Logical Cohesion
Introduction
Logical cohesion is a concept in software engineering that pertains to the degree of interrelatedness between elements of a software module. It is a critical aspect of software design, as it impacts the maintainability, understandability, and reliability of the software system. Logical cohesion is one of the seven types of cohesion identified by software engineering researchers, each representing a different level of module strength.
Understanding Cohesion
Before delving into the specifics of logical cohesion, it is essential to understand the broader concept of cohesion in software engineering. Cohesion refers to the degree to which the elements inside a module belong together. In other words, it is a measure of how closely the responsibilities of a module are related to each other. High cohesion is generally desirable in software design, as it promotes system maintainability and reduces complexity.
Types of Cohesion
There are seven types of cohesion, listed from weakest to strongest: coincidental, logical, temporal, procedural, communicational, sequential, and functional. Each type represents a different level of interrelatedness between the elements of a module. The type of cohesion present in a module can significantly impact the module's quality and the overall quality of the software system.
Logical Cohesion
Logical cohesion is when parts of a module are grouped because they are logically categorized to do the same thing, even if they are different by nature. For example, a module may contain a group of functions that each perform a file operation, such as open file, close file, or delete file. Even though these functions perform different operations, they are logically related because they all pertain to file management.
Advantages and Disadvantages of Logical Cohesion
Logical cohesion can offer several advantages in software design. For one, it can make the software easier to understand and maintain, as related functions are grouped together. However, logical cohesion also has its disadvantages. For instance, it can lead to higher coupling, as a change in one function may require changes in other logically related functions. Additionally, logically cohesive modules may be more difficult to reuse, as they may contain functions that are not needed in other contexts.
Improving Logical Cohesion
Improving logical cohesion involves refining the design of software modules to ensure that each module has a single, well-defined purpose. This can be achieved through various techniques, such as refactoring, which involves restructuring existing code without changing its external behavior. Another technique is encapsulation, which involves hiding the internal details of a module and exposing only what is necessary.
Conclusion
Logical cohesion is a crucial aspect of software design that can significantly impact the maintainability, understandability, and reliability of a software system. By understanding and effectively applying the principles of logical cohesion, software engineers can create more robust and efficient software systems.