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Difference between revisions of "EclipseLink/DesignDocs/277920"

(Specifying the Externalized Metadata File)
 
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Line 24: Line 24:
  
 
Goals:  
 
Goals:  
 +
*Support JAXB 2.1 annotations via XML external metadata. 
 +
*Support MOXy metadata (used to extend JAXB) via external metadata.
 +
*Support the use of the XML metadata as a means to override metadata specified by annotations.
  
*Support a limited number JAXB 2.1 annotations via XML external metadata
+
Note:
 +
*This work will continue past the 2.0 release, [https://bugs.eclipse.org/bugs/show_bug.cgi?id=293925 ER 293925] will cover the work extending past the 2.0 release.
  
 
== Concepts  ==
 
== Concepts  ==
  
None to mention.  
+
* Although JAXB annotations can be applied independently they are logically linked.  For example @XmlList can only be used with XmlElement, XmlAttribute, XmlValue, XmlIDREF.  These rules will be enforced through the XML metadata.
 +
* Overriding will be handled at the property level.
  
 
== Requirements  ==
 
== Requirements  ==
Line 79: Line 84:
 
***Object Reference  
 
***Object Reference  
 
***Collection Reference
 
***Collection Reference
 +
*[http://wiki.eclipse.org/EclipseLink/DesignDocs/277920/Phase5.1 Phase #5.1 – Attachments]
 +
**Provide support for WebService attachments
  
 
== Design / Functionality  ==
 
== Design / Functionality  ==
  
 
=== XML Schema  ===
 
=== XML Schema  ===
 
==== Naming Convention  ====
 
 
 
  
 
==== Design Notes ====
 
==== Design Notes ====
Line 96: Line 99:
 
==== Annotations to XML  ====
 
==== Annotations to XML  ====
  
The following table outlines the mapping of annotations to schema components:  
+
The following table outlines how annotations relate to schema components:  
  
 
{|{{BMTableStyle}}
 
{|{{BMTableStyle}}
Line 164: Line 167:
 
| align="center" |  
 
| align="center" |  
 
|-
 
|-
| XmlBidirectional (MOXy)
+
| XmlAttributeRef
| xml-bidirectional
+
| xml-attribute-ref
| align="center" | X
+
| align="center" |
 
| align="center" |  
 
| align="center" |  
 
| align="center" |  
 
| align="center" |  
 +
| align="center" | X
 
| align="center" |  
 
| align="center" |  
 +
|-
 +
| XmlCustomizer (MOXy)
 +
| xml-customizer
 +
| align="center" |
 +
| align="center" |
 +
| align="center" |
 +
| align="center" | X
 
| align="center" |  
 
| align="center" |  
 
|-
 
|-
Line 222: Line 233:
 
| XmlList  
 
| XmlList  
 
| xml-List  
 
| xml-List  
 +
| align="center" |
 +
| align="center" |
 +
| align="center" |
 +
| align="center" | X
 +
| align="center" |
 +
|-
 +
| N/A
 +
| xml-map
 +
| align="center" | X
 +
| align="center" |
 +
| align="center" |
 +
| align="center" | 
 +
| align="center" |
 +
|-
 +
| XmlMimeType
 +
| xml-mime-type
 
| align="center" |  
 
| align="center" |  
 
| align="center" |  
 
| align="center" |  
Line 300: Line 327:
 
| align="center" |  
 
| align="center" |  
 
|}
 
|}
 
  
 
==== Schema file  ====
 
==== Schema file  ====
  
The XML schema that will be supported in EclipseLink 2.0 follows:
+
The schema file for EclipseLink 2.0 can be found in the <code>eclipselink.jar</code> here: <code>xsd\eclipselink_oxm_2_0.xsd</code>. The JAR can be downloaded on the [http://www.eclipse.org/eclipselink/downloads/nightly.php EclipseLink nightly build page].
 
