One of thinking in UML Reading Notes

• Grady booch's discussion about Object-Oriented Programming: "I have never reused the objective of object-oriented programming. On the contrary, for me, objects provide a way to deal with complexity issues, this question can be traced back to Aristotle: Do you regard this world as a process or an object? Prior to the rise of object-oriented movement, programming was process-centric, such as structured design methods. However, the system has reached the extreme level of complexity that surpasses its processing capabilities. With objects, we can build a larger and more complex system by improving the Abstraction Level-I think this is the true victory of the object-oriented programming movement ".
• The process-oriented method assumes that our world is composed of small systems that are mutually associated. Each small system has a clear start and end, and there is a rigorous causal relationship between the start and the end. As long as we analyze every step of these small systems and all the factors that affect the evolution of the small system, we can fully define the behavior of this system.
• We need to analyze the world and use computers to simulate it. The first task is to depict this process and define their causal relationships. Then, through a structured design method, these processes are refined to form a controllable part with a smaller scope. Usually, the process-oriented analysis method is to find the starting point of the process, and then analyze each part until it reaches the end of the process. Every part of this process is an integral part of the process chain.
• The difficulty of process-oriented methods in practical application is that it regards the world as a process-oriented, closely connected small systems, and each part of the system has an inseparable causal relationship. This analysis method is very useful when the demand complexity is low, but the simulated system is very complicated and unpredictable. There are too many factors to form a system, it is not difficult to take all possible factors into account, analyze all the causal relationships clearly, and simulate this process.
• The object-oriented method regards the world as an independent object and has no causal relationship between them. They are usually "heard from each other and never die" and only driven by a certain external force, objects transmit information to each other based on a certain rule. These interactions constitute a "process" in this vivid world ". Without external force, the object remains static.
• Object-oriented methods and process-oriented methods are fundamentally different in that they do not regard the world as a closely related system, but as independent small parts which are organized according to certain rules, complete a specific function. The process is not the source of the world. It is expressed by some objects organized by specific rules.
• Difficulties in Object-Oriented Methods: 1. How are objects abstracted? The real world and the object world seem very different. Why is it so abstract rather than so abstract? 2. Because of its flexibility, the object world can be combined at will. But how can we know that a combination meets the needs of the real world? What kind of combination is good and what kind of combination is poor? 3. Aside from the real world, the object world is so hard to understand. How can I understand the meaning of an object combination?
• There is an abstract gap between the real world and the object world. to cross this gap, we need to: 1. A method to map the real world to the object world. 2. A method to describe the real world from the object world. 3. A method to verify whether the behavior of the object world correctly reflects the real world.
• If we stand at a very high level of abstraction and look at the operation of the world from a highly summarized perspective, we will find that no matter how complicated the real world is, no matter what industry or business we do, it is essentially composed of people, things, things, and rules. People are the center of everything. If people want to do things, they will use things and generate other things. At the same time, they must follow certain rules. A human-driven system that reflects the process and records the results. The rule is control. The key to building a model is to understand who is, who is doing, what is generated, and what rules are in the middle, then define the relationship between people, things, and things, and a model is basically formed.
• Modeling process: from the real world to the business model, from the business model to the conceptual model, from the conceptual model to the design model.