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EclipseLink/UserGuide/MOXy/Runtime/Bootstrapping/From Schema
EclipseLink MOXy
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Key API
Contents
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.
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
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
If the XML schema that you use to bootstrap imports other schemas, you must configure an org.xml.sax.EntityResolver to resolve the locations of the imported schemas. You can then pass the EntityResolver to the DynamicJAXBContextFactory.
In this example, each type is defined in its own schema:
<!-- customer.xsd --> <?xml version="1.0" encoding="UTF-8"?> <xs:schema xmlns:myns="myNamespace" xmlns:add="addressNamespace" xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="myNamespace"> <xs:import namespace="addressNamespace" schemaLocation="address.xsd"/> <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="add:address"/> </xs:sequence> </xs:complexType> </xs:schema>
You must supply an EntityResolver implementation to resolve the location of the imported schema.
This sample illustrates the EntityResolver:
class MyEntityResolver implements EntityResolver { public InputSource resolveEntity(String publicId, String systemId) throws SAXException, IOException { // Imported schemas are located in ext\appdata\xsd\ // Grab only the filename part from the full path String filename = new File(systemId).getName(); // Now prepend the correct path String correctedId = "ext/appdata/xsd/" + filename; InputSource is = new InputSource(ClassLoader.getSystemResourceAsStream(correctedId)); is.setSystemId(correctedId); return is; } }
When you create the DynamicJAXBContext, pass the EntityResolver to it, as shown in this example:
InputStream inputStream = ClassLoader.getSystemResourceAsStream("com/foo/sales/xsd/customer.xsd"); DynamicJAXBContext dContext = DynamicJAXBContextFactory.createContextFromXSD(inputStream, new MyEntityResolver(), null, null);
NOTE: If you encounter the following exception when importing another shema:
Internal Exception: org.xml.sax.SAXParseException: schema_reference.4: Failed to read schema document '<imported-schema-name>', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>.
You should disable XJC's schema correctness check option, either in code:
<soucre lang="java"> System.setProperty("com.sun.tools.xjc.api.impl.s2j.SchemaCompilerImpl.noCorrectnessCheck", "true") </source>
or from the command line:
-Dcom.sun.tools.xjc.api.impl.s2j.SchemaCompilerImpl.noCorrect
Customizing Generated Mappings with EclipseLink Metadata