Folks,
 
I am interested in people's experiences with code generation tools.  We =
have found several key constructs that cause
problems with these tools.  Don't know if people have work arounds or =
recommendations on better tools.  We would love to
recommend tools for our member companies who are asking us for advice.
 
So far, we have reports on Castor, XSDObjectGen, XSD.exe (ships with =
vs.net), and CodeXS (built on xsd.exe).  I hope to
get reports on Axis and I believe XMLBeans sometime soon.
 
The key constructs that cause problems when creating classes are:
 
1) xsd:union.  - This is the least supported feature of our schemas.  We =
had already been considering removing these as
bad design anyway, so this may add some force to that effort.
2) xsd:pattern  - This is supported by some tools and not others.  
3) having an element and a type with the same name. (also a problem even =
if casing is different, as in a "MyType"
element and a "mytype" attribute)
4) recursive content models
 
Other oddities that only cause problems in some tools:
 
5) extension of complexTypes - XSDObjectGen in particular has a problem =
with this, which seems odd as this is a major
design feature of xml schema.  
6) simpleContent extension using a xsd base type
7) reserved keyword element names (such as "Value")
8) too many anonymous types can lead to some class name collisions when =
classes are generated
9) enumerations in elements (enumerations in attributes worked fine.  =
wierd but true for a tool to remain nameless)
 
 
Here are features we don't even use, so we can't comment on (but suspect =
there may be possible problems):
 
A) substitutionGroups
B) redefine
C) abstract types
D) nillable
E) complexType restriction
F) list types
 
I would very much be interested in a code generation tool that supports =
# 1-9 above if you know of one.  (Of course I
also want a million dollars to appear in my bank accout.)
 
 
Paul Kiel
HR-XML Consortium