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Difference between revisions of "EclipseLink/UserGuide/MOXy/Runtime/Bootstrapping/From Schema"

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With EclipseLink MOXy, you can provide an existing XML schema from which to create a '''DynamicJAXBContext'''. EclipseLink will parse the schema and generate '''DynamicTypes''' for each complex type.  
 
With EclipseLink MOXy, you can provide an existing XML schema from which to create a '''DynamicJAXBContext'''. EclipseLink will parse the schema and generate '''DynamicTypes''' for each complex type.  
  
As with conventional JAXB, the first step is to create a '''JAXBContext'''. This is achieved by use of the '''DynamicJAXBContextFactory''' class. A '''DynamicJAXBContext''' ''cannot'' be instantiated directly; it must be created through the factory API.
+
This is achieved by use of the '''DynamicJAXBContextFactory''' class. A '''DynamicJAXBContext''' ''cannot'' be instantiated directly; it must be created through the factory API.
  
 
EclipseLink MOXy uses Sun's XJC (XML-to-Java Compiler) APIs to parse the schema into an in-memory representation and  generate dynamic types and mappings.  
 
EclipseLink MOXy uses Sun's XJC (XML-to-Java Compiler) APIs to parse the schema into an in-memory representation and  generate dynamic types and mappings.  

Revision as of 14:43, 15 March 2011

EclipseLink MOXy

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Bootstrapping from XML Schema (XSD)

With EclipseLink MOXy, you can provide an existing XML schema from which to create a DynamicJAXBContext. EclipseLink will parse the schema and generate DynamicTypes for each complex type.

This is achieved by use of the DynamicJAXBContextFactory class. A DynamicJAXBContext cannot be instantiated directly; it must be created through the factory API.

EclipseLink MOXy uses Sun's XJC (XML-to-Java Compiler) APIs to parse the schema into an in-memory representation and generate dynamic types and mappings.

Idea.png
When bootstrapping from XSD, you will need to include jaxb-xjc.jar (from the JAXB reference implementation) on your CLASSPATH.



You can pass the XML Schema to DynamicJAXBContextFactory by using:

  • java.io.InputStream
  • org.w3c.dom.Node
  • javax.xml.transform.Source

The following example demonstrates these methods:

/**
 * Create a DynamicJAXBContext, using XML Schema as the metadata source.
 *
 * @param schemaStream
 *      java.io.InputStream from which to read the XML Schema.
 * @param resolver
 *      An org.xml.sax.EntityResolver, used to resolve schema imports.  Can be null.
 * @param classLoader
 *      The application's current class loader, which will be used to first lookup
 *      classes to see if they exist before new DynamicTypes are generated.  Can be
 *      null, in which case Thread.currentThread().getContextClassLoader() will be used.
 * @param properties
 *      Map of properties to use when creating a new DynamicJAXBContext.  Can be null.
 *
 * @return
 *      A new instance of DynamicJAXBContext.
 *
 * @throws JAXBException
 *      if an error was encountered while creating the DynamicJAXBContext.
 */
public static DynamicJAXBContext createContextFromXSD(java.io.InputStream schemaStream, EntityResolver resolver,
   ClassLoader classLoader, Map<String, ?> properties) throws JAXBException
 
public static DynamicJAXBContext createContextFromXSD(org.w3c.dom.Node schemaDOM, EntityResolver resolver,
   ClassLoader classLoader, Map<String, ?> properties) throws JAXBException
 
public static DynamicJAXBContext createContextFromXSD(javax.xml.transform.Source schemaSource, EntityResolver resolver,
   ClassLoader classLoader, Map<String, ?> properties) throws JAXBException


Idea.png
The classLoader parameter is your application's current class loader, and will be used to first lookup classes to see if they exist before new DynamicTypes are generated. The user may pass in null for this parameter, and Thread.currentThread().getContextClassLoader() will be used instead.



Example

This example shows how to create and marshall a new object using Dynamic MOXy.


Sample XML Schema:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="mynamespace" xmlns:myns="mynamespace" xmlns:xs="http://www.w3.org/2001/XMLSchema"
    attributeFormDefault="qualified" elementFormDefault="qualified">
 
    <xs:element name="customer" type="myns:customer"/>
 
    <xs:complexType name="customer">
        <xs:sequence>
            <xs:element name="first-name" type="xs:string"/>
            <xs:element name="last-name" type="xs:string"/>
            <xs:element name="address" type="myns:address"/>
        </xs:sequence>
    </xs:complexType>
 
    <xs:complexType name="address">
        <xs:sequence>
            <xs:element name="street" type="xs:string"/>
            <xs:element name="city" type="xs:string"/>
            <xs:element name="province" type="xs:string"/>
            <xs:element name="postal-code" type="xs:string"/>
        </xs:sequence>
    </xs:complexType>
 
</xs:schema>

The following code:

  • Passes the XML Schema to DynamicJAXBContextFactory to create a DynamicJAXBContext
  • Creates new DynamicEntities and setting their properties
  • Creates a JAXBMarshaller and marshalling the Java objects to XML
InputStream inputStream = myClassLoader.getSystemResourceAsStream("mynamespace/resources/xsd/customer.xsd");
DynamicJAXBContext dContext = DynamicJAXBContextFactory.createContextFromXSD(inputStream, null, myClassLoader, null);
 
DynamicEntity newCustomer = dContext.newDynamicEntity("mynamespace.Customer");
newCustomer.set("firstName", "George");
newCustomer.set("lastName", "Jones");
 
DynamicEntity newAddress = dContext.newDynamicEntity("mynamespace.Address");
newAddress.set("street", "227 Main St.");
newAddress.set("city", "Toronto");
newAddress.set("province", "Ontario");
newAddress.set("postalCode", "M5V1E6");
 
newCustomer.set("address", newAddress);
 
dContext.createMarshaller().marshal(newCustomer, System.out);


Importing other Schemas / EntityResolvers


Customizing Generated Mappings with EclipseLink Metadata


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Version: 2.2.0 - DRAFT
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