"simpleType" Components with "restriction" Child Components

XSD Tutorials - Herong's Tutorial Examples - Version 5.10, by Dr. Herong Yang

XSD Tutorials - Herong's Tutorial Examples

∟"simpleType" - Defining Your Own Simple Datatypes

∟"simpleType" Components with "restriction" Child Components

This section describes the 'restriction' child component in 'simpleType' component. 'restriction' child components are used to reduce the value space on a base datatype by changing its constraining facets.

In earlier tutorials, we learned datatype facets can be modified to create new datatypes using "restriction" components. Now let's take closer look at the "restriction" component.

Here is an XSD template showing you how to use the "restriction" as a child component in a "simpleType" component:

Format 1:
<simpleType ...>
  <restriction base="base_type">
    facet component
    facet component
    ...
  </restriction>
</simpleType>

Format 2:
<simpleType ...>
  <restriction>
    <simpleType ...>
      definition of the base datatype
    </simpleType>

    facet component
    facet component
    ...
  </restriction>
</simpleType>

Some notes on using the "restriction" component:

base="base_type" - Optional attribute to specify a name to the base datatype. If not provided, the base datatype must be defined with "simpleType" as the first child.
The base datatype must be a simple datatype that supports one or more constraining facets.
Each facet component must make the facet more restrictive than the base datatype, or at least unchanged.
The same facet can only be specified once, except for "enumeration".

For example, the following XSD document uses "restriction" components to define 2 new simple datatypes:

<?xml version="1.1"?>
<!-- restriction_simpleType_test.xsd
 - Copyright (c) 2013, HerongYang.com, All Rights Reserved.
-->
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
<xs:element name="Restriction_SimpleType_Test">
  <xs:complexType>
    <xs:sequence>

      <xs:element name="IPAddress" maxOccurs="unbounded">
        <!-- "restriction" with no "base" attribute -->
        <xs:simpleType>
          <xs:restriction>
            <xs:simpleType>
              <xs:restriction base="xs:string">
<xs:pattern value="\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}"/>
              </xs:restriction>
            </xs:simpleType>
            <xs:maxLength value="15"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:element>

      <xs:element name="Port" maxOccurs="unbounded">
        <!-- "restriction" with "base" attribute -->
        <xs:simpleType>
          <xs:restriction base="xs:unsignedByte">
            <xs:enumeration value="80"/>
            <xs:enumeration value="23"/>
          </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"?>
<!-- restriction_simpleType_test.xml
 - Copyright (c) 2013, HerongYang.com, All Rights Reserved.
-->
<Restriction_SimpleType_Test>
   
   <!-- Valid "IPAddress" values -->
   <IPAddress>127.0.0.1</IPAddress>

   <!-- Invalid "IPAddress" values -->
   <IPAddress>::1:</IPAddress>

   <!-- Valid "Port" values -->
   <Port>80</Port>

   <!-- Invalid "Port" values -->
   <Port>8080</Port>

</Restriction_SimpleType_Test>

When validating this XML document with my XsdSchemaValidator.java program presented earlier in the book, I get these errors:

c:\Progra~1\Java\jdk1.7.0_07\bin\java XsdSchemaValidator 
   restriction_simpleType_test.xsd restriction_simpleType_test.xml

Error:
   Line number: 11
   Column number: 31
   Message: cvc-pattern-valid: Value '::1:' is not facet-valid with 
   respect to pattern '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}' for type 
   '#AnonType_IPAddressRestriction_SimpleType_Test'.

Error:
   Line number: 11
   Column number: 31
   Message: cvc-type.3.1.3: The value '::1:' of element 'IPAddress' is
   not valid.

Error:
   Line number: 17
   Column number: 21
   Message: cvc-enumeration-valid: Value '8080' is not facet-valid 
   with respect to enumeration '[80, 23]'. It must be a value from the
   enumeration.

Error:
   Line number: 17
   Column number: 21
   Message: cvc-type.3.1.3: The value '8080' of element 'Port' is not
   valid.

Failed with errors: 4

Last update: 2013.

Table of Contents

About This Book

Introduction to XML Schema

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

Using Xerces2 Java API

XML Schema Language - Basics

Introduction of XSD Built-in Datatypes

"string" and Its Derived Datatypes