void addClient(const std::string &appid, unsigned layer, unsigned surface, const std::string &role);
void removeClient(const std::string &appid);
bool contains(const std::string &appid) const;
int countClient() const;
std::shared_ptr<WMClient> lookUpClient(const std::string &appid);
void removeSurface(unsigned surface);
void addClient(const std::string &appid, unsigned layer, unsigned surface, const std::string &role);
void removeClient(const std::string &appid);
bool contains(const std::string &appid) const;
int countClient() const;
std::shared_ptr<WMClient> lookUpClient(const std::string &appid);
void removeSurface(unsigned surface);