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Difference between revisions of "EclipseLink/Development/DBWS/MetadataSupport"
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==== org.eclipse.persistence.tools.dbws.XmlBindingsGenerator ==== | ==== org.eclipse.persistence.tools.dbws.XmlBindingsGenerator ==== | ||
This class is responsible for generating one or more <code><xml-bindings></code> elements (one per package) based on a given list of Descriptor instances - these elements will make up the JAXB metadata file. The following OX mappings must be supported: | This class is responsible for generating one or more <code><xml-bindings></code> elements (one per package) based on a given list of Descriptor instances - these elements will make up the JAXB metadata file. The following OX mappings must be supported: | ||
− | *XMLBinaryDataMapping | + | *<code>XMLBinaryDataMapping</code> |
− | *XMLCompositeCollectionMapping | + | *<code>XMLCompositeCollectionMapping</code> |
− | *XMLCompositeDirectCollectionMapping | + | *<code>XMLCompositeDirectCollectionMapping</code> |
− | *XMLCompositeObjectMapping | + | *<code>XMLCompositeObjectMapping</code> |
− | *XMLDirectMapping | + | *<code>XMLDirectMapping</code> |
The following API is required: | The following API is required: | ||
<source lang="java"> | <source lang="java"> |
Revision as of 14:19, 4 January 2013
Contents
- 1 Design document for adding JPA/JAXB metadata support to DBWS
- 1.1 Overview
- 1.2 Requirements
- 1.3 JAXB Metadata support
- 1.3.1 org.eclipse.persistence.internal.xr.XmlBindingsModel
- 1.3.2 org.eclipse.persistence.tools.dbws.XmlBindingsGenerator
- 1.3.3 org.eclipse.persistence.internal.xr.XRServiceFactory$DBWSMetadataSource
- 1.3.4 Example: XmlBindings list generation and marshal operation
- 1.3.5 Example: Unmarshal a JAXB metadata file and use DynamicJAXBContext to retrieve the resulting OX Project
Design document for adding JPA/JAXB metadata support to DBWS
The purpose of this document is to outline what changes are to be made to the DBWS codebase to allow support for reading/writing JPA/JAXB metadata in place of EclipseLink deployment XML. This feature is required to resolve EclipseLink Bug 332227.
Overview
The DBWS builder constructs OR/OX projects, which are marshalled to a given output stream by the builder and placed in a generated .war archive for use by the DBWS runtime. The builder currently utilizes the legacy EclipseLink deployment XML format for this purpose, but is required to move to the modern JPA/JAXB metadata format.
Requirements
- Support generation and marshal of JPA and JAXB metadata files in the DBWS builder
- Support unmarshal of JPA and JAXB metadata files in the DBWS runtime
- Support unmarshal of legacy OR/OX deployment XML for backward compatibility
JAXB Metadata support
The existing DBWS builder code utilizes the ObjectPersistenceWorkbenchXMLProject
class to marshal the OX project at design time and unmarshal it at runtime. The code will be changed to instead use JAXB metadata for these operations. The following pages contain information pertaining to EclipseLink's support for JAXB annotations via XML metadata:
- http://wiki.eclipse.org/EclipseLink/DesignDocs/277920
- http://wiki.eclipse.org/EclipseLink/DesignDocs/293925
- http://wiki.eclipse.org/EclipseLink/DesignDocs/293925/MOXyExtensions
The DBWS builder creates an OX project; this project's descriptors - and each descriptor's mappings - will be used to generate one or more <xml-bindings>
elements (one per package) that make up the JAXB metadata file. Three classes are needed to accomplish this task:
XmlBindingsModel
- used to create a JAXB context that can be used to marshal/unmarshal the metadata file.XmlBindingsGenerator
- generates one or more<xml-bindings>
elements (one per package) based on a list of Descriptor instancesDBWSMetadataSource
- implementation oforg.eclipse.persistence.jaxb.metadata.MetadataSource
to allow passingorg.eclipse.persistence.jaxb.xmlmodel.XmlBindings
to aorg.eclipse.persistence.jaxb.dynamic.DynamicJAXBContextFactory
instance
The generated metadata file will have the format:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <xml-bindings-list xmlns="http://www.eclipse.org/eclipselink/xsds/persistence/oxm"> <xml-bindings package-name="simpletable"> ... </xml-bindings> <xml-bindings package-name="complextable"> ... </xml-bindings> ... </xml-bindings-list>
org.eclipse.persistence.internal.xr.XmlBindingsModel
The XmlBindingsModel
class will be used to create a JAXBContext
instance that is able to marshal and unmarshal the generated JAXB metadata file.
