3.1 About the bank example

The example described in this tutorial is a simple simulation of a bank. The architecture of the bank is composed of three components:

• A database that provides persistent storage for accounts managed by the bank. (This is simulated in the following code, but is easily replaced by a real database backend.)
• A CORBA server that represents the bank and provides an object-oriented interface to its accounts.
• A CORBA client that provides a graphical user interface to the bank.

The server provides a single CORBA object that represents the bank. This object manages a collection of CORBA objects that represent customer accounts. The bank has operations for opening and closing accounts, and for retrieving existing accounts from the database. In turn, accounts support operations for querying and updating their balance.

The client initially contacts the server by obtaining a reference to the bank object from The LispWorks ORB. It then presents the user with a graphical interface to the bank.

In response to user requests, the interface invokes operations on the bank, obtaining further references to accounts created on the server. The client manages separate graphical objects for the bank and each of the accounts that are active in the server.

The user interface is implemented using the LispWorks CAPI library. Note that this application is a typical example of a three-tier architecture comprising a database access layer, a business logic layer, and a user interface layer.