tutorial about processing XML Schema using Java with XSOM API https://xsom.java.net/

1. Java and XML Schema
XSOM
XML Schema Object Model
Raji GHAWI
19/01/2009

2. Import required packages
import
import
import
import
com.sun.xml.xsom.*;
com.sun.xml.xsom.XSModelGroup.*;
com.sun.xml.xsom.impl.*;
com.sun.xml.xsom.parser.*;

3. Create the parser
XSOMParser parser = new XSOMParser();
parser.setErrorHandler(new MyErrorHandler());

4. MyErrorHandler
public class MyErrorHandler implements ErrorHandler{
public void warning(SAXParseException se){
System.err.println("warning : "+se.getMessage());
}
public void error(SAXParseException se){
System.err.println("error : "+se.getMessage());
}
public void fatalError(SAXParseException se){
System.err.println("fatal error : "+se.getMessage());
}
}

5. Parse an XML schema file
try {
parser.parse(new File("./example.xsd"));
// ....
} catch (IOException ioe) {
ioe.printStackTrace();
} catch (SAXException se) {
se.printStackTrace();
}

6. XSSchemaSet
XSSchemaSet schemaSet = parser.getResult();
Iterator<XSSchema> schemaIter = schemaSet.iterateSchema();
while (schemaIter.hasNext()) {
XSSchema schema = (XSSchema) schemaIter.next();
if(schema.getTargetNamespace().
equals("http://www.w3.org/2001/XMLSchema"))
continue;
// ....
}

7. <xs:element name="product">
<xs:complexType>
<xs:attribute name="prodid" type="xs:positiveInteger" />
</xs:complexType>
</xs:element>
anonymous complex type
<xs:element name="member" type="personinfo" />
<xs:complexType name="personinfo">
<xs:sequence>
<xs:element name="firstname" type="xs:string" />
<xs:element name="lastname" type="xs:string" />
</xs:sequence>
</xs:complexType>
named complex type
<xs:element name="car" default="Audi">
<xs:simpleType>
<xs:restriction base="xs:string">
<xs:enumeration value="Audi" />
<xs:enumeration value="Golf" />
<xs:enumeration value="BMW" />
</xs:restriction>
</xs:simpleType>
</xs:element>
anonymous simple type
<xs:element name="car2" type="carType" fixed="BMW" />
<xs:simpleType name="carType">
<xs:restriction base="xs:string">
<xs:enumeration value="Audi" />
<xs:enumeration value="Golf" />
<xs:enumeration value="BMW" />
</xs:restriction>
</xs:simpleType>
named simple type
<xs:element name="dateborn" type="xs:date" abstract="true" />
primitive type

8. Elements
System.out.println("--------- elements ---------");
Iterator<XSElementDecl> elemIter = schema.iterateElementDecls();
while (elemIter.hasNext()) {
XSElementDecl elem = elemIter.next();
System.out.println(describeElement(elem));
}

9. Elements
public static String describeElement(XSElementDecl elem) {
String txt = elem.getName();
XSType type = elem.getType();
txt += (" t ("+type.toString()+")");
if (elem.isGlobal())
txt += " (global)";
else if (elem.isLocal())
txt += " (local)";
if (elem.isAbstract())
txt += " t(abstract)";
XmlString defaultValue = elem.getDefaultValue();
if(defaultValue!=null){
txt += " t(default='"+defaultValue+"')";
}
}
XmlString fixedValue = elem.getFixedValue();
if(fixedValue!=null){
txt += " t(fixed='"+fixedValue+"')";
}
return txt;
--------- elements --------car (anonymous simple type) (global) (default='Audi')
member (personinfo complex type) (global)
product (anonymous complex type) (global)
dateborn (date simple type) (global) (abstract)
car2 (carType simple type) (global) (fixed='BMW')

10. Attributes
System.out.println("--------- attributes ---------");
Iterator<XSAttributeDecl> attIter = schema.iterateAttributeDecls();
while (attIter.hasNext()) {
XSAttributeDecl att = attIter.next();
System.out.println(describeAttribute(att));
}

11. Attributes
public static String describeAttribute(XSAttributeDecl att) {
String txt = att.getName()+" t "+att.getType().getName();
XmlString defaultValue = att.getDefaultValue();
if(defaultValue!=null){
txt += " t(default='"+defaultValue+"')";
}
XmlString fixedValue = att.getFixedValue();
if(fixedValue!=null){
txt += " t(fixed='"+fixedValue+"')";
}
// isRequired ??
return txt;
}
<xs:attribute
<xs:attribute
<xs:attribute
<xs:attribute
name="lang1"
name="lang2"
name="lang3"
name="lang4"
type="xs:string"
type="xs:string"
type="xs:string"
type="xs:string"
/>
default="EN" />
fixed="EN" />
use="required" />
--------- attributes --------lang1 string
lang3 string (fixed='EN')
lang2 string (default='EN')
lang4 string

12. Types
System.out.println("--------- types ---------");
Iterator<XSType> typeIter = schema.iterateTypes();
while (typeIter.hasNext()) {
XSType st = typeIter.next();
System.out.println(describeType(st));
}

13. Types
public static String describeType(XSType type) {
String txt = "";
if(type.isAnonymous()) txt += "(anonymous)";
else txt += type.getName();
if (type.isGlobal()) txt += " (global)";
else if (type.isLocal()) txt += " (local)";
if(type.isComplexType()) txt += " (complex)";
else if(type.isSimpleType()) txt += " (simple)";
}
int deriv = type.getDerivationMethod();
switch(deriv){
case XSType.EXTENSION:
txt += " (EXTENSION)";
break;
case XSType.RESTRICTION:
txt += " (RESTRICTION)";
break;
case XSType.SUBSTITUTION:
txt += " (SUBSTITUTION)";
break;
}
return txt;
--------- types --------carType (global) (simple) (RESTRICTION)
personinfo (global) (complex) (RESTRICTION)
Global Types only !!

