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EclipseLink/DesignDocs/317962/Phase2.1
Phase 2.1 - Additional MOXy external metadata support
This phase of development involves providing additional MOXy external metadata support that will allow configuration similar to that of deployment XML
Xml Metadata Tags
The following Xml metadata tags will be targeted in this phase:
XML Metadata Tag | MOXy Annotation | Package | Type | Field | Method |
---|---|---|---|---|---|
xml-class-extractor | XmlClassExtractor | X | |||
xml-property | XmlProperty | X | X | X | |
xml-transformation | XmlTransformation | X | X | ||
xml-read-transformer | XmlReadTransformer | X | X | ||
xml-write-transformer | XmlWriteTransformer | X | X |
xml-class-extractor
Purpose
The xml-class-extractor
element allows complex inheritance support. A class extractor is registered with the descriptor to override the default inheritance mechanism. This allows for a user defined class indicator in place of providing an explicit class indicator field. The instance registered must extend the org.eclipse.persistence.descriptors.ClassExtractor
class and implement the extractClassFromRow(Record, Session)
method; this method is used to determine which class to instantiate when unmarshalling.
XML Schema
Following is the proposed schema structure for xml-class-extractor
- it will be added to java-type
:
<xs:element name="xml-class-extractor"> <xs:complexType> <xs:attribute name="class" type="xs:string" use="required"/> </xs:complexType> </xs:element>
Example
The following example will demonstrate how the xml-class-extractor
can be applied.
Setting xml-class-extractor
via EclipseLink XML metadata can be accomplished as follows:
<java-type name="org.example.Employee"> <xml-class-extractor class="org.example.MyClassExtractor" /> </java-type>
xml-property
Purpose
The xml-property
element provides a means to set a property on a mapping or descriptor.
XML Schema
Following are the proposed schema structures for xml-property
:
<xs:element name="xml-property" type="xml-property" /> <xs:complexType name="xml-property"> <xs:attribute name="name" type="xs:string" use="required" /> <xs:attribute name="value" type="xs:string" use="required" /> <xs:attribute name="value-type" type="xs:string" /> </xs:complexType>
An element ref to the new global xml-property
element will be added to:
- java-type
- xml-any-attribute
- xml-attribute
- xml-any-element
- xml-element
- xml-elements
- xml-element-ref
- xml-element-refs
- xml-inverse-reference
- xml-value
- xml-transformation
Example: type-level xml-property
The following example will demonstrate how a type-level xml-property
can be applied.
Setting xml-property
on a type via EclipseLink XML metadata can be accomplished as follows:
<java-type name="org.example.Employee"> <xml-property name="identifier" value="101" value-type="Integer.class" /> <xml-property name="isTrue" value="false" value-type="Boolean.class" /> </java-type>
Example: property-level xml-property
The following example will demonstrate how a property-level xml-property
can be applied.
Setting xml-property
on a property via EclipseLink XML metadata can be accomplished as follows:
<java-type name="org.example.Employee"> <java-attributes> <xml-element java-attribute="myelement"> <xml-property name="isAttribute" value="false" value-type="Boolean.class" /> <xml-property name="comment" value="this is an element" value-type="String.class" /> </xml-element> </java-attributes> </java-type>
xml-transformation
Purpose
The xml-transformation
element is used to configure an org.eclipse.persistence.oxm.mappings.XMLTransformationMapping. Transformation 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.
XML Schema
Following is the proposed schema structure for xml-transformation
:
<xs:element name="xml-transformation" substitutionGroup="java-attribute"> <xs:complexType> <xs:complexContent> <xs:extension base="java-attribute"> <xs:all> <xs:element name="xml-read-transformer"> <xs:complexType> <xs:attribute name="transformer-class" type="xs:string" /> <xs:attribute name="method" type="xs:string" /> </xs:complexType> </xs:element> <xs:element name="xml-write-transformer" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:attribute name="xml-path" type="xs:string" /> <xs:attribute name="transformer-class" type="xs:string" /> <xs:attribute name="method" type="xs:string" /> </xs:complexType> </xs:element> <!-- xs:element name="xml-accessor-type" type="xml-access-type" minOccurs="0"/ --> <xs:element name="xml-property" type="xml-property" minOccurs="0" maxOccurs="unbounded"/> <xs:element name="xml-access-methods" type="xml-access-methods" minOccurs="0"/> </xs:all> <xs:attribute name="name" type="xs:string" use="required"/> <!-- xs:attribute name="fetch" type="orm:fetch-type"/ --> <xs:attribute name="optional" type="xs:boolean" default="false"/> <xs:attribute name="xml-accessor-type" type="xml-access-type" minOccurs="0" default="PUBLIC_MEMBER"/> <xs:attribute name="mutable" type="xs:boolean" default="false"/> <xs:attribute name="attribute-type" type="xs:string" /> </xs:extension> </xs:complexContent> </xs:complexType> </xs:element>
Example
The following example will demonstrate how xml-transformation
can be applied.
Setting xml-transformation
via EclipseLink XML metadata can be accomplished as follows:
<java-type name="org.example.Employee"> <java-attributes> <xml-transformation java-attribute="hours" optional="true"> <xml-read-transformer transformer-class="org.example.NormalHoursTransformer" /> <xml-write-transformer xml-path="normal-hours/start-time/text()" transformer-class="org.example.StartTimeTransformer"/> <xml-write-transformer xml-path="normal-hours/end-time/text()" transformer-class="org.example.EndTimeTransformer"/> <xml-access-methods get-method="getNormalHours" set-method="setNormalHours" /> </xml-transformation> </java-attributes> </java-type>