code: private void updateMessage(ClientSocket client, DataInputStream buffer, byte messageSystemId, byte from)
              throws IOException
      {
          switch (messageSystemId)
          {
              case NetworkMessageSystemId.CONNECTING:
                  receiveConnecting(client, buffer, from, StateConnection.CONNECTING);
                  break;
              case NetworkMessageSystemId.CONNECTED:
                  receiveConnected(client, from, StateConnection.CONNECTED);
                  break;
              case NetworkMessageSystemId.PING:
                  client.getOut().writeByte(NetworkMessageSystemId.PING);
                  client.getOut().flush();
                  bandwidth += 1;
                  break;
              case NetworkMessageSystemId.OTHER_CLIENT_DISCONNECTED:
                  receiveDisconnected(client, from, StateConnection.CONNECTED);
                  break;
              case NetworkMessageSystemId.OTHER_CLIENT_RENAMED:
                  receiveRenamed(client, buffer, from, StateConnection.CONNECTED);
                  break;
              case NetworkMessageSystemId.USER_MESSAGE:
                  receiveMessage(client, buffer, from, StateConnection.CONNECTED);
                  break;
              default:
                  break;
          }
      }
docs: Update the message depending of its ID.
  
  @param client The client socket.
  @param buffer The buffer input.
  @param messageSystemId The message system ID.
  @param from The source ID.
  @throws IOException If error when reading.