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EclipseLink/UserGuide/MOXy/Advanced Concepts/Refreshing Metadata

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Refreshing Metadata

EclipseLink MOXy 2.3 introduces the ability to refresh your JAXBContext's metadata at runtime. This allows you to make changes to existing mappings in a live application environment and see those changes immediately without having to create a new JAXBContext.

In order to use the Metadata Refresh feature, your metadata information must be provided in one of the following formats:

  • javax.xml.transform.Source
  • org.w3c.dom.Node
  • org.eclipse.persistence.jaxb.metadata.MetadataSource


Our example will be bootstrapped from the following EclipseLink OXM file:

<?xml version="1.0"?>
        <java-type name="Root">
                <xml-element java-attribute="name" name="orig-name"/>

Our JAXBContext is created in the standard way:

ClassLoader classLoader = ClassLoader.getSystemClassLoader();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
InputStream metadataStream = classLoader.getResourceAsStream("example/eclipselink-oxm.xml";
Document metadataDocument = db.parse(metadataStream);
Map<String, Object> props = new HashMap<String, Object>(1);
props.put(JAXBContextFactory.ECLIPSELINK_OXM_XML_KEY, metadataDocument);
JAXBContext context = JAXBContextFactory.createContext(new Class[] { Root.class }, props);

At this point, if we were to marshal a Root object to XML, it would look like this:


For this example, we will modify the metadata Document directly to change the XML name for the name field. We can then refresh the metadata using the refreshMetadata() API:

Element xmlElementElement = (Element) metadataDocument.getElementsByTagNameNS("http://www.eclipse.org/eclipselink/xsds/persistence/oxm", "xml-element").item(0);
xmlElementElement.setAttribute("name", "new-name");

After refreshing metadata, the same Root object will be marshalled as follows: