Jump to: navigation, search

EclipseLink/UserGuide/MOXy/Relationships/Privately Owned/One-to-Many


link="http://wiki.eclipse.org/EclipseLink"
EclipseLink
Website
Download
Community
Mailing ListForumsIRC
Bugzilla
Open
Help Wanted
Bug Day
Contribute
Browse Source


One-to-Many Mapping

This section illustrates how to map one-to-many relationships with Eclipselink.

The schema below shows a typical 1:M relationship between Customer and PhoneNumber

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
 
   <xsd:element name="customer" type="customer-type"/>
 
   <xsd:complexType name="customer-type">
      <xsd:sequence>
         <xsd:element name="first-name" type="xsd:string"/>
         <xsd:element name="last-name" type="xsd:string"/>
         <xsd:element name="phone-number" type="phone-type" minOccurs="0" maxOccurs="unbounded"/>
      </xsd:sequence>
   </xsd:complexType>
 
   <xsd:complexType name="phone-type">
      <xsd:sequence>
         <xsd:attribute name="type" type="xsd:string"/>
         <xsd:element name="number" type="xsd:int"/>
      </xsd:sequence>
   </xsd:complexType>
 
</xsd:schema>

XML Composite Collection Mapping

The following example shows how to annotate your Java class to obtain this mapping with EclipseLink. The standard JAXB @XmlElement annotation, when used on a Collection field, can achieve this.

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
   @XmlElement(name="first-name")
   private String firstName;
   @XmlElement(name="last-name")
   private String lastName;
   @XmlElement(name="phone-number")
   private List<PhoneNumber> phoneNumbers;
 
   ...
}
 
@XmlAccessorType(XmlAccessType.FIELD)
public class PhoneNumber {
   private String type;
   private Integer number;
 
   ...
}

The following example shows how to define your mapping information in EclipseLink's OXM metadata format.

...
<java-type name="Customer">
   <xml-root-element name="customer"/>
   <java-attributes>
      <xml-element java-attribute="firstName" name="phone-number" type="java.lang.String"/>
      <xml-element java-attribute="lastName" name="phone-number" type="java.lang.String"/>
      <xml-element java-attribute="phoneNumbers" name="phone-number" type="PhoneNumber"/>
   </java-attributes>
</java-type>
 
<java-type name="PhoneNumber">
   <java-attributes>
      <xml-attribute java-attribute="type" type="java.lang.String"/>
      <xml-value java-attribute="number" type="java.lang.Integer"/>
   </java-attributes>
</java-type>
...

Using EclipseLink's @XmlPath Annotation

By default, your Java attributes will be mapped to XML based on their attributes Java name, or by a name specified in an @XmlElement annotation. This mapping is based on XPath, and EclipseLink's @XmlPath annotation allows you to customize this mapping. For example, you can use it to control the nesting of your elements in XML:

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
   @XmlPath("contact-info/phone-number")
   private PhoneNumber phoneNumber;
 
   ...
}

This will produce the following XML:

<customer>
   <contact-info>
      <phone-number>
         <number>555-631-2124</number>
      </phone-number>
   </contact-info>
</customer>

You can also use @XmlPath to map to different occurrences of the same element in XML, by index. For example:

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
   @XmlPath("contact-info/phone[1]")
   private PhoneNumber homePhone;
   @XmlPath("contact-info/phone[2]")
   private PhoneNumber workPhone;
   ...
}

will produce the following XML:

<customer>
   <contact-info>
      <phone>
         <number>555-631-2124</number>
      </phone>
      <phone>
         <number>555-631-8298</number>
      </phone>
   </contact-info>
</customer>


Eclipselink-logo.gif
Version: 2.2.0 DRAFT
Other versions...