diff --git a/lesson_04/server/tcp_server.cpp b/lesson_04/server/tcp_server.cpp
index 0b26b9a..db90e6c 100644
--- a/lesson_04/server/tcp_server.cpp
+++ b/lesson_04/server/tcp_server.cpp
@@ -18,11 +18,6 @@ namespace azh
     {
     }
 
-    TCPServer::~TCPServer()
-    {
-
-    }
-
     int TCPServer::run()
     {
         try
@@ -52,4 +47,19 @@ namespace azh
             startAccept();
         });
     }
+
+    template<typename T>
+    void writeToConnection(int connectionIndex, const T& message)
+    {
+
+    }
+
+    template<typename T>
+    using listenCallback = std::function<void(int, const T&)>;
+
+    template<typename T>
+    void registerListenCallback(int connectionIndex, listenCallback<T> callback)
+    {
+
+    }
 }
diff --git a/lesson_04/server/tcp_server.hpp b/lesson_04/server/tcp_server.hpp
index aa400a1..9d29a60 100644
--- a/lesson_04/server/tcp_server.hpp
+++ b/lesson_04/server/tcp_server.hpp
@@ -10,6 +10,7 @@
 #include <boost/asio.hpp>
 #include <connection/connection.hpp>
 #include <vector>
+#include <functional>
 
 namespace azh
 {
@@ -22,8 +23,17 @@ namespace azh
     {
     public:
         TCPServer(IPV ipv, int port);
-        virtual ~TCPServer();
+
         int run();
+
+        template<typename T>
+        void writeToConnection(int connectionIndex, const T& message);
+
+        template<typename T>
+        using listenCallback = std::function<void(int, const T&)>;
+
+        template<typename T>
+        void registerListenCallback(int connectionIndex, listenCallback<T> callback);
     private:
         IPV _ipVersion;
         int _port;