Software reuse can take many forms from simple code reuse to complete application reuse. There are various levels of reuse including components, frameworks, libraries, services, patterns and full applications. The optimal approach depends on the available software, skills, and needs of the organization, with factors like schedule, lifetime, team, criticality and domain determining the best fit. Software reuse provides a cost-effective way to develop software.

1. The software reuse landscape
Software Engineering 10

2. Since the beginning of the 21st
century, there has been a major
switch to reuse-based software
engineering

3. Although reuse is often simply
thought of as the reuse of system
components, there are many
different approaches to reuse that
may be used.

4. Reuse is possible at a range of levels
from simple functions to complete
application systems.

5. The reuse landscape
Chapter 15 Software reuse 517/11/2014

6. Application frameworks:
Collections of abstract and concrete
classes are adapted and extended to
create application systems.

7. Application frameworks

8. Application system integration:
Two or more application systems are
integrated to provide extended
functionality.

9. Configurable application systems:
Domain-specific systems are designed so
that they can be configured to the needs of
specific system customers.

10. Systems of systems:
Two or more independently-owned,
distributed systems are integrated to create
a new system.

11. ERP systems:
Large-scale systems that encapsulate
generic business functionality and rules are
configured for an organization.

12. ERP systems

13. Legacy system reuse:
Legacy systems (Chapter 9) are ‘wrapped’
by defining a set of interfaces and
providing access to these legacy systems
through these interfaces.

14. Legacy system wrapping

15. Software product lines:
An application type is generalized around a
common architecture so that it can be
adapted for different customers.
.

16. Product lines

17. Component-based software engineering:
Systems are developed by integrating
components (collections of objects) that
conform to component-model standards.

18. Program libraries:
Class and function libraries that implement
commonly used abstractions are available
for reuse.

19. Service-oriented development:
Systems are developed by linking shared
services, which may be externally
provided.

20. Program generators:
A generator system embeds knowledge of
a type of application and is used to
generate systems in that domain from a
user-supplied system model.

21. Program generation

22. Model-driven engineering:
Software is represented as domain models
and implementation independent models
and code is generated from these models.

23. Model transformations

24. Aspect-oriented software development:
Shared components are woven into an
application at different places when the
program is compiled.

25. Aspect weaving

26. Design patterns:
Generic abstractions that occur across
applications are represented as design
patterns showing abstract and concrete
objects and interactions.

27. Architectural patterns:
Standard software architectures that
support common types of application
system are used as the basis of
applications.

28. There is no ‘best approach’ to software
reuse. The approach to be used depends
on software available, skills and the
organization itself.

29. Key factors include:
Development schedule, software lifetime,
the development team, the criticality of the
software, non-functional requirements,
application domain, the software execution
platform

30. Software reuse is a cost-effective approach
to software development and there are a
range of different ways that software can
be reused.