Just one more thought. It comes down to how often you think the property
will not be found. returning a pointer (or even a re counting ptr object)
requires the user to ALWAYS code an if (xxx) following the getProperty. This
is why the API is as it is today so that the "normal" use case is simple for
the user.
I'd like to understand the use case where we are trying to do
Type::getProperty("propname") where you are not expecting propname to be a
property.
Cheers,
On 11/01/07, Yang ZHONG <[EMAIL PROTECTED]> wrote:
Agree, neither Property* nor Property& tracks references.
On 1/11/07, Pete Robbins <[EMAIL PROTECTED]> wrote:
>
> Maybe the best solution would be to return a PropertyPtr (we do not like
> returning raw pointers to our internal data so this is better than
> Property*
> ... avoids lifetime of the Pointee problems):
>
>
> PropertyPtr x = myType->getProperty("ID");
> if (x)
> {
>
> x->what_ever_it_is_you_want_to_do_with_the_property??
>
> }
>
>
>
> On 11/01/07, Pete Robbins <[EMAIL PROTECTED]> wrote:
>
> > The reason getProperty throws an exception is that it's a exceptional
> > condition ;-)
> > The expectation is that you KNOW the names of the properties on the
SDO
> > that you are dealing with. If not, then you would use getPropertyList
or
> > getInstanceProperties and iterate over the list.
> >
> > I'm assuming in your case that ALL your DO's are expected to have a
> > particular property (ID)??. In which case isn't it an error if they
> don't =
> > exception?
> >
> >
> >
> > On 11/01/07, Adriano Crestani <[EMAIL PROTECTED]> wrote:
> > >
> > > I think it wouldn't be a good idea, because if you want to check if
> > > there is
> > > a property with the specified name using hasProperty method and
later
> to
> > > get
> > > the property with getProperty(string) it would look for the property
> > > name
> > > twice in the property list, for example:
> > >
> > > if (hasProperty("ID")) { // look on the list here
> > > const Property& t = getProperty("ID"); // and here
> > > }
> > >
> > > The best way should be:
> > >
> > > int propertyIndex = getPropertyIndex("ID");
> > >
> > > if (propertyIndex != -1) { // if it hasn't been found
> > > const Property& t = getProperty(propertyIndex); // and here to get
> the
> > >
> > > Property directly
> > > }
> > >
> > > However, if the method getPropertyIndex(string) doesn't find any
> > > property
> > > with the specified name it also throws a
SDOPropertyNotFoundException.
> I
> > > think we could purpose not a bool
> > > Type::hasProperty(std::string propertyName) method, but a int
> > > Type::getPropertyIndex(string) that returns a -1 value if the
property
> > > name
> > > is not found, instead of an exception.
> > >
> > > Another question, where do I find the sdo spec?
> > >
> > > Adriano Crestani
> >
> >
> > http://osoa.org/display/Main/Service+Data+Objects+Specifications
> >
> > On 1/11/07, Pete Robbins <[EMAIL PROTECTED] > wrote:
> > > >
> > > > On 11/01/07, Adriano Crestani < [EMAIL PROTECTED]> wrote:
> > > > >
> > > > > Thanks Pete, I thought there would be an easier way to do this.
> But
> > > if
> > > > you
> > > > > say so, I think it's the only way. Thanks again!
> > > >
> > > >
> > > > That is what is in the spec. Maybe we could propose a bool
> > > > Type::hasProperty(std::string propertyName); method
> > > >
> > > > Cheers,
> > > >
> > > > Adriano Crestani
> > > > >
> > > > > On 1/10/07, Pete Robbins <[EMAIL PROTECTED]> wrote:
> > > > > >
> > > > > > On 10/01/07, Adriano Crestani < [EMAIL PROTECTED]>
> wrote:
> > > > > > >
> > > > > > > I'm begginer with C++ and I have one doubt about the
function
> > > > defined
> > > > > in
> > > > > > > Type.h: "virtual SDO_API const Property& getProperty(const
> char*
> > > > > > > propertyName) const = 0". It's supposed to return a
reference
> > > to a
> > > > > > > Property
> > > > > > > object that has the name equal to the parameter
propertyName,
> > > but if
> > > > > > there
> > > > > > > is no Property object with this name? What does this
function
> > > > return?
> > > > > >
> > > > > >
> > > > > > It would through a SDOPropertyNotFoundException.
> > > > > >
> > > > > > I tried to do this...
> > > > > > >
> > > > > > > if (type.getProperty ("ID") == NULL)
> > > > > > >
> > > > > > > ...but as long as far as I know it's not possible. Is there
a
> > > way to
> > > >
> > > > > > check
> > > > > > > if the function has found Property object with the specified
> > > name or
> > > > > > not.
> > > > > > >
> > > > > > > Adriano Crestani
> > > > > >
> > > > > >
> > > > > >
> > > > > > There is no easy way to do this. You would need to wrap the
> > > > getProperty
> > > > > in
> > > > > > a
> > > > > > try/catch block.
> > > > > >
> > > > > > Cheers,
> > > > > >
> > > > > > --
> > > > > > Pete
> > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > > --
> > > > Pete
> > > >
> > > >
> > >
> > >
> >
> >
> > --
> > Pete
>
>
>
>
> --
> Pete
>
>
--
Yang ZHONG
--
Pete
