Information Technology Reference
In-Depth Information
9.5 Post-Implementation Considerations
Once a system has been developed, tested, and deployed it will enter the Opera-
tions and Maintenance Phase. All development resources and documentation
should be transferred to a library or the operations and maintenance staff (IRM
2003
).
9.6 Language Choice
In most cases, programming language for implementation is not an issue. Unless
the client wants a particular language to be used, allowing for the possibility of
unforeseen limitations, and issues. Such details are most commonly irrelevant to
the client. However, if the product has to be implemented on a specific computer
and only a specific language is available on that computer then there is no choice.
In these types of cases the choice of programming language is clearly predeter-
mined and unchangeable due to factors that cannot be controlled. The most
interesting situation is choosing the most suitable programming language when it
is not specified (Schach
2007
). Object-oriented programming languages (OOPLs)
are the natural choice for implementation of an Object-Oriented Design because
they directly support the object notions of classes, inheritance, information hiding,
and dynamic binding. Because they support these object notions, OOPLs make an
object-oriented design easier to implement. An object-oriented system pro-
grammed with an OOPL results in less complexity in the system design and
implementation, which can lead to an increase in maintainability. Current OOPLs
include C++, Objective C, Smalltalk, Eiffel, Common LISP Object System
(CLOS), Object Pascal and Java. The use of OOPL technology requires a cor-
porate commitment to formal training in the proper use of the OOPL features and
the purchase of the language compiler. Object-oriented (OO) applications can be
written in either conventional languages or OOPLs, but they are much easier to
write in languages especially designed for OO programming. OO language experts
divide OOPLs into two categories, hybrid languages and pure OO languages.
Hybrid languages are based on some non-OO model that has been enhanced with
OO concepts. C++ (a superset of C), Ada 95, and CLOS (an object-enhanced
version of LISP) are hybrid languages. Pure OO languages are based entirely on
OO principles; Smalltalk, Eiffel, Java, and Simula are pure OO languages. In terms
of numbers of applications, the most popular OO language in use is C++. One
advantage of C++ for commercial use is its syntactical familiarity to C, which
many programmers already know and use; this lowers training costs. Additionally,
C++ implements all the concepts of object-orientation, which include classes,
inheritance, information hiding, polymorphism and dynamic binding. One disad-
vantage of C++ is that it lacks the level of polymorphism and dynamics most OO
programmers expect. The major alternative to C++ or Ada 95 is Smalltalk. Its
