that report internal event occurrences, such as action states. The
 	 * <code>onEvent()</code> method of the flow involved in the flow execution will be called.
 	 * @param event the event that occurred
+	 * @return a boolean indicating if handling this event caused the current state to exit and a new state to enter
 	 * @throws FlowExecutionException if an exception was thrown within a state of the flow during execution of this
 	 * signalEvent operation
 	 * @see Flow#handleEvent(RequestControlContext)
 	 */
-	public void handleEvent(Event event) throws FlowExecutionException;
+	public boolean handleEvent(Event event) throws FlowExecutionException;
 
 	/**
 	 * End the active flow session of the current flow execution. This method should be called by clients that terminate
@@ -108,7 +109,7 @@ public interface RequestControlContext extends RequestContext {
 	 * @param transition the transition
 	 * @see Transition#execute(State, RequestControlContext)
 	 */
-	public void execute(Transition transition);
+	public boolean execute(Transition transition);
 
 	/**
 	 * Returns true if the 'always redirect pause' flow execution attribute is set to true, false otherwise.

spring-webflow/src/main/java/org/springframework/webflow/engine/SubflowState.java

@@ -105,7 +105,7 @@ public class SubflowState extends TransitionableState {
 	 * Called on completion of the subflow to handle the subflow result event as determined by the end state reached by
 	 * the subflow.
 	 */
-	public void handleEvent(RequestControlContext context) {
+	public boolean handleEvent(RequestControlContext context) {
 		if (subflowAttributeMapper != null) {
 			AttributeMap subflowOutput = context.getLastEvent().getAttributes();
 			if (logger.isDebugEnabled()) {
@@ -113,7 +113,7 @@ public class SubflowState extends TransitionableState {
 			}
 			subflowAttributeMapper.mapFlowOutput(subflowOutput, context);
 		}
-		super.handleEvent(context);
+		return super.handleEvent(context);
 	}
 
 	protected void appendToString(ToStringCreator creator) {

spring-webflow/src/main/java/org/springframework/webflow/engine/Transition.java

@@ -121,7 +121,7 @@ public class Transition extends AnnotatedObject implements TransitionDefinition
 	 * @param matchingCriteria the transition matching criteria
 	 */
 	public void setMatchingCriteria(TransitionCriteria matchingCriteria) {
-		Assert.notNull(matchingCriteria, "The matching criteria is required");
+		Assert.notNull(matchingCriteria, "The criteria for matching this transition is required");
 		this.matchingCriteria = matchingCriteria;
 	}
 
@@ -140,7 +140,6 @@ public class Transition extends AnnotatedObject implements TransitionDefinition
 	 * @param executionCriteria the transition execution criteria
 	 */
 	public void setExecutionCriteria(TransitionCriteria executionCriteria) {
-		Assert.notNull(executionCriteria, "The execution criteria is required");
 		this.executionCriteria = executionCriteria;
 	}
 
@@ -157,7 +156,6 @@ public class Transition extends AnnotatedObject implements TransitionDefinition
 	 * @param targetStateResolver the target state resolver
 	 */
 	public void setTargetStateResolver(TargetStateResolver targetStateResolver) {
-		Assert.notNull(targetStateResolver, "The target state resolver is required");
 		this.targetStateResolver = targetStateResolver;
 	}
 
@@ -178,7 +176,11 @@ public class Transition extends AnnotatedObject implements TransitionDefinition
 	 * @return true if this transition can complete execution, false if it should roll back
 	 */
 	public boolean canExecute(RequestContext context) {
-		return executionCriteria.test(context);
+		if (executionCriteria != null) {
+			return executionCriteria.test(context);
+		} else {
+			return false;
+		}
 	}
 