14. How to get all types ?
public static Vector<XSType> allTypes = new Vector<XSType>();
Iterator<XSType> typeIter = schema.iterateTypes();
while (typeIter.hasNext()) {
XSType st = typeIter.next();
allTypes.addElement(st);
}
//
....
System.out.println("--------- types ---------");
for (int i = 0; i < allTypes.size(); i++) {
XSType type = allTypes.get(i);
System.out.println(describeType(type));
}
public static String describeElement(XSElementDecl elem) {
String txt = elem.getName();
XSType type = elem.getType();
if(!allTypes.contains(type)){
allTypes.addElement(type);
}
// ....
}
primitive type !!
--------- types --------carType (global) (simple) (RESTRICTION)
personinfo (global) (complex) (RESTRICTION)
(anonymous) (local) (simple) (RESTRICTION)
(anonymous) (local) (complex) (RESTRICTION)
date (global) (simple) (RESTRICTION)

15. How to ignore primitive types ?
public static String describeElement(XSElementDecl elem) {
String txt = elem.getName();
XSType type = elem.getType();
if(!allTypes.contains(type)){
if(type.isSimpleType()){
if(!type.asSimpleType().isPrimitive()){
allTypes.addElement(type);
}
} else {
allTypes.addElement(type);
}
}
// ....
}
--------- types --------carType (global) (simple) (RESTRICTION)
personinfo (global) (complex) (RESTRICTION)
(anonymous) (local) (simple) (RESTRICTION)
(anonymous) (local) (complex) (RESTRICTION)

16. Complex and Simple Types
// XSType type
if(type.isComplexType()){
XSComplexType complex = type.asComplexType();
//
} else if(type.isSimpleType()){
XSSimpleType simple = type.asSimpleType();
//
}
schema.iterateSimpleTypes();
schema.iterateComplexTypes();

17. XSComplexType
// XSComplexType complex
XSContentType contenetType = complex.getContentType();
if(contenetType instanceof EmptyImpl){
XSContentType empty = contenetType.asEmpty();
//
} else if(contenetType instanceof ParticleImpl){
XSTerm term = contenetType.asParticle().getTerm();
//
} else if(contenetType instanceof SimpleTypeImpl){
XSSimpleType st = contenetType.asSimpleType();
//
}

18. XSTerm
//
XSTerm term
if(term.isElementDecl()){
XSElementDecl elem = term.asElementDecl();
//
} else if(term.isModelGroup()){
XSModelGroup mg = term.asModelGroup();
//
} else if(term.isModelGroupDecl()){
XSModelGroupDecl mgd = term.asModelGroupDecl();
XSModelGroup mg = mgd.getModelGroup();
//
} else if(term.isWildcard()){
XSWildcard wildcard = term.asWildcard();
//
}

19. XSModelGroup
// XSModelGroup modelGroup
Compositor comp = modelGroup.getCompositor();
if(comp.equals(Compositor.SEQUENCE)){
//
} else if(comp.equals(Compositor.ALL)){
//
} else if(comp.equals(Compositor.CHOICE)){
//
}
XSParticle[] particles = modelGroup.getChildren();
for (int i = 0; i < particles.length; i++) {
XSTerm term = particles[i].getTerm();
// ....
}

20. XSSimpleType
// XSSimpleType simpe
if(simple.isList()){
XSListSimpleType lst = simple.asList();
//
} else if(simple.isUnion()){
XSUnionSimpleType ust = simple.asUnion();
//
} else if(simple.isRestriction()){
XSRestrictionSimpleType rst = simple.asRestriction();
//
}

21. XSRestrictionSimpleType
// XSRestrictionSimpleType restriction
XSType baseType = restriction.getBaseType();
// ....
Iterator<?> facets = restriction.getDeclaredFacets().iterator();
while (facets.hasNext()) {
XSFacet facet = (XSFacet) facets.next();
String name = facet.getName();
XmlString value = facet.getValue();
if(name.equalsIgnoreCase("enumeration")){
//
} else if(name.equalsIgnoreCase("minInclusive")){
//
} else if(name.equalsIgnoreCase("minExclusive")){
//
} else if(name.equalsIgnoreCase("maxInclusive")){
//
} else if(name.equalsIgnoreCase("maxExclusive")){
//
} else if(name.equalsIgnoreCase("whiteSpace")){
//
}
}

22. References

https://xsom.dev.java.net/
(Kohsuke Kawaguchi, Sun Microsystems )

http://www.stylusstudio.com/w3c/schema0/_index.htm