Concepts in Software Design

Abstraction

• Solution is stated in large terms using the language of the problem environment at the highest level abstraction.
• The lower level of abstraction provides a more detail description of the solution.
• A sequence of instruction that contain a specific and limited function refers in a procedural abstraction.
• A collection of data that describes a data object is a data abstraction.

Architecture

• The complete structure of the software is known as software architecture.
• Structure provides conceptual integrity for a system in a number of ways.
• The architecture is the structure of program modules where they interact with each other in a specialized way.
• The components use the structure of data.
• The aim of the software design is to obtain an architectural framework of a system.
• The more detailed design activities are conducted from the framework.

Patterns

• Describe a design structure and that structure solves a particular design problem in a specified content.

Modularity

• A software is separately divided into name and addressable components.
• Modularity is the single attribute of a software that permits a program to be managed easily.

Information Hiding

• Modules must be specified and designed so that the information like algorithm and data presented in a module is not accessible for other modules not requiring that information.

Functional Independence

• The functional independence is the concept of separation and related to the concept of modularity, abstraction, and information hiding.
• It is accessed using two criteria, Cohesion and Coupling.
  • Cohesion is an extension of the information hiding concept. A cohesive module performs a single task, and it requires a small interaction with the other components in other parts of the program.
  • Coupling is an indication of interconnection between modules in a structure of software.

Refinement

• It is a top-down design approach.
• It is a process of elaboration.
• A program is established for refining levels of procedural details.
• A hierarchy is established by decomposing a statement of function in a stepwise manner till the programming language statement are reached.

Refactoring

• It is a reorganization technique, which simplifies the design of components without changing its function behavior.
• It does not change the external behavior of the code still improves its internal structure.

Design Classes

• The model of software is defined as a set of design classes.
• Every class describes the elements of problem domain and the features of the problem which are user visible.