Get expected firstchild/siblings

[Patrick Lightbody <plightbo@cisco.com>]

I'm using the latest (1.2.3) apache XML parser. I have two dummy files (XML 
and XSD file) attached below. I'd need to be able to parse through test.xml 
and be able to somehow see that the element node "foo" can ONLY (and must) 
legally have the element "bar" as it's first child. I'd also like to be 
able to see that "bar" can have no child element, and either another "bar" 
sibling or no more siblings. Is this possible using any available parser? 
It doesn't seem hard, as parser's validator seem to already do such a 
thing. XML Spy also has helpers in the program that do such a task. 
However, I need to present this in a servlet via an XML parser. So, if 
anyone has ideas, please let me know. Thanks.

-Pat

test.xsd:

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/1999/XMLSchema" 
elementFormDefault="qualified">
         <xsd:element name="foo">
                 <xsd:annotation>
                         <xsd:documentation>Comment describing your root 
element</xsd:documentation>
                 </xsd:annotation>
                 <xsd:complexType>
                         <xsd:sequence>
                                 <xsd:element name="bar" type="xsd:string" 
maxOccurs="unbounded"/>
                         </xsd:sequence>
                 </xsd:complexType>
         </xsd:element>
</xsd:schema>

test.xml:
<?xml version="1.0" encoding="UTF-8"?>
<foo xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance" 
xsi:noNamespaceSchemaLocation="file:test.xsd">
         <bar>foo</bar>
</foo>