OXM Jaxb2Unmarshaller to support non-root elements [SPR-10282] #14916
Description
David J. M. Karlsen opened SPR-10282 and commented
The JAXB2Unmarshaller should support JaxbElement/partial unmarshalling (e.g. classes not having a @RootElement).
#12586/SPR-9742 are analogue cases but for marshalling.
My usecase is using org.springframework.batch.item.xml.StaxEventItemReader in Spring Batch where I want to delegate unmarshalling of each event to the OXM unmarshaller.
This will fail if I cannot call the more specific unmarshalling method where the expected JAXB class can be provided.
This hack would make this possible by setting the expected class to return as a parameter to the Spring unmarshaller class:
public class ImprovedJaxb2Marshaller
extends Jaxb2Marshaller
{
private Class<?> partClass;
public void setPartClass( Class<?> partClass )
{
this.partClass = partClass;
}
@Override
public Object unmarshal( Source source, MimeContainer mimeContainer )
throws XmlMappingException
{
if ( partClass == null )
{
return super.unmarshal( source, mimeContainer );
}
else
{
try
{
Unmarshaller jaxbUnmarshaller = createUnmarshaller();
return source instanceof StAXSource ?
unmarshalStaxSource( jaxbUnmarshaller, source ) :
jaxbUnmarshaller.unmarshal( source, partClass );
}
catch ( JAXBException e )
{
throw super.convertJaxbException( e );
}
}
}
private Object unmarshalStaxSource( Unmarshaller jaxbUnmarshaller, Source staxSource )
throws JAXBException
{
XMLStreamReader streamReader = StaxUtils.getXMLStreamReader( staxSource );
if ( streamReader != null )
{
return jaxbUnmarshaller.unmarshal( streamReader, partClass ).getValue();
}
else
{
XMLEventReader eventReader = StaxUtils.getXMLEventReader( staxSource );
if ( eventReader != null )
{
return jaxbUnmarshaller.unmarshal( eventReader, partClass ).getValue();
}
else
{
throw new IllegalArgumentException( "StaxSource contains neither XMLStreamReader nor XMLEventReader" );
}
}
}
Affects: 3.1.4