In software and systems engineering, the USE CASE diagram is a list of actions or steps of an event that typically define the interaction between a role (known in the language of unified modeling as “actor”) and a system to achieve a goal. An “actor” can be a human or other external system.
Definition
UML USE CASE diagrams are an important and valuable requirement analysis method that has been widely used in modern software development since its official introduction by Ivar Jacobson in 1992. Application development depends on many process models and structures, such as ICONIX, Unified Process (UP), IBM Rational Unified Process (RUP), and Oracle Unified Method (OUM).
History
In 1986, Ivar Jacobson first formulated textual, structural, and visual modeling techniques to identify use cases. In 1992, his co-author of the book "Object-oriented software development - an approach based on the USE CASE", helped to popularize the technique of collecting functional requirements, especially in software development.
Other experts have also made significant contributions, in particular Alistair Cockburn, Larry Konstantin, Dean Leffingwell, Kurt Bittner and Gunnar Overgaard.
In 2011, Jacobson published an update on his work called Use Case 2.0 with the intention of incorporating many of his case studies from the moment the concept was created.
The nature of the interaction of elements
The diagram defines the interaction between external participants and the system in question to achieve the goal. An actor can be a person, company, or organization, a computer program, system hardware, or software.
A participant can play both an active and a passive role: for example, a consumer is both a buyer (not interacting with the system) and a user ("actor" actively interacting with the purchased product). In turn, the user is a regular operator (an “actor” using the system for its intended purpose) and a functional beneficiary (an interested party using the system).
USE CASE diagrams: composition, types of relationships
USE CASE is a software and systems engineering term that describes how the user uses the system to achieve a specific goal. This process acts as a software modeling method that defines the functions that must be implemented and the resolution of any errors that may occur.
There are three main elements to the process:
"Actors" are the type of users who interact with the system.
System - functional requirements that determine the intended behavior of the elements.
Goals - The USE CASE is usually initiated by the user to accomplish goals that describe the actions and options involved in achieving them.
Method characteristics:
Organization of functional requirements.
Modeling the goals of interaction between users of the system.
Record scripts from trigger events to end targets.
A description of the main course of action and the exceptional flow of events.
Allow access to the functions of another event.
Steps in developing diagrams:
Identify system users.
For each category, create a user profile. This includes all roles related to the system.
Identify the important goals associated with each role to support the system. The price offer of the system determines a significant role.
Create usage examples for each target associated with the template, and maintain the same level of abstraction throughout the use case.
The steps for using a higher level are considered goals for a lower level.
Terminology
The USE CASE diagram in Rational Rose is a dynamic behavior diagram in UML that models the functionality of a system using participants, use cases, and other critical objects. Use cases are a set of actions, services, and functions that a system must perform. In this context, a system is something that is developed or operated, such as a website. “Actors” (conditional term) are people or organizations that work under certain roles within the system.
What are USE CASE diagrams used for?
Diagrams are valuable for visualizing the functional requirements of the system, which will be embodied in the choice of design and development priorities. They also help identify any internal or external factors that may affect the system and should be taken into account.
USE CASE use case diagrams provide good, high-level, off-system analysis and indicate how the system interacts with participants without worrying about the details of implementing this functionality.
What is a UML diagram?
USE CASE Chart UML is a way to visualize software using a set of charts. The founders of the technology are Grady Butch, James Rumbo, Ivar Jacobson and Rational Software Corporation. Their work formed the basis of object-oriented design, then the specifications were expanded to cover a wider range of software development projects. Today, UML is being adopted by the Object Management Group (OMG) as a standard for the development of simulation software.
To answer the question of what a usage diagram is in UML, you must first understand its building blocks. Common components include:
users who interact with the system;
a certain sequence of actions and interactions between participants and the scenario of the system;
end result - a successful diagram should describe the actions and options used to achieve the goal.
In the professional community of programmers, USE CASE “Ryaba hen” charts are often used to explain the structure - a visual depiction of the plot of a popular fairy tale in the form of a diagram.
What is UML?
UML stands for Unified Modeling Language. UML 2.0 helped expand the original specification to cover a wider portion of software development efforts, including agile methods. The following developments were also implemented:
improved integration between structural models, such as class diagrams and behavior models (activity diagrams);
added the ability to define a hierarchy and decompose a software system into components and subcomponents;
there are nine diagrams in the original UML - UML 2.0 increases this number to 13;
four new diagrams are called: communication diagram, composite structural diagram, interaction overview diagram, and time diagram. This release also renamed state diagrams to state machine diagrams, or state diagrams.
The key to creating a UML diagram is combining the forms representing an object or class with other shapes to illustrate the relationship between the flow of information and data.
Chart types
Current UML standards require thirteen different types of diagrams: class, activity, object, use case, sequence, package, state, component, relationship, composite structure, interaction overview, time, and deployment.
These diagrams are organized into two different groups: structural and behavior (or interaction) diagrams.
Structural, in turn, are divided into the following types of diagrams:
Classes are the foundation of almost every object-oriented method, including UML. They describe the static structure of the system.
Packages are a subset of class diagrams. Developers sometimes consider them as a separate method. Packet charts organize system elements into related groups to minimize dependencies between packages.
Objects - describe the static structure of the system at a specific time. They can be used to check class diagrams for accuracy.
Composite structural diagrams show the inside of the class. Model the functionality of the system using participants and use cases.
Components - describe the organization of physical software components, including source code, executable file (binary code).
