3. Coupling
Coupling is measure of the
independence of components.
Coupling is related to cohesion.
It is an indication the strength of inter
connections between the components
in a design .
Jagnesh
Chawla(jagneshchawla@gmail.com)
4. Highly coupled
These types of systems have
interconnections , with program units
dependent on each other.
Jagnesh
Chawla(jagneshchawla@gmail.com)
6. Loosely coupled
Loosely coupled systems are made up
of components which are independent
or almost independent.
In this less dependences are
available.
Jagnesh
Chawla(jagneshchawla@gmail.com)
10. The range of coupling
measures:
Content coupling High coupling
Common
coupling
Loose
Control coupling
Stamp coupling
Data coupling Low
Uncoupled
Jagnesh
Chawla(jagneshchawla@gmail.com)
11. Content coupling:
When one component actually
modifies another .
Then the modified component is
completely dependent on the
modifying one.
Jagnesh
Chawla(jagneshchawla@gmail.com)
13. Common coupling:
We can reduce the amount of coupling
somewhat by organizing our design so
that data are accessible from a
common data store.
Global:
A1
A2
A3
Variables:
V1
V2
Component Component
Component
X Y
Z
Change V1 Increment T T
V =V2+A
To zero V1
Jagnesh
Chawla(jagneshchawla@gmail.com)
14. Control coupling:
When one component passes
parameters to control the activity of
another component.
We say that there is control coupling
between the two.
Jagnesh
Chawla(jagneshchawla@gmail.com)
15. Stamp coupling:
When data structure is used to pass
information from one component to
another.
Jagnesh
Chawla(jagneshchawla@gmail.com)
16. Data coupling:
If only data are passed, the
components are connected by data
coupling.
Jagnesh
Chawla(jagneshchawla@gmail.com)
17. Cohesion:
The cohesion of a component is a
measure of the closeness of the
relationship between its components.
Jagnesh
Chawla(jagneshchawla@gmail.com)
18. Coincidental:
The worst degree of cohesion,
coincidental is found in a component
whose parts are unrelated to one
another.
Jagnesh
Chawla(jagneshchawla@gmail.com)
19. Logical cohesion:
It is the next higher level of cohesion ,
where several logically related functions
or data elements are placed in same
component.
Jagnesh
Chawla(jagneshchawla@gmail.com)
20. Temporal cohesion:
Sometime a component is used to
initialize a system or a set variables.
Such a component performs several
functions in sequence ,but the
functions are related by the timing
involved, so its cohesion is temporal.
Jagnesh
Chawla(jagneshchawla@gmail.com)
21. Procedurally cohesion:
When function are grouped together in a
component just to ensure this order the
component is procedurally cohesive.
Jagnesh
Chawla(jagneshchawla@gmail.com)
22. Communicationally:
Communicationally cohesion often
destroys the modularity and functional
independence of the design.
Jagnesh
Chawla(jagneshchawla@gmail.com)
23. Sequential cohesion:
If the output from one part of a
component is input to the next part the
component has sequential cohesion.
Jagnesh
Chawla(jagneshchawla@gmail.com)
24. Thank you ……
Jagnesh
Chawla(jagneshchawla@gmail.com)
