Module org.eclipse.persistence.core

Package org.eclipse.persistence.oxm.annotations

Annotation Type XmlReadTransformer

@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface XmlReadTransformer

Purpose: XmlReadTransformer is used to allow the user direct access to the XML in order to populate their object model. XmlReadTransformer is used in conjunction with XmlWriteTransformers/XmlWriteTransformer to create a customised mapping for a specific attribute. XmlReadTransformer specifies the transformer to be invoked on the unmarshal.

Mapping a transformation: A transformer can be configured to perform both the XML instance-to-Java attribute transformation at unmarshall time (via attribute transformer) and the Java attribute-to-XML instance transformation at marshal time (via field transformer).

Example:

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="name" type="xsd:string"/>
<xsd:element name="normal-hours" type="normal-hours-type"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="normal-hours-type">
<xsd:sequence>
<xsd:element name="start-time" type="xsd:string"/>
<xsd:element name="end-time" type="xsd:string"/>
</xsd:sequence>
</xsd:complexType>
</xsd:schema>


Employee Class

 @XmlRootElement(name="employee")
 public class Employee {
   public String name;
   @XmlReadTransformer(transformerClass = NormalHoursTransformer.class)
   @XmlWriteTransformers({
     @XmlWriteTransformer(transformerClass = StartTimeTransformer.class, xmlPath= "normal-hours/start-time/text()"),
     @XmlWriteTransformer(transformerClass = EndTimeTransformer.class, xmlPath="normal-hours/end-time/text()")
   })
   public String[] normalHours;
 }
 

Normal Hours Transformer

 public class NormalHoursTransformer implements AttributeTransformer {
   public String[] buildAttributeValue(Record record, Object object, Session session) {
     String startTime = (String)record.get("normal-hours/start-time/text()");
     String endTime = (String)record.get("normal-hours/end-time/text()");
       return new String[]{startTime, endTime};
     }
     public void initialize(AbstractTransformationMapping mapping) {
     }
   }
 }
 

See Also:

• AttributeTransformer
• XmlWriteTransformer
• XmlWriteTransformers

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
String	method	The mapped class must have a method with this name which returns a value to be assigned to the attribute (not assigns the value to the attribute).
Class<? extends AttributeTransformer>	transformerClass	User-defined class that must implement the org.eclipse.persistence.mappings.transformers.AttributeTransformer interface.

Element Details

transformerClass

Class<? extends AttributeTransformer> transformerClass

User-defined class that must implement the org.eclipse.persistence.mappings.transformers.AttributeTransformer interface. The class will be instantiated, its buildAttributeValue will be used to create the value to be assigned to the attribute. Either transformerClass or method must be specified, but not both.

Default:

org.eclipse.persistence.mappings.transformers.AttributeTransformer.class

method

String method

The mapped class must have a method with this name which returns a value to be assigned to the attribute (not assigns the value to the attribute). Either transformerClass or method must be specified, but not both.

Default:

""