102 Managing Information Access to an EIS Using J2EE and Services Oriented Architecture
either a call back mechanism or some intermediate event store that is used for
triggering and sending the events to the resource adapter. Finally, the message
endpoint is notified of the event by a call to MessageEndPoint.
The delivery of events from the EIS can also be transacted using container
managed transactions and Java Transaction API (JTA). This method of delivery
uses the transaction management contract and controlling the transaction
boundaries using the beforeDelivery and afterDelivery methods. These methods
signify when the application server should enlist an XAResource to start and end
the transaction.
For more information, see the JCA 1.5 specification at:
http://java.sun.com/j2ee/connector/download.html
5.3 The integration building block using J2C
This section describes the integration building blocks that use J2C and how the
IBM CICS J2C resource adapter helps to solves the scenario problem. It
describes the components of the building block and the system architecture that
we used for the EIS integration.
5.3.1 Scenario problem statement
Many EIS have their services and functions exposed through the use of a J2C
resource adapter that is 1.0 or 1.5 compliant. Application components are more
often being built to run in a J2EE application server. To manage EIS data and use
existing functionality, the application components use resource adapters to
interact with these enterprise systems.
For our specific scenario, the ITSO Trading Firm has an Internet Trading System
J2EE application that processes trade requests made over the Web. The Internet
Trading System uses a company listing to verify whether buy or sell requests can
be made through the system. The information for the company list is stored in a
CICS system that the firm owns.
Our Buy Shares scenario requires verification of the order against the company
list. The trade shares business component of the Internet Trading System uses
the list of available companies from which customers are allowed to buy shares.
The component needs this process to be quick, synchronous retrieval from the
CICS system. This process is facilitated by the CICS resource adapter which can
be integrated into the trade shares business component as a service.