Introduction
Unified Modeling Language (UML) is a visual modeling language used to represent software systems. It provides a standardized set of graphical symbols and notations for creating visual models that facilitate the exchange of design concepts and requirements among collaborators involved in the design process (Unhelkar, 2017). Generally, UML is widely used in software development because it reduces complexity, improves communication among development teams, and ensures that the system’s design aligns with its requirements. Consequently, UML can be used to model various types of projects, or diagrams to be more specific. There are different types of diagrams, the most common examples being use case diagrams, class diagrams, and sequence diagrams, all of which vary in size.
The UML Project Types
Overview
UML diagrams are a visual representation of software systems and their components. They are widely used in software engineering to illustrate the structure, behavior, and relationships of various elements within a system. UML diagrams provide a way to describe complex software systems in a manner that is easily understood by developers, testers, and project managers with minimal effort. They can be used throughout software development, from gathering requirements to designing, testing, and distributing.
Use Case Diagrams
The use case diagram is one of the most common representations of UML diagrams. To put it briefly, it provides an overview of the user’s interactions with the system and the system’s response to those interactions. According to Fenn (2017), “The use case diagrams allow consultants to present a high-level project view to clients and ensure all parties have a clear understanding of the system functionality…” (p. 48). Additionally, the use case diagrams are considered to be behavioral-static in nature. The behavior concerns how a user interacts with the system, whereas the static aspect means that the concept of time is absent in the model.
Class Diagrams
Class diagrams, in turn, deal with classes, their definitions, and the relationships between them. They are used to depict the static structure of a system, including its attributes and methods. In such a diagram, each class is represented as a rectangle, with the class name at the top and its attributes and methods listed below.
The attributes represent the data that the class stores, and the methods represent the actions that the class performs. Arrows between classes show their relationships, such as inheritance, composition, or aggregation (Unhelkar, 2017). As can be seen, class diagrams help reflect the relationships between classes and provide an understanding of a system’s structure, regardless of the project’s size.
Sequence Diagrams
The sequence diagram is the last-mentioned representative of the most common UML diagram types. These diagrams depict the interactions between objects or components in a system or process over time. Unlike the use case type, this type is rather dynamic than static in terms of changes over time, as its objects interact with each other based on their timelines. In practice, time flows from top to bottom: the vertical axis displays time, with each vertical line indicating a moment. In contrast, the horizontal axis shows different objects involved in the interaction.
Again, objects and other system components are represented as rectangles. Conditions and loops can also be visualized using UML sequence diagrams, providing the possibility for implementing complex interactions (Unhelkar, 2017). UML sequence diagrams generally help in understanding the behavior of complex systems and identifying potential related errors.
UML Project Sizes
Overview
Despite the diversity in project types, there is also a diversity in UML project sizes. There are four main types: small, medium, large, and collaborative. Each size handles a different amount of information represented in a diagram, with the collaborative size offering an interpersonal approach. UML projects require specific sizes depending on the type of diagram being created and described.
Small Size
UML may be used to create small diagrams to illustrate the architecture and behavior of a simple software system. These can include class diagrams, use case diagrams, or activity diagrams. UML is also helpful in creating sequence diagrams that illustrate the data flow between objects in the system (Unhelkar, 2017). These diagrams can help communicate the design to other team members quickly and without additional explanations, ensuring that the entire project is consistent and complete.
Medium Size
In medium-sized projects, UML is a helpful tool for creating complex diagrams that capture the system’s details, such as class or sequence diagrams. These diagrams can help identify the system’s key components and interactions. However, such diagrams are now more elaborate and decadent regarding objects and their relations (Unhelkar, 2017). They may be used to visualize the flow of information and the interactions between different modules or components.
Large Size
A large project size uses UML for designing and documenting complex systems that require a thorough and precise development process. It includes modeling the system’s architecture, specifying its components and interfaces, defining its behavior, and representing its interactions with external systems and actors (Unhelkar, 2017). Some UML diagrams commonly used in large projects include case, class, sequence, activity, and component diagrams.
Collaborative Size
The last UML project size is somewhat peculiar in terms of its fulfillment. A collaborative project involves multiple teams developing a large and complex software system. In such projects, UML defines the architecture and design of the system, ensuring that all teams work cooperatively to achieve a common goal (Unhelkar, 2017). Class, sequence, and use case diagrams are commonly used to exchange the system’s design and requirements among different teams.
Conclusion
The Unified Modeling Language (UML) is a standard visual modeling language used to analyze, design, and implement software-based systems. It is a general-purpose language that can be used for modeling systems in various domains, including software engineering, business, and finance. As Bashir et al. (2016) point out, “UML is the most popular modeling language and has become the de facto standard to design today’s large object-oriented systems” (p. 883).
The UML models are generally referred to as diagrams, the most popular being use case, class, and sequence diagrams. Additionally, each type has to have its own project size. There are specific UML project sizes, including small, medium, large, and collaborative, which involve multiple teams working on the same project. UML can boast about 14 different diagram types and four diagram sizes. UML is an effective tool for detailed projects because it helps manage complexity, maintain consistency, and communicate design decisions to collaborators and contributors.
References
Bashir, R. S., Lee, S. P., Khan, S. U. R., Chang, V., & Farid, S. (2016). UML models consistency management: Guidelines for software quality manager. International Journal of Information Management, 36(6), 883-899. Web.
Fenn, B. (2017). UML in agile development: Back to basics: Unified modeling language (UML) diagrams can clarify project requirements at the front end of agile development to visually explain how a project should look and function. Control Engineering.
Unhelkar, B. (2017). Software Engineering with UML. CRC Press.
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