Object-oriented design is divided into two stages, namely high-rise design and low-level design
High-level design
The overall model of development software for the development of the system in the high-rise design stage. At this stage, identify the concepts needed to solve problems in a specific computer environment, adding a batch of required classes that include classes that enable software systems to interact with the outside world.
The output of the high level design stage is suitable for the application of the software requirements of the class, the relationship between the classes and application subsystem of the view specification. Typically, the system framework that is derived from object-oriented design is shown in the following illustration.
In the process of high level design, the communication between the high-level parts of the subsystem should be minimized, and the classes with high interaction between each other in the subsystem should be grouped logically.
Low-level design
The low-level design focuses on the detailed design phase of the class. The goal of class design is to form a single concept model---an independent class represents a concept, and the designed parts should be reusable and reliable.
The design principles of information concealment, cohesion well-structured classes coupling and so on should be adopted in the design process of class. In object-oriented technology, the reuse of the stored class is a great advantage.