public static  void resolveAll() 
{
        // resolve tree of types
        StscState state = StscState.get();
        SchemaType[] documentTypes = state.documentTypes();
        for (int i = 0 ; i <  documentTypes.length ; i++)
            resolveSubstitutionGroup((SchemaTypeImpl)documentTypes[i]);
        List allSeenTypes = new ArrayList();
        allSeenTypes.addAll(Arrays.asList(state.documentTypes()));
        allSeenTypes.addAll(Arrays.asList(state.attributeTypes()));
        allSeenTypes.addAll(Arrays.asList(state.redefinedGlobalTypes()));
        allSeenTypes.addAll(Arrays.asList(state.globalTypes()));
        for (int i = 0; i <  allSeenTypes.size(); i++)
        {
            SchemaType gType = (SchemaType)allSeenTypes.get(i);
            resolveType((SchemaTypeImpl)gType);
            allSeenTypes.addAll(Arrays.asList(gType.getAnonymousTypes()));
        }
        // Resolve all keyref refs
        resolveIdentityConstraints();
}

Does a topo walk of all the types to resolve them.

 public static  void resolveAttributeType(SchemaTypeImpl sImpl) 
{
        assert sImpl.isResolving();
        assert sImpl.isAttributeType();
        List anonTypes = new ArrayList();
        SchemaGlobalAttributeImpl attribute =
            (SchemaGlobalAttributeImpl) StscTranslator.translateAttribute(
                (Attribute) sImpl.getParseObject(), sImpl.getTargetNamespace(), null,
                sImpl.isChameleon(), anonTypes, sImpl, null, false );
        SchemaAttributeModelImpl attributeModel = new SchemaAttributeModelImpl();
        if (attribute != null)
        {
            StscState.get().addGlobalAttribute( attribute );
            SchemaLocalAttributeImpl attributeCopy = new SchemaLocalAttributeImpl();
            StscTranslator.copyGlobalAttributeToLocalAttribute( attribute, attributeCopy );
            attributeModel.addAttribute( attributeCopy );
        }
        sImpl.setBaseTypeRef( BuiltinSchemaTypeSystem.ST_ANY_TYPE.getRef() );
        sImpl.setBaseDepth( sImpl.getBaseDepth() + 1 );
        sImpl.setDerivationType( SchemaType.DT_RESTRICTION );
        sImpl.setComplexTypeVariety( SchemaType.EMPTY_CONTENT );
        Map attributePropertyModel =
            StscComplexTypeResolver.buildAttributePropertyModelByQName(
                attributeModel, sImpl );
        sImpl.setContentModel(
            null, attributeModel, Collections.EMPTY_MAP, attributePropertyModel, false );
        sImpl.setWildcardSummary(
            QNameSet.EMPTY, false, QNameSet.EMPTY, false );
        sImpl.setAnonymousTypeRefs( makeRefArray( anonTypes ) );
}

 public static  void resolveDocumentType(SchemaTypeImpl sImpl) 
{
        assert sImpl.isResolving();
        assert sImpl.isDocumentType();
        // translate the global element associated with this document type
        // and construct a content model which allows just that element
        List anonTypes = new ArrayList();
        SchemaGlobalElementImpl element =
            (SchemaGlobalElementImpl)
                StscTranslator.translateElement(
                    (Element) sImpl.getParseObject(),
                    sImpl.getTargetNamespace(), sImpl.isChameleon(), null, null,
                    anonTypes, sImpl );
        SchemaLocalElementImpl contentModel = null;
        if (element != null)
        {
            StscState.get().addGlobalElement( element );
            contentModel = new SchemaLocalElementImpl();
            contentModel.setParticleType( SchemaParticle.ELEMENT );
            StscTranslator.copyGlobalElementToLocalElement( element, contentModel );
            contentModel.setMinOccurs( BigInteger.ONE );
            contentModel.setMaxOccurs( BigInteger.ONE );
            contentModel.setTransitionNotes(QNameSet.EMPTY, true);
        }
        Map elementPropertyModel =
            StscComplexTypeResolver.buildContentPropertyModelByQName(
                contentModel, sImpl );
        SchemaTypeImpl baseType = sImpl.getSubstitutionGroup() == null ?
            BuiltinSchemaTypeSystem.ST_ANY_TYPE :
            StscState.get().findDocumentType(sImpl.getSubstitutionGroup(), 
                sImpl.isChameleon() ? sImpl.getTargetNamespace() : null, null/*already added*/)
            ;
        sImpl.setBaseTypeRef( baseType.getRef() );
        sImpl.setBaseDepth( baseType.getBaseDepth() + 1 );
        sImpl.setDerivationType( SchemaType.DT_RESTRICTION );
        sImpl.setComplexTypeVariety( SchemaType.ELEMENT_CONTENT );
        sImpl.setContentModel(
            contentModel, new SchemaAttributeModelImpl(),
            elementPropertyModel, Collections.EMPTY_MAP, false );
        sImpl.setWildcardSummary(
            QNameSet.EMPTY, false, QNameSet.EMPTY, false );
        sImpl.setAnonymousTypeRefs( makeRefArray( anonTypes ) );
}

 public static  void resolveIdentityConstraints() 
{
        StscState state = StscState.get();
        SchemaIdentityConstraintImpl[] idcs = state.idConstraints();
        for (int i = 0 ; i <  idcs.length ; i++)
        {
            if (!idcs[i].isResolved())
            {
                Keyref xsdkr = (Keyref)idcs[i].getParseObject();
                QName keyName = xsdkr.getRefer();
                SchemaIdentityConstraintImpl key = null;
                key = state.findIdConstraint(keyName, idcs[i].getChameleonNamespace(), idcs[i].getTargetNamespace());
                if (key == null)
                {
                    state.notFoundError(keyName, SchemaType.IDENTITY_CONSTRAINT, xsdkr, true);
                }
                else 
                {
                    if (key.getConstraintCategory() == SchemaIdentityConstraintImpl.CC_KEYREF)
                        state.error(XmlErrorCodes.IDENTITY_CONSTRAINT_PROPERTIES$KEYREF_REFERS_TO_KEYREF,
                            null, idcs[i].getParseObject());
                    if (key.getFields().length != idcs[i].getFields().length)
                        state.error(XmlErrorCodes.IDENTITY_CONSTRAINT_PROPERTIES$KEY_KEYREF_FIELD_COUNT_EQ,
                            null, idcs[i].getParseObject());
                    idcs[i].setReferencedKey(key.getRef());
                }
            }
        }
}

 public static boolean resolveSubstitutionGroup(SchemaTypeImpl sImpl) 
{
        assert sImpl.isDocumentType();
        if (sImpl.isSGResolved())
            return true;
        if (sImpl.isSGResolving())
        {
            StscState.get().error("Cyclic dependency error", XmlErrorCodes.CYCLIC_DEPENDENCY, sImpl.getParseObject());
            return false; // cyclic dependency error
        }
        sImpl.startResolvingSGs();
        // Resolve substitution group
        TopLevelElement elt = (TopLevelElement)sImpl.getParseObject();
        SchemaTypeImpl substitutionGroup = null;
        QName eltName = new QName(sImpl.getTargetNamespace(), elt.getName());
        // BUG: How do I tell if the type is in this compilation unit?
        if (elt.isSetSubstitutionGroup())
        {
            substitutionGroup = StscState.get().findDocumentType(elt.getSubstitutionGroup(), 
                sImpl.getChameleonNamespace(), sImpl.getTargetNamespace());
            if (substitutionGroup == null)
                StscState.get().notFoundError(elt.getSubstitutionGroup(), SchemaType.ELEMENT, elt.xgetSubstitutionGroup(), true);
                // recovery - ignore substitution group
            else if (! resolveSubstitutionGroup(substitutionGroup) )
                substitutionGroup = null;
            else
                sImpl.setSubstitutionGroup(elt.getSubstitutionGroup());
        }
        // Walk up the chain of subtitution groups adding this schematype to each head's
        // member list
        while (substitutionGroup != null)
        {
            substitutionGroup.addSubstitutionGroupMember(eltName);
            if (substitutionGroup.getSubstitutionGroup() == null)
                break;
            substitutionGroup = StscState.get().findDocumentType(
                substitutionGroup.getSubstitutionGroup(), substitutionGroup.getChameleonNamespace(), null/*no dependency added*/);
            assert substitutionGroup != null : "Could not find document type for: " + substitutionGroup.getSubstitutionGroup();
            if (! resolveSubstitutionGroup(substitutionGroup) )
                substitutionGroup = null; // cyclic dependency - no subst group
        }
        sImpl.finishResolvingSGs();
        return true;
}

 public static boolean resolveType(SchemaTypeImpl sImpl) 
{
        if (sImpl.isResolved())
            return true;
        if (sImpl.isResolving())
        {
            StscState.get().error("Cyclic dependency error", XmlErrorCodes.CYCLIC_DEPENDENCY, sImpl.getParseObject());
            return false; // cyclic dependency error
        }
        // System.out.println("Resolving " + sImpl);
        sImpl.startResolving();
        if (sImpl.isDocumentType())
            resolveDocumentType(sImpl);
        else if (sImpl.isAttributeType())
            resolveAttributeType(sImpl);
        else if (sImpl.isSimpleType())
            StscSimpleTypeResolver.resolveSimpleType(sImpl);
        else
            StscComplexTypeResolver.resolveComplexType(sImpl);
        sImpl.finishResolving();
        // System.out.println("Finished resolving " + sImpl);
        return true;
}