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Difference between revisions of "EclipseLink/Development/2.1/DynamicMOXy/296967/Documentation"
< EclipseLink | Development | 2.1 | DynamicMOXy/296967
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Currently, a <tt>DynamicJAXBContext</tt> can be created with metadata from an XML Schema file (XSD), or from an EclipseLink Project specified in the EclipseLink <tt>sessions.xml</tt> file. | Currently, a <tt>DynamicJAXBContext</tt> can be created with metadata from an XML Schema file (XSD), or from an EclipseLink Project specified in the EclipseLink <tt>sessions.xml</tt> file. | ||
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<source lang="java"> | <source lang="java"> | ||
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== From XML Schema (XSD) == | == From XML Schema (XSD) == | ||
| + | |||
| + | <source lang="java"> | ||
| + | /** | ||
| + | * 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(InputStream schemaStream, EntityResolver resolver, | ||
| + | ClassLoader classLoader, Map<String, ?> properties) throws JAXBException | ||
| + | </source> | ||
Metadata in XML Schema format can be used to create a <tt>DynamicJAXBContext</tt> as follows: | Metadata in XML Schema format can be used to create a <tt>DynamicJAXBContext</tt> as follows: | ||
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</xs:schema> | </xs:schema> | ||
| + | </source> | ||
| + | |||
| + | == From an EclipseLink Project == | ||
| + | |||
| + | <source lang="java"> | ||
| + | /** | ||
| + | * Create a <tt>DynamicJAXBContext</tt>, using an EclipseLink <tt>sessions.xml</tt> as the metadata source. | ||
| + | * The <tt>sessionNames</tt> parameter is a colon-delimited list of session names within the | ||
| + | * <tt>sessions.xml</tt> file. <tt>Descriptors</tt> in this session's <tt>Project</tt> must <i>not</i> | ||
| + | * have <tt>javaClass</tt> set, but <i>must</i> have <tt>javaClassName</tt> set. | ||
| + | * | ||
| + | * @param sessionNames | ||
| + | * A colon-delimited <tt>String</tt> specifying the session names from the <tt>sessions.xml</tt> file. | ||
| + | * @param classLoader | ||
| + | * The application's current class loader, which will be used to first lookup | ||
| + | * classes to see if they exist before new <tt>DynamicTypes</tt> are generated. Can be | ||
| + | * <tt>null</tt>, in which case <tt>Thread.currentThread().getContextClassLoader()</tt> will be used. | ||
| + | * @param properties | ||
| + | * Map of properties to use when creating a new <tt>DynamicJAXBContext</tt>. Can be null. | ||
| + | * | ||
| + | * @return | ||
| + | * A new instance of <tt>DynamicJAXBContext</tt>. | ||
| + | * | ||
| + | * @throws JAXBException | ||
| + | * if an error was encountered while creating the <tt>DynamicJAXBContext</tt>. | ||
| + | */ | ||
| + | public static DynamicJAXBContext createContext(String sessionNames, ClassLoader classLoader, | ||
| + | Map<String, ?> properties) throws JAXBException | ||
</source> | </source> | ||
Revision as of 14:42, 27 April 2010
Dynamic MOXy - JAXB with Dynamically Generated Java Classes
EclipseLink Dynamic MOXy introduces a new concept in JAXB development - the freedom to bootstrap a JAXBContext from a variety of metadata sources and use conventional JAXB APIs to marshal and unmarshal data, all without having actual compiled Java class files on the classpath. This gives the user the flexibility to alter their metadata at any time, and not have to worry about updating and recompiling the previously-generated Java source code.
Creating a DynamicJAXBContext
As with conventional JAXB, the first step is to create a JAXBContext. This is achieved by use of the DynamicJAXBContextFactory class. DynamicJAXBContexts cannot be instantiated directly, they must be created through the factory API.
Currently, a DynamicJAXBContext can be created with metadata from an XML Schema file (XSD), or from an EclipseLink Project specified in the EclipseLink sessions.xml file.
/** * Create a <tt>DynamicJAXBContext</tt>, using an EclipseLink <tt>sessions.xml</tt> as the metadata source. * The <tt>sessionNames</tt> parameter is a colon-delimited list of session names within the * <tt>sessions.xml</tt> file. <tt>Descriptors</tt> in this session's <tt>Project</tt> must <i>not</i> * have <tt>javaClass</tt> set, but <i>must</i> have <tt>javaClassName</tt> set. * * @param sessionNames * A colon-delimited <tt>String</tt> specifying the session names from the <tt>sessions.xml</tt> file. * @param classLoader * The application's current class loader, which will be used to first lookup * classes to see if they exist before new <tt>DynamicTypes</tt> are generated. Can be * <tt>null</tt>, in which case <tt>Thread.currentThread().getContextClassLoader()</tt> will be used. * @param properties * Map of properties to use when creating a new <tt>DynamicJAXBContext</tt>. Can be null. * * @return * A new instance of <tt>DynamicJAXBContext</tt>. * * @throws JAXBException * if an error was encountered while creating the <tt>DynamicJAXBContext</tt>. */ public static DynamicJAXBContext createContext(String sessionNames, ClassLoader classLoader, Map<String, ?> properties) throws JAXBException
From XML Schema (XSD)
/** * 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(InputStream schemaStream, EntityResolver resolver, ClassLoader classLoader, Map<String, ?> properties) throws JAXBException
Metadata in XML Schema format can be used to create a DynamicJAXBContext as follows:
InputStream inputStream = ClassLoader.getSystemResourceAsStream("com/foo/sales/xsd/customer.xsd"); JAXBContext jaxbContext = DynamicJAXBContextFactory.createContextFromXSD(inputStream, null, null, null);
Example 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:complexType name="customer"> <xs:sequence> <xs:element name="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>
From an EclipseLink Project
/** * Create a <tt>DynamicJAXBContext</tt>, using an EclipseLink <tt>sessions.xml</tt> as the metadata source. * The <tt>sessionNames</tt> parameter is a colon-delimited list of session names within the * <tt>sessions.xml</tt> file. <tt>Descriptors</tt> in this session's <tt>Project</tt> must <i>not</i> * have <tt>javaClass</tt> set, but <i>must</i> have <tt>javaClassName</tt> set. * * @param sessionNames * A colon-delimited <tt>String</tt> specifying the session names from the <tt>sessions.xml</tt> file. * @param classLoader * The application's current class loader, which will be used to first lookup * classes to see if they exist before new <tt>DynamicTypes</tt> are generated. Can be * <tt>null</tt>, in which case <tt>Thread.currentThread().getContextClassLoader()</tt> will be used. * @param properties * Map of properties to use when creating a new <tt>DynamicJAXBContext</tt>. Can be null. * * @return * A new instance of <tt>DynamicJAXBContext</tt>. * * @throws JAXBException * if an error was encountered while creating the <tt>DynamicJAXBContext</tt>. */ public static DynamicJAXBContext createContext(String sessionNames, ClassLoader classLoader, Map<String, ?> properties) throws JAXBException