Design Patterns

Design Patterns

Introduction

Software quality has been recognized as an important topic since the early days of software engineering. In this paper, we describe our research and why we focus on evaluating a design pattern. In the past, researchers and practitioners have various approaches to examine how systems can meet specific software quality requirements. Recently, a growing number of practitioners have shown great interest in using design patterns for high-quality software, since design patterns represent high-level abstractions that reflect their own experiences. Design patterns have become a popular means to encapsulate object-oriented designs. They capture successful solutions to recurring problems that arise when building software systems.

As the paradigm continues to increase in popularity, analyzing design patterns in order to verify their correctness is becoming increasingly important. In general, a design pattern consists of four essential sessions : the pattern name session which describes the design problem, its solutions, and consequences in short sentences, the intent session which describes situations in which the pattern may be applied, the solution session which provides an abstract description of the solution, including the elements of the solution as well as their relationships and collaborations, and the consequences session which describes the benefits and drawbacks of using this pattern. In a well-designed design pattern, the sessions should be consistent with each other. For example, the structural model in the solution session should resolve the problem indicated in the intent session. In this paper, we focus on the consistency validation between the intent and solution sessions.

Design patterns and design metrics, we propose a quantitative approach in this paper to measure the effectiveness of a pattern to improve the quality properties of a design. Our approach provides the following benefits:

• An evaluation approach is proposed to help pattern developers check if a design pattern is well-designed.

• A quantitative method is proposed to measure the effectiveness of the quality improvement of a design pattern. Based on this information, pattern users can determine which design patterns are applicable to meet their functional and quality requirements.

In general, a design pattern consists of four essential sessions: pattern name, intent, solution, and consequences. The solution is informally presented by using class and interaction diagrams in model level, i.e., the model is an example model. For example, the structure of the solution of the design pattern Abstract Factory is presented in Fig. 1a, showing an example of two products families (family A and family B). The limitation of this concept is, though Abstract Factory can be applied to multiple product families, the structure cannot convey this concept in a systematic way.

Figure 1: Structure of a pattern solution: two kinds of representation.

Literature Review

The term “design patterns” sounds a bit formal to the uninitiated and can be somewhat off-putting when you first encounter it. (Alexander, 2007) But, in fact, design patterns are just convenient ways of reusing object-oriented code between projects and between programmers. The idea behind design patterns is simple-- write down and catalog common interactions between objects that programmers have frequently found ...