Use Case Conceptual Analysis and staruml instances in UML

Use Case Conceptual Analysis and staruml instances in UML

In UML, use case is similar
The most simple function of case modeling is to express the functional requirements or behaviors of the system. In my understanding, Case modeling can be divided into use case diagrams and use case descriptions. The use case diagram consists of the actors and use cases.
(Use
Case), system boundary, arrows, and draw. Use case description is used to describe each use case in the use case diagram in detail, completed in a text document, and various relationships composed of arrows, including
Integration, inclusion, and expansion. This article will introduce the following content. All the diagrams are drawn by powerdesigner.

U usage

U participants

U Generalization

U <use>

U <include>

U <extend>

U case description

1. Usage ( Use Case ) 

　

Figure 1 usage Diagram

Is a description of a group of action sequences (including its variants). The system executes this action to generate an observed result value for the participants who execute this action. For example, if you use a calculator, you can consider the calculator as a usage. The participant is the peak, and the peak is 3 + 3 (the sequence of Running Conditions). The calculation machine returns a result 6.

2. Participants (Actor)

A participant is not a specific person, but a role outside the system in the use of the system or in interaction with the system. Therefore, participants can be people, things, or
Time or other systems. Note that participants do not refer to people or things themselves, but to the roles played by people or things at the time. For example, James is a library administrator who participates in the library management department.
At this time, he can take the role of administrator to participate in management, or as a borrower to borrow books from the library. Here, James plays two roles, two different participants. Simple use of participants in drawing
The name of the participant is attached to the figure.

　

3.Generalization

Generalization is the same as generalization in a class. The sub-condition inherits the behavior and meaning of the parent condition, and can also increase or overwrite the behavior of the parent condition; the sub-condition can appear in any parent condition (the parent and the sub-condition have specific instances ). The following two diagrams describe the concept and meaning of generalization.

Figure 2 meaning inheritance Figure 3 behavior inheritance

 4.<User>

<Use>: the relationship is very similar to a function call or a subprocess.

Because the use case cannot exist independently, it must be used by other use cases. See

 

　

Figure 4 Use <use> example

 

 

5.<Include>

How to explain this definition? Let's explain its functions. <include> you can separate the common steps of several use cases into a separate included use case. A friend who has learned C knows what it means. Haha

Okay, I already know the definition. The following is an example to help you better understand it. If there is a personnel system, the manager can view the employee information and add, modify, and delete the employee. However, each time the three operations are performed, the corresponding employee should be located, locate the employee to be operated. Figure 5 shows the use case diagram of this expression. Please understand the meaning of <include>

 

　

Figure 5 usage of <include>

6.<Extend>

<Extend> This provides a method for adding new behaviors to existing use cases. The basic use case provides a set of extended points (extend points), which are hooks. You can add new behaviors here. The extended use case provides a set of inserted fragments, these fragments can be inserted to the hooks of the basic case. Note that the basic use case does not know any details about the extended use case. It only provides hooks for the extended use case. This is different from <include>. If no use case is included, the customer use case is incomplete. Figure 6 Description

　

Figure 6 usage of <extend>

7. use case description

Of course, the case description is a textual description of the case. I will not talk about the specific items to describe here. I will give you a specific example to understand. Assume that there is a tutor network, and the following is just an abstract clip. The main purpose is to explain the meaning of the case description.

　

The following describes the use cases of website announcements.

Case name: Website announcement

Use Case ID202

Participants: Owner

Brief Description: The owner is used to fill in and modify the home page announcement of the tutor website. The announcement is displayed on the home page of the tutor website.

Prerequisites: The Administrator has logged on to the tutor website management system.

Basic event stream: 1. The owner clicks the "Modify announcement" button. 2. The system displays a text box showing the original announcement content. 3. The owner can modify or delete the announcement in the text box and re-write the new announcement. 4. After editing the text box, press the "Submit" button to modify the homepage announcement. 5. Use case termination

Other event streamsA1: Before you press the "Submit" button, the owner can press the "return" button at any time. Any modification to the text box will not affect the announcement of the website homepage.

Abnormal event stream: 1. An error message is displayed. The owner confirms the error message. 2. Go back to the Management System homepage.

Post Condition: The announcement information on the homepage is modified.

Note: None

Well, we will introduce this in the case section. It is mainly used for the abstract description of the entire system in modeling. Is the description at the function layer. It's time for work, huh?