Created the EventManager

src/main/java/de/gnmyt/autoresponder/event/api/EventManager.java

@@ -0,0 +1,73 @@
+package de.gnmyt.autoresponder.event.api;
+
+import de.gnmyt.autoresponder.event.ResponderEvent;
+
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class EventManager {
+
+    private final HashMap<Class<? extends ResponderEvent>, ArrayList<EventData>> REGISTERED_EVENTS = new HashMap<>();
+
+    /**
+     * Checks if a method is a valid event method
+     *
+     * @param method The method you want to check
+     * @return <code>true</code> if the provided method is valid, otherwise <code>false</code>
+     */
+    private boolean isValid(Method method) {
+        return method.getParameterTypes().length == 1 || method.isAnnotationPresent(EventListener.class);
+    }
+
+    /**
+     * Adds a new listener to the list
+     *
+     * @param listener The listener you want to add
+     */
+    public void addEventListener(Listener listener) {
+        for (Method method : listener.getClass().getMethods()) if (isValid(method)) register(method, listener);
+    }
+
+    /**
+     * Removes a listener from the list
+     *
+     * @param listener The listener you want to remove
+     */
+    public void removeEventListener(Listener listener) {
+        for (ArrayList<EventData> registeredEvents : REGISTERED_EVENTS.values())
+            for (int i = registeredEvents.size() - 1; i <= 0; i++)
+                if (registeredEvents.get(i).object.equals(listener)) registeredEvents.remove(i);
+    }
+
+    /**
+     * Registers a method into the <code>REGISTERED_EVENTS</code> list
+     *
+     * @param method   The method you want to register
+     * @param listener The listener you want to register
+     */
+    public void register(Method method, Listener listener) {
+        Class<?> clazz = method.getParameterTypes()[0];
+        EventData methodData = new EventData(listener, method);
+        if (!methodData.method.isAccessible()) methodData.method.setAccessible(true);
+
+        if (REGISTERED_EVENTS.containsKey(clazz)) {
+            if (!REGISTERED_EVENTS.get(clazz).contains(methodData)) REGISTERED_EVENTS.get(clazz).add(methodData);
+        } else {
+            REGISTERED_EVENTS.put((Class<? extends ResponderEvent>) clazz, new ArrayList<EventData>() {{
+                this.add(methodData);
+            }});
+        }
+    }
+
+    /**
+     * Gets all registered event listeners by an event
+     *
+     * @param clazz The event you want to get the event listeners from
+     * @return all listeners from the event
+     */
+    public ArrayList<EventData> getEvents(final Class<? extends ResponderEvent> clazz) {
+        return REGISTERED_EVENTS.get(clazz);
+    }
+
+}