 	/**
@@ -186,44 +188,40 @@ public class Transition extends AnnotatedObject implements TransitionDefinition
 	 * for the given context.
 	 * @param sourceState the source state to transition from, may be null if the current state is null
 	 * @param context the flow execution control context
+	 * @return a boolean indicating if executing this transition caused the current state to exit and a new state to
+	 * enter
 	 * @throws FlowExecutionException when transition execution fails
 	 */
-	public void execute(State sourceState, RequestControlContext context) throws FlowExecutionException {
+	public boolean execute(State sourceState, RequestControlContext context) throws FlowExecutionException {
 		if (canExecute(context)) {
-			if (sourceState != null) {
-				if (logger.isDebugEnabled()) {
-					logger.debug("Executing " + this + " out of state '" + sourceState.getId() + "'");
-				}
-				if (sourceState instanceof TransitionableState) {
-					// make exit call back on transitionable state
-					((TransitionableState) sourceState).exit(context);
-				}
-			} else {
-				if (logger.isDebugEnabled()) {
-					logger.debug("Executing " + this);
-				}
+			if (logger.isDebugEnabled()) {
+				logger.debug("Executing " + this);
 			}
-			State targetState = targetStateResolver.resolveTargetState(this, sourceState, context);
 			context.setLastTransition(this);
-			// enter the target state (note: any exceptions are propagated)
-			targetState.enter(context);
-		} else {
-			if (sourceState != null && sourceState instanceof TransitionableState) {
-				((TransitionableState) sourceState).reenter(context);
-			} else {
-				throw new IllegalStateException("Execution of '" + this + "' was blocked by '" + getExecutionCriteria()
-						+ "', " + "; however, no source state is set at runtime.  "
-						+ "This is an illegal situation: check your flow definition.");
-			}
-		}
-		if (logger.isDebugEnabled()) {
-			if (context.getFlowExecutionContext().isActive()) {
-				logger.debug("Completed execution of " + this + "; as a result, the new state is '"
-						+ context.getCurrentState().getId() + "' in flow '" + context.getActiveFlow().getId() + "'");
-			} else {
-				logger.debug("Completed execution of " + this + "; as a result, the flow execution has ended");
+			if (targetStateResolver != null) {
+				State targetState = targetStateResolver.resolveTargetState(this, sourceState, context);
+				if (sourceState != null) {
+					if (logger.isDebugEnabled()) {
+						logger.debug("Exiting state '" + sourceState.getId() + "'");
+					}
+					if (sourceState instanceof TransitionableState) {
+						((TransitionableState) sourceState).exit(context);
+					}
+				}
+				targetState.enter(context);
+				if (logger.isDebugEnabled()) {
+					if (context.getFlowExecutionContext().isActive()) {
+						logger.debug("Completed transition execution.  As a result, the new state is '"
+								+ context.getCurrentState().getId() + "' in flow '" + context.getActiveFlow().getId()
+								+ "'");
+					} else {
+						logger.debug("Completed transition execution.  As a result, the flow execution has ended");
+					}
+				}
+				return true;
 			}
 		}
+		return false;
 	}
 
 	public String toString() {

spring-webflow/src/main/java/org/springframework/webflow/engine/TransitionableState.java

@@ -101,19 +101,8 @@ public abstract class TransitionableState extends State implements Transitionabl
 	 * @param context the flow execution control context
 	 * @throws NoMatchingTransitionException when a matching transition cannot be found
 	 */
-	public void handleEvent(RequestControlContext context) throws NoMatchingTransitionException {
-		context.execute(getRequiredTransition(context));
-	}
-
-	/**
-	 * Re-enter this state. This is typically called when a transition out of this state is selected, but transition
-	 * execution rolls back and as a result the flow reenters the source state.
-	 * <p>
-	 * By default, this just calls <code>enter()</code>.
-	 * @param context the flow control context in an executing flow (a client instance of a flow)
-	 */
-	public void reenter(RequestControlContext context) {
-		enter(context);
+	public boolean handleEvent(RequestControlContext context) throws NoMatchingTransitionException {
+		return context.execute(getRequiredTransition(context));
 	}
 
 	/**

spring-webflow/src/main/java/org/springframework/webflow/engine/ViewState.java

@@ -169,13 +169,7 @@ public class ViewState extends TransitionableState {
 			context.sendFlowExecutionRedirect();
 		} else {
 			View view = viewFactory.getView(context);
-			renderActionList.execute(context);
-			if (logger.isDebugEnabled()) {
-				logger.debug("Rendering view " + view);
-			}
-			view.render();
-			context.getMessageContext().clearMessages();
-			context.getFlashScope().clear();
+			render(context, view);
 		}
 	}
 
@@ -187,15 +181,12 @@ public class ViewState extends TransitionableState {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Event '" + event.getId() + "' signaled on view " + view);
 			}
-			context.handleEvent(event);
-		} else {
-			renderActionList.execute(context);
-			if (logger.isDebugEnabled()) {
-				logger.debug("Rendering refreshed view " + view);
+			boolean stateExited = context.handleEvent(event);
+			if (!stateExited) {
+				render(context, view);
 			}
-			view.render();
-			context.getMessageContext().clearMessages();
-			context.getFlashScope().clear();
+		} else {
+			render(context, view);
 		}
 	}
 
@@ -206,14 +197,6 @@ public class ViewState extends TransitionableState {
 
 	// internal helpers
 
-	private boolean shouldRedirect(RequestControlContext context) {
-		if (redirect != null) {
-			return redirect.booleanValue();
-		} else {
-			return context.getAlwaysRedirectOnPause();
-		}
-	}
-
 	private void createVariables(RequestContext context) {
 		Iterator it = variables.values().iterator();
 		while (it.hasNext()) {
@@ -225,6 +208,24 @@ public class ViewState extends TransitionableState {
 		}
 	}
 
+	private boolean shouldRedirect(RequestControlContext context) {
+		if (redirect != null) {
+			return redirect.booleanValue();
+		} else {
+			return context.getAlwaysRedirectOnPause();
+		}
+	}
+
+	private void render(RequestControlContext context, View view) {
+		if (logger.isDebugEnabled()) {
+			logger.debug("Rendering + " + view);
+		}
+		renderActionList.execute(context);
+		view.render();
+		context.getMessageContext().clearMessages();
+		context.getFlashScope().clear();
+	}
+
 	private void restoreVariables(RequestContext context) {
 		Iterator it = variables.values().iterator();
 		while (it.hasNext()) {

spring-webflow/src/main/java/org/springframework/webflow/engine/impl/FlowExecutionImpl.java