+
<source lang="xml">
+
<?xml version="1.0" encoding="UTF-8"?>
+
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"
+
    targetNamespace="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" elementFormDefault="qualified"
+
    attributeFormDefault="unqualified">
+
    <xs:element name="xml-bindings">
+
        <xs:complexType>
+
            <xs:all>
+
                <xs:element ref="xml-schema" />
+
                <xs:element ref="xml-java-type-adapters" />
+
                <xs:element name="java-types">
+
                    <xs:complexType>
+
                        <xs:sequence>
+
                            <xs:element ref="java-type" maxOccurs="unbounded" />
+
                        </xs:sequence>
+
                    </xs:complexType>
+
                </xs:element>
+
            </xs:all>
+
            <xs:attribute name="xml-accessor-type" type="xml-access-type" default="PUBLIC_MEMBER" />
+
            <xs:attribute name="xml-accessor-order" type="xml-access-order" default="UNDEFINED" />
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="java-type">
+
        <xs:complexType>
+
            <xs:all>
+
                <xs:element ref="xml-type" />
+
                <xs:element ref="xml-root-element" />
+
                <xs:element ref="xml-see-also" />
+
                <xs:element ref="xml-java-type-adapter" />
+
                <xs:element name="java-attributes">
+
                    <xs:complexType>
+
                        <xs:sequence>
+
                            <xs:element ref="java-attribute" maxOccurs="unbounded" />
+
                        </xs:sequence>
+
                    </xs:complexType>
+
                </xs:element>
+
            </xs:all>
+
            <xs:attribute name="name" type="xs:string" />
+
            <xs:attribute name="xml-transient" type="xs:boolean" default="false" />
+
            <xs:attribute name="xml-customizer" type="xs:string" />
+
            <xs:attribute name="xml-accessor-type" type="xml-access-type" default="PUBLIC_MEMBER" />
+
            <xs:attribute name="xml-accessor-order" type="xml-access-order" default="UNDEFINED" />
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="java-attribute" type="java-attribute" />
+
    <xs:complexType name="java-attribute" abstract="true">
+
        <xs:attribute name="java-attribute" type="xs:string" />
+
    </xs:complexType>
+
 
+
    <!-- Enums -->
+
    <xs:simpleType name="xml-access-order">
+
        <xs:restriction base="xs:string">
+
            <xs:enumeration value="ALPHABETICAL" />
+
            <xs:enumeration value="UNDEFINED" />
+
        </xs:restriction>
+
    </xs:simpleType>
+
    <xs:simpleType name="xml-access-type">
+
        <xs:restriction base="xs:string">
+
            <xs:enumeration value="FIELD" />
+
            <xs:enumeration value="NONE" />
+
            <xs:enumeration value="PROPERTY" />
+
            <xs:enumeration value="PUBLIC_MEMBER" />
+
        </xs:restriction>
+
    </xs:simpleType>
+
    <xs:simpleType name="xml-ns-form">
+
        <xs:restriction base="xs:string">
+
            <xs:enumeration value="UNQUALIFIED" />
+
            <xs:enumeration value="QUALIFIED" />
+
            <xs:enumeration value="UNSET" />
+
        </xs:restriction>
+
    </xs:simpleType>
+
 
+
    <!-- @Target(value=PACKAGE) -->
+
    <xs:element name="xml-schema">
+
        <xs:complexType>
+
            <xs:sequence>
+
                <xs:element name="xml-ns" minOccurs="0" maxOccurs="unbounded">
+
                    <xs:complexType>
+
                        <xs:attribute name="namespace-uri" type="xs:string" />
+
                        <xs:attribute name="prefix" type="xs:string" />
+
                    </xs:complexType>
+
                </xs:element>
+
            </xs:sequence>
+
            <xs:attribute name="attribute-form-default" type="xml-ns-form" default="UNSET" />
+
            <xs:attribute name="element-form-default" type="xml-ns-form" default="UNSET" />
+
            <xs:attribute name="location" type="xs:string" />
+
            <xs:attribute name="namespace" type="xs:string" />
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-java-type-adapters">
+
        <xs:complexType>
+
            <xs:sequence>
+
                <xs:element ref="xml-java-type-adapter" maxOccurs="unbounded" />
+
            </xs:sequence>
+
        </xs:complexType>
+
    </xs:element>
+
 
+
    <!-- @Target(value={PACKAGE,FIELD,METHOD,TYPE,PARAMETER}) -->
+
    <xs:element name="xml-java-type-adapter" substitutionGroup="java-attribute">
+
        <xs:complexType>
+
            <xs:complexContent>
+
                <xs:extension base="java-attribute">
+
                    <xs:attribute name="value" type="xs:string" />
+
                    <xs:attribute name="type" type="xs:string" default="javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter.DEFAULT" />
+
                </xs:extension>
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
 
