Why object oriented analysis and design useful?

:-- Object-oriented development is not a new technology but it has not had widespread use and is still maturing. Object-oriented analysis starts you on a path that can lead to benefits not only in the analysis process but in subsequent development phases. Proponents of the object-oriented approach list the benefits as an easier way to promote the understanding of a system, reusability of models and programming, modifiability and reduced costs associated with change, and reduced development risk. These benefits lead to a superior method of analyzing business processes and requirements. Finally, because the contemporary view of development is from the object-oriented perspective, object-oriented analysis allows you to take advantage of the contemporary programming languages, operating systems and associated tools. [1 p.215, 16 p.493, 12, 2 p.11]

Objects are said to replicate what humans see in real life and, therefore, appeals to human cognition. The object-oriented paradigm views the world as composed of objects with well-defined properties, with objects replicating things in an environment. [19] It is easier to promote a user's understanding when the user is presented with objects describing things found in the normal course of conducting business. For example, it is much easier for Accountants to view a system when entities such as customers, checks, invoices and receipts are used. The user can, therefore, better visualize the concepts of the system and assist the analyst in describing the system by focusing on what is to be accomplished rather than focusing on procedures. [12, 16 p.493]

Reusability is a desired goal of all development and is based on the reluctance of reinventing something when it has already been invented. Object-oriented development supports this, especially in the concept of abstraction. [3] Abstraction supports continual iterations of analysis until unique objects are found in a class hierarchy. These unique objects inherit characteristics from the higher level classes and this allows you to reuse information from the previously defined classes, eliminating the need to reinvent it. Class structure leads to the development of class libraries that allow the sharing of models and programming throughout a system. The development process can be simplified, from analysis to requirements to implementation, through the use of the building blocks of classes and objects. [12, 18, 3]

The use of objects makes it easier to change and modify systems. For example, the year 2000 (Y2K) problem may have been eliminated by identifying a date object within a system and accessing this object when you needed to date an operation. If the date object had the state variables of month, day and year with each defined as two-character variables, the only change that would be necessary to correct the Y2K problem was to change the year state variable of only the date object. No need to examine multiply lines of code or to use significant resources to locate all the processes using a date functionality and the appearance of it in a procedural program. Modification of systems can also be accomplished through adding methods or state variables to objects. Because encapsulation isolates unnecessary methods and messages from other objects, you can add this type of information to an object to allow it to interact with another object. Theoretically, you are changing the system without having an effect on the existing object interactions. [12, 3]

The risks associated with the development process are reduced by providing a methodology that promotes understanding of a system, making information easy to use and reuse throughout a system, and developing a system that is easier to modify and change making the maintenance process easier. It helps to reduce the complexity of the analysis and development process.