Deployment diagrams show the physical resources in the system, including nodes, components, and connections.
Behavioral diagrams include:
Activities - illustrate the dynamic nature of the system by modeling the flow of control from activity to activity. An action is an operation on a certain class in a system, which leads to a change in the state of the system. Typically, activity charts are used to model a workflow or business processes and internal work.
Sequences - Describe interactions between classes in terms of messaging over time.
States - describe the dynamic behavior of the system in response to external stimuli. State diagrams are especially useful in modeling reactive objects whose states are triggered by certain events.
Relationships - model the interaction between objects in a sequence. They describe both the static structure and the dynamic behavior of the system. In many ways, they are a simplified version of the collaboration diagram introduced in UML 2.0.
Interaction Overview - A combination of activity and sequence diagrams. They simulate a sequence of actions and allow deconstructing more complex interactions into controlled occurrences.
Temporary - A type of behavioral or interactive UML diagram that focuses on processes that occur over a period of time. They are a special example of a sequence diagram.
Symbols and Designations
There are many different types of UML diagrams, and each of them has its own character set. Class diagrams are one of the most common UML diagrams, and class diagram symbols are one of the important attributes. For example, there are characters for active classes and interfaces. A class symbol can be fragmented to show the operations, attributes, and responsibilities of a class.
Lines are also important symbols to indicate relationships between components. Generalization and inheritance are indicated by empty arrows.
Dependencies are indicated by a dashed line with an arrow. Using << >> allows you to specify the properties of this dependency. Plurality is usually displayed with a number at one end of the arrow and * at the other.
Package diagrams have characters that identify a package that looks like a folder. Action diagrams include separate characters for the start and end state. The control flow is usually indicated by an arrow, and the flow of an object by a dashed arrow.
Case use diagrams have symbols for participants and use cases.
Why do we use UML?
A comprehensive corporate application with a large staff requires a solid planning framework and clear communication between team members as the project progresses. Visualization of user interaction, processes and the structure of the system that you are trying to create will help save time and make sure that all team members are actively involved in the process.
Sequential diagrams describe interactions between classes in terms of messaging over time. They are also called event diagrams and are a good way to visualize and validate various execution scripts. These objects can help predict how the system will behave and discover the responsibilities that a class must fulfill in the process of modeling a new system.
An example of a USE CASE diagram is a graphic representation of interactions between system elements. This is the methodology used in system analysis to identify, refine and organize system requirements. In this context, the term “system” refers to what is being developed or operated, for example, a website for the sale and maintenance of goods by mail. USE CASE diagram in UML (Unified Modeling Language) is a standard notation for modeling objects and real-world systems.
Deciphering concepts
The goals of the system may include planning general requirements, checking hardware design, testing and debugging a software product being developed, creating help on-line help, or performing a customer-oriented task. For example, using the USE CASE diagram option diagram in a sales environment includes ordering products, updating a catalog, processing payments, and customer relationships. The usage chart looks like a block diagram. Intuitive symbols are elements of a system. USE CASE ATM chart use case scenarios contain four components:
The border that defines the system of interest in the world.
"Actors", usually people associated with the system, are defined according to their roles.
Use cases that are specific roles played by "actors" in and around the system.
The relationship between the subjects.
In a unified modeling language, a diagram can summarize information about users of your system (also known as subjects) and their interaction with the system. To build a single object, you will use a set of specialized symbols and connectors. For example, the USE CASE diagram of an online store can help your team discuss and present:
Scenarios in which your system or application interacts with people, organizations, or external systems
goals and methods to achieve them;
system volume.
Practical use
The USE CASE diagram is not very important in the absence of a clear understanding of the process - it will not simulate the order of the steps if a clear algorithm is not laid. Experts recommend using these charts to complement the text version. The high-level diagram illustrates the relationship between use cases, actors, and systems. For this reason, USE CASE uml diagrams for a political party are often used in modeling the structure.
The diagram is ideal in such situations:
presentation of the goals of system-user interactions;
definition and organization of functional requirements in the system;
identification of the context and requirements of the system;
modeling the main flow of events in a use case.
Thanks to optimal visualization, when modeling USE washing machine software, CASE diagrams are used very widely.
For modeling the system, the most important aspect is the capture of dynamic behavior, which means the behavior of the system at its launch and further work. In UML, there are five diagrams available for dynamic modeling, and the USE CASE diagram example is the most obvious.
Appointment
The purpose of the chart is to capture the dynamic aspect of the system. However, this definition is too general to describe the purpose. Since the other four charts (activity, sequence, sharing and Statechart) also have the same goal. USE CASE diagrams are used to collect system requirements, including internal and external influences (as a rule, these are design requirements). Therefore, when a system is analyzed to collect its functionality, examples of use are developed and participants are identified.
When the initial task is completed, the charts of random situations are modeled to represent the appearance. The goals when creating USE CASE diagrams are:
collection of requirements;
obtaining the appearance of the system;
the influence of external and internal factors;
visualization of the interaction between requirements and actors.
Process of creation
Usage diagrams are used to analyze high-level system requirements. When system requirements are analyzed, functionality is captured in use cases.
It can be said that use cases are nothing more than system functions written in an organized way.
Charts are used to account for the functional requirements of the system. After defining the above points, we should use the following recommendations to build an effective use chart:
The use case name is very important - select it in such a way that it can identify the functions performed.
Give a suitable name for the actors.
Show the relationships and dependencies in the diagram.
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