Use void.class to determine how the event handler type is defined

The dummy class USE_PARAMETER was necessary when the IEvent interface
still existed, as void.class could not be used as a Class<? extends
IEvent>. As no explicit reference to USE_PARAMETER should be present
anywhere, a proper deprecation would've made little sense.

core/src/main/java/dev/kske/eventbus/core/Event.java

@@ -30,13 +30,5 @@ public @interface Event {
 	 * @return the event type accepted by the handler
 	 * @since 1.0.0
 	 */
-	Class<?> value() default USE_PARAMETER.class;
-
-	/**
-	 * Signifies that the event type the handler listens to is determined by the type of its only
-	 * parameter.
-	 *
-	 * @since 0.0.3
-	 */
-	static final class USE_PARAMETER {}
+	Class<?> value() default void.class;
 }

core/src/main/java/dev/kske/eventbus/core/handler/ReflectiveEventHandler.java

@@ -3,7 +3,6 @@ package dev.kske.eventbus.core.handler;
 import java.lang.reflect.*;
 
 import dev.kske.eventbus.core.*;
-import dev.kske.eventbus.core.Event.USE_PARAMETER;
 
 /**
  * An event handler wrapping a method annotated with {@link Event} and executing it using
@@ -37,7 +36,7 @@ public final class ReflectiveEventHandler implements EventHandler {
 		boolean defPolymorphism, int defPriority) throws EventBusException {
 		this.listener	= listener;
 		this.method		= method;
-		useParameter	= annotation.value() == USE_PARAMETER.class;
+		useParameter	= annotation.value() == void.class;
 
 		// Check handler signature
 		if (method.getParameterCount() == 0 && useParameter)

proc/src/main/java/dev/kske/eventbus/proc/EventProcessor.java

@@ -47,13 +47,12 @@ public class EventProcessor extends AbstractProcessor {
 
 				// Task failed successfully
 				eventType		= e.getTypeMirror();
-				useParameter	= processingEnv.getTypeUtils().isSameType(eventType,
-					getTypeMirror(Event.USE_PARAMETER.class));
+				useParameter	= eventType.getKind() == TypeKind.VOID;
 			}
 
 			// Check handler signature
 			boolean pass = false;
-			if (useParameter && eventHandler.getParameters().size() == 0)
+			if (useParameter && eventHandler.getParameters().isEmpty())
 				error(eventHandler, "The method or the annotation must define the event type");
 			else if (!useParameter && eventHandler.getParameters().size() == 1)
 				error(eventHandler,
@@ -100,14 +99,15 @@ public class EventProcessor extends AbstractProcessor {
 			boolean		hasListenerPriority	= listenerPriority != null;
 
 			// Effective polymorphism
-			boolean polymorphic =
+			boolean	polymorphic				=
 				hasListenerPolymorphic ? listenerPolymorphic.value() : defPolymorphic;
 			boolean	hasHandlerPolymorphic	= eventHandler.getAnnotation(Polymorphic.class) != null;
 			if (hasHandlerPolymorphic)
 				polymorphic = eventHandler.getAnnotation(Polymorphic.class).value();
 
 			// Effective priority
-			int priority = hasListenerPriority ? listenerPriority.value() : defPriority;
+			int		priority			=
+				hasListenerPriority ? listenerPriority.value() : defPriority;
 			boolean	hasHandlerPriority	= eventHandler.getAnnotation(Priority.class) != null;
 			if (hasHandlerPriority)
 				priority = eventHandler.getAnnotation(Priority.class).value();
@@ -137,14 +137,6 @@ public class EventProcessor extends AbstractProcessor {
 		}
 	}
 
-	private TypeMirror getTypeMirror(Class<?> clazz) {
-		return getTypeElement(clazz).asType();
-	}
-
-	private TypeElement getTypeElement(Class<?> clazz) {
-		return processingEnv.getElementUtils().getTypeElement(clazz.getCanonicalName());
-	}
-
 	private void warning(Element e, String msg, Object... args) {
 		processingEnv.getMessager().printMessage(Kind.WARNING, String.format(msg, args), e);
 	}