"Demand analysis and system design" reading notes two

I read the fourth chapter of this book is a requirement specification, which illustrates the importance of architecture in system development and shows all aspects of UML. The Pcbmer architecture is also described in the book. Pcbmer represents-controller-bean-Mediator-entity-resource Architecture framework. has been observed in UML modeling. This book is the most detailed introduction to UML, by reading this chapter, it is more clear that the importance of UML modeling in software requirements analysis, compared to learning UML more profound understanding.

The fifth chapter completes the discussion on the requirement analysis and the transition from analysis to the system design, and examines the support of the object technology to the development of large-scale system. Stereotype is the main extension technology of UML. When you complete an extended task, they require constraints and label assistance. The extension mechanism allows modeling outside of the UML pre-defined attributes. The extension mechanism of UML--especially the stereotype--is frequently used. UML provides a number of additional modeling concepts to improve the expression capabilities of the class model, including export properties, export associations, and qualified associations. The most confusing aspect about class modeling is the choice between the association class and the materialized class. The concept of generalization and inheritance is a double-edged sword in the system modeling. On the one hand, it supports software reuse, which improves the abstraction of expressive ability, comprehensible and system model. On the other hand, if used improperly, it has the possibility of destroying all of its advantages. The concept of aggregation and delegation is an important substitute for modeling generalization and inheritance. The delegation and prototyping system has the advantage of supporting hierarchy architecture. Monolithic Component abstraction provides an interesting perspective on how complex systems should be structured. Sequence diagram is a kind of interactive modeling visualization tool that people prefer to use, which provides very good support for deep-level technology-related modeling tasks.

Through the study in this chapter, we make it clear that the design is about system implementation. This chapter describes the two main aspects of design-the system architecture design and the detailed design of the program in the system. A typical is application system is based on client/server architecture principles. Modern software systems are very complex. It is important that the modeling scheme simplify and reduce this intrinsic complexity as much as possible. The most important mechanism for dealing with software complexity is the hierarchical organization of the system architecture. It is the most important architectural goal to logically organize classes into layers according to Pcbmer or similar frameworks. Layered architecture allows us to reduce the structural complexity of the software from exponential to polynomial. Architectural modeling is critical for enforcing the architectural principles of software.

Architecture modeling involves assigning software elements to packages, artifacts, and nodes. These concepts have complex dependencies and interactions-largely because they intersect with logic, physical programs, and data structures.

Reuse is a major design consideration, and it has an impact on architecture and detailed design. You can choose between toolkit reuse, frame multiplexing, and pattern multiplexing. This option is not mutually exclusive-it is recommended to use a hybrid multiplexing strategy.

"Demand analysis and system design" reading notes two