[xsd-users] abstract types access

[Azadeh Omrani]

Hi,
Thanks for your response on polymorphism Boris.

Can you please help me on the following problem?

The schema (in aq.xds) is this:


<xsd:complexType name="AcquisitionType">
    <xsd:sequence>
      <xsd:element name="ComponentDescription"
type="ComponentDescriptionType"
      maxOccurs="unbounded"/>
      [...]
  </xsd:complexType>

  <xsd:complexType name="ComponentDescriptionType">
    <xsd:sequence>
    [...]
      <xsd:element name="SessionDescription"
type="SessionDescriptionBaseType"/>
    </xsd:sequence>
  </xsd:complexType>


  <xsd:complexType name="SessionDescriptionBaseType" abstract="true" />

  <xsd:complexType name="InlinedSDPType">
    <xsd:complexContent>
      <xsd:extension base="SessionDescriptionBaseType">
        <xsd:sequence>
          <xsd:element name="SDP" type="SDPType"/>
        [...]
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>

  <xsd:complexType name="SDPRefType">
    <xsd:complexContent>
      <xsd:extension base="SessionDescriptionBaseType">
        <xsd:sequence>
          <xsd:element name="SDPStream" type="SDPType"/>
          [...]
        </xsd:sequence>
      </xsd:extension>
    </xsd:complexContent>
  </xsd:complexType>



 I set the --generate -polymorphysm option, then I have the following error
on line 36 of aq.cxx (below):

"Unhandled exception at 0x7c812aeb in ESG.exe: Microsoft C++ exception:
xsd::cxx::tree::not_derived<char> at memory location 0x0012d5bc.."


1    void ComponentDescriptionType::
2      parse (::xsd::cxx::xml::dom::parser< char >& p,
3             ::xml_schema::flags f)
4      {
5        for (; p.more_elements (); p.next_element ())
6        {
7          const ::xercesc::DOMElement& i (p.cur_element ());
8          const ::xsd::cxx::xml::qualified_name< char > n (
9            ::xsd::cxx::xml::dom::name< char > (i));
10
11          // SessionDescription
12          //
13          {
14            ::xsd::cxx::tree::type_factory_map< char >& tfm (
15              ::xsd::cxx::tree::type_factory_map_instance< 0, char > ());
16
17            ::std::auto_ptr< ::xsd::cxx::tree::type > tmp (
18                tfm.create (
19                "SessionDescription",
20                "urn:dvb:ipdc:esg:2005",
21                &::xsd::cxx::tree::factory_impl< SessionDescription_type
>,
22                false, true, i, n, f, this));
23
24            if (tmp.get () != 0)
25          {
26              if (!SessionDescription_.present ())
27              {
28                ::std::auto_ptr< SessionDescription_type > r (
29                  dynamic_cast< SessionDescription_type* > (tmp.get ()));
30
31                if (r.get ())
32                tmp.release ();
33                else
34                  throw ::xsd::cxx::tree::not_derived< char > ();
35
36                this->SessionDescription_.set (r);
37                continue;
38              }
39        }
40          }


What does this line do and where do you think this problem comes from?


P.S. If I remove the option then there is no error like that but non of the
following "if clauses" come true. I think it is natural in this case.

acquisition::ComponentDescriptionType::SessionDescription_type& sd
(cdi->SessionDescription());

                     if (acquisition::SDPRefType* reff =
dynamic_cast<acquisition::SDPRefType*> (&sd))
                    {
                      //======== We've got SDPRefType.

                        acquisition::SDPRefType::SDPStream_type sdpstr
(reff->SDPStream());
                        sdp=(char *)sdpstr.c_str();
                     }
                     else if (acquisition::InlinedSDPType* inll =
dynamic_cast<acquisition::InlinedSDPType*> (&sd))
                     {
                       //======== We've got InlinedSDPType.

                         acquisition::InlinedSDPType::SDP_type sdp (
inll->SDP());
                         sdp= (char *) sdp.c_str();
                    }





On Thu, Jan 8, 2009 at 3:06 PM, Boris Kolpackov <boris at codesynthesis.com>wrote:

> Hi Azadeh,
>
> I noticed that you sent two identical copies of this email. Please
> refrain from doing this in the future to avoid unnecessary traffic
> on the mailing list.
>
> Azadeh Omrani <a.omrani at gmail.com> writes:
>
> > esg::ESGType::ComponentDescription_sequence& cds
> > (eagdata.esgData->ComponentDescription());
> > for(esg::ESGType::ComponentDescription_iterator i (cds.begin ());i !=
> > cds.end (); ++j)
> >    {
> >          esg::ComponentDescriptionType::SessionDescription_type sdt
> > (i->SessionDescription());
>
> You can test which type it is using dynamic_cast:
>
>  esg::ComponentDescriptionType::SessionDescription_type& sdt (
>    i->SessionDescription());
>
>   if (SDPRefType* ref = dynamic_cast<SDPRefType*> (&sdt))
>  {
>    // We've got SDPRefType.
>  }
>  else if (InlinedSDPType* inl = dynamic_cast<InlinedSDPType*> (&sdt))
>  {
>    // We've got InlinedSDPType.
>  }
>
> Notice that I changed your 'sdt' declaration to use a reference. This
> is important for the polymorphism to work.
>
> For more information on working with polymorphic object models see
> Section 2.11, "Mapping for xsi:type and Substitution Groups" in the
> C++/Tree Mapping User Manual:
>
>
> http://www.codesynthesis.com/projects/xsd/documentation/cxx/tree/manual/#2.11
>
>
> Boris
>