+
    <!-- @Target(value={FIELD,METHOD,TYPE}) -->
+
    <xs:element name="xml-transient" substitutionGroup="java-attribute">
+
        <xs:complexType>
+
            <xs:complexContent>
+
                <xs:extension base="java-attribute" />
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
 
+
    <!-- @Target(value=TYPE) -->
+
    <xs:element name="xml-type">
+
        <xs:complexType>
+
            <xs:attribute name="name" type="xs:string" default="##default" />
+
            <xs:attribute name="namespace" type="xs:string" default="##default" />
+
            <xs:attribute name="prop-order">
+
                <xs:simpleType>
+
                    <xs:list itemType="xs:string" />
+
                </xs:simpleType>
+
            </xs:attribute>
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-root-element">
+
        <xs:complexType>
+
            <xs:attribute name="name" type="xs:string" default="##default" />
+
            <xs:attribute name="namespace" type="xs:string" default="##default" />
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-see-also">
+
        <xs:simpleType>
+
            <xs:list itemType="xs:string" />
+
        </xs:simpleType>
+
    </xs:element>
+
 
+
    <!-- @Target(value={FIELD,METHOD}) -->
+
    <xs:element name="xml-any-attribute" substitutionGroup="java-attribute">
+
        <xs:complexType>
+
            <xs:complexContent>
+
                <xs:extension base="java-attribute" />
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-attribute" substitutionGroup="java-attribute">
+
        <xs:complexType>
+
            <xs:complexContent>
+
                <xs:extension base="java-attribute">
+
                    <xs:all>
+
                        <xs:element ref="xml-java-type-adapter" />
+
                        <xs:element ref="xml-bidirectional" />
+
                    </xs:all>
+
                    <xs:attribute name="name" type="xs:string" default="##default" />
+
                    <xs:attribute name="namespace" type="xs:string" default="##default" />
+
                    <xs:attribute name="required" type="xs:boolean" default="false" />
+
                    <xs:attribute name="xml-id" type="xs:boolean" default="false" />
+
                    <xs:attribute name="xml-idref" type="xs:boolean" default="false" />
+
                    <xs:attribute name="xml-list" type="xs:boolean" default="false" />
+
                </xs:extension>
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-any-element" substitutionGroup="java-attribute">
+
        <xs:complexType>fckLR            <xs:complexContent>
+
                <xs:extension base="java-attribute">
+
                    <xs:all>
+
                        <xs:element ref="xml-java-type-adapter" />
+
                    </xs:all>
+
                    <xs:attribute name="xml-mixed" type="xs:boolean" default="false" />
+
                    <xs:attribute name="lax" type="xs:boolean" default="false" />
+
                    <xs:attribute name="dom-handler" type="xs:string" default="javax.xml.bind.annotation.W3CDomHandler" />
+
                </xs:extension>
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-element" substitutionGroup="java-attribute">
+
        <xs:complexType>
+
            <xs:complexContent>
+
                <xs:extension base="java-attribute">
+
                    <xs:all>
+
                        <xs:element ref="xml-element-wrapper" />
+
                        <xs:element ref="xml-java-type-adapter" />
+
                        <xs:element ref="xml-bidirectional" />
+
                    </xs:all>
+
                    <xs:attribute name="name" type="xs:string" default="##default" />
+
                    <xs:attribute name="namespace" type="xs:string" default="##default" />
+
                    <xs:attribute name="default-value" type="xs:string" />
+
                    <xs:attribute name="nillable" type="xs:boolean" default="false" />
+
                    <xs:attribute name="required" type="xs:boolean" default="false" />
+
                    <xs:attribute name="type" type="xs:string" default="javax.xml.bind.annotation.XmlElement.DEFAULT" />
+
                    <xs:attribute name="xml-id" type="xs:boolean" default="false" />
+
                    <xs:attribute name="xml-idref" type="xs:boolean" default="false" />
+
                    <xs:attribute name="xml-list" type="xs:boolean" default="false" />
+
                </xs:extension>
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-element-wrapper">
+
        <xs:complexType>
+
            <xs:attribute name="name" type="xs:string" default="##default" />
+
            <xs:attribute name="namespace" type="xs:string" default="##default" />
+
            <xs:attribute name="nillable" type="xs:boolean" default="false" />
+
            <xs:attribute name="required" type="xs:boolean" default="false" />
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-value" substitutionGroup="java-attribute">
+
        <xs:complexType>
+
            <xs:complexContent>
+
                <xs:extension base="java-attribute" />
+
            </xs:complexContent>
+
        </xs:complexType>
+
    </xs:element>
+
    <xs:element name="xml-bidirectional">
+
        <xs:complexType>
+
            <xs:attribute name="target-attribute" type="xs:string" />
+
        </xs:complexType>
+
    </xs:element>
+
</xs:schema>
+
</source>
+
  
 
==== XML Bindings  ====
 
==== XML Bindings  ====
  
A given XML metadata bindings file will correspond to a single package. This association is made by using the package name for the key in the properties map that is passed in to the JAXBContext. See [http://wiki.eclipse.org/EclipseLink/DesignDocs/277920#Boot_Strapping below] for information on boot strapping the JAXBContext. The bindings file may contain information that applies to the entire package, as well as class-specific information. The <code>java-type</code> element is used for a java class. Each <code>java-type</code> may have a number of attributes and sub-elements set (refer to the [http://wiki.eclipse.org/EclipseLink/DesignDocs/277920#Schema_file XML Schema] above for more information) as well as zero or more <code>java-attributes</code>. A <code>java-attribute</code> corresponds to a property (field/method). In order to handle various settings applicable to a given property, a number of <code>java-attribute</code> extensions exist:  
+
A given XML metadata bindings file will correspond to a single package. This association is made by using the package name for the key in the properties map that is passed in to the JAXBContext. See [http://wiki.eclipse.org/EclipseLink/DesignDocs/277920#Boot_Strapping below] for information on boot strapping the JAXBContext. The bindings file may contain information that applies to the entire package, as well as class-specific information. The <code>java-type</code> element is used for a java class. Each <code>java-type</code> may have a number of attributes and elements set (refer to the [http://wiki.eclipse.org/EclipseLink/DesignDocs/277920#Schema_file XML Schema] above for more information) as well as zero or more <code>java-attributes</code>. A <code>java-attribute</code> corresponds to a property (field/method). In order to handle various settings applicable to a given property, a number of <code>java-attribute</code> extensions exist:  
  
 
*xml-java-type-adapter  
 
*xml-java-type-adapter  
Line 582: Line 382:
 
   </java-types>
 
   </java-types>
 
</xml-bindings>
 
</xml-bindings>
</source>  
+
</source>
  
 
=== Boot Strapping  ===
 
=== Boot Strapping  ===
Line 588: Line 388:
 
==== Specifying the Externalized Metadata File  ====
 
==== Specifying the Externalized Metadata File  ====
  
The externalized metadata file (one per package) can be passed in through a property when creating the JAXBContext.  
+
The externalized metadata file (one per package) can be passed in through a property when creating the JAXBContext.  Prior to EclipseLink 2.2 the only supported input format for specifying the externalized metadata file(s) was <code>Map<String, Source></code>.  For EclipseLink 2.2, however, the following will be supported:
 +
* Map<String, Object>
 +
** String is the package name
 +
** Object is one of File, Reader, etc. listed below
 +
* List<Object>
 +
** Object is one of File, Reader, etc. listed below
 +
** Package name is set via <code>package-name</code> attribute on <code>xml-bindings</code> element in the bindings file.
 +
* One of:
 +
** java.io.File
 +
** java.io.InputStream
 +
** java.io.Reader
 +
** java.net.URL
 +
** javax.xml.stream.XMLEventReader
 +
** javax.xml.stream.XMLStreamReader
 +
** javax.xml.transform.Source
 +
** org.w3c.dom.Node
 +
** org.xml.sax.InputSource
 +
** --
 +
** Package name is set via <code>package-name</code> attribute on <code>xml-bindings</code> element in the bindings file.
  
