Optimize way of putting constraints in calling methods of an existing library

Lets say I have a class library which has these following classes:

class A
{
    void A1() {}
    void A2() {}
}

class B
{
    void B1() {}
    void B2() {}
}

class C
{
    void C1() {}
    void C2() {}
}

In my client code I开发者_如何学JAVA am doing this:

Class Client
{
    A objA = new A();
    objA.A1();
     // Same for other classes and their methods 

}

Now I have a change request which requires me put some constraints (say RightAcess etc.) while calling the library methods. I have more than 30 classes to update. What is the optimized way to achieve this?

---

Its better to have base class for all your class and implement the same function inside the base class

class  BaseClass
{
    public object RightAcess()
    {
       //[Code]

    }
}

class A : BaseClass
{
  ...
}

class B : BaseClass
{
  ...
}

class C : BaseClass
{
  ...
}