Cohesion is a measure of degree of how strongly a class focuses on its responsibilities. It is of the following two types:

High cohesion: This means that a class is designed to carry on a specific and precise task. Using high cohesion, methods are easier to understand, as they perform a single task.
Low cohesion: This means that a class is designed to carry on various tasks. Using low cohesion, methods are difficult to understand and maintain.
In object-oriented design, high cohesion is desirable, as it is easy to understand and maintain.

Answered by Ashish Yadav , an ibibo Master, at 4:09 PM on September 11, 2008

Cohesion may mean:

* Cohesion (chemistry): the intermolecular attraction between like-molecules.
* Cohesion (computer science): a measure of how well the lines of source code within a module work together to provide a specific piece of functionality. In object-oriented programming, the degree to which a method implements a single function. Methods that implement a single function are described as having high cohesion.
* Cohesion (Desktop Grid Computing): a platform for distributed parallel computation, see also List of distributed computing projects
* Cohesion (geology): the part of shear strength that is independent of the normal effective stress in mass movements.
* Cohesion (linguistics): the linguistic elements that make a discourse semantically coherent.
* Cohesion (military): the bonding together of members of an organization/unit in such a way as to sustain their will and commitment to each other, their unit, and the mission (Cohesion the Human Element in Combat, William Henderson, 1985).
* Cohesion (structural): the sociological and graph theoretical conception and measurement for maximal group or graphical boundaries where related elements cannot be disconnected except by removal of a certain minimal number of other nodes
* Cohesion (band): a musical group from Manchester, England.
* Cohesion (social policy): the bonds or "glue" between members of a community or society.


http://en.wikipe dia.org/wiki/Cohesive

Answered by Sharad Singh , an ibibo Master, at 7:32 PM on September 09, 2008

Cohesion is a measure of degree of how strongly a class focuses on its responsibilities. It is of the following two types:

High cohesion: This means that a class is designed to carry on a specific and precise task. Using high cohesion, methods are easier to understand, as they perform a single task.
Low cohesion: This means that a class is designed to carry on various tasks. Using low cohesion, methods are difficult to understand and maintain.
In object-oriented design, high cohesion is desirable, as it is easy to understand and maintain. Moreover, it is easier to reuse.

TYPES OF COHESSION :
Cohesion is a qualitative measure meaning that the source code text to be measured is examined using a rubric to determine a cohesion classification. The types of cohesion, in order of the worst to the best type, are as follows:

Coincidental cohesion (worst)
Coincidental cohesion is when parts of a module are grouped arbitrarily (at random); the parts have no significant relationship (e.g. a module of frequently used mathematical functions).
Logical cohesion
Logical cohesion is when parts of a module are grouped because they logically are categorised to do the same thing, even if they are different by nature (e.g. grouping all I/O handling routines).
Temporal cohesion
Temporal cohesion is when parts of a module are grouped by when they are processed - the parts are processed at a particular time in program execution (e.g. a function which is called after catching an exception which closes open files, creates an error log, and notifies the user).

FOR MORE DETAILS PLEASE VISIT :http://en.wikipedia.org/wiki/ Cohesion_(computer_science)

Answered by Sanya Tahir , an ibibo Master, at 12:11 PM on September 06, 2008

ell , Cohesion is the measure of the strength of functional relatedness of elements within a module.

A functionally cohesive module contains elements that all contribute to the execution of one and only one problem-related task. Examples of functionally cohesive modules are

COMPUTE COSINE OF ANGLE
VERIFY ALPHABETIC SYNTAX
READ TRANSACTION RECORD
DETERMINE CUSTOMER MORTGAGE REPAYMENT
COMPUTE POINT OF IMPACT OF MISSILE
CALCULATE NET EMPLOYEE SALARY
ASSIGN SEAT TO AIRLINE CUSTOMER

For more details , Please visit the source site :

http://www.waysys.com/ws_conte nt_bl_pgssd_ch06.html

Answered by Alok Gupta , an ibibo Guru, at 12:52 AM on September 06, 2008

In computer programming, cohesion is a measure of how strongly-related and focused the various responsibilities of a software module are. Cohesion is an ordinal type of measurement and is usually expressed as "high cohesion" or "low cohesion" when being discussed. Modules with high cohesion tend to be preferable because high cohesion is associated with several desirable traits of software including robustness, reliability, reusability, and understandability whereas low cohesion is associated with undesirable traits such as being difficult to maintain, difficult to test, difficult to reuse, and even difficult to understand.

