Cohesion: a module inside each element bonded to each other tightly degree.
It is a measure of a part of the internal module measures between the overall unity. Common cohesive seven categories.
1) functional poly (Functional Cohesion)
If a complete all processing elements within a module, and complete only one function, the function is called polypropylene.
Functional cohesiveness is the highest degree of cohesion. However, in the software configuration, each module can not be designed to function within a poly module.
2) the order of poly (Sequential Cohesion)
If the processing elements within a module, and is closely related to a function, and these elements must perform the processing order is called sequential cohesion.
3) within the communication poly (Communicational Cohesion)
If all the elements of a processing module uses the same input data, and (or) to produce the same output data, referred to as poly within the communication.
4) over the course of a poly (Procedural Cohesion)
If the processing elements within a module are related, and must be performed in a particular order, the process is called polymerization.
Over the course of the sequential polymerization and the polymerization except that: the sequential polymerization is a data stream flowing from one processing unit to another processing unit, and the polymerization process is a control operation from one flow to another operation.
5) time poly (Temporal Cohesion)
If a module contains the task must be performed in the same period of time, the polymerization times referred to. Also known as transient cohesion.
6) within the logical poly (Logical Cohesion)
If the task module of the same or a similar class of logically called logical cohesion.
7) occasional cohesion (Coincidental Cohesion)
If a module is completed by the processing elements of several unrelated functions combined together by chance, occasionally called cohesive.
Software design should: strive to achieve high cohesion, minimize the use of cohesion, not low cohesion.