Exercises Message-Based Application Integration WS 2010 ... - IAAS

Frank Leymann / Olha Danylevych
Institut of Architecture of Application Systems
University of Stuttgart
Exercises
Message-Based Application Integration
WS 2010
Exercise 5
Date: 15.09.10 (14:00 – 15:30, Room 38.02)
Task 5.1: Error Handling
Message can be faulty because of wrong formatting (e.g. binary data instead of
XML), missing headers, or encrypted with the wrong algorithms. When dealing
with such errors in a message-based system, one has to consider that it is often
impossible to identify the sender of a message. The message should not be
erased from the system because of its possibly important content. Moreover, it
may be desirable to save the faulty message and process/analyze it later. The
mechanisms dealing with the faulty messages are of corrective and remedial
nature.
With these assumptions in mind, try to develop patterns to deal with messaging
faults. Use the already known EAI patterns as foundation for the new ones when
appropriate. In the description of your patter, use the following example for
explanatory purposes:
Debit $100
B
Task 5.2: Widgets & Gadgets ‚R Us: an Integration example
In this task we will discuss the integration of applications of a fictional company
“Widgets & Gadgets ‘R Us” (WiGRUS). This task is borrowed from the the book
“Enterprice Integration Patterns” by Gregor Hohpe and Bobby Woolf, p.17-37.
Consider the online shop WiGRUS that buys widgets and gadgets from its
suppliers, and resells them to the end customers.
Assume the following (simplified) requirements:
• Take Orders: the customers can place orders by telephone or fax, or over
the web
• Process Orders: processing the order involves multiple steps, including
verifying the inventory, shipping the goods, invoicing the customer.

• Check Status: customers can check the status of the order.
• Change Address: customers can use a Web front-end to change their
billing and shipping address.
• New Catalog: suppliers update their catalog periodically. WiGRUS needs to
update its pricing and availability on the basis of the new catalogs.
• Announcements: customers can subscribe to selective announcements
from WiGRUS.
• Testing and Monitoring: the operations staff needs to be able to monitor
all individual components and the message flows between them.
Consider each of these requirements separately and create a solution using the
EAI pattern language.