@@ -344,14 +344,14 @@ public class FlowExecutionImpl implements FlowExecution, Externalizable {
 		listeners.fireStateEntered(context, previousState);
 	}
 
-	void handleEvent(Event event, RequestControlContext context) {
+	boolean handleEvent(Event event, RequestControlContext context) {
 		listeners.fireEventSignaled(context, event);
-		getActiveSessionInternal().getFlow().handleEvent(context);
+		return getActiveSessionInternal().getFlow().handleEvent(context);
 	}
 
-	void execute(Transition transition, RequestControlContext context) {
+	boolean execute(Transition transition, RequestControlContext context) {
 		listeners.fireTransitionExecuting(context, transition);
-		transition.execute(getCurrentState(), context);
+		return transition.execute(getCurrentState(), context);
 	}
 
 	FlowSession endActiveFlowSession(MutableAttributeMap output, RequestControlContext context) {

spring-webflow/src/main/java/org/springframework/webflow/engine/impl/RequestControlContextImpl.java

@@ -196,13 +196,13 @@ class RequestControlContextImpl implements RequestControlContext {
 		flowExecution.start(flow, input, this);
 	}
 
-	public void handleEvent(Event event) throws FlowExecutionException {
+	public boolean handleEvent(Event event) throws FlowExecutionException {
 		this.lastEvent = event;
-		flowExecution.handleEvent(event, this);
+		return flowExecution.handleEvent(event, this);
 	}
 
-	public void execute(Transition transition) {
-		flowExecution.execute(transition, this);
+	public boolean execute(Transition transition) {
+		return flowExecution.execute(transition, this);
 	}
 
 	public FlowSession endActiveFlowSession(MutableAttributeMap output) throws IllegalStateException {

spring-webflow/src/main/java/org/springframework/webflow/test/MockRequestControlContext.java

@@ -73,9 +73,9 @@ public class MockRequestControlContext extends MockRequestContext implements Req
 		flow.start(this, input);
 	}
 
-	public void handleEvent(Event event) {
+	public boolean handleEvent(Event event) {
 		setLastEvent(event);
-		((Flow) getActiveFlow()).handleEvent(this);
+		return ((Flow) getActiveFlow()).handleEvent(this);
 	}
 
 	public FlowSession endActiveFlowSession(MutableAttributeMap output) throws IllegalStateException {
@@ -85,8 +85,8 @@ public class MockRequestControlContext extends MockRequestContext implements Req
 		return endingSession;
 	}
 
-	public void execute(Transition transition) {
-		transition.execute((TransitionableState) getCurrentState(), this);
+	public boolean execute(Transition transition) {
+		return transition.execute((TransitionableState) getCurrentState(), this);
 	}
 
 	public FlowExecutionKey assignFlowExecutionKey() {

spring-webflow/src/test/java/org/springframework/webflow/engine/TransitionTests.java

@@ -24,7 +24,6 @@ import org.springframework.webflow.test.MockRequestControlContext;
 
 public class TransitionTests extends TestCase {
 
-	private boolean reenterCalled;
 	private boolean exitCalled;
 
 	public void testExecuteTransitionFromState() {
@@ -50,7 +49,8 @@ public class TransitionTests extends TestCase {
 		MockRequestControlContext context = new MockRequestControlContext(flow);
 		context.setCurrentState(source);
 		Transition t = new Transition(targetResolver);
-		t.execute(source, context);
+		boolean stateExited = t.execute(source, context);
+		assertTrue(stateExited);
 		assertTrue(exitCalled);
 		assertSame(target, context.getCurrentState());
 	}
@@ -69,19 +69,14 @@ public class TransitionTests extends TestCase {
 		};
 		MockRequestControlContext context = new MockRequestControlContext(flow);
 		Transition t = new Transition(targetResolver);
-		t.execute(null, context);
+		boolean stateChanged = t.execute(null, context);
+		assertTrue(stateChanged);
 		assertSame(target, context.getCurrentState());
 	}
 
 	public void testTransitionExecutionRefused() {
 		Flow flow = new Flow("flow");
 		final TransitionableState source = new TransitionableState(flow, "state 1") {
-
-			public void reenter(RequestControlContext context) {
-				reenterCalled = true;
-				super.reenter(context);
-			}
-
 			public void exit(RequestControlContext context) {
 				exitCalled = true;
 			}
@@ -107,9 +102,9 @@ public class TransitionTests extends TestCase {
 				return false;
 			}
 		});
-		t.execute(source, context);
+		boolean stateExited = t.execute(source, context);
+		assertFalse(stateExited);
 		assertFalse(exitCalled);
-		assertTrue(reenterCalled);
 		assertSame(source, context.getCurrentState());
 	}