I learned the "basics" in the UML modeling series.

There are several important concepts that must be understood before you begin to describe UML. These are very important concepts hidden in UML. However, these concepts are hard to understand. The reason for not using UML is that they do not know where to use and how to use them. In essence, they are not understood. The following describes these concepts one by one:

I. Modeling

Modeling is to establish an abstract method of objective things to characterize things and gain an understanding of the things themselves. At the same time, this understanding is conceptual and these logical concepts are organized, it forms an easy-to-understand expression of the internal structure and working principle of the observed object.

Business modeling formula:

 

Ii. Case-driven

Case-driven is a very important concept, or the entire software production process is a case-driven. The implementation case is a required task. Once the use case is implemented, the problem domain is resolved. This is the principle of case-driven methods.

Use Case drivers include:

. Logical view: the system has only one logical view, which graphically describes the implementation of key use cases, including subsystems and classes.

. Process view: There is a process view in the system. This view graphically describes the detailed organizational structure of processes that process activities in the system, including mappings between classes and subsystems to processes or threads.

. Deployment view: the system has only one deployment view. This view graphically describes the distribution of processing activities among nodes in the system, including the physical distribution of processes and threads.

. Implementation view: the implementation view is used to obtain the architectural decisions customized for implementation. It usually includes the following content:

1. List all subsystems in the Implementation Model

2. Describe how subsystems are organized into hierarchical component Diagrams

3. Describe the dependency between subsystems

The role of the Implementation view is:

1. Individual teams and subcontractors allocate implementation work,

2. estimate the number of codes to be developed, modified, and deleted

3. clarify the reasons for large-scale reuse

4. Considering release strategies

The diagram of the use case view is as follows:

　　

Iii. Abstraction Level

Abstract layers are extremely important and difficult to grasp in Object-Oriented Knowledge. First, the higher the abstraction level, the less specific information, but the strongest generalization ability. The richer the generalization information, the more accurate the result. On the contrary, the generalization force is not that obvious. In terms of information expression ability, the higher the abstract level, the richer the expression ability, and the easier to understand. Many friends who use UML will think that it is very difficult to select the granularity of use cases. In fact, the essence of the difficulty in selecting use cases is that they did not find the abstract level.

There are two methods for Abstraction: top-down, bottom-up, and top-down, which are used to let people know things from the beginning. For example, a vehicle can work in a higher level of concept, such as an engine, a sensor device, or a transmission. It is easier to understand the principle of a lower level of motivation. No one can understand the thermodynamic and mechanical principles of a lower level. The bottom-up approach is applicable to the recognition of improvement and improvement in practice. For example, discovering engine problems in practice, improving or improving the engine performance, or replacing a new engine to improve the overall performance of the car. In software programming, the subject should adopt the top-down method, cover the system requirements with a small number of concepts, and gradually reduce the abstraction level until coding. At the same time, the bottom-up method should be used to improve high-level concepts by summing up practical experience at a lower abstraction level to improve the quality of software.

A general abstract hierarchical Process Diagram for a unified process:

 

Iv. View

A view is another very important concept in UML. A view is used to organize UML elements and express elements of a model. Accurate application of views is an important factor in establishing a good model. The angle of view is that people observe things. Different people observe things from different angles. The angle of view is for the view, different perspectives show different cognitive perspectives of the same information for ease of understanding. On the one hand, from the perspective of information display, an appropriate perspective can make it easier for the observer to grasp the essence of information. On the other hand, from the perspective of the observer, he only cares about a part of the information he is interested in. Other perspectives do not make much sense to him. Therefore, it is necessary to select an appropriate perspective and display the information to the appropriate observer.

V. Object analysis methods

Object analysis has the following features:

. Everything is an object

. Objects are independent.

. All objects are atomic.

. Objects are abstract.

. Objects are hierarchical.

The following is an illustration of the object analysis method:

Remember: it is of great significance to quickly understand modeling when you understand these features.