Preprocessing concept implementation

event-loop/src/main/java/mc/core/events/BaseEventLoop.java

@@ -7,35 +7,28 @@ import java.lang.reflect.Modifier;
 
 @Slf4j
 public abstract class BaseEventLoop implements EventLoop {
-    @Override
+
-    public void addEventHandler(Object object) {
+    protected boolean notValidEventHandler(EventHandler annotation, Method method) {
-        for (Method method : object.getClass().getDeclaredMethods()) {
-            EventHandler annotation = method.getAnnotation(EventHandler.class);
         if (annotation == null)
-                continue; // We are not interested in methods without @EventHandler annotation
+            return true;
 
         if (!Modifier.isPublic(method.getModifiers())) {
             log.error("Unable to register {} as an EventHandler. Method must have a 'private' access modifier.", method.toString());
-                continue;
+            return true;
 
         }
 
         if (method.getParameterCount() != 1) {
             log.error("Unable to register {} as an EventHandler. Method must have exactly one argument.", method.toString());
-                continue;
+            return true;
         }
 
         Class<?> firstParamType = method.getParameterTypes()[0];
         if (!Event.class.isAssignableFrom(firstParamType)) {
             log.error("Unable to register {} as an EventHandler. First parameter type must implement 'Event' interface.", method.toString());
-                continue;
+            return true;
         }
 
-            @SuppressWarnings("unchecked") Class<? extends Event> eventType = (Class<? extends Event>) firstParamType;
+        return false;
-
-            registerMethod(object, method, annotation, eventType);
     }
 }
-
-    protected abstract void registerMethod(Object object, Method method, EventHandler annotation, Class<? extends Event> eventType);
-}

event-loop/src/main/java/mc/core/events/SimpleEventLoop.java

@@ -6,7 +6,6 @@ import lombok.extern.slf4j.Slf4j;
 
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.lang.reflect.Modifier;
 import java.util.*;
 
 @Slf4j
@@ -27,11 +26,21 @@ public class SimpleEventLoop extends BaseEventLoop {
         }
     }
 
-    protected void registerMethod(Object object, Method method, EventHandler annotation, Class<? extends Event> eventType) {
+    @Override
+    public void addEventHandler(Object object) {
+        for (Method method : object.getClass().getDeclaredMethods()) {
+            EventHandler annotation = method.getAnnotation(EventHandler.class);
+
+            if (notValidEventHandler(annotation, method))
+                continue;
+
+            @SuppressWarnings("unchecked") Class<? extends Event> eventType = (Class<? extends Event>) method.getParameterTypes()[0];
+
             List<SimpleEventLoop.ExecutorLink> eventHandlers = handlers.computeIfAbsent(eventType, s -> new ArrayList<>());
             eventHandlers.add(new SimpleEventLoop.ExecutorLink(annotation.priority().getValue(), annotation.ignoreCancelled(), method, object));
             eventHandlers.sort(Comparator.comparingInt(o -> o.priority));
         }
+    }
 
