I have been hopping between chapters and haven’t read the book cover to cover (yet ;-)), so hopefully I’m not asking a question that is answered in a portion of the book I haven’t yet read. While I understand and like the DTO pattern for the most part, I was hoping to find some guidance for the situation where the business tier interface is a contract-first, Web Service (implemented as a SLSB). This leads to the issue of generated application domain classes (i.e., from the contractual WSDL) that don’t necessarily coincide w/ the application domain classes designed for the business logic and persistence layer, thus requiring translation. My current thinking is to put a 2nd façade layer between the web service implementation and the business service implementation, which will simply translate the service call arguments from WSDL generated domain objects to application domain objects and back. Is there some other more ‘standard’, best practice to address this situation?

Thanks!

Hi

The last section of chapter 9 partly discusses this and the upshot for Interface/Contract First development is don't try to share the JPA DTOs as a common data model for both the EJB layer and the Web Services Layer and likewise don't use JAX-WS annotations on your SLSBs to generate Web Services. By definition, if you start from your SLSBs you are doing Code First development not Contract/Interface Development for your Web Services. You will get no re-use of any XML Schemas used across your Web Services and other parts of your systems in your enterprise which need to use your common XML based business data definitions.

More info here:

• http://pauldone.blogspot.com/2008/09...bal-types.html
• http://pauldone.blogspot.com/2008/10...g-nirvana.html
• http://pauldone.blogspot.com/2009/06...-weblogic.html

HTH

Paul