What is a mode? What is a framework? Why is software layered?

Patterns and frameworks are everywhere in software design. A friend once asked me what is the mode? I am also studying and give the following summary about my learning experience. (Note: personal opinions are for reference only. please correct me .)

1. What is the mode?

Pattern. It is actually a methodology for solving a certain type of problems. You sum up the methods for solving a certain type of problems to the theoretical level, that is, the mode. Alexander's classic definition is that each mode describes a problem that is constantly emerging in our environment, and then describes the core of the solution to the problem. In this way, you can use existing solutions countless times without repeating the same work. The mode has different fields, the construction field has the construction mode, and the software design field also has the design mode. When a domain gradually matures, many models will naturally emerge.

2. What is the framework?

Framework. In fact, it is a semi-finished product of an application, that is, a group of parts for you to choose to complete your own system. Simply put, you can use a stage set up by others to perform performances. In addition, the framework is generally mature and constantly upgraded software.

3. Why use the mode?

Because the mode is a kind of guidance, under a good guidance, it will help you complete the task, and help you make a good design solution to achieve twice the result with half the effort. In addition, we can find the best solution to the problem.

4. Why use the framework?

As software systems have become very complex today, especially the knowledge, content, and problems of server-side software and design. Using someone else's mature framework in some ways is equivalent to letting someone else do some basic work for you. You only need to concentrate on completing the business logic design of the system. In addition, the framework is generally mature and robust. It can handle many details of the system, such as transaction processing, security, and data flow control. There are also frameworks that are generally used by many people, so the structure is very good, so the scalability is also very good, and it is constantly upgraded, you can directly enjoy others' upgradesCodeBenefits. The framework is generally located at the intermediate layer between the low-level application platform (such as J2EE) and the high-level business logic.

5. Why is software layered?

To achieve "High Cohesion and low coupling ". The problem is divided into various solutions, easy to control, easy to extend, and easy to allocate resources... in short, there are many advantages :).

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