Can we create a class from a xml file ?

Question

Hello,

Is it possible to create a class dynamically by reading an xml file ( in java preferably) ? if yes, please provide pointers on how to do it.

In the process of development, we have come up with a class that has 5 attributes, all these attributes correspond to an entry in the xml file, now if the user adds/modifies the xml entry the object corresponding to it must change automatically, one approach would be generate the source code, before compile time.Is there any other way ?

Is there any common pattern to model such changes in the system ?

Thanks,

Answer 1

The process usually works the other way around (ie. defining a class with those attributes, and serializing an instance of the class to XML)

If you really need that sort of flexibility, a scripting language would save you a lot of trouble.

Answer 2

If you have an XML Schema for your XML there are a number of kits for this. Start with JAX-B.

Answer 3

I think JAX-B can provide functionality like that.

Answer 4

If you're looking for byte code generation, have a look at cglib, it is the one used in Hibernate.

But maybe some annotations can also fulfill your requirement, just like Google Guice's dependency injection.

Answer 5

If you stored your attributes in a HashMap then you could simply parse the XML and then set the attributes accordingly.

Answer 6

Assuming you have a XML schema (xsd), you can feed that schema to JAXB's xjc command to generate Java classes. xjc is included with the Java 6 JDK.