Developing JAXB Applications Using EclipseLink MOXy,
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This section demonstrates several ways to map a collection of simple Java values directly to XML 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
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 jakarta.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.
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
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 jakarta.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.
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
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 jakarta.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.
@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 jakarta.xml.bind.annotation.*;
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
@XmlAttribute
@XmlList
private List<Integer> ids;
...
}
package example;
import jakarta.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>
...
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