Parsing and Substitution Groups

[Sanh, Ai-Hoa]

I have the following in my xsd:

   <xs:complexType name="Alpha>
      <xs:complexContent>
         <xs:extension base="gml:AbstractFeatureType">
            <xs:sequence>
               <xs:element name="alphaString" type="xs:string"/>
               <xs:element ref="gml:Polygon"/>
               <xs:element name="aString" type="xs:string"/>
            </xs:sequence>
         </xs:extension>
      </xs:complexContent>
   </xs:complexType>

   <xs:element name="alpha" type="tns:Alpha" substitutionGroup="gml:_Feature"/>


gml:AbstractFeatureType extends gml:AbstractGMLType, which has a "gml:name" 
element that is unbounded.

After compiling the schemas, I get the following classes:

   public abstract interface net.opengis.gml.AbstractGMLType extends 
org.apache.xmlbeans.XmlObject
   public class net.opengis.gml.impl.AbstractGMLTypeImpl extends 
org.apache.xmlbeans.impl.values.XmlComplexContentImpl implements 
net.opengis.gml.AbstractGMLType

   public abstract interface net.opengis.gml.AbstractFeatureType extends 
net.opengis.gml.AbstractGMLType
   public class net.opengis.gml.impl.AbstractFeatureTypeImpl extends 
net.opengis.gml.impl.AbstractGMLTypeImpl implements 
net.opengis.gml.AbstractFeatureType

   public abstract interface mypackage.Alpha extends 
net.opengis.gml.AbstractFeatureType
   public class mypackage.AlphaImpl extends 
net.opengis.gml.impl.AbstractFeatureTypeImpl implements mypackage.Alpha

   public abstract interface mypackage.AlphaDocument extends 
net.opengis.gml.FeatureDocument
   public class mypackage.AlphaDocumentImpl extends 
net.opengis.gml.impl.FeatureDocumentImpl implements mypackage.AlphaDocument


This is my xml snippet:

<alpha
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";
    xsi:schemaLocation="http://myserver/myns 
../../xsd/polygon.xsd<http://myserver/xsd/polygon.xsd>"
    xmlns="http://myserver/myns";
    xmlns:gml="http://www.opengis.net/gml";
    gml:id="alpha.A1">
    <gml:description>This is my description</gml:description>
    
<gml:name>http://myserver/myns/alpha</gml:name<http://myserver/myns/alpha%3c/gml:name>>
    <alphaString>AA123</alphaString>
    <gml:Polygon srsName="">
        <gml:outerBoundaryIs>
            <gml:LinearRing>
                <gml:coordinates decimal="." cs="," ts=" ">0,0 84,0 84,48 0,48 
0,0</gml:coordinates>
            </gml:LinearRing>
        </gml:outerBoundaryIs>
    </gml:Polygon>
    <aString>aa123</aString>
</alpha>


I am testing this snippet of Java code:

    AbstractFeatureType feature = AbstractFeatureType.Factory.parse( xml );
    System.out.println( feature.getNameArray().length );
    System.out.println( feature.getId() );


The code compiles, but I am getting "0" for the length and "null" for the id.

However, if I were to use:

    AlphaDocument doc = AlphaDocument.Factory.parse( xml );
    Alpha a = doc.getAlpha();
    System.out.println( a.getId() );
    System.out.println( a.getNameArray().length );

Then I get "1" and "alpha.A1", as I expect.

Is this working as designed? Or am I doing something incorrectly.

I would like very much to be able to get at these parts of the xml without 
having to know that I am dealing with an Alpha or a Beta, as long as they both 
extend the AbstractFeatureType. Is there another means of doing so if parsing 
is not the answer?

Thank you for your help.
Ai-Hoa Sanh