What I think happens is that your main program and your plugin use different instances of the XMLBeans library. In particular, I don't think that substitution groups play any important role here, even though I would warn you that if the substitution group member elements are compiled in a different jar than the substitution group head, that would not be supported by XMLBeans. But, like I said, you don't seem to be in that situation.
Therefore, you don't need to change the xsd, but you need to set up your application in such a way that there are no two different classloaders loading the XMLBeans library; how to do that I don't know, it depends on your environment really. Radu On Wed, 2009-04-22 at 18:43 +0200, Martinez Sergio wrote: > Hello, > > I have a problem regarding the use of substitution > groups and class loaders. In practise, I get an exception > when trying to access a base class defined in a plugin > which has been loaded with a typical class loader. > Below I give the schema definition and source code: > > 1. I have created the following XSD (simple_agenda.xsd): > > <?xml version="1.0" encoding="UTF-8"?> > <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"; > elementFormDefault="qualified" attributeFormDefault="unqualified"> > <xs:element name="agenda"> > <xs:complexType> > <xs:sequence> > <xs:element name="version" > type="xs:string"/> > <xs:element ref="person" > maxOccurs="unbounded"/> > </xs:sequence> > </xs:complexType> > </xs:element> > <xs:element name="person" type="personType" abstract="false"/> > <xs:complexType name="personType" abstract="true"> > <xs:sequence> > <xs:element name="name" type="xs:string"/> > </xs:sequence> > </xs:complexType> > <xs:complexType name="friendType"> > <xs:complexContent> > <xs:extension base="personType"> > <xs:sequence> > <xs:element name="telephone" > > type="xs:string"/> > </xs:sequence> > </xs:extension> > </xs:complexContent> > </xs:complexType> > <xs:element name="friend" type="friendType" abstract="false" > > substitutionGroup="person"/> > </xs:schema> > > This schema has then been compiled with XmlBeans scomp command into a > JAR file (simple_agenda.jar). > > 2. An example of XML file which follows the previous XSD (agenda.xml): > > <?xml version="1.0" encoding="UTF-8"?> > <agenda xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; > xsi:noNamespaceSchemaLocation="simple_agenda.xsd"> > <version>1.0.0</version> > <friend> > <name>Some name</name> > <telephone>0123456789</telephone> > </friend> > </agenda> > > 3. The following is a plugin (SimpleAgendaImporter.java) used > to load the XML file agenda.xml: > > package com.mycompany.xmlimport; > > import java.io.File; > import java.io.IOException; > import noNamespace.AgendaDocument; > import noNamespace.PersonType; > import org.apache.xmlbeans.XmlException; > > public class SimpleAgendaImporter implements Importer { > > public boolean loadFile(File input_xmlFile) { > AgendaDocument agenda_doc = null; > > try { > agenda_doc = AgendaDocument.Factory.parse(input_xmlFile); > } catch (XmlException ex) { > ex.printStackTrace(); > } catch (IOException ex) { > ex.printStackTrace(); > } > > AgendaDocument.Agenda root_agenda = agenda_doc.getAgenda(); > String version = root_agenda.getVersion(); > System.out.println("Version: " + version ); > > int num_persons = root_agenda.sizeOfPersonArray(); > PersonType person; > > for (int i_per = 0; i_per < num_persons; i_per++) { > person = root_agenda.getPersonArray(i_per); > System.out.println("Current person's name: " + > person.getName()); > } > > return true; > } > } > > N.B.: the compiled JAR for this plugin has been named > AgendaImporter.jar. > > 4. In the following main program I load and (try to) execute > the previous plugin: > > package agendamanager; > > import com.mycompany.xmlimport.IImporterFactory; > import com.mycompany.xmlimport.Importer; > import java.io.File; > import java.io.FilenameFilter; > import java.net.MalformedURLException; > import java.net.URL; > import java.net.URLClassLoader; > > public class Main { > > public Main() { > } > > public static void main(String[] args) { > // --- Load the agenda entries > > String plugin_dirname = "plugins"; > File plugin_dir = new File(plugin_dirname); > File plugin_file = new File(plugin_dir, "AgendaImporter.jar"); > > IImporterFactory importer_factory = null; > Importer importer = null; > > URLClassLoader fileScroll = null; > Class c = null; > > System.out.println("Loading jar for AGENDA import..."); > > try { > fileScroll = new URLClassLoader( > new URL[]{plugin_file.toURI().toURL()}); > } catch (MalformedURLException ex) { > ex.printStackTrace(); > return; > } > > try { > c = fileScroll.loadClass( > "com.mycompany.xmlimport.ImporterFactory"); > } catch (ClassNotFoundException ex) { > System.out.println("Current plug-in (file " + > plugin_file.getName() + > ") is not for agenda import (I)."); > return; > } > > try { > importer_factory = (IImporterFactory) c.newInstance(); > } catch (IllegalAccessException ex) { > ex.printStackTrace(); > } catch (InstantiationException ex) { > System.out.println("Current plug-in (file " + > plugin_file.getName() + > ") is not for agenda import (II)."); > return; > } > > importer = importer_factory.getInstance(); > > File xml_agenda = new File("data/agenda.xml"); > System.out.println("Parsing agenda from file " + > xml_agenda.getName()); > importer.loadFile(xml_agenda); > } > } > > 5. Here follows the Importer interface... > > package com.mycompany.xmlimport; > import java.io.File; > > public interface Importer { > boolean loadFile( File input_xmlFile ); > } > > 6. Here follows the class IImporterFactory... > > package com.mycompany.xmlimport; > > public interface IImporterFactory { > public Importer getInstance(); > } > > 7. Here follows the class ImporterFactory... > > package com.mycompany.xmlimport; > > public class ImporterFactory implements IImporterFactory { > > public SimpleAgendaImporter getInstance() { > return new SimpleAgendaImporter(); > } > } > > ================================================================== > When executing the main program I get the following exception > > Exception in thread "main" java.lang.ClassCastException: > org.apache.xmlbeans.impl.values.XmlAnyTypeImpl cannot be cast to > noNamespace.PersonType > at noNamespace.impl.AgendaDocumentImpl$AgendaImpl.getPersonArray( > Unknown Source) > > at this line > > person = root_agenda.getPersonArray(i_per); > > of the plugin. > > However, if I read in the file agenda.xml directly from the main > program (see below), I do not get any exception: > > ---------------------------------------------------------------- > package agendamanager; > > import com.mycompany.xmlimport.Importer; > import com.mycompany.xmlimport.SimpleAgendaImporter; > import java.io.File; > > public class Main { > > public Main() { > } > > public static void main(String[] args) { > // --- Load the agenda entries > > Importer importer = new SimpleAgendaImporter(); > > File xml_agenda = new File("data/agenda.xml"); > System.out.println("Parsing agenda from file " + > xml_agenda.getName()); > importer.loadFile(xml_agenda); > } > } > ---------------------------------------------------------------- > > Maybe this kind of problem or a similar one has been implicitly > solved in some other mail in this forum, but I really did not succeed > in extrapolating a solution to my case. > Maybe the XSD can be slightly modified in order to overcome > the problem? > > Thanks to all, > S. Martinez > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
