JavaTM 2 Platform Std. Ed. v1.6.0
javax.xml.bind.annotation
Annotation Type XmlIDREF
@Retention(value=RUNTIME)
@Target(value={FIELD,METHOD})
public @interface XmlIDREF
Maps a JavaBean property to XML IDREF.
To preserve referential integrity of an object graph across XML
serialization followed by a XML deserialization, requires an object
reference to be marshalled by reference or containment
appropriately. Annotations @XmlID and @XmlIDREF
together allow a customized mapping of a JavaBean property's
type by containment or reference.
Usage
The @XmlIDREF annotation can be used with the following
program elements:
- a JavaBean property
- non static, non transient field
See "Package Specification" in javax.xml.bind.package javadoc for
additional common information.
The usage is subject to the following constraints:
Example: Map a JavaBean property to xs:IDREF
(i.e. by reference rather than by containment)
//EXAMPLE: Code fragment
public class Shipping {
@XmlIDREF public Customer getCustomer();
public void setCustomer(Customer customer);
....
}
<!-- Example: XML Schema fragment -->
<xs:complexType name="Shipping">
<xs:complexContent>
<xs:sequence>
<xs:element name="customer" type="xs:IDREF"/>
....
</xs:sequence>
</xs:complexContent>
</xs:complexType>
Example 2: The following is a complete example of
containment versus reference.
// By default, Customer maps to complex type xs:Customer
public class Customer {
// map JavaBean property type to xs:ID
@XmlID public String getCustomerID();
public void setCustomerID(String id);
// .... other properties not shown
}
// By default, Invoice maps to a complex type xs:Invoice
public class Invoice {
// map by reference
@XmlIDREF public Customer getCustomer();
public void setCustomer(Customer customer);
// .... other properties not shown here
}
// By default, Shipping maps to complex type xs:Shipping
public class Shipping {
// map by reference
@XmlIDREF public Customer getCustomer();
public void setCustomer(Customer customer);
}
// at least one class must reference Customer by containment;
// Customer instances won't be marshalled.
@XmlElement(name="CustomerData")
public class CustomerData {
// map reference to Customer by containment by default.
public Customer getCustomer();
// maps reference to Shipping by containment by default.
public Shipping getShipping();
// maps reference to Invoice by containment by default.
public Invoice getInvoice();
}
<!-- XML Schema mapping for above code frament -->
<xs:complexType name="Invoice">
<xs:complexContent>
<xs:sequence>
<xs:element name="customer" type="xs:IDREF"/>
....
</xs:sequence>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="Shipping">
<xs:complexContent>
<xs:sequence>
<xs:element name="customer" type="xs:IDREF"/>
....
</xs:sequence>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="Customer">
<xs:complexContent>
<xs:sequence>
....
</xs:sequence>
<xs:attribute name="CustomerID" type="xs:ID"/>
</xs:complexContent>
</xs:complexType>
<xs:complexType name="CustomerData">
<xs:complexContent>
<xs:sequence>
<xs:element name="customer" type="xs:Customer"/>
<xs:element name="shipping" type="xs:Shipping"/>
<xs:element name="invoice" type="xs:Invoice"/>
</xs:sequence>
</xs:complexContent>
</xs:complexType>
<xs:element name"customerData" type="xs:CustomerData"/>
<!-- Instance document conforming to the above XML Schema -->
<customerData>
<customer customerID="Alice">
....
</customer>
<shipping customer="Alice">
....
</shipping>
<invoice customer="Alice">
....
</invoice>
</customerData>
Example 3: Mapping List to repeating element of type IDREF
// Code fragment
public class Shipping {
@XmlIDREF
@XmlElement(name="Alice")
public List customers;
}
<!-- XML schema fragment -->
<xs:complexType name="Shipping">
<xs:sequence>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element name="Alice" type="xs:IDREF"/>
</xs:choice>
</xs:sequence>
</xs:complexType>
Example 4: Mapping a List to a list of elements of type IDREF.
//Code fragment
public class Shipping {
@XmlIDREF
@XmlElements(
@XmlElement(name="Alice", type="Customer.class")
@XmlElement(name="John", type="InternationalCustomer.class")
public List customers;
}
<!-- XML Schema fragment -->
<xs:complexType name="Shipping">
<xs:sequence>
<xs:choice minOccurs="0" maxOccurs="unbounded">
<xs:element name="Alice" type="xs:IDREF"/>
<xs:element name="John" type="xs:IDREF"/>
</xs:choice>
</xs:sequence>
</xs:complexType>
- Since:
- JAXB2.0
- See Also:
XmlID
Copyright 2003 Sun Microsystems, Inc. All rights reserved
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