Object-oriented Requirement Analysis-use case diagram and activity diagram

Object-oriented software development methods include: A, object-oriented analysis (OOA) B, object-oriented design (OOD) C, object-oriented implementation (00i) d, the main steps of object-oriented testing (OOT), E, and object-oriented maintenance (OOM) are as follows. Next we will learn the related diagrams of UML from the object-oriented perspective. This section describes the use case diagram and Activity diagram of the object-oriented analysis stage.

 

In the object-oriented analysis stage, we need to clarify the responsibilities, scope and boundaries of the system, determine the functions and performance of the software, and build a demand model (case model ).

 

The main reason for putting these two graphs together is that the activity diagram aims to describe the use case diagram in more detail and use it with the document, make the use case diagram clearer.

 

First introduce: use case diagram

 

1. Concept: Use Cases are a functional unit of the system and a description of user requirements.

2. Composition: participants, use cases, and their relationships (including associations, General relationships, including relationships, and extended relationships ):

3. Steps for case Modeling: A. determine the scope and boundaries of the system; B. Determine System Use Cases and participants; C. Describe use cases; D. classify use cases, determine the relationship between use cases. E. Create a use case diagram and define the hierarchy of the use case diagram. f. Review the use case model.

 

Let's look at an example below: this is a general example of the educational administration system and a sublevel use case diagram. Of course, you can also divide it:

 

 

 

In the above six steps, I will briefly summarize: A, the system boundary, is the line between all elements in a system and the system's external things. B. Use Cases and participants must be abstracted based on actual conditions. C. Describe the use case. Here I will focus on writing (for example, Course Selection Registration ):

 

Case No.: 0101

Case name: Course Selection Registration

Performer: Student

Function: implements the course selection registration process.

Type: main use cases, basic Use Cases

Level: Level 1

Process description:

1. Students enter the system account and password for verification;

2. query course information

3. Query personal course selection information

4. If you can select a course, register the course and write the course selection information to the database.

5. Return whether the course selection registration is successful

Abnormal event stream processing:

1. The student's account and password are incorrect. You can re-enter them three times)

2. students fail to pay tuition on time and cannot select courses.

3. The number of students has reached the upper limit and cannot be selected.

 

(Of course, you can add the following activity diagram here)

 

D. Relationship between case classification and determination. There are endpoint cases, basic cases, main cases, and auxiliary cases. The relationship can be accurate. E. Draw a Use Case chart. the hierarchical structure is the one above, which is divided into Level 1, level 2, and so on, just like the forking tree. F, and finally the specification. Here, you can refer to the standardized Requirement Specification and then review it.

 

Activity diagram:

Activity digraphs can be used to model the dynamic behaviors of the system. They mainly refine the use cases, that is, the internal details of the use cases can be described as activity diagrams. The activity diagram describes the activity sequence. The control flow between the main table activities is an internal processing-driven process. In essence, it is a flow chart. First look at the BASIC icon.

 

 

Since it is a detailed description of the use case diagram, we will describe the course selection registration in the educational administration:

 

 

Here, we use the learning examples and activity diagrams to sort out the object-oriented demand analysis stages. Of course, in actual work, the complexity of the system requires us to use many, multi-layer Use Case Diagrams to describe the actual situation. It is mainly used to learn the basic methods, rules, principles, and steps of drawing. What we need to do is to put aside the opposite, so as to remain unchanged.