Improve registration methods.

src/main/java/emu/grasscutter/server/game/GameServerPacketHandler.java

@@ -23,25 +23,15 @@ public class GameServerPacketHandler {
 		this.registerHandlers(handlerClass);
 	}
 
-	public void registerPacketHandler(int opcode, PacketHandler handler) {
-		this.handlers.put(opcode, handler);
-	}
-
-	public void registerHandlers(Class<? extends PacketHandler> handlerClass) {
-		Reflections reflections = new Reflections("emu.grasscutter.server.packet");
-		Set<?> handlerClasses = reflections.getSubTypesOf(handlerClass);
-		
-		for (Object obj : handlerClasses) {
-			Class<?> c = (Class<?>) obj;
-			
+	public void registerPacketHandler(Class<? extends PacketHandler> handlerClass) {
 		try {
-				Opcodes opcode = c.getAnnotation(Opcodes.class);
+			Opcodes opcode = handlerClass.getAnnotation(Opcodes.class);
 
 			if (opcode == null || opcode.disabled() || opcode.value() <= 0) {
-					continue;
+				return;
 			}
 
-				PacketHandler packetHandler = (PacketHandler) c.newInstance();
+			PacketHandler packetHandler = (PacketHandler) handlerClass.newInstance();
 
 			this.handlers.put(opcode.value(), packetHandler);
 		} catch (Exception e) {
@@ -49,6 +39,14 @@ public class GameServerPacketHandler {
 		}
 	}
 
+	public void registerHandlers(Class<? extends PacketHandler> handlerClass) {
+		Reflections reflections = new Reflections("emu.grasscutter.server.packet");
+		Set<?> handlerClasses = reflections.getSubTypesOf(handlerClass);
+		
+		for (Object obj : handlerClasses) {
+			this.registerPacketHandler((Class<? extends PacketHandler>) obj);
+		}
+		
 		// Debug
 		Grasscutter.getLogger().info("Registered " + this.handlers.size() + " " + handlerClass.getSimpleName() + "s");
 	}