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EclipseLink Developing JAXB Applications Using EclipseLink
Release 2.5
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Beta Draft: 2013-02-28

Mapping Collections of Simple Values

This section demonstrates several ways to map a collection of simple Java values directly to XML text nodes.

Mapping to Text Nodes

Given the XML schema in Example 4-25, Figure 4-10 illustrates the mapping of a Java collection to elements in a corresponding XML document.

Example 4-25 Sample XML Schema

<?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="email-address" type="xsd:string" minOccurs="0" maxOccurs="unbounded"/>
      </xsd:sequence>
   </xsd:complexType>
 
</xsd:schema>
 

Figure 4-10 XML Direct Collection Mapping to Text Nodes

XML Direct Collection Mapping to Text Nodes
Description of "Figure 4-10 XML Direct Collection Mapping to Text Nodes"

Example 4-26 shows how to annotate your Java class to obtain this mapping with EclipseLink. All that is needed is the standard JAXB @XmlElement annotation.

Example 4-26 Using the @XmlElement Annotation

package example;
 
import javax.xml.bind.annotation.*;
 
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
   @XmlElement(name="email-address")
   private List<String> emailAddress;
 
   ...
}
 

Example 4-27 shows how to define your mapping information in EclipseLink's OXM metadata format.

Example 4-27 Sample XML Mapping

...
<java-type name="Customer">
   <xml-root-element name="customer"/>
   <java-attributes>
      <xml-element java-attribute="emailAddresses" name="email-address"/>
   </java-attributes>
</java-type>
...
 

Mapping to Text Nodes with a Grouping Element

Given the XML schema in Example 4-28, Figure 4-11 illustrates the mapping of a Java collection to elements in a corresponding XML document, using a grouping element to organize the elements of the collection.

Example 4-28 Sample XML Schema

<?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="email-address" type="xsd:string" minOccurs="0" maxOccurs="unbounded"/>
      </xsd:sequence>
   </xsd:complexType>
 
</xsd:schema>
 

Figure 4-11 XML Direct Collection Mapping to Text Nodes with a Grouping Element

XML Direct Collection Mapping to Text Nodes with a Grouping Element
Description of "Figure 4-11 XML Direct Collection Mapping to Text Nodes with a Grouping Element"

Example 4-29 shows how to annotate your Java class to obtain this mapping with EclipseLink. We specify the grouping element with the @XmlElementWrapper annotation.

Example 4-29 Using the @XmlElementWrapper Annotation

package example;
 
import javax.xml.bind.annotation.*;
 
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
   @XmlElement(name="email-address")
   @XmlElementWrapper(name="email-addresses")
   private List<String> emailAddresses;
 
   ...
}
 

Example 4-30 shows how to define your mapping information in EclipseLink's OXM metadata format.

Example 4-30 Sample XML Mapping

...
<java-type name="Customer">
   <xml-root-element name="customer"/>
   <java-attributes>
      <xml-element java-attribute="emailAddresses" name="email-address">
         <xml-element-wrapper name="email-addresses"/>
      </xml-element>
   </java-attributes>
</java-type>
...
 

Mapping to a List Element

Given the XML schema in Example 4-31, Figure 4-12 illustrates a mapping to an xsd:list type in a corresponding XML document. Using this mapping, you can represent the collection of simple Java objects as a String of white space delimited tokens in XML. Here, the tasks list contains three entries: Design, Code and Test.

Example 4-31 Sample XML Schema

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
 
   <xsd:element name="employee" type="employee-type"/>
 
   <xsd:complexType name="employee-type">
      <xsd:sequence>
         <xsd:element name="tasks" type="tasks-type"/>
      </xsd:sequence>
   </xsd:complexType>
 
   <xsd:simpleType name="tasks-type">
      <xsd:list itemType="xsd:string"/>
   </xsd:simpleType>
 
</xsd:schema>
 

Figure 4-12 XML Direct Mapping to a List Field

XMLDirect Mapping to a List Field
Description of "Figure 4-12 XML Direct Mapping to a List Field"

Example 4-32 shows how to annotate your Java class to obtain this mapping with EclipseLink.

Example 4-32 Using the @XmlList Annotation

package example;
 
import javax.xml.bind.annotation.*;
 
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Employee {
   @XmlList
   private List<String> tasks;
 
   ...
}
 

Example 4-33 shows how to define your mapping information in EclipseLink's OXM metadata format.

Example 4-33 Sample XML Mapping

...
<java-type name="Employee">
   <xml-root-element name="employee"/>
   <java-attributes>
      <xml-element java-attribute="tasks" xml-list="true"/>
   </java-attributes>
</java-type>
...
 

Mapping a Collection of XmlAttributes or XmlValues

@XmlList can also be used in conjunction with @XmlAttribute or @XmlValue, as shown in Example 4-34. The collection will be represented as a space-separated string in the attribute.

Example 4-34 Java Annotations

package example;
 
import javax.xml.bind.annotation.*;
 
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
   @XmlAttribute
   @XmlList
   private List<Integer> ids;
 
   ...
}
 
package example;
 
import javax.xml.bind.annotation.*;
 
@XmlRootElement(name="phone-numbers")
@XmlAccessorType(XmlAccessType.FIELD)
public class PhoneNumbers {
   @XmlValue
   @XmlList
   private List<String> numbers;
 
   ...
}
 

Example 4-35 EclipseLink OXM Metadata

 
...
<java-type name="Customer">
   <xml-root-element name="customer"/>
   <java-attributes>
      <xml-attribute java-attribute="ids" xml-list="true"/>
   </java-attributes>
</java-type>
...
 
...
<java-type name="PhoneNumbers">
   <xml-root-element name="phone-numbers"/>
   <java-attributes>
      <xml-value java-attribute="numbers" xml-list="true"/>
   </java-attributes>
</java-type>
...
 

Example 4-36 Example XML Documents

<customer ids="726 1982 1989 2991"/>
 
<phone-numbers>6132883982 6139828817 18882982298</phone-numbers>
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