Cohesion is often contrasted with coupling, a different concept. Nonetheless high cohesion often correlates with loose coupling, and vice versa. The software quality metrics of coupling and cohesion were defined by Wayne P. Stevens, Glenford J. Myers, and Larry L. Constantine from source code analysis they conducted on several programming projects while at IBM, all in an effort to identify the characteristics of "good" programming practices.

http://www.answe rs.com/topic/cohesion-computer -science

Answered by Nishu's , an ibibo Master, at 10:24 PM on September 05, 2008

hi,friend
Types of cohesion
Cohesion is a qualitative measure meaning that the source code text to be measured is examined using a rubric to determine a cohesion classification. The types of cohesion, in order of the worst to the best type, are as follows:

Coincidental cohesion (worst)
Coincidental cohesion is when parts of a module are grouped arbitrarily (at random); the parts have no significant relationship (e.g. a module of frequently used mathematical functions).
Logical cohesion
Logical cohesion is when parts of a module are grouped because they logically are categorised to do the same thing, even if they are different by nature (e.g. grouping all I/O handling routines).
Temporal cohesion
Temporal cohesion is when parts of a module are grouped by when they are processed - the parts are processed at a particular time in program execution (e.g. a function which is called after catching an exception which closes open files, creates an error log, and notifies the user).
Procedural cohesion
Procedural cohesion is when parts of a module are grouped because they always follow a certain sequence of execution (e.g. a function which checks file permissions and then opens the file).
Communicational cohesion
Communicational cohesion is when parts of a module are grouped because they operate on the same data (e.g. a module which operates on the same record of information).
Sequential cohesion
Sequential cohesion is when parts of a module are grouped because the output from one part is the input to another part like an assembly line (e.g. a function which reads data from a file and processes the data).
Functional cohesion (best)
Functional cohesion is when parts of a module are grouped because they all contribute to a single well-defined task of the module (e.g. parsing XML in the case of Expat (XML)).
Since cohesion is a ranking type of scale, the ranks do not indicate a steady progression of improved cohesion. Studies by various people including Larry Constantine, Edward Yourdon, and Steve McConnell [2] indicate that the first two types of cohesion are inferior; communicational and sequential cohesion are very good; and functional cohesion is superior.

While functional cohesion is considered the most desirable type of cohesion for a software module, it may not be achievable. There are cases where communicational cohesion is the highest level of cohesion that can be attained under the circumstances.

Answered by Nz , an ibibo Master, at 9:35 PM on September 05, 2008

In computer programming, cohesion is a measure of how strongly-related and focused the various responsibilities of a software module are. Cohesion is an ordinal type of measurement and is usually expressed as "high cohesion" or "low cohesion" when being discussed. Modules with high cohesion tend to be preferable because high cohesion is associated with several desirable traits of software including robustness, reliability, reusability, and understandability whereas low cohesion is associated with undesirable traits such as being difficult to maintain, difficult to test, difficult to reuse, and even difficult to understand.

There are various types of cohesions, you can follow them here: http://en.wikipedia.org/wiki/C ohesion_(computer_science)

Cohesion is often contrasted with coupling, a different concept. Nonetheless high cohesion often correlates with loose coupling, and vice versa. The software quality metrics of coupling and cohesion were invented by Larry Constantine based on characteristics of "good" programming practices that reduced maintenance and modification costs.

Answered by Keshto Patel , an ibibo Master, at 8:08 PM on September 05, 2008

Hello ..

Cohesion is a qualitative measure meaning that the source code text to be measured is examined using a rubric to determine a cohesion classification. The types of cohesion, in order of the worst to the best type, are as follows:

Coincidental cohesion (worst):
Coincidental cohesion is when parts of a module are grouped arbitrarily (at random); the parts have no significant relationship (e.g. a module of frequently used mathematical functions).
Logical cohesion:
Logical cohesion is when parts of a module are grouped because they logically are categorised to do the same thing, even if they are different by nature (e.g. grouping all I/O handling routines).
Temporal cohesion:
Temporal cohesion is when parts of a module are grouped by when they are processed - the parts are processed at a particular time in program execution (e.g. a function which is called after catching an exception which closes open files, creates an error log, and notifies the user).
Procedural cohesion:
Procedural cohesion is when parts of a module are grouped because they always follow a certain sequence of execution (e.g. a function which checks file permissions and then opens the file).
Communicational cohesion:
Communicational cohesion is when parts of a module are grouped because they operate on the same data (e.g. a module which operates on the same record of information).
Sequential cohesion:
Sequential cohesion is when parts of a module are grouped because the output from one part is the input to another part like an assembly line (e.g. a function which reads data from a file and processes the data).
Functional cohesion (best):
Functional cohesion is when parts of a module are grouped because they all contribute to a single well-defined task of the module (e.g. parsing XML in the case of Expat (XML)).

Answered by Saq , an ibibo Specialist, at 8:04 PM on September 05, 2008