33.3. Deriving Complex Types from Simple Types

Overview

Apache CXF supports derivation of a complex type from a simple type. A simple type has, by definition, neither sub-elements nor attributes. Hence, one of the main reasons for deriving a complex type from a simple type is to add attributes to the simple type.
There are two ways of deriving a complex type from a simple type:

Derivation by extension

Example 33.12, “Deriving a Complex Type from a Simple Type by Extension” shows an example of a complex type, internationalPrice, derived by extension from the xsd:decimal primitive type to include a currency attribute.

Example 33.12. Deriving a Complex Type from a Simple Type by Extension

<complexType name="internationalPrice">
    <simpleContent>
        <extension base="xsd:decimal">
            <attribute name="currency" type="xsd:string"/>
        </extension>
    </simpleContent>
    </complexType>
The simpleContent element indicates that the new type does not contain any sub-elements. The extension element specifies that the new type extends xsd:decimal.

Derivation by restriction

Example 33.13, “Deriving a Complex Type from a Simple Type by Restriction” shows an example of a complex type, idType, that is derived by restriction from xsd:string. The defined type restricts the possible values of xsd:stringto values that are ten characters in length. It also adds an attribute to the type.

Example 33.13. Deriving a Complex Type from a Simple Type by Restriction

<complexType name="idType">
  <simpleContent>
    <restriction base="xsd:string">
     <length value="10" />
     <attribute name="expires" type="xsd:dateTime" />
    </restriction>
  </simpleContent>
</complexType>
As in Example 33.12, “Deriving a Complex Type from a Simple Type by Extension” the simpleContent element signals that the new type does not contain any children. This example uses a restriction element to constrain the possible values used in the new type. The attribute element adds the element to the new type.

Mapping to Java

A complex type derived from a simple type is mapped to a Java class that is decorated with the @XmlType annotation. The generated class contains a member variable, value, of the simple type from which the complex type is derived. The member variable is decorated with the @XmlValue annotation. The class also has a getValue() method and a setValue() method. In addition, the generated class has a member variable, and the associated getter and setter methods, for each attribute that extends the simple type.

Example 33.14. idType Java Class

@XmlType(name = "idType", propOrder = {
    "value"
})
public class IdType {

    @XmlValue
    protected String value;
    @XmlAttribute
    @XmlSchemaType(name = "dateTime")
    protected XMLGregorianCalendar expires;

    public String getValue() {
        return value;
    }

    public void setValue(String value) {
        this.value = value;
    }

    public XMLGregorianCalendar getExpires() {
        return expires;
    }

    public void setExpires(XMLGregorianCalendar value) {
        this.expires = value;
    }

}