 +
==== Example:  Map<String, Object> ====
 
<source lang="java">
 
<source lang="java">
 
InputStream employeeExternalizedMetadata =  
 
InputStream employeeExternalizedMetadata =  
Line 613: Line 432:
 
classes[1] = Employee.class;
 
classes[1] = Employee.class;
 
JAXBContext.newInstance(classes, properties);
 
JAXBContext.newInstance(classes, properties);
</source>  
+
</source>
 +
 
 +
==== Example:  List<Object> ====
 +
<source lang="java">
 +
List<Object> inputFiles = new ArrayList<Object>();
 +
inputFiles.add(new java.io.File("org/example/employee/metadata.xml"));
 +
inputFiles.add(new java.io.FileInputStream("org/example/customer/metadata.xml"));
 +
 
 +
Map<String, Object> properties = new HashMap<String, Object>();
 +
properties.put("eclipselink-oxm-xml", inputFiles);
 +
 
 +
Class[] classes = new Class[] { org.example.employee.Employee.class, org.example.customer.Customer.class };
 +
 
 +
JAXBContext.newInstance(classes, properties);
 +
</source>
 +
 
 +
Following shows sample externalized metadata files for Employee and Customer:
 +
===== org/example/employee/metadata.xml =====
 +
<source lang="xml">
 +
<?xml version="1.0" encoding="US-ASCII"?>
 +
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" package-name="org.example.employee">
 +
    <java-types>
 +
        <java-type name="Employee">
 +
            <xml-root-element name="emp"/>
 +
            <java-attributes>
 +
                <xml-attribute java-attribute="id"/>
 +
            </java-attributes>
 +
        </java-type>
 +
    </java-types>
 +
</xml-bindings>
 +
</source>
 +
===== org/example/customer/metadata.xml =====
 +
<source lang="xml">
 +
<?xml version="1.0" encoding="US-ASCII"?>
 +
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" package-name="org.example.customer">
 +
    <java-types>
 +
        <java-type name="Customer">
 +
            <xml-root-element name="cust"/>
 +
            <java-attributes>
 +
                <xml-attribute java-attribute="id"/>
 +
            </java-attributes>
 +
        </java-type>
 +
    </java-types>
 +
</xml-bindings>
 +
</source>
 +
 
 +
==== Example:  java.io.File ====
 +
<source lang="java">
 +
Map<String, Object> properties = new HashMap<String, Object>();
 +
properties.put("eclipselink-oxm-xml", new java.io.File("org/example/customer/metadata.xml")));
 +
 
 +
Class[] classes = new Class[] { org.example.customer.Customer.class };
 +
 
 +
JAXBContext.newInstance(classes, properties);
 +
</source>
 +
 
 +
Following shows a sample externalized metadata file for Customer:
 +
===== org/example/customer/metadata.xml =====
 +
<source lang="xml">
 +
<?xml version="1.0" encoding="US-ASCII"?>
 +
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" package-name="org.example.customer">
 +
    <java-types>
 +
        <java-type name="Customer">
 +
            <xml-root-element name="cust"/>
 +
            <java-attributes>
 +
                <xml-attribute java-attribute="id"/>
 +
            </java-attributes>
 +
        </java-type>
 +
    </java-types>
 +
</xml-bindings>
 +
</source>
  
 
== Testing  ==
 
== Testing  ==
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This section lists the open issues that are still pending that must be decided prior to fully implementing this project's requirements.  
 
This section lists the open issues that are still pending that must be decided prior to fully implementing this project's requirements.  
  
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This section lists decisions made. These are intended to document the resolution of open issues or constraints added to the project that are important.  
 
This section lists decisions made. These are intended to document the resolution of open issues or constraints added to the project that are important.  
  
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! Description / Notes  

Latest revision as of 12:38, 25 November 2010

Design Specification: OXM XSD

ER 277920

Document History

Date Author Version Description & Notes
2009/05/26 Blaise Doughan Skeleton
2009/11/09 David McCann Added information pertaining to JAXB annotation support design phases. Moving phases 6 - 10, WebService support and OXM mapping support to design document for ER 293925

Project overview

Goals:

  • Support JAXB 2.1 annotations via XML external metadata.
  • Support MOXy metadata (used to extend JAXB) via external metadata.
  • Support the use of the XML metadata as a means to override metadata specified by annotations.

Note:

  • This work will continue past the 2.0 release, ER 293925 will cover the work extending past the 2.0 release.

Concepts

  • Although JAXB annotations can be applied independently they are logically linked. For example @XmlList can only be used with XmlElement, XmlAttribute, XmlValue, XmlIDREF. These rules will be enforced through the XML metadata.
  • Overriding will be handled at the property level.