     /**
      * This class describes

event-loop/src/main/java/mc/core/events/async/AsyncEventLoop.java

@@ -0,0 +1,105 @@
+package mc.core.events.async;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import mc.core.events.BaseEventLoop;
+import mc.core.events.Event;
+import mc.core.events.EventHandler;
+
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.*;
+
+@SuppressWarnings("Duplicates")
+@Slf4j
+public class AsyncEventLoop extends BaseEventLoop {
+    private Map<Class<? extends Event>, List<ExecutorLink>> handlers = new HashMap<>();
+
+    @Override
+    public void callEvent(Event event) {
+        Class<? extends Event> eventType = event.getClass();
+        if (handlers.containsKey(eventType)) {
+            for (ExecutorLink link : handlers.get(eventType)) {
+                if (link.getPreprocessMethod() != null) {
+                    try {
+                        link.getPreprocessMethod().invoke(link.object, event);
+                    } catch (IllegalAccessException | InvocationTargetException e) {
+                        log.error("Exception caught while attempting to run event preprocessing for {}.", eventType.getSimpleName(), e);
+                    }
+                }
+
+                try {
+                    link.getMethod().invoke(link.object, event);
+                } catch (IllegalAccessException | InvocationTargetException e) {
+                    log.error("Exception caught while attempting to dispatch {}.", eventType.getSimpleName(), e);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void addEventHandler(Object object) {
+        Map<String, Method> preprocessors = new HashMap<>();
+
+        for (Method method : object.getClass().getDeclaredMethods()) {
+            EventPreprocessor annotation = method.getAnnotation(EventPreprocessor.class);
+            if (annotation == null)
+                continue;
+
+            if (!Modifier.isPublic(method.getModifiers())) {
+                log.error("Unable to register {} as an EventPreprocessor. Method must have a 'private' access modifier.", method.toString());
+                continue;
+
+            }
+
+            if (method.getParameterCount() != 1) {
+                log.error("Unable to register {} as an EventPreprocessor. Method must have exactly one argument.", method.toString());
+                continue;
+            }
+
+            Class<?> firstParamType = method.getParameterTypes()[0];
+            if (!Event.class.isAssignableFrom(firstParamType)) {
+                log.error("Unable to register {} as an EventPreprocessor. First parameter type must implement 'Event' interface.", method.toString());
+                continue;
+            }
+
+            if (preprocessors.containsKey(annotation.eventName()))
+                log.warn("Attempted to register multiple EventPreprocessors for the event {}. Please note, that only the last one will be registered.", annotation.eventName());
+            preprocessors.put(annotation.eventName(), method);
+        }
+
+
+        for (Method method : object.getClass().getDeclaredMethods()) {
+            EventHandler annotation = method.getAnnotation(EventHandler.class);
+
+            if (notValidEventHandler(annotation, method))
+                continue;
+
+            @SuppressWarnings("unchecked") Class<? extends Event> eventType = (Class<? extends Event>) method.getParameterTypes()[0];
+
+            List<ExecutorLink> eventHandlers = handlers.computeIfAbsent(eventType, s -> new ArrayList<>());
+            eventHandlers.add(new ExecutorLink(annotation.priority().getValue(), annotation.ignoreCancelled(), method, object, preprocessors.remove(method.getName())));
+            eventHandlers.sort(Comparator.comparingInt(o -> o.priority));
+        }
+
+        for (Map.Entry<String, Method> preprocessor : preprocessors.entrySet())
+            log.error("EventPreprocessor ({}) missing target: unable to find target method ({})", preprocessor.getValue(), preprocessor.getKey());
+
+    }
+
+    /**
+     * This class describes
+     */
+    @RequiredArgsConstructor
+    @Getter
+    private static class ExecutorLink {
+        private final int priority;
+        private final boolean ignoreCancelled;
+        private final Method method;
+        private final Object object;
+        private final Method preprocessMethod;
+    }
+}
+

event-loop/src/main/java/mc/core/events/async/EventPreprocessor.java

@@ -0,0 +1,12 @@
+package mc.core.events.async;
+
+
+import java.lang.annotation.*;
+
+@Documented
+@Target(ElementType.METHOD)
+@Inherited
+@Retention(RetentionPolicy.RUNTIME)
+public @interface EventPreprocessor {
+    String eventName();
+}

event-loop/src/test/java/ru/core/events/AsyncEventLoopTest.java

@@ -0,0 +1,22 @@
+package ru.core.events;
+
+import mc.core.events.LoginEvent;
+import mc.core.events.async.AsyncEventLoop;
+import org.junit.Assert;
+import org.junit.Test;
+import ru.core.events.handlers.AsyncEventHandler;
+
+public class AsyncEventLoopTest {
+
+    @Test
+    public void loopWorks() {
+        AsyncEventLoop asyncEventLoop = new AsyncEventLoop();
+        asyncEventLoop.addEventHandler(new AsyncEventHandler());
+        LoginEvent testEvent = new LoginEvent(null);
+        testEvent.setDenyReason("none");
+
+        asyncEventLoop.callEvent(testEvent);
+
+        Assert.assertEquals("Event handler was not called", "Hello from Async Event Handler!", testEvent.getDenyReason());
+    }
+}

event-loop/src/test/java/ru/core/events/handlers/AsyncEventHandler.java

@@ -0,0 +1,18 @@
+package ru.core.events.handlers;
+
+import mc.core.events.EventHandler;
+import mc.core.events.LoginEvent;
+import mc.core.events.async.EventPreprocessor;
+
+public class AsyncEventHandler {
+
+    @EventHandler
+    public void onLogin(LoginEvent event) {
+        event.setDenyReason("Hello from Async Event Handler!");
+    }
+
+    @EventPreprocessor(eventName = "onLogin")
+    public void onLoginPreprocess(LoginEvent event) {
+
+    }
+}