On Fri, Mar 23, 2001 at 09:20:22AM -0500, David E. Cleary wrote:
>
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of John
> > Snelson
> >
> > The C++ way of doing this is the following code fragment:
> >
> > if(node.getNodeType() == DOM_Node::ELEMENT_NODE) {
> > DOM_Element element = static_cast<DOM_Element&>(node);
> > }
>
> Wouldn't dynanic_cast be more what Curt is looking to do, as that will
> actually perform a runtime check to see in node is indeed a DOM_Element?
> I've never used these casting constructs myself, so I am interested in
> hearing other's thoughts on them.
The cleanest way to do casting is using class specific cast operator or cast
constructor.
element = (DOM_Element) node
is clean (???) cast in Java but it does not work in C++.
element = static_cast<DOM_Element&>(node);
says "I do know what I do" (what about the future?)
The solution 1 (cast operator):
class DOM_Node
{
...
operator DOM_Element(void);
};
The solution 2 (cast constructor):
class DOM_Element
{
...
DOM_Element (const DOM_Node&);
};
Both solution are better then direct cast because the casts are method calls
which can do what they want to guarantee the correct casting. For invalid
conversion one could throw a appropriate exception. I (and many others as I
guess) would wellcome one of them in Xerces DOM.
regards.
--
Miroslaw Dobrzanski-Neumann
MOSAIC SOFTWARE AG
Base Development and Research
Tel +49-2225-882-291
Fax +49-2225-882-201
E-mail: [EMAIL PROTECTED]
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