Re: static virtual method

From:
Fei Liu <fei.liu@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Wed, 09 Apr 2008 15:01:14 -0400
Message-ID:
<47FD127A.90503@gmail.com>
Christian Hackl wrote:

Fei Liu wrote:

Typically one models this behavior (static virtual) through a static
method that calls a virtual method with argument that contains a
polymorphic object.


Is that a polymorphic object of the same class hierarchy the class
containing the static method belongs to?

In other words, something along the lines of:

class Base
{
 //...

 virtual void func() = 0;

 static Base *strategy_;
 static void staticFunc()
 {
   strategy_->func();
 }
};

class Derived : public Base
{
  //...
  virtual void func();
};

Base *ptr = new Derived;
Base::strategy_ = ptr;
Base::staticFunc(); // "virtual" static function call


Not really, in pseudo code:

A::static_method(poly_object * obj){
   do1();
   obj->some_method();
   do2();
}

Of course, this also nicely uses the 'template method' pattern, your
static_method defines a template method that all callers will follow,
then some_method can implement polymorphic behavior on demand.

Fei

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