Re: [platform-swt-dev] Re: Subclassing Shell

[Bob Foster <bob@xxxxxxxxxx>]

David Whiteman wrote:
> You are definitely well versed in the pros and cons of subclassing vs.
> composition.

And these pros and cons do not belong on this list. Whether SWT should 
be more "object-oriented" is a permathread and should be directed to the 
eclipse-platform newsgroup.

> You are *probably* safe if you override an API method to do something
> simple, and then call the superclass version of the method.  But it
> was still not designed to guarantee safe subclassing.  The whole thing
> is being aware of the risks involved, even if they are small.

With respect, the whole thing is that "not designed to be subclassed" 
means that subclassing is not supported. The names or arguments of 
protected methods may change in any future release or may the methods 
may go away entirely. They may be different on different platforms. Even 
if they stay the same, the semantics of the methods and/or the order in 
which they are invoked may change. There is no way to assess the risk of 
change.

Classes like this should be subclassed only to fix urgent bugs there is 
no other way to fix.

Bob Foster
http://xmlbuddy.com/