278
Data Integration Guidelines
LODGING_INVOICE
COMPLETED
Code Example 6.3
XML Document With Invoice Information
It is usually a good idea to provide the schema for the canonical data model.
By having the schema available, you can validate the translated documents
against it and newer applications can use the schema to define their own models.
Code Example 6.4 shows the XSD schema file for this invoice information.
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace="http://java.sun.com/blueprints/ns/invoice"
xmlns="http://java.sun.com/blueprints/ns/invoice"
elementFormDefault="qualified">
Code Example 6.4
XSD Schema for Invoice Information
In addition to the XML form, the canonical model representation may be
needed in the Java
Object
form. Often, the Java
Object
form is needed, for exam
ple, when a substantial amount of business logic is written in the J2EE application
server. To use the canonical form for new code, you convert the canonical data
types (from an XML schema to Java or vice versa) in Java objects. That is, you
use the XML documents or their Java object representations as the stable integra
tion point. (See Web Services Approach on page 266.) For example, Code
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