web service client code generation with JAXB

If you used Xfire or JBossWS to create client code to call a web service and used JAXB bindings, it was probably very annoying to see all the generated classes having properties as generics (ie. **JAXBElement**<**String**> property instead of just **String**). This happens because the generator doesn’t handle the minoccurs=”0” attribute properly (especially along with the nillable=”true” attribute) when it is found in the WSDL for the definition of types.

Many people solved this by simply editing the WSDL by hand and modifying the minoccurs=”0” attribute into minoccurs=”1” which then made the generator work properly. This, however has impact on maintainability of the code and future changes and it is not recommended.

Others approached the problem by simply unpacking the JARs that come with XFire distribution and manually modifying the generator configuration. This also makes the deployment somewhat difficult unless you’re packing the xfire distribution along with your project.

However, the solution can be even simpler. JAXB code generator supports defining how the JAXB binding classes will be created through a XML configuration file. The configuration attribute we’re looking for is under globalBindings directive and it is called generateElementProperty – which is by default true. If set to false, it will direct the JAXB code generator NOT to generate the properties as JAXBElement generics, so it will use the simple types instead.

The external bindings file can look as simple as this:

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<jxb:bindings version="2.0" 
              xmlns:jxb="http://java.sun.com/xml/ns/jaxb" 
              xmlns:xs="http://www.w3.org/2001/XMLSchema">
        <jxb:globalBindings generateElementProperty="false" />
</jxb:bindings>

(more information about this problem and the solution with bindings can be found here)

The amount of fine-tuning the generator using the external Bindings file is extremely wealthy. Make sure to check the JAXB documentation for more details.

(JbossWS) - Save the file and use the option -b on WSConsume, or if you use ANT you have to set the binding option.

Happy new year!