RAII Idiom

From:
Peter_APIIT <peterapiit@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Fri, 3 Jul 2009 10:12:27 CST
Message-ID:
<99ac0a58-b1af-49a2-beac-e49471081e8d@d36g2000prb.googlegroups.com>
Hello to all, as you all know that RAII use to keep track of dynamic
memory allocation in different hierarchy.

For instance, i have class objectCreator and objectBase.
Code:

class objectCreator
{
   private:
   objecrBase* pObject;
};

class objectBase
{
};

Main.cpp
Code:

ObjectCreator obc;
ObjectBase* ob = obc.Create(name);

When obc goes out of scope, then the object created which pointed by
ob also will get destroyed.

I create objectCreator in main as object, then if objectCreator goes
out of scope, then objectBase also will get delete in destructor of
objectCreator.

My question is i have class hierarchy such as

usernameType(Base class)
AdminUsernameType(Derived from usernameType)
HRUsernameType(Derived from usernameType)

Based on the username of login i dynamic create a derived type.

Code:

class usernameType
{
protected:
login loginSessionObject;

public:
    usernameType();
    usernameType(const login&);
    ~usernameType();

    static usernameType* FactoryMethodCreate(const login&);

class AdministratorType : public usernameType
{
public:
    AdministratorType();
    ~AdministratorType();

    void ForwardCreator();

    void setInstance(Human* );
};

Definition:
Code:

usernameType* usernameType::FactoryMethodCreate(const login&
theLoginObject)
{
    switch (theLoginObject.getUsername().at(0))
    {
        case 'A':
        {
            return new AdministratorType();
            break;
        }

        case 'H':
        {
            return new HumanResourceType();
            break;
        }

        case 'S':
        {
            return new StaffType();
            break;
        }

        default:
        {
            break;
        }
    }

    return new AdministratorType();

}

How can i keep track which derived class get created and delete them
accordingly when theAccountUser goes out of scope.

Main.cpp
Code:

usernameType theAccountUser(loginSession);
usernameType* theAccountType = theAccountUser.FactoryMethodCreate
(loginSession);

Thanks for your help.

I really appreciated any advice. I won't ignore your advice.

Is it possible for usernameType base class contains pointer to derived
class which is create using new().

Thanks again.

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