/** * This class is responsible for holding a list of XmlBindings. * */ @XmlAccessorType(javax.xml.bind.annotation.XmlAccessType.FIELD) @XmlRootElement(name="xml-bindings-list", namespace="http://www.eclipse.org/eclipselink/xsds/persistence/oxm") public class XmlBindingsModel { @XmlElement(name="xml-bindings", namespace="http://www.eclipse.org/eclipselink/xsds/persistence/oxm") public List<XmlBindings> bindingsList; /** * Return the list of XmlBindings */ public List<XmlBindings> getBindingsList() { return bindingsList; } /** * Set the list of XmlBindings. */ public void setBindingsList(List<XmlBindings> bindingsList) { this.bindingsList = bindingsList; } }
org.eclipse.persistence.tools.dbws.XmlBindingsGenerator
This class is responsible for generating one or more <xml-bindings>
elements (one per package) based on a given list of Descriptor instances - these elements will make up the JAXB metadata file. The following OX mappings must be supported:
XMLBinaryDataMapping
XMLCompositeCollectionMapping
XMLCompositeDirectCollectionMapping
XMLCompositeObjectMapping
XMLDirectMapping
The following API is required:
/** * Generate one or more XmlBindings based on a given list of * ClassDescriptor instances. * */ public static List<XmlBindings> generateXmlBindings(List<ClassDescriptor> descriptors)
/** * Generate an XmlBindings instance based on a list of XML descriptors. * * OXM metadata files are processed on a per package basis, hence it is * assumed that the given list of descriptors are from the same package. * */ public static XmlBindings generateXmlBindings(String packageName, List<XMLDescriptor> descriptors)
org.eclipse.persistence.internal.xr.XRServiceFactory$DBWSMetadataSource
This inner class holds on to an org.eclipse.persistence.jaxb.xmlmodel.XmlBindings
instance, allowing it to be passed to the DynamicJAXBContextFactory.
/** * Implementation of MetadataSource to allow passing XmlBindings * to the DynamicJAXBContextFactory * */ public class DBWSMetadataSource implements MetadataSource { XmlBindings xmlbindings; public DBWSMetadataSource(XmlBindings bindings) { xmlbindings = bindings; } @Override public XmlBindings getXmlBindings(Map<String, ?> properties, ClassLoader classLoader) { return xmlbindings; } }
Example: XmlBindings
list generation and marshal operation
The following example illustrates how the XmlBindingsGenerator
can be used to generate a list of org.eclipse.persistence.jaxb.xmlmodel.XmlBindings
instances, and how this list can be marshalled to a given output stream:
List<XmlBindings> xmlBindingsList = XmlBindingsGenerator.generateXmlBindings(oxProject.getOrderedDescriptors()); if (xmlBindingsList.size() > 0) { XmlBindingsModel model = new XmlBindingsModel(); model.setBindingsList(xmlBindingsList); try { JAXBContext jc = JAXBContext.newInstance(XmlBindingsModel.class); Marshaller marshaller = jc.createMarshaller(); marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true); marshaller.marshal(model, dbwsOxStream); } catch (JAXBException jaxbEx) { throw new DBWSException(OXM_MARSHAL_EX_MSG, jaxbEx); } }
Note that the existing marshal code in BaseDBWSBuilderHelper.writeOrOxProjects
should be removed and the above code (or similar) should be used.
Example: Unmarshal a JAXB metadata file and use DynamicJAXBContext to retrieve the resulting OX Project
The following example illustrates how DBWS generated JAXB metadata can be unmarshalled to an XmlBindingsModel
, and how this can be used with DynamicJAXBContext
to retrieve the OX Project.
Map<String, DBWSMetadataSource> metadataMap = new HashMap<String, DBWSMetadataSource>(); StreamSource xml = new StreamSource(inStream); try { JAXBContext jc = JAXBContext.newInstance(XmlBindingsModel.class); Unmarshaller unmarshaller = jc.createUnmarshaller(); JAXBElement<XmlBindingsModel> jaxbElt = unmarshaller.unmarshal(xml, XmlBindingsModel.class); XmlBindingsModel model = jaxbElt.getValue(); for (XmlBindings xmlBindings : model.getBindingsList()) { metadataMap.put(xmlBindings.getPackageName(), new DBWSMetadataSource(xmlBindings)); } } catch (JAXBException jaxbex) { throw new DBWSException(OXM_PROCESSING_EX, jaxbex); } Map<String, Map<String, DBWSMetadataSource>> properties = new HashMap<String, Map<String, DBWSMetadataSource>>(); properties.put(JAXBContextProperties.OXM_METADATA_SOURCE, metadataMap); try { DynamicJAXBContext jCtx = DynamicJAXBContextFactory.createContextFromOXM(xrdecl, properties); oxProject = jCtx.getXMLContext().getSession(0).getProject(); } catch (JAXBException e) { throw new DBWSException(OXM_PROCESSING_EX, e); }
Note that the existing unmarshal code in XRServiceFactory.buildSessions
should be removed and the above code (or similar) should be used.