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Xerces 2.6 and validation of XML schema constraints

Apprentently xerces 2.6.0 (Java) does not validate against contraints
specified in the schema (e.g. constraints specified via unique element).

The validation works with the XML editor I'm using (XMLSpy4) but not
with Xerces 2.6.0.

I've included a really short and simple example to illustrate it. I
would like to get some comments on the validation capabilities of Xerces
2.6.0. I though it *fully* supported W3C Schema!

Here's the XML file:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns="http://www.mynames.org"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.mynames.org
x:/work/sjrodc/xml/constraint.xsd">
<object id="1"/>
<!-- Here's the uniqueness violation -->
<object id="1"/>
</root>

Here's the Schema file. It defines a uniqueness constraint on the
object's 'id' attribute.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="http://www.mynames.org"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.mynames.org" elementFormDefault="qualified">
<xs:element name="root">
<xs:complexType>
<xs:sequence>
<xs:element name="object" maxOccurs="unbounded">
<xs:complexType>
<xs:attribute name="id"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
<xs:unique name="objectId">
<xs:selector xpath=".//object"/>
<xs:field xpath="@id"/>
</xs:unique>
</xs:element>
</xs:schema>

And here's the Java code that does the parsing:
import java.io.File;
import java.io.IOException;

import java.text.MessageFormat;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.SAXException;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;
public class XmlValidationTest
{
public static String SCHEMA_LANGUAGE =
"http://java.sun.com/xml/jaxp/properties/schemaLanguage";
public static String XML_SCHEMA = "http://www.w3.org/2001/XMLSchema";
public static String SCHEMA_SOURCE =
"http://java.sun.com/xml/jaxp/properties/schemaSource";

public static final void main( String[] args )
throws IOException, SAXException, ParserConfigurationException
{
if( args.length < 2 )
{
System.err.println( "usage is:" );
System.err.println( " <xml file> <schema file>" );

return;
}

File input = new File( args[0] );
File schema = new File( args[1] );
SAXParserFactory factory = SAXParserFactory.newInstance( );
factory.setNamespaceAware( true );
factory.setValidating( true );

SAXParser parser = factory.newSAXParser( );

try
{
parser.setProperty( SCHEMA_LANGUAGE, XML_SCHEMA );
parser.setProperty( SCHEMA_SOURCE, schema );
}
catch( SAXNotRecognizedException x )
{
System.err.println( "Your SAX parser is not JAXP 1.2
compliant." );
}

System.out.println( "Parsing '" + args[0] +
"' against W3C schema '" +
args[1] + "' ..." );

parser.parse( input, new ErrorPrinter( ) );

System.out.println( "Done." );
}

static class ErrorPrinter
extends DefaultHandler
{
private MessageFormat message =
new MessageFormat( "({0}: {1}, {2}): {3}" );

private void print( SAXParseException x )
{
String msg =
message.format( new Object[]
{
x.getSystemId( ),
new Integer( x.getLineNumber( ) ),
new Integer( x.getColumnNumber( ) ),
x.getMessage( )
} );
System.out.println( msg );
}
public void warning( SAXParseException x )
{
print( x );
}
public void error( SAXParseException x )
{
print( x );
}
public void fatalError( SAXParseException x )
throws SAXParseException
{
print( x );
throw x;
}
}
}
Jul 20 '05 #1
2 4458


Olaf Meyer wrote:
Apprentently xerces 2.6.0 (Java) does not validate against contraints
specified in the schema (e.g. constraints specified via unique element).

The validation works with the XML editor I'm using (XMLSpy4) but not
with Xerces 2.6.0.

I've included a really short and simple example to illustrate it. I
would like to get some comments on the validation capabilities of Xerces
2.6.0. I though it *fully* supported W3C Schema!

Here's the XML file:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns="http://www.mynames.org"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.mynames.org
x:/work/sjrodc/xml/constraint.xsd">
It could be a URL issue, what is
x:/work...
that doesn't look like a URL to me.
Maybe you want
file:///x:/work...
<object id="1"/>
<!-- Here's the uniqueness violation -->
<object id="1"/>
</root>

Here's the Schema file. It defines a uniqueness constraint on the
object's 'id' attribute.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="http://www.mynames.org"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.mynames.org" elementFormDefault="qualified">
<xs:element name="root">
<xs:complexType>
<xs:sequence>
<xs:element name="object" maxOccurs="unbounded">
<xs:complexType>
<xs:attribute name="id"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
<xs:unique name="objectId">
<xs:selector xpath=".//object"/>


But more likely it is an XPath namespace issue, XPath 1.0 doesn't know a
default namespace, as your elements are in the namespace
http://www.mynames.org I suggest you declare a prefix for that e.g.
<xs:schema xmlns:mynamespace="http://www.mynames.org" ...>
and use that prefix in the XPath expression e.g.
<xs:selector xpath=".//mynamespace:object"/>
When I do that with your example schema and then check the XML instance
file in jEdit (which uses Xerces Java) it indeed flags an error

test20040115.xml:5:Duplicate unique value [ID Value: 1] declared for
identity constraint of element "root".


--

Martin Honnen
http://JavaScript.FAQTs.com/

Jul 20 '05 #2
Martin Honnen wrote:


Olaf Meyer wrote:
Apprentently xerces 2.6.0 (Java) does not validate against contraints
specified in the schema (e.g. constraints specified via unique element).

The validation works with the XML editor I'm using (XMLSpy4) but not
with Xerces 2.6.0.

I've included a really short and simple example to illustrate it. I
would like to get some comments on the validation capabilities of
Xerces 2.6.0. I though it *fully* supported W3C Schema!

Here's the XML file:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns="http://www.mynames.org"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.mynames.org
x:/work/sjrodc/xml/constraint.xsd">

It could be a URL issue, what is
x:/work...
that doesn't look like a URL to me.
Maybe you want
file:///x:/work...
<object id="1"/>
<!-- Here's the uniqueness violation -->
<object id="1"/>
</root>

Here's the Schema file. It defines a uniqueness constraint on the
object's 'id' attribute.

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="http://www.mynames.org"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.mynames.org" elementFormDefault="qualified">
<xs:element name="root">
<xs:complexType>
<xs:sequence>
<xs:element name="object" maxOccurs="unbounded">
<xs:complexType>
<xs:attribute name="id"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
<xs:unique name="objectId">
<xs:selector xpath=".//object"/>

But more likely it is an XPath namespace issue, XPath 1.0 doesn't know a
default namespace, as your elements are in the namespace
http://www.mynames.org I suggest you declare a prefix for that e.g.
<xs:schema xmlns:mynamespace="http://www.mynames.org" ...>
and use that prefix in the XPath expression e.g.
<xs:selector xpath=".//mynamespace:object"/>
When I do that with your example schema and then check the XML instance
file in jEdit (which uses Xerces Java) it indeed flags an error

test20040115.xml:5:Duplicate unique value [ID Value: 1] declared for
identity constraint of element "root".


Martin,

thanks alot, this solve the problem ;-)

Olaf
Jul 20 '05 #3

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