Figure 14.4 Components of the system
first layer of the architecture: the former implements the graphical user
interface, while the second embeds the problem of the interaction with the
rest of the system. The Market component performs all the computational
activities. In its operation it makes use of the Market DB component that
embeds all the interactions with the persistent storage. This module simplifies
The development process of the supermarket operation support system is
organized into four phases that produce the following prototypes.
Prototype 1: Counter terminal . A system is developed to test the counter
user interface. This is a dummy interface detached from any server.
Prototype 2: Centralized system . A full working system is developed in a
centralized fashion; all the components reside in the same process. There
is no persistent storage of the database and the communication is
implemented through direct method invocation.
Prototype 3: Distributed system . The fully distributed system is
implemented; the communication takes places through a TCP
Prototype 4: Data persistence . A persistent database is introduced; an
SQL DBMS is used to hold the static data and to store the information
about the transactions.
Prototype 1: Counter terminal
This section identifies both the functional and non-functional requirements
of the counter terminal user interface. The functional requirements are