Package org.eclipse.persistence.oxm.mappings

Class XMLTransformationMapping

java.lang.Object
org.eclipse.persistence.core.mappings.CoreMapping<AttributeAccessor,org.eclipse.persistence.internal.sessions.AbstractSession,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField>
org.eclipse.persistence.mappings.DatabaseMapping
org.eclipse.persistence.mappings.foundation.AbstractTransformationMapping
org.eclipse.persistence.oxm.mappings.XMLTransformationMapping
All Implemented Interfaces:
Serializable, Cloneable, org.eclipse.persistence.internal.oxm.mappings.Mapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,XMLRecord>, org.eclipse.persistence.internal.oxm.mappings.TransformationMapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,org.eclipse.persistence.internal.oxm.record.XMLTransformationRecord,XMLRecord>, XMLMapping
public class XMLTransformationMapping extends AbstractTransformationMapping implements org.eclipse.persistence.internal.oxm.mappings.TransformationMapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,org.eclipse.persistence.internal.oxm.record.XMLTransformationRecord,XMLRecord>, XMLMapping

Transformation XML mappings are used to create a custom mapping where one or more XML nodes can be used to create the object to be stored in a Java class's attribute. To handle the custom requirements at marshal (write) and unmarshall (read) time, a transformation mapping takes instances of org.eclipse.persistence.mappings.transformers (such as AttributeTransformer and FieldTransformer), providing a non-intrusive solution that avoids the need for domain objects to implement any 'special' interfaces.

Setting the XPath: TopLink XML mappings make use of XPath statements to find the relevant data in an XML document. The XPath statement is relative to the context node specified in the descriptor. The XPath may contain node type, path, and positional information. The XPath is specified on the field transformer that is set on the mapping. The XPath is set as the first parameter of the addFieldTransformer method.

The following XPath statements may be used to specify the location of XML data relating to an object's name attribute:

XPath statements
XPath Description
@name The "@" character indicates that the node is an attribute.
text() "text()" indicates that the node is a text node. In this case the name value in the text node belongs to the context node.
full-name/text() The name information is stored in the text node of the full-name element.
personal-info/name/text() The XPath statement may be used to specify any valid path.
name[2]/text() The XPath statement may contain positional information. In this case the name information is stored in the text node of the second occurrence of the name element.

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).

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>

Code Sample
XMLTransformationMapping mapping = new XMLTransformationMapping();
mapping.setAttributeName("normalHours");
mapping.setAttributeTransformerClassName("org.eclipse.persistence.testing.oxm.mappings.transformation.NormalHoursAttributeTransformer");
mapping.addFieldTransformer("normal-hours/start-time/text()", new StartTimeTransformer());
mapping.addFieldTransformer("normal-hours/end-time/text()", new EndTimeTransformer()");

More Information: For more information about using the XML Transformation Mapping, see the "Understanding XML Mappings" chapter of the Oracle TopLink Developer's Guide.

See Also:

  • Constructor Details

    • XMLTransformationMapping

      public XMLTransformationMapping()

  • Method Details

    • isXMLMapping

      public boolean isXMLMapping()
      INTERNAL:
      Overrides:
      isXMLMapping in class DatabaseMapping

    • addFieldTransformer

      public void addFieldTransformer(String fieldName, FieldTransformer transformer)
      Description copied from class: AbstractTransformationMapping
      PUBLIC: Add the name of field and the transformer that returns the value to be placed in the field when the object is written to the database.
      Overrides:
      addFieldTransformer in class AbstractTransformationMapping

    • addFieldTransformerClassName

      public void addFieldTransformerClassName(String fieldName, String className)
      Description copied from class: AbstractTransformationMapping
      INTERNAL: Add the name of a field and the name of a class which implements the FieldTransformer interface. When the object is written, the transform method will be called on the FieldTransformer to acquire the value to put in the field.
      Specified by:
      addFieldTransformerClassName in interface org.eclipse.persistence.internal.oxm.mappings.TransformationMapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,org.eclipse.persistence.internal.oxm.record.XMLTransformationRecord,XMLRecord>
      Overrides:
      addFieldTransformerClassName in class AbstractTransformationMapping

    • addFieldTransformation

      public void addFieldTransformation(String fieldName, String methodName)
      Description copied from class: AbstractTransformationMapping
      PUBLIC: Add the name of field and the name of the method that returns the value to be placed in said field when the object is written to the database. The method may take zero arguments, or it may take a single argument of type org.eclipse.persistence.sessions.Session.
      Specified by:
      addFieldTransformation in interface org.eclipse.persistence.internal.oxm.mappings.TransformationMapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,org.eclipse.persistence.internal.oxm.record.XMLTransformationRecord,XMLRecord>
      Overrides:
      addFieldTransformation in class AbstractTransformationMapping

    • writeSingleValue

      public void writeSingleValue(Object value, Object parent, XMLRecord row, org.eclipse.persistence.internal.sessions.AbstractSession session)
      Description copied from interface: XMLMapping
      INTERNAL: A method that marshals a single value to the provided Record based on this mapping's XPath. Used for Sequenced marshalling.
      Specified by:
      writeSingleValue in interface org.eclipse.persistence.internal.oxm.mappings.Mapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,XMLRecord>
      Specified by:
      writeSingleValue in interface XMLMapping
      Parameters:
      value - - The value to be marshalled
      row - - The Record the value is being marshalled too.

    • setIsWriteOnly

      public void setIsWriteOnly(boolean b)
      Specified by:
      setIsWriteOnly in interface XMLMapping

    • preInitialize

      public void preInitialize(org.eclipse.persistence.internal.sessions.AbstractSession session) throws DescriptorException
      Description copied from class: AbstractTransformationMapping
      INTERNAL: Allow for initialization of properties and validation.
      Overrides:
      preInitialize in class AbstractTransformationMapping
      Throws:
      DescriptorException

    • writeFromAttributeIntoRow

      public void writeFromAttributeIntoRow(org.eclipse.persistence.internal.oxm.record.UnmarshalRecord unmarshalRecord, org.eclipse.persistence.internal.oxm.mappings.Field field, Object value, boolean isElement)
      INTERNAL: Put value into a record keyed on field.
      Specified by:
      writeFromAttributeIntoRow in interface org.eclipse.persistence.internal.oxm.mappings.TransformationMapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,org.eclipse.persistence.internal.oxm.record.XMLTransformationRecord,XMLRecord>

    • readFromRowIntoObject

      public Object readFromRowIntoObject(XMLRecord row, Object object, org.eclipse.persistence.internal.sessions.AbstractSession executionSession, boolean isTargetProtected) throws DatabaseException
      INTERNAL: Extract value from the row and set the attribute to the value in the object.
      Specified by:
      readFromRowIntoObject in interface org.eclipse.persistence.internal.oxm.mappings.TransformationMapping<org.eclipse.persistence.internal.sessions.AbstractSession,AttributeAccessor,org.eclipse.persistence.internal.queries.ContainerPolicy,ClassDescriptor,org.eclipse.persistence.internal.helper.DatabaseField,org.eclipse.persistence.internal.oxm.record.XMLTransformationRecord,XMLRecord>
      Throws:
      DatabaseException