// "interface"
class UMSConnector {
public:
    static UMSConnector * instance(const string& name) {
        static UMSConnector *pInstance;
        if( ! pInstance ) {
            pInstance = new UMSConnector(name);
            return pInstance;
        }
        return pInstance;
    }

    // interface API to be implemented by UMSConnector_impl
    bool addEventHandler(string event);

private:
    class UMSConnector_impl;
    UMSConnector_impl *pImpl;
    Logger log;
    string name;

    UMSConnector(const string& name);
    ~UMSConnector();
    UMSConnector(UMSConnector const& ) {};  // copy constructor
    void operator=(const UMSConnector&) {};  // assignment constructor
};

UMSConnector::UMSConnector(const string& name)
             : name(name) {
  LOG_TRACE(log,"called");
  pImpl = new UMSConnector_impl();
}

UMSConnector::~UMSConnector() {
  LOG_TRACE(log,"called");
  delete pImpl;
  pImpl = NULL;
}

bool UMSConnector::addEventHandler(string event)
{
    if( pImpl ) {
        return pImpl->addEventHandler(event);
    }
    return false;
}

// "implementation"
class UMSConnector::UMSConnector_impl {
public:
    bool addEventHandler(const string& event);

private:
    Logger log;
};

bool UMSConnector::UMSConnector_impl::addEventHandler(const string& event)
{
  LOG_TRACE(log,"UMSConnector_impl::addEventHandler: event=%s",event.c_str());
  return true;
}