ServiceObject.IsValid() method

[Ivan R. Judson]

Yeah, I don't expect this is one of those 'use it all the time' things, but
for example to verify that a venue url actually maps to a venue the first
time would make the code a lot less twisty and turny.

I can't think of any other cases, actually.

--Ivan

> -----Original Message-----
> From: Robert Olson [mailto:olson at mcs.anl.gov] 
> Sent: Saturday, February 08, 2003 2:33 PM
> To: judson at mcs.anl.gov; 'AG Dev'
> Subject: RE: ServiceObject.IsValid() method
> 
> 
> Hm. The price you pay is an expensive roundtrip to verify if 
> you have the 
> object you're looking for, rather than just handling the 
> exception when you 
> have it wrong.
> 
> --bob
> 
> At 01:55 PM 2/8/2003 -0600, Ivan R. Judson wrote:
> 
> >I don't know. The behavior I'm trying to avoid is that a 
> client object 
> >(result of ...get_proxy() isn't really anything until a call 
> is made, 
> >but if that call fails your down the error handling path -- you'd 
> >really like to know if the handle is valid ahead of time in some 
> >cases...
> >
> >Does that make it any more clear?  The words that come to 
> mind are "you 
> >want to know you have a valid proxy object before you use 
> it", but I'm 
> >not sure that helps make it more clear :-)
> >
> >--Ivan
> >
> > > -----Original Message-----
> > > From: Robert Olson [mailto:olson at mcs.anl.gov]
> > > Sent: Saturday, February 08, 2003 1:38 PM
> > > To: judson at mcs.anl.gov; 'AG Dev'
> > > Subject: Re: ServiceObject.IsValid() method
> > >
> > >
> > > is that doing the same thing as isinstance(obj, ServiceObject) ?
> > >
> > > At 01:32 PM 2/8/2003 -0600, Ivan R. Judson wrote:
> > > >I propose we add amethod IsValid() to the service object
> > > that returns
> > > >true. Then you can verify that your handle is good *before*
> > > you try to
> > > >use it. This makes it significantly easier to handle cases
> > > like venue
> > > >entering...
> > > >
> > > >Thoughts?
> > >
>