Advice on Global classes using MFC Doc/View

[milner]

I'm making an application with many dialog windows and classes that perform different actions. I want users to log in to the program before they can do anything.

Different users have different permissions for the programs operations. Every time a button is pressed to do something, I need to check if the current user is allowed to do that action.

What I'm wondering is, should I make a Current User class global to my project? If so, how can I do it and still be using good programming practice (I'd rather not have to pass this object to ALL my functions every time they are called).

I also need to do a similar thing with a logging class. Every action has to add an entry to the log.

Any help or advice is appreciated,

- Milner -

 

[palbano]

Milner,

If this is a single user desktop application you can use the Singleton pattern to solve your problem. If it is a server (multi-user) application that won't work.

A Singleton would work something like this:


class UserSession{

static UserSession* _pInstance;

protected:
UserSession(){}
~UserSession(){}
UserSession( const UserSession& rhs){}
const UserSession& operator=( const UserSession& rhs){return *this;}

static UserSession* instance(){

if ( NULL == _pInstance)
_pInstance = new UserSession();

return _pInstance;
}

// actual member variables and functions
CString _name;
long _id;

public:
// public interface
static void setName(LPCTSTR name){ instance()->_name = name; }
static void setID(long id){ instance()->_id = id; }

static LPCTSTR getName(){ return instance()->_name; }
static long getID(){ return instance()->_id; }

};


In a single .CPP file

// Initialize the one and ONLY UserSession pointer
UserSession* UserSession::_pInstance = NULL;


Hope this helps
-pete