What is Object Design & How its Different from UML Notations?


Object design is the process of designing objects in software systems that represent real-world objects, concepts, or entities. It is a critical aspect of software engineering that involves creating a blueprint or a set of specifications that describes the attributes, behaviors, and relationships between objects in a software system. The primary objective of object design is to create a robust and scalable software architecture that is easy to maintain, extend, and modify. In contrast, UML notations are graphical representations that are used to document the various aspects of a software system, including its architecture, structure, behavior, and interactions between components. In this article, we will explore the differences between object design and UML notations and how they are used in software development.

Object Design

Object design is a systematic approach to designing software systems that are object-oriented. In object-oriented programming, objects are used to represent real-world entities or concepts, and they encapsulate their data and behavior. Object design involves identifying the objects and classes that are required to implement the functionality of the software system. This involves defining the attributes of the objects, the methods they use to interact with other objects, and the relationships between them.

Let us consider an example to illustrate the process of object design. Suppose we are designing a library management system. In this system, there are several objects that we need to consider, such as books, borrowers, and librarians. We would start by identifying the attributes of these objects. For example, a book object might have attributes such as title, author, ISBN, and publication date. A borrower object might have attributes such as name, address, and library card number. Similarly, a librarian object might have attributes such as name and employee ID.

Once we have identified the objects and their attributes, we can move on to defining the methods that these objects will use to interact with each other. For example, a borrower might check out a book from the library by using a check-out method provided by the library system. The check-out method would update the book's status to "checked out" and associate it with the borrower's library card number. Similarly, the borrower might return the book by using a return method, which updates the book's status to "available" and removes the association with the borrower's card number.

In addition to defining the methods and attributes of the objects, object design also involves defining the relationships between the objects. In the library management system example, we might define a "has-a" relationship between the borrower and the book objects, indicating that a borrower can have several books checked out at any given time. Similarly, we might define a "has-a" relationship between the librarian and the book objects, indicating that a librarian can manage the circulation of books.

UML Notations

UML notations are graphical representations that are used to document various aspects of a software system. UML stands for Unified Modeling Language, and it is a standardized language that is used in software engineering to design, document, and communicate the various aspects of a software system. UML notations are used to describe the architecture, structure, behavior, and interactions between components in a software system.

There are several types of UML notations, including class diagrams, use case diagrams, sequence diagrams, and activity diagrams. Each type of UML notation is used to represent a different aspect of the software system.

Class diagrams are used to represent the structure of a software system. They show the various classes in the system, the attributes of each class, and the relationships between the classes. For example, a class diagram for the library management system might show the Book, Borrower, and Librarian classes, along with their attributes and relationships.

Use case diagrams are used to represent the functionality of a software system. They show the various use cases or scenarios that the system can support and the actors that interact with the system. For example, a use case diagram for the library management system might show use cases such as "check out book," "return book," and "search for book," along with the actors that perform these actions, such as borrowers and librarians.

Sequence diagrams are used to represent the interactions between objects in a software system. They show the order in which messages are sent between objects and the responses that are received. For example, a sequence diagram for the check-out process in the library management system might show the borrower object sending a message to the library system to check out a book, and the system responding with a confirmation message.

Activity diagrams are used to represent the workflows or processes in a software system. They show the steps involved in completing a task or process and the decisions that are made along the way. For example, an activity diagram for the check-out process in the library management system might show the steps involved in checking out a book, such as searching for the book, verifying the borrower's eligibility, and updating the book's status.

Differences Between Object Design and UML Notations

Object design and UML notations are closely related, but they serve different purposes in software development. Object design is concerned with the actual implementation of the software system, while UML notations are used to document and communicate the design.

One key difference between object design and UML notations is the level of detail. Object design is a detailed process that involves identifying the objects, attributes, methods, and relationships that are required to implement the system. UML notations, on the other hand, provide a high-level overview of the system's architecture, structure, behavior, and interactions.

Another difference between object design and UML notations is the audience. Object design is primarily intended for developers who will be implementing the system, while UML notations are used to communicate the design to a wider audience, including project managers, stakeholders, and other developers who may not be familiar with the details of the implementation.

Finally, object design is an iterative process that involves refining the design as the system is developed, while UML notations are typically created at the beginning of the development process and are used as a reference throughout the project.

Conclusion

Object design and UML notations are both important aspects of software engineering. Object design is concerned with the actual implementation of the software system, while UML notations are used to document and communicate the design. Object design involves identifying the objects, attributes, methods, and relationships that are required to implement the system, while UML notations provide a high-level overview of the system's architecture, structure, behavior, and interactions. By understanding the differences between object design and UML notations, software developers can create more robust and scalable software systems that are easy to maintain, extend, and modify.

       

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