Chapter 4 XML Processing

149

 Account Processing

 XML

 Workflow 

Document 

Credit Card 

Dispatching 

Processing

Logic

 Airline Reservation 

Processing

Figure 4.7

Flexible Mapping Applied to a Travel Service Scenario

This technique is particularly useful for implementing a document oriented

workflow where components exchange or have access to entire documents but

only manipulate portions of the documents. For example, Figure 4.7 shows how a

PurchaseOrder

 document may sequentially go through all the stages of a work 

flow. Each stage may process specific information within the document. A credit

card processing stage may only retrieve the 

CreditCard

 element from the

PurchaseOrder

 document. Upon completion, a stage may  stamp  the document

by inserting information back into the document. In the case of a credit card pro 

cessing stage, the credit card authorization date and status may be inserted back

into the 

PurchaseOrder

 document.

4.3.4.3

XML Componentization

For a document centric processing model, especially when processing documents in

the EJB tier, you may want to create generic, reusable components whose state is

serializable to and from XML. (See  Designing Domain Specific XML Schemas