Requirements

The following sections will expand the goals of this project into more concrete requirements.

Design Constraints

JAXB Annotations

The XML should have the same feel as the JAXB annotations.

javax.xml.bind.annotation Javadoc

EclipseLink JPA Metadata

The XML should have the same feel as the equivalent XML for EclipseLink JPA

EclipseLink JPA XSD

EclipseLink MOXy Metadata

The metadata that will be available in EclipseLink 2.0 is outlined below.

Design Phases

JAXB 2.1 annotation support via XML external metadata

This support will be added as outlined in the following phases:

Design / Functionality

XML Schema

Design Notes

  • The XML names are based directly on the corresponding annotation name. The annotation name is lower cased, and hyphens ('-') are used as separators between each word in the name. For example, the annotation XmlJavaTypeAdapter would correspond to xml-java-type-adapter in XML.
  • Where applicable xs:all is used instead of xs:sequence, such that specific ordering is not required. This is done to avoid placing an unnecessary requirement on the user.
  • To facilitate metadata processing, more specifically to align with MOXy mapping creation, where possible any single valued information (boolean, String, etc.) will be mapped as an attribute in the schema. Other items with multiple values will be mapped as sub-elements.

Annotations to XML

The following table outlines how annotations relate to schema components:

Annotation XML Global Element Global Attribute Local Element Local Attribute Enum
XmlAccessOrder xml-access-order X
XmlAccessorOrder xml-accessor-order X
XmlAccessorType xml-accessor-type X
XmlAccessType xml-access-type X
XmlAnyAttribute xml-any-attribute X
XmlAnyElement xml-any-element X
XmlAttribute xml-attribute X
XmlAttributeRef xml-attribute-ref X
XmlCustomizer (MOXy) xml-customizer X
XmlElement xml-element X
XmlElementWrapper xml-element-wrapper X
XmlID xml-id X
XmlIDREF xml-idref X
XmlJavaTypeAdapter xml-java-type-adapter X
XmlJavaTypeAdapters xml-java-type-adapters X
XmlList xml-List X
N/A xml-map X
XmlMimeType xml-mime-type X
XmlMixed xml-mixed X
XmlNs xml-ns X
XmlNsForm xml-ns-form X
XmlRootElement xml-root-element X
XmlSchema xml-schema X
XmlSeeAlso xml-see-also X
XmlTransient xml-transient X
XmlType xml-type X
XmlValue xml-value X

Schema file

The schema file for EclipseLink 2.0 can be found in the eclipselink.jar here: xsd\eclipselink_oxm_2_0.xsd. The JAR can be downloaded on the EclipseLink nightly build page.

XML Bindings

A given XML metadata bindings file will correspond to a single package. This association is made by using the package name for the key in the properties map that is passed in to the JAXBContext. See below for information on boot strapping the JAXBContext. The bindings file may contain information that applies to the entire package, as well as class-specific information. The java-type element is used for a java class. Each java-type may have a number of attributes and elements set (refer to the XML Schema above for more information) as well as zero or more java-attributes. A java-attribute corresponds to a property (field/method). In order to handle various settings applicable to a given property, a number of java-attribute extensions exist:

  • xml-java-type-adapter
  • xml-transient
  • xml-any-attribute
  • xml-attribute
  • xml-any-element
  • xml-element
  • xml-value
Example

Following is a simple example showing java-attribute use in a bindings file. Here, the 'id' property is set as an attribute and made required, the 'name' property is renamed 'employee-name', and the 'thing' property is set transient. Note that the 'java-attribute' attribute in each corresponds to the field name or method name (for methods, is/set/get is stripped off and the first letter is lower cased).

org.example.Employee.java
package org.example;
 
public class Employee {
    public int id;
    public String name;
    private Object theThing;
 
    public void setThing(Object theThing) {
        this.theThing = theThing;
    }
    public Object getThing() { 
        return theThing;
    }
}
eclipselink-oxm.xml
<?xml version="1.0" encoding="US-ASCII"?>
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm">
  <java-types>
    <java-type name="org.example.Employee">
      <java-attributes>
        <xml-attribute java-attribute="id" required="true" />
        <xml-element java-attribute="name" name="employee-name" />
        <xml-transient java-attribute="thing" />
      </java-attributes>
    </java-type>
  </java-types>
</xml-bindings>

Boot Strapping

Specifying the Externalized Metadata File

The externalized metadata file (one per package) can be passed in through a property when creating the JAXBContext. Prior to EclipseLink 2.2 the only supported input format for specifying the externalized metadata file(s) was Map<String, Source>. For EclipseLink 2.2, however, the following will be supported:

  • Map<String, Object>
    • String is the package name
    • Object is one of File, Reader, etc. listed below
  • List<Object>
    • Object is one of File, Reader, etc. listed below
    • Package name is set via package-name attribute on xml-bindings element in the bindings file.
  • One of:
    • java.io.File
    • java.io.InputStream
    • java.io.Reader
    • java.net.URL
    • javax.xml.stream.XMLEventReader
    • javax.xml.stream.XMLStreamReader
    • javax.xml.transform.Source
    • org.w3c.dom.Node
    • org.xml.sax.InputSource
    • --
    • Package name is set via package-name attribute on xml-bindings element in the bindings file.

Example: Map<String, Object>

InputStream employeeExternalizedMetadata = 
     aClassLoader.getResourceAsStream("org/example/employee/metadata.xml";
InputStream customerExternalizedMetadata = 
     aClassLoader.getResourceAsStream("org/example/customer/metadata.xml";
 
HashMap<String, Source> metadataSourceMap = new HashMap<String, Source>();
metadataSourceMap.put("org.example.employee", new StreamSource(employeeExternalizedMetadata));
metadataSourceMap.put("org.example.customer", new StreamSource(customerExternalizedMetadata));
 
Map<String, Map<String, Source>> properties = new HashMap<String, Map<String, Source>>();
properties.put("eclipselink-oxm-xml", metadataSourceMap);
 
JAXBContext.newInstance("org.example.customer:org.example.employee", aClassLoader, properties);

Following is an example of how to pass in the property when creating the JAXBContext based on an array of classes:

Class[] classes = new Class[2];
classes[0] = Customer.class;
classes[1] = Employee.class;
JAXBContext.newInstance(classes, properties);

Example: List<Object>

List<Object> inputFiles = new ArrayList<Object>();
inputFiles.add(new java.io.File("org/example/employee/metadata.xml"));
inputFiles.add(new java.io.FileInputStream("org/example/customer/metadata.xml"));
 
Map<String, Object> properties = new HashMap<String, Object>();
properties.put("eclipselink-oxm-xml", inputFiles);
 
Class[] classes = new Class[] { org.example.employee.Employee.class, org.example.customer.Customer.class };
 
JAXBContext.newInstance(classes, properties);

Following shows sample externalized metadata files for Employee and Customer:

org/example/employee/metadata.xml
<?xml version="1.0" encoding="US-ASCII"?>
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" package-name="org.example.employee">
    <java-types>
        <java-type name="Employee">
            <xml-root-element name="emp"/>
            <java-attributes>
                <xml-attribute java-attribute="id"/>
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>
org/example/customer/metadata.xml
<?xml version="1.0" encoding="US-ASCII"?>
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" package-name="org.example.customer">
    <java-types>
        <java-type name="Customer">
            <xml-root-element name="cust"/>
            <java-attributes>
                <xml-attribute java-attribute="id"/>
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

Example: java.io.File

Map<String, Object> properties = new HashMap<String, Object>();
properties.put("eclipselink-oxm-xml", new java.io.File("org/example/customer/metadata.xml")));
 
Class[] classes = new Class[] { org.example.customer.Customer.class };
 
JAXBContext.newInstance(classes, properties);

Following shows a sample externalized metadata file for Customer:

org/example/customer/metadata.xml
<?xml version="1.0" encoding="US-ASCII"?>
<xml-bindings xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm" package-name="org.example.customer">
    <java-types>
        <java-type name="Customer">
            <xml-root-element name="cust"/>
            <java-attributes>
                <xml-attribute java-attribute="id"/>
            </java-attributes>
        </java-type>
    </java-types>
</xml-bindings>

Testing

API

GUI

Config files

Documentation

Open Issues

This section lists the open issues that are still pending that must be decided prior to fully implementing this project's requirements.

Issue # Owner Description / Notes

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.

Issue # Description / Notes Decision

Future Considerations

During the research for this project the following items were identified as out of scope but are captured here as potential future enhancements. If agreed upon during the review process these should be logged in the bug system.