Define constraints in one of two ways: "standalone" allows for the reuse
of constraints across many properties; "inline" defines the constraint specifically for a
single property.
<xs:complexType name="constraint">
<xs:attribute name="name" use="optional" type="string" />
<xs:attribute name="type" type="string" use="optional"/>
<xs:sequence>
<xs:element name="parameter" maxOccurs="unbounded" type="namedValue"
minOccurs="0"/>
</xs:sequence>
<xs:attribute name="ref" use="optional" type="string" />
</xs:complexType>
<xs:complexType name="namedValue">
<xs:attributeGroup ref="name" />
<xs:choice>
<xs:element name="value" type="string" maxOccurs="1"minOccurs="0" />
<xs:element name="list" maxOccurs="1" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element name="value" type="string"maxOccurs="unbounded"
minOccurs="0"/>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:choice>
</xs:complexType>
A standalone constraint must specify a unique name and a type. There are several constraint
types provided out of the box; the commonly used types are:
- REGEX; Property value matches regular expression.
- LENGTH: Text property value length must reside within minimum and maximum length limits.
- MINMAX: Numeric property value must reside within minimum and maximum range limits.
- LIST: Property value must be one of those specified in the list of values.
- REGEX: Expression
- LENGTH: minLength and maxLength
- MINMAX: minValue and maxValue
- LIST: allowedValues and caseSensitive
A content model may define one or more standalone constraints.
<xs:element name="model">
...
<xs:element name="constraints" maxOccurs="1" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element name="constraint" type="constraint" maxOccurs="unbounded"
minOccurs="1" />
</xs:sequence>
</xs:complexType>
</xs:element>
...
</xs:element>
Each property may support one or more constraints either by referencing an existing standalone constraint definition or defining one inline via the constraint element.
<xs:complexType name="property">
...
<xs:element name="constraints" maxOccurs="1" minOccurs="0">
<xs:complexType>
<xs:sequence>
<xs:element name="constraint" type="constraint" maxOccurs="unbounded"
minOccurs="1" />
</xs:sequence>
</xs:complexType>
</xs:element>
...
</xs:complexType>
An existing constraint is referenced via the ref element, whose value is the name of the constraint to reference. Otherwise, an inline constraint is defined in the same manner as a standalone constraint.