working dispatcher + factory

include/sp/protocol/ConcreteMessage.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <sp/protocol/MessageBase.h>
+
+namespace sp {
+
+template <typename TData, typename TMessageID, TMessageID ID, typename THandler>
+class ConcreteMessage : public MessageBase<TMessageID, THandler> {
+  public:
+	using DataType = TData;
+
+	template <typename... T>
+	ConcreteMessage(const T&... args) : m_Data{args...} {}
+
+	virtual ~ConcreteMessage() {}
+
+	virtual constexpr TMessageID GetId() const override {
+		return ID;
+	}
+
+	virtual void Dispatch(THandler& handler) const override {
+		handler.Handle(static_cast<const ConcreteMessage<TData, TMessageID, ID, THandler>&>(*this));
+	}
+
+  private:
+	DataType m_Data;
+};
+
+}  // namespace sp