XSD Tutorials - Herong's Tutorial Examples - v5.23, by Herong Yang
Constraining Facets on Union Datatypes
This section describes constraining facets on union datatypes. New simple datatype can be defined with a 'restriction' construction component using a union datatype as the base.
From the previous tutorial, we know that there are 2 categories of union datatypes:
Both atomic union datatypes and list union datatypes support the following constraining facets:
pattern = undefined enumeration = undefined assertions = undefined
For example, the following XSD document uses "restriction" components on union datatypes to define 2 new simple datatypes:
<?xml version="1.1"?> <!-- union_facet_test.xsd - Copyright (c) 2002-2013 HerongYang.com. All Rights Reserved. --> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:simpleType name="atomicUnion"> <xs:union memberTypes="xs:positiveInteger xs:negativeInteger"/> </xs:simpleType> <xs:simpleType name="listUnion"> <xs:union memberTypes="xs:gYear"> <xs:simpleType> <xs:list itemType="xs:unsignedByte"/> </xs:simpleType> </xs:union> </xs:simpleType> <xs:element name="Union_Facet_Test"> <xs:complexType> <xs:sequence> <xs:element name="AtomicUnion" maxOccurs="unbounded"> <!-- "restriction" on atomic list datatype --> <xs:simpleType> <xs:restriction base="atomicUnion"> <!-- "maxInclusive" not allowed on union <xs:maxInclusive value="999"/> --> <xs:pattern value="-?\d\d\d|\d"/> </xs:restriction> </xs:simpleType> </xs:element> <xs:element name="ListUnion" maxOccurs="unbounded"> <!-- "restriction" on list union datatype --> <xs:simpleType> <xs:restriction base="listUnion"> <xs:pattern value="\d\d\d\d|\d\d \d\d"/> </xs:restriction> </xs:simpleType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:schema>
Here is a sample XML document to test the above XSD document:
<?xml version="1.1"?> <!-- union_facet_test.xml - Copyright (c) 2002-2013 HerongYang.com. All Rights Reserved. --> <Union_Facet_Test> <!-- Valid "AtomicUnion" list of 3 items --> <AtomicUnion> 999 </AtomicUnion> <AtomicUnion> 100 </AtomicUnion> <!-- Invalid "AtomicUnion" values --> <AtomicUnion> 1000 </AtomicUnion> <AtomicUnion> 0 </AtomicUnion> <!-- Valid "ListUnion" list values --> <ListUnion> 2013 </ListUnion> <ListUnion> 11 22 </ListUnion> <!-- Invalid "ListUnion" values --> <ListUnion> -2013 </ListUnion> <ListUnion> 11 22 33 </ListUnion> </Union_Facet_Test>
When validating this XML document with my XsdSchemaValidator.java program presented earlier in the book, I get these errors:
herong> java XsdSchemaValidator ^^^ union_facet_test.xsd union_facet_test.xml Error: Line number: 12 Column number: 38 Message: cvc-pattern-valid: Value '1000' is not facet-valid with respect to pattern '-?\d\d\d|\d' for type '#AnonType_AtomicUnionUnion_Facet_Test'. Error: Line number: 12 Column number: 38 Message: cvc-type.3.1.3: The value '1000' of element 'AtomicUnion' is not valid. Error: Line number: 13 Column number: 35 Message: cvc-datatype-valid.1.2.3: '0' is not a valid value of union type '#AnonType_AtomicUnionUnion_Facet_Test'. Error: Line number: 13 Column number: 35 Message: cvc-type.3.1.3: The value '0' of element 'AtomicUnion' is not valid. Error: Line number: 20 Column number: 35 Message: cvc-pattern-valid: Value '-2013' is not facet-valid with respect to pattern '\d\d\d\d|\d\d \d\d' for type '#AnonType_ListUnionUnion_Facet_Test'. Error: Line number: 20 Column number: 35 Message: cvc-type.3.1.3: The value '-2013' of element 'ListUnion' is not valid. Error: Line number: 21 Column number: 38 Message: cvc-pattern-valid: Value '11 22 33' is not facet-valid with respect to pattern '\d\d\d\d|\d\d \d\d' for type '#AnonType_ListUnionUnion_Facet_Test'. Error: Line number: 21 Column number: 38 Message: cvc-type.3.1.3: The value '11 22 33' of element 'ListUnion' is not valid. Failed with errors: 8
Table of Contents
XML Editor and Schema Processor - XMLPad
Java API for XML Processing - JAXP
JAXP - XML Schema (XSD) Validation
Xerces2 Java Parser - Java API of XML Parsers
Introduction of XSD Built-in Datatypes
"string" and Its Derived Datatypes
"decimal" and Its Derived Datatypes
"dateTime" and Its Related Datatypes
Miscellaneous Built-in Datatypes
Facets, Constraining Facets and Restriction Datatypes
►"simpleType" - Defining Your Own Simple Datatypes
"simpleType" Components - User-Defined Simple Datatypes
"simpleType" Components with "restriction" Child Components
"simpleType" Components with "union" Child Components
"simpleType" Components with "list" Child Components
Atomic, List, Atomic Union and List Union Datatypes
Constraining Facets on List Datatypes
►Constraining Facets on Union Datatypes
Nested List Datatypes - Not Allowed
Nested Atomic and List Union Datatypes
Identity-Constraints: unique, key and keyref
Assertion as Custom Validation Rules
XML Schema Location and Namespace in XML Documents
Overriding Element Types in XML Documents