Re: [Boost-users] Need a method to compare types of data objects at runtime

From: Jeff Garland (jeff_at_[hidden])
Date: 2005-04-24 14:14:09

On Sun, 24 Apr 2005 14:46:22 -0400, Stephen Torri wrote
>...snip...
>
> Each item expect a distinctive input type. If it receives something that 
> it does not know how to handle or need I want to throw an error.
> 
> In order to do this I would like to do something like:
>         
>         void process (Base* sobj)
>         {
>         	if (! (isExpectedType(sobj))
>         	{
>         		throw NotForMeException ();
>         	}
>         
>         	Brake_Pedal* bp = dynamic_cast<Brake_Pedal>(sobj);
>         	bp.set_pressure (50);
>         }
> 
> So perhaps my design is flawed that I am running into this 
> situation. 

I'd say so.  You might want to read about the Liskov Substitution Principle: 
http://www.objectmentor.com/resources/articles/lsp.pdf

Jeff