event-bus-core/src/main/java/dev/kske/eventbus/core/EventBus.java

@@ -27,21 +27,7 @@ public final class EventBus {
 	 */
 	private static final class DispatchState {
 
-		/**
-		 * Indicates that the last event handler invoked has called {@link EventBus#cancel}. In that
-		 * case, the event is not dispatched further.
-		 *
-		 * @since 0.1.0
-		 */
-		boolean isCancelled;
-
-		/**
-		 * Is incremented when {@link EventBus#dispatch(Object)} is invoked and decremented when it
-		 * finishes. This allows keeping track of nested dispatches.
-		 *
-		 * @since 1.2.0
-		 */
-		int nestingCount;
+		boolean isDispatching, isCancelled;
 	}
 
 	/**
@@ -93,11 +79,9 @@ public final class EventBus {
 		Objects.requireNonNull(event);
 		logger.log(Level.INFO, "Dispatching event {0}", event);
 
-		// Look up dispatch state
+		// Set dispatch state
 		var state = dispatchState.get();
-
-		// Increment nesting count (becomes > 1 during nested dispatches)
-		++state.nestingCount;
+		state.isDispatching = true;
 
 		Iterator<EventHandler> handlers = getHandlersFor(event.getClass());
 		if (handlers.hasNext()) {
@@ -110,14 +94,14 @@ public final class EventBus {
 					try {
 						handlers.next().execute(event);
 					} catch (InvocationTargetException e) {
-						if (e.getCause() instanceof Error)
-
-							// Transparently pass error to the caller
-							throw (Error) e.getCause();
-						else if (event instanceof DeadEvent || event instanceof ExceptionEvent)
+						if (event instanceof DeadEvent || event instanceof ExceptionEvent)
 
 							// Warn about system event not being handled
 							logger.log(Level.WARNING, event + " not handled due to exception", e);
+						else if (e.getCause() instanceof Error)
+
+							// Transparently pass error to the caller
+							throw (Error) e.getCause();
 						else
 
 							// Dispatch exception event
@@ -134,8 +118,8 @@ public final class EventBus {
 			dispatch(new DeadEvent(this, event));
 		}
 
-		// Decrement nesting count (becomes 0 when all dispatches on the thread are finished)
-		--state.nestingCount;
+		// Reset dispatch state
+		state.isDispatching = false;
 
 		logger.log(Level.DEBUG, "Finished dispatching event {0}", event);
 	}
@@ -171,7 +155,7 @@ public final class EventBus {
 	 */
 	public void cancel() {
 		var state = dispatchState.get();
-		if (state.nestingCount > 0 && !state.isCancelled)
+		if (state.isDispatching && !state.isCancelled)
 			state.isCancelled = true;
 		else
 			throw new EventBusException("Calling thread not an active dispatching thread!");

event-bus-core/src/test/java/dev/kske/eventbus/core/NestedTest.java

@@ -1,73 +0,0 @@
-package dev.kske.eventbus.core;
-
-import static org.junit.jupiter.api.Assertions.*;
-
-import org.junit.jupiter.api.*;
-
-/**
- * Tests nested event dispatches.
- *
- * @author Kai S. K. Engelbart
- * @since 1.2.0
- */
-class NestedTest {
-
-	EventBus	bus;
-	boolean		nestedHit;
-
-	/**
-	 * Constructs an event bus and registers this test instance as an event listener.
-	 *
-	 * @since 1.2.0
-	 */
-	@BeforeEach
-	void registerListener() {
-		bus = new EventBus();
-		bus.registerListener(this);
-	}
-
-	/**
-	 * Dispatches a simple event, which should in turn cause a string to be dispatched as a nested
-	 * event. If the corresponding handler sets {@link #nestedHit} to {@code true}, the test is
-	 * successful.
-	 *
-	 * @since 1.2.0
-	 */
-	@Test
-	void testNestedDispatch() {
-		bus.dispatch(new SimpleEvent());
-		assertTrue(nestedHit);
-	}
-
-	/**
-	 * Dispatches a string as a nested event and cancels the current dispatch afterwards.
-	 *
-	 * @since 1.2.0
-	 */
-	@Event(SimpleEvent.class)
-	void onSimpleEvent() {
-		bus.dispatch("Nested event");
-		bus.cancel();
-	}
-
-	/**
-	 * Sets {@link #nestedHit} to {@code true} indicating that nested dispatches work.
-	 *
-	 * @since 1.2.0
-	 */
-	@Event(String.class)
-	void onString() {
-		nestedHit = true;
-	}
-
-	/**
-	 * Fails the test if an exception is caused during the dispatch.
-	 *
-	 * @param e the event containing the exception
-	 * @since 1.2.0
-	 */
-	@Event
-	void onException(ExceptionEvent e) {
-		fail("Exception during dispatch", e.getCause());
-	}
-}