Revision as of 13:57, 18 August 2010

Phase 3 - MOXy Equivalents of Relevant JPA Annotations

This phase of development involves providing additional MOXy annotations and XML metadata support equivalent to that of any relevant JPA annotations.

Annotations/XML Metadata

The following MOXy annotations/XML metadata will be targeted in this phase:

Inheritance Support

XmlDiscriminatorNode

Purpose

Provide a means to set the class indicator field name when using inheritance.

Java Metadata

package org.eclipse.persistence.oxm.annotations;
 
@Target({TYPE}) 
@Retention(RUNTIME)
public @interface XmlDiscriminatorNode {
    String value();
}

XML Metadata

xml-discriminator-node

The xml-discriminator-node metadata tag will be used to set the class indicator field name when using inheritance. The value will be in the form of an XPath to an attribute, i.e. @xsi:type.

XmlDiscriminatorValue

Purpose

Provide a means to set a class indicator when using inheritance.

Java Metadata

package org.eclipse.persistence.oxm.annotations;
 
@Target({TYPE}) 
@Retention(RUNTIME)
public @interface XmlDiscriminatorValue {
    String value();
}

XML Metadata

xml-discriminator-value

The xml-discriminator-value metadata tag will be used to set a class indicator when using inheritance.

XML Schema

Following is the proposed XSD change necessary to provide support for inheritance:

<xs:element name="java-type">
    <xs:complexType>
        <xs:all>
            <xs:element ref="xml-type" minOccurs="0"/>
            <xs:element ref="xml-root-element" minOccurs="0"/>
            <xs:element ref="xml-see-also" minOccurs="0"/>
            <xs:element ref="xml-java-type-adapter" minOccurs="0"/>
            <xs:element ref="xml-class-extractor" minOccurs="0"/>
            <xs:element ref="xml-properties" minOccurs="0" />
            <xs:element name="java-attributes" minOccurs="0">
                <xs:complexType>
                    <xs:sequence>
                        <xs:element ref="java-attribute" minOccurs="0" maxOccurs="unbounded" />
                    </xs:sequence>
                </xs:complexType>
            </xs:element>
        </xs:all>
        <xs:attribute name="name" type="xs:string" />
        <xs:attribute name="xml-accessor-order" type="xml-access-order" default="UNDEFINED" />
        <xs:attribute name="xml-accessor-type" type="xml-access-type" default="PUBLIC_MEMBER" />
        <xs:attribute name="xml-customizer" type="xs:string" />
        <xs:attribute name="xml-discriminator-node" type="xs:string" />
        <xs:attribute name="xml-discriminator-value" type="xs:string" />
        <xs:attribute name="xml-inline-binary-data" type="xs:boolean" default="false" />
        <xs:attribute name="xml-transient" type="xs:boolean" default="false" />
    </xs:complexType>
</xs:element>

Example

The following example will demonstrate how inheritance can be configured.

Using the xml-discriminator-node and xml-discriminator-value EclipseLink XML metadata tags to set the class indicator field name and class indicator(s) can be accomplished as follows:

<java-types>
    <java-type name="org.example.Vehicle" xml-discriminator-node="@vtype" xml-discriminator-value="vehicle">
        <xml-root-element name="vehicle-data" />
        <java-attributes>
            <xml-element java-attribute="topSpeed" name="top-speed" />
        </java-attributes>
    </java-type>
    <java-type name="org.example.Car" xml-discriminator-value="car">
        <xml-root-element name="car-data" /> 
        <java-attributes>
            <xml-element java-attribute="numberOfDoors" name="number-of-doors" />
            <xml-element java-attribute="milesPerGallon" name="miles-per-gallon" />
        </java-attributes>
    </java-type>
</java-types>

Setting the class indicator field name and class indicator(s) via Annotations would be accomplished as follows:

org.example.Vehicle.java

package org.example;
 
import org.eclipse.persistence.oxm.annotations.XmlDiscriminatorNode;
import org.eclipse.persistence.oxm.annotations.XmlDiscriminatorValue;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement("vehicle-data")
@XmlDiscriminatorNode("@vtype")
@XmlDiscriminatorValue("vehicle")
class Vehicle {
    public String model;
    public String manufacturer;
    @XmlElement(name="top-speed")
    public int topSpeed;
}

org.example.Car.java

package org.example;
 
import org.eclipse.persistence.oxm.annotations.XmlDiscriminatorValue;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
 
@XmlRootElement("car-data")
@XmlDiscriminatorValue("car")
class Car {
    @XmlElement(name="number-of-doors")
    public int numberOfDoors;
    @XmlElement(name="miles-per-gallon")
    public int milesPerGallon;
}

Sample XML Instance Document

<vehicle-data vtype="car">
    <model>Mustang GT</model>
    <manufacturer>Ford</manufacturer>
    <top-speed>354</top-speed>
    <number-of-doors>2</number-of-doors>
    <miles-per-gallon>26</miles-per-gallon>
</vehicle-data>

Relationship Mapping Support

We currently support relationship mappings through @ID/@IDREF annotations, and xml-id/xml-idref metadata tags. There are a number of limitations when using these:

• ID property must be of type String
• Target class of an IDREF must have an ID property
• Since a given class can have at most one ID property, there is no way to configure composite keys

Using XmlJoinNode(s) will allow one or more properties in the target class to be used as the key for a relationship mapping.

XmlJoinNodes

Purpose

XmlJoinNodes is used to group one or more XmlJoinNode entries. Please see XmlJoinNode below for more information and examples of use.

Java Metadata

@Target({METHOD, FIELD}) 
@Retention(RUNTIME)
public @interface XmlJoinNodes {
    XmlJoinNode[] value();
}

XmlJoinNode

Purpose

XmlJoinNode identifies a key in the target object. For composite keys, XmlJoinNodes can be used.

Java Metadata

@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface XmlJoinNode {
    String name() default "";
    String referencedColumnName() default "";
    boolean unique() default false;
    boolean nullable() default true;
    boolean insertable() default true;
    boolean updatable() default true;
    String columnDefinition() default "";
    String table() default "";
}

XML Metadata

Example

TBD.

Testing

This section identifies the test package(s) for each feature outlined on this page.

XML Metadata

Annotations

Open Issues

This section lists open issues.

Decisions

This section lists decisions made. These are intended to document the resolution of open issues or constraints added to the project that are important.