Software Composition Using Behavioral Models of Design Patterns

Software design patterns classification and selection using text categorization approach

Generative software product line development using variability-aware design patterns

Software design patterns are solutions to common software problems that are proven to work adequately in particular scenarios. Deciding which design pattern to use for a given software problem often requires practical knowledge acquired with experience in a similar domain and can be highly subjective and error-prone. Further, for novice programmers, an automated approach would be of tremendous help as it would provide practical knowledge required for deciding which design pattern to use for a particular software problem. The majority of research in software design pattern prediction involves using software structure and features in determining which design pattern to implement. However, there are circumstances where software engineers would prefer to know which design pattern to be used by looking at the design problem during or before the implementation phase. Existing design pattern prediction tools cannot be utilized in this scenario due to the absence of code and class structures. To address this issue, this paper proposes a new approach that analyzes the context of the software problem from text and predicts a suitable design pattern for the given problem context using feature learning, neural embedding, and classification. We evaluate our approach on a case study from Stack Overflow with more than 66,000 questions that discuss problems and consequences related to 23 design patterns. Results show that our approach can predict design patterns from the text with 82% overall accuracy.

A methodology to assess the impact of design patterns on software quality

The aim of the paper is to investigate applicability of object-oriented software design patterns in the context of aspect-oriented design. The paper analyses which of the GoF 23 patterns have a meaning in this context and how they are affected by it. The main assumption is that there exist design patterns that solve software engineering paradigm independent design problems and that such patterns, in the contrast to the patterns solving paradigm-specific design problems, can be expressed in terms of any software engineering paradigm. However, the paper deals only with two paradigms: aspect-oriented (AO) paradigm and object-oriented (OO) paradigm. It proposes a classification of design problems based on this assumption and a technique for redesigning object-oriented patterns into pure aspect-oriented ones. It presents a number of examples how to apply this technique and discusses the results obtained. The results show that 20 of the GoF 23 design patterns solve such design problems that are common at least for both mentioned paradigms and demonstrate in which way these patterns can be adapted for the needs of aspect-oriented design.

Design patterns have received a lot of attention recently, especially from the object-oriented community as a technique for design reuse. It has proved itself as an important piece that was missing from object-oriented design methods. Design patterns make it easier to reuse successful designs and architectures by providing solutions to common design problems at the abstract level. We have adopted an object-oriented development method complemented with design patterns in the development of a multimedia courseware system. The adoption of design patterns has helped us reuse software architectures and successful design experiences of design experts. In the system architectures, some design patterns are used only once, while others are used more than once in different places. This paper introduces some uses of design patterns in the design of a multimedia courseware system to obtain a flexible and reusable architecture as well as some of our experience in applying design patterns.

Design patterns are a common strategy employed in software development to promote several aspects of software quality, including code maintainability. Game development is a multidisciplinary field that includes not only software development but also animations, interactivity, sound design and others. Given the short deadlines in which game developers commonly operate, on top of the intrinsic complexity of the field itself, code maintainability is often overlooked by game developers. Hence, this work investigates how design patterns can impact the code maintainability of games. First, we performed a review to understand how (and which) design patterns can be applied to different game mechanics. Next, we selected two small games and refactored the code by applying design patterns to some of the games’ mechanics. By leveraging static analysis to assess the games’ code maintainability before and after the application of the design patterns, we observed an overall code maintainability improvement of 5.5%. The preliminary results indicate the potential to use design patterns as a strategy to improve code maintainability in the context of game development.

The use of design patterns for creating technology-enhanced learning (TEL) environments has gained significant momentum in recent years. In the TEL community the concept of patterns was introduced and spread by various pattern initiatives and projects. Patterns are meanwhile a widely familiar concept for both researchers and practitioners. Essentially, a pattern gives a description of a reusable solution to a common design problem in some context. In the context of TEL and in pedagogy, patterns are typically used to describe effective teaching methods, situations or teaching/learning activities. Even with a significant number of e-learning and TEL design patterns available today, there is still only little evidence of actual usage and usability of that knowledge base in the TEL domain. The past focus has been on introducing patterns to the field and creating patterns from existing design and application experience. But any innovation needs to show its qualities and benefits to the users if it is intended to succeed; patterns without users working with them are, literally, useless artefacts. Therefore, in this paper, we aim to provide a thorough exploration of the user’s view on design patterns for TEL. We intend to investigate qualities and features of patterns and pattern collections which we consider essential for raising the usability of patterns. Thereby we consulted several sources on pattern qualities, requirements, life cycle and use cases as found in the original pattern work by Alexander as well as in more recent literature. On the other hand, we draw from own experience and research during several years of finding, writing and applying patterns in higher-education TEL settings. To enable continuing research and improvement based on findings, insights and lessons learned during TEL pattern application, we propose a cyclic model of the pattern application process; we investigate the application of design patterns along the five phases of Action Research: diagnosing, action planning, action taking, evaluating, and specifying learning. This cyclic phase arrangement seems particularly suited for pattern application, as we believe that the quality of patterns and the success of their application heavily rely on the user’s ability to integrate lessons learned and experiences drawn into future application cycles. In the core part of the paper we use the cyclic process of design pattern application for definition and analysis of critical factors of the user’s perspective for each phase as well as input and output elements of each phase. In a nutshell, the phases of the application cycle and their relation to pattern features from the user’s viewpoint are characterized as follows. The diagnosing phase includes understanding the application context, finding appropriate patterns and understanding the patterns. This is supported by building a pattern repository upon some clearly expressed value base or philosophy. Also, patterns need to be structured to guide users in finding and selecting appropriate patterns for their design problems. To be understandable, patterns need to convey their advice in an efficient, generative way. For action planning and action taking patterns should, particularly in the TEL domain, include details on required technology support, essential actions and critical success factors to be considered, as well as pitfalls known from previous applications. To be amenable to evaluation, patterns need to clearly express their intent and expected effects, and include evidence on their effectiveness; to collect evidence each pattern can, for instance, provide guidance on collecting empirical data. The pattern user also has a responsible role in pattern evolution through feeding back his/her insights and experience during pattern application. We should strive to exploit network effects by sharing advice, feedback, and experience through design patterns. In the paper, we ‘walk through’ the phases of the proposed application cycle based on an example case in the context of involving students in the evaluation of their learning at the end of a concrete course. We conclude that continuous information flow and cooperation between pattern designers and users are essential in equipping patterns with the features needed to facilitate their finding, selection, application, organization and evolution.

This paper introduces the concepts of design patterns and demonstrates the potential of applying this technique for power system modeling. Captured by experienced object-oriented designers, design patterns solve specific design problems and make object-oriented designs more flexible, extensible and elegant. This technique has been successfully applied in the design of a generic distribution circuit object model. Some of the more powerful design patterns, such as object composition, delegation, recursive composition and proxy etc., have been effectively used to help determine modeling granularity, find appropriate objects and achieve modeling flexibility. When properly applied, the design patterns can help solve many of the design problems in the object-oriented modeling of power systems.

Design patterns in software development have shown great promise in improving software quality. Traditionally, software developