Chapter 6 

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Example 6.5 shows the equivalent Java classes for the canonical model of invoice

information. 

public class Invoice {

public string getInvoiceId();

public Address getOPCPoId();

public string getSupplierId();

public string getStatus();

// class implementation ...

}

Code Example 6.5

Java Class Equivalents for Canonical Invoice Information

Once the XML is defined, you can also use tools such as JAXB to generate the Java

classes. (See  Flexible Mapping  on page 148.)

After establishing a canonical data model, you must devise a strategy to

convert any alternate data representations to this model. Because it plugs its enter 

prise systems billing, order processing, and CRM in via an application server,

the adventure builder enterprise exposes the canonical data model only through

the external interfaces exposed by the application server. That is, only those com 

ponents with external interfaces Web service applications, remote enterprise

beans, and so forth expose the canonical data model. Since the external world

needs (and sees) only the canonical data model, the adventure builder enterprise

must transform its internal data representations which have their own data

model devised by its various EISs to this same canonical model. 

The data translation between the internal and external representations can be

done before the data goes from the EIS into the application server that is, the

application server internally uses the canonical data model, which is generally

recommended. Or, the data translation can take place just prior to sending the data

out to the external world that is, the application server uses the various EISs'

native data representations. Sometimes the business logic necessitates this latter

approach because the logic needs to know the precise native format. The transla 

tion is accomplished in one of two ways:

1. Use XSL style sheets to transform these alternate data representations, either 

when data comes in or when data goes out. XSL style sheets work for XML 

based interfaces. In this approach, the application server internally uses the EIS