RE: ClassCastException using changeType()

Radu,
>When you first compile SchemaConcreteA,B,C you automatically pull in SchemaAbstractBase, because it is needed in order to resolve the base type references. That >creates some SchemaTypes with an identity (set a)
>When you subsequently compile SchemaReferencesAbstractBase you automatically pull SchemaAbstractBase in again, because it is needed. This creates another set >of types, including the types in SchemaAbstractBase, but with a different identity (set b). Now, unfortunately the SchemaAbstractBase types in (a) are different than >SchemaAbstractBase types in (b), therefore your SchemaConcreteA,B,C don't extend the latter.

yes that it what appears is happening.

>There are good reasons for this design decision. Basically, when you have a reference to a type that can be found either in the set of current Schemas that you compile >or in a set of already compiled Schemas, we always resolve the reference internally. Also, if you want to declare a new type with a name equal to that of another type >that was compiled previously, we let you do it, we have to.

yes good logic, but. I have now rebuilt the abstract set into its own jar file. -what I am trying to do is to allow somebody to later on use the abstract schema and define a concrete type of it, use the already-built abstract jar (and set A types I guess) and build a concrete jar. All of this works at build time. at runtime, what I want to do is to dynamically changeType() on an abstract instance to his new class (using a class loader to load his schema-compiler generated concrete class type). this is what does not work........Think what I am doing is building an an XML Framework with a concrete plugins........

>Have you confirmed that the problem still occurs if all the Schemas are compiled simultaneously? If it still does, all I said earlier is just general info.

have not tried it.

>As to why you can use only the last SchemaConcrete in your other case, it must be some peculiarity which I can't detect from the set of information you provide in this >e-mail. In any case, xsb files are never clobbered, though it is the case that a runtime QName lookup for a particular entity will find the first entity with that name and kind >(element, type etc) available on the classpath, just as in Java, so there is an obscuring effect going on, which you would expect.

I think it comes down to the ability to changeType() in code using a different identity set than the code being to changed to. this may not be able to work under the current design of XMLBeans.............or is there some other suggestion on how to do this?


Scott

------------
Scott R. Hinkelman, Senior Software Engineer
IBM Software Group / Emerging Technologies
Cross-Industry Foundation Standards Strategy
Office: 512.823.8097 (TL 793.8097)
Cell: 512.415.8490
"Radu Preotiuc-Pietro" <radup@xxxxxxx>

"Radu Preotiuc-Pietro" <radup@xxxxxxx>

01/11/2005 07:22 PM

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user

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cc
Subject	RE: ClassCastException using changeType()

Hm, I think I know what's happening, I'll try to guess based on the information that you provide:
 
When you first compile SchemaConcreteA,B,C you automatically pull in SchemaAbstractBase, because it is needed in order to resolve the base type references. That creates some SchemaTypes with an identity (set a)
When you subsequently compile SchemaReferencesAbstractBase you automatically pull SchemaAbstractBase in again, because it is needed. This creates another set of types, including the types in SchemaAbstractBase, but with a different identity (set b). Now, unfortunately the SchemaAbstractBase types in (a) are different than SchemaAbstractBase types in (b), therefore your SchemaConcreteA,B,C don't extend the latter. There are good reasons for this design decision. Basically, when you have a reference to a type that can be found either in the set of current Schemas that you compile or in a set of already compiled Schemas, we always resolve the reference internally. Also, if you want to declare a new type with a name equal to that of another type that was compiled previously, we let you do it, we have to.
Have you confirmed that the problem still occurs if all the Schemas are compiled simultaneously? If it still does, all I said earlier is just general info.
As to why you can use only the last SchemaConcrete in your other case, it must be some peculiarity which I can't detect from the set of information you provide in this e-mail. In any case, xsb files are never clobbered, though it is the case that a runtime QName lookup for a particular entity will find the first entity with that name and kind (element, type etc) available on the classpath, just as in Java, so there is an obscuring effect going on, which you would expect.
 
Hope this makes sense
Radu

-----Original Message-----
From: Scott Hinkelman [mailto:srh@xxxxxxxxxx]
Sent: Tuesday, January 11, 2005 8:13 AM
To: user@xxxxxxxxxxxxxxxxxxx
Subject: RE: ClassCastException using changeType()


Radu and folks,
This story is not over yet. The ClassCastException I am having with my real code comes from the order I am executing the SchemaCompiler on my schemas.
My fleet of schemas is organized such:

SchemaReferencesAbstractBase imports SchemaAbstractBase (which has the abstract type) in order to reference the abstract type (classic polymorphism - reference the base type).
3 concrete schemas, SchemaConcreteA,B,C provide concrete extensions the abstract type in SchemaAbstractBase, and they also import the SchemaAbstractBase in order
to force instance documents to always use the top level element of SchemaAbstractBase.

If I execute the SchemaCompiler on SchemaReferencesAbstractBase after compiling the SchemaConcretes I get the Cast exception.
Also, running the SchemaReferenceAbstractBase first, only the last SchemaConcrete allows casting. I believe xsb's are getting clobbered.

Does anyone have any suggestion on dependencies/abstract types, etc, for compiling the bindings - and specifically not clobbering xsb's ?

Scott

------------
Scott R. Hinkelman, Senior Software Engineer
IBM Software Group / Emerging Technologies
Cross-Industry Foundation Standards Strategy
Office: 512.823.8097 (TL 793.8097)
Cell: 512.415.8490
Scott Hinkelman/Austin/IBM@IBMUS



Scott Hinkelman/Austin/IBM@IBMUS

01/11/2005 08:54 AM
Please respond to
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Subject	RE: ClassCastException using changeType()


Thanks Radu.
Apparently in my larger code I have a build problem causing this to take place.
I put together a simple test case which does indeed behave correctly. - so it looks like my problem.

For example sake, here is my simple example of abstract complex-type to concrete type using changeType().
The objective is to build aninstance document using the top A element that includes a concrete xsi type of the abstract type in the A namespace, and utilized both the extension element in the concrete extension.

Feel free to use this in documentation, as I think there could be an example like this.

Abstract complex type schema:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="http://namespace.a" elementFormDefault="qualified" attributeFormDefault="unqualified" version="2.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:a="http://namespace.a">
<xs:element name="ATop" type="a:ATopType"/>
<xs:complexType name="ATopType">
<xs:sequence>
<xs:element name="A" type="a:AType" minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence>
</xs:complexType>
<xs:complexType name="AType" abstract="true">
<xs:sequence>
<xs:element name="ADescription" minOccurs="0">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:minLength value="1"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:schema>

Concrete extension schema of "AType". Seperate namespace.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="http://namespace.b" elementFormDefault="qualified" attributeFormDefault="unqualified" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:b="http://namespace.b" xmlns:a="http://namespace.a">
<xs:import namespace="http://namespace.a" schemaLocation="./a.xsd"/>
<xs:complexType name="BType">
<xs:complexContent>
<xs:extension base="a:AType">
<xs:sequence>
<xs:element name="BDescription" minOccurs="0">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:minLength value="1"/>
</xs:restriction>
</xs:simpleType>
</xs:element>
</xs:sequence>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:schema>

Test driver:

package xmlbeanstest;
import a.namespace.*;
import b.namespace.*;
import org.apache.xmlbeans.*;

public class Test{
public static void main(String args[]) {
ATopDocument _d=ATopDocument.Factory.newInstance();
ATopType atop_type=_d.addNewATop();
AType a_type=atop_type.addNewA();
System.out.println("a_type before: "+a_type.schemaType());
//a_type=(AType)a_type.changeType(BType.type);
BType b_type=(BType)a_type.changeType(BType.type);
System.out.println("a_type after: "+a_type.schemaType());
b_type.setADescription("adescription");
b_type.setBDescription("bdescription");
System.out.println(_d.toString());
}
}

Output:

a_type before: T=AType@http://namespace.a
a_type after: T=AType@http://namespace.a
<ATop xmlns="http://namespace.a" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<A xsi:type="nam:BType" xmlns:nam="http://namespace.b">
<ADescription>adescription</ADescription>
<nam:BDescription>bdescription</nam:BDescription>
</A>
</ATop>

Again, I am still having trouble with my real code, but now convinced it should work.
thanks for your time and keep up the good work on this.

Scott

------------
Scott R. Hinkelman, Senior Software Engineer
IBM Software Group / Emerging Technologies
Cross-Industry Foundation Standards Strategy
Office: 512.823.8097 (TL 793.8097)
Cell: 512.415.8490
"Radu Preotiuc-Pietro" <radup@xxxxxxx>

"Radu Preotiuc-Pietro" <radup@xxxxxxx>

01/10/2005 07:03 PM


Please respond to
user

To	<user@xxxxxxxxxxxxxxxxxxx>
cc
Subject	RE: ClassCastException using changeType()


Hi Scott,
I have reviewed my post ([1]) and indeed I don't know why I used .schemaType() in there, it should have been .type, apologies (.type will return the static SchemaType associated to the class in question, while .schemaType() will return rhe runtime SchemaType of an object instance).
But beyond that, I just tried the example again, and it works for me. Can you share the code that you are using?

Radu
-----Original Message-----
From: Scott Hinkelman [mailto:srh@xxxxxxxxxx]
Sent: Friday, January 07, 2005 11:23 AM
To: user@xxxxxxxxxxxxxxxxxxx
Subject: Re: ClassCastException using changeType()

Girish/all,
Again thanks. But I after fully qualifying everything with the names generated from the namespaces I still have the problem. I am very certain that I don't have dup .xsb's or .class in the classpath..........

I can get by the cast exception by changing the casted return type to the base abstract type (not surprising in of itself) - even while leaving the parameter type on changetype() as it is (type to the concrete).......instanceof then reveals the result to only be of the abstract type and not concrete.........
I can new up a concrete independently using it's factory with no problem.......but can't get changeType() to work on the abstract.....
The generated concrete interface does indeed extend the abstract interface.......

?

Scott

Girish Bhatia <bhatiagirish@xxxxxxxxx>

Girish Bhatia <bhatiagirish@xxxxxxxxx>

01/07/2005 12:20 PM


Please respond to
user

To	user@xxxxxxxxxxxxxxxxxxx
cc
Subject	Re: ClassCastException using changeType()


I have the similar error of ClassCastException. In my case, my jar
included two class files for the same type in two different
namespaces. My issue was resolved, when I used the full package name
with the class. for example. com.girsh.schema.Order order.

- Girish



On Fri, 7 Jan 2005 13:06:22 -0500, Murphy, Eric
<erimurph@xxxxxxxxxxxxxxxxxxx> wrote:
>  
> Scott -
>  
> I had this problem which was caused by the situation described in my earlier
> email titled ' Generated .jar files cause conflict' sent to the list on
> Jan.5.  Essentially there were two objects of the same name and same
> namespace in two different jar files.  I was asking for an object in one
> package but an object with the same name but different package was being
> returned.
>  
> Eric
>  
>  
>  ________________________________
>  From: Scott Hinkelman [mailto:srh@xxxxxxxxxx]
> Sent: Thursday, January 06, 2005 11:55 AM
> To: user@xxxxxxxxxxxxxxxxxxx
> Subject: ClassCastException using changeType()
>
>  
>  
>
> Hello XMLBeans experts.
> I essentially have the same situation discussed in the post [1] concerning
> polymorphism.
> However, I get a runtime ClassCastExecption during the operation containing
> changeType().
> Also, I have seen several uses of changeType() with parameters of
> <class>.type, <class>.type(),
> and as in the post <class>.schemaType(). The only one I can get to compile
> is <class>.type, which
> is where my exception occurs.
>
> I am using JDK 1.5 and a svn pull of Trunk on 1/6/05.
>
> If anyone can shed light on why I get that cast exception I would be very
> appreciative.
>
> [1]
> http://nagoya.apache.org/eyebrowse/ReadMsg?listName=user@xxxxxxxxxxxxxxxxxxx&msgId=1852352
>
> thanks,
> Scott
>

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