Object-oriented method is a system approach to object-oriented ideas to guide development activities, referred to as an OO method, which is based on object concepts (objects, classes, and inheritance). Since the mid-1980s, people focus on object-oriented analysis and design, and gradually formed an object-oriented methodology. Typical methods include P. COAD and E.YOURDON Object-Oriented Analysis (OOA) and object-oriented design (OOCH object-oriented development), Object Modeling Technology (OMT), which is proposed by J.Rumbauh et al. (OMT), Object-oriented Software Engineering (OOSE), Jacobson. In the 1990s, G.Booch, J.Rumbaugh, Jacobson et al., Launched a unified modeling language (UML) on the basis of the Booch method, OMT method, and OOSE, and was organized by international object management in 1997 ( OMG) Determine as a standard modeling language.
The appearance of object-oriented methods is quickly favored by the computer software industry, and has become the mainstream development method of the 1990s, and the cause can be analyzed from the following aspects:
(1) From the perspective of a cognitive, the object-oriented method is in line with people's understanding of the objective world.
For a long time, we analyzed, design, and realize a software system process with the process of knowing a system. For example, use structured analysis and design methods, information engineering methods. Object-oriented analysis and design use the same graphical representation, analysis, design, and implementation are based on objects, so there is a good seamless connection between the phases of object-oriented development. When the user's demand has changed, due to the entity in the objective world, the connection between the entities is basically unchanged, so the overall structure of object-oriented is relatively stable, and most of the changes caused by most concentrated in the object. Attributes and operations between operations and objects. In short, the object-oriented method is in line with the law of the understanding of the objective world, and the system developed is relatively stable.
(2) Software systems developed for object-oriented methods are easy to maintain, and their architecture is easy to understand, expand and modify.
Software systems developed by an object-oriented method consists of object classes, and the encapsulation of objects excels with abstract and information hidden characteristics. Objects are used as an interface (interface), and users can only access objects (request their services), and the specific implementation details of the object are invisible. These features make the architecture of the software system modularly, which is easy to understand, expand and modify. When the object's interface is determined, the modification of the implementation details will not affect other objects, easy to maintain. It also facilitates the distribution to different developers, and the system can be easily assembled according to the specified interface.
(3) Inheritance mechanism in the object-oriented method strongly supports the reuse of software.
In different application systems in the same application, there is often a lot of the same or similar entities that there are many identical attributes and operations in different application systems, and there are also some different application systems. The properties and operations. . When developing a new software system, you can copy some classes in the existing system, by inheritance and supplementing a class of new systems. In the same application system, there are also some public properties and operations between some classes, and their respective private properties and operations are also included. This can also be multiplexed by inheritance to reuse public attributes and operations.
