Showing posts with label JAXB. Show all posts
Showing posts with label JAXB. Show all posts

Friday, February 24, 2012

JAXB - II (jaxb.index file and ObjectFactory)

I was getting a Exception like, javax.xml.bind.JAXBException: "doesnt contain ObjectFactory.class or jaxb.index" while trying to create a JAXBContext using JAXBContext.newInstance(String contextPath).

It took me a while to figure out what went wrong. So now that I've got things working correctly, I thought I'd post this example and solution to hopefully save you some time.

When we create a marshaller, we first need to create a JAXBContext via its newInstance() factory method. You can create a context for a specific JAXB class  or you can create a context for a list of packages.

There are two ways to resolve this issue : 
  - By creating ObjectFactory
  - By adding jaxb.index file

jaxb.index :

The jaxb.index file is a text file contains a listing of the classes on the containing package that have JAXB annotations.
Note : The name of the clases is their simple name not their classified name.

Rather than creating a ObjectFactory, I guess adding a jaxb.index file is much easy part. Just you need to add class names to the file and place the file in the package (directory) where your JAXB annotated classes reside.
Its just the class name, not the fully qualified name (the package name is determined by the directory you placed the file in) or the.class name.

     JAXBContext context = JAXBContext.newInstance(className.getClass().getPackage().getName());

If the package following package does not have jaxb.index file, this change will cause the test to throw the JAXBException. Add the file and everything works great.

Thursday, February 23, 2012

Java Architecture for XML Binding (JAXB)

 - Java Architecture for XML Binding (JAXB) is a Java standard that defines how Java objects are converted to/from XML (specified using a standard set of mappings).

 - It defines a programmer API for reading and writing Java objects to / from XML documents and a service provider which / from from XML documents allows the selection of the JAXB implementation

 - It makes reading  and writing of XML via Java very easy.

 - It allows Java developers to access and process XML data without having to know XML or XML processing

 - It is used heavily by JAX-WS


 - It provides ways to generate XML content from a Java representation , to generate a Java representation from XML file , to generate XML schema from Java Objects

 - The JAXBContext class provides the client's entry point to the JAXB API. It provides an abstraction for managing the XML/Java binding information necessary to implement the JAXB binding framework operations: unmarshal, marshal and validate.

- A client application obtains new instances of this class via the newInstance(contextPath) method.            
          JAXBContext jc = JAXBContext.newInstance( "customer.class" );
The contextPath contains a list of Java package names that contain schema derived interfaces

Marshalling :

The Marshaller class provides the client application the ability to convert a Java content tree back into XML data. 

Here is a simple example that unmarshals an XML document and then marshals it back out:

          JAXBContext jc = JAXBContext.newInstance( "Customer.class" );
          Unmarshaller u = jc.createUnmarshaller(); 
          Customer customer = (Customer)u.unmarshal( new File( "test.xml" ) );
          Marshaller m = jc.createMarshaller(); m.marshal( customer, System.out );


The Unmarshaller class provides the client application the ability to convert XML data into a tree of Java content objects. 

For example: 
       JAXBContext jc = JAXBContext.newInstance( "customer.class" ); 
       Unmarshaller u = jc.createUnmarshaller();
       Customer customer = (Customer)u.unmarshal( new File( "test.xml" ) ); // ok                                                                                                            
                                                                                          to be continued...



How TOPT Works: Generating OTPs Without Internet Connection

Introduction Have you ever wondered how authentication apps like RSA Authenticator generate One-Time Passwords (OTPs) without requiring an i...