Pattern based design is a technique that reuses the design elements. Each architectural pattern, design pattern, or idiom is cataloged, thoroughly documented and carefully considered as it is assessed for inclusion in a specific application.
A description of design pattern may consider a set of design forces. Design forces are those characteristics of the problem and attributes of the solution that constrain the way in which the design is developed. These design forces also describe the environment and conditions that must exist to make design pattern applicable.
Types of design patterns available are:
- Architectural patterns
The overall structure of software, relationship among subsystems and software components and rules are defined for relationship among elements of architecture.
- Design patterns
It addresses a specific element of design to solve some design problem, relationships among components or mechanisms for good communication among components.
- Idioms
These are language specific patterns. They implement the algorithmic element of a component. They can act as a specific interface protocol or a mechanism for communication among components.
Sunday, July 24, 2011
Introduction to Pattern-based design in software design?
What are four major elements of design model in software engineering ?
There are two dimensions in which a design model can be illustrated: process and abstraction dimension. Process dimension points the changes in the design model as the design tasks are implemented as part of software process. Abstraction dimension represents the level of detail as each element of analysis model is transformed into design equivalent and refined iteratively.
Design model elements are not developed in a sequential fashion. The design model has four major elements:
- Data
- Architecture
- Components
- Interface
Data design focuses on files or databases at an architectural level and on a component level, data design considers the data structures that are required to implement local data objects.
The architectural model is derived from the application domain, the analysis model and available styles and patterns.
The interface design elements for software tells us how the information flows in and out of the system and how it is communicated among the components. There are three parts to interface design elements: the user interface, interfaces to systems external to application and interfaces to components within the application.
User interface elements include aesthetic elements, ergonomic elements and technical elements. External interface design requires information about entity to which information is sent or received. Internal interface design is closely related to component level design.
The component level design elements describes the internal detail of software component. The component level design defines data structures for all local data objects and algorithmic detail processing that occurs within a component and an interface that allows access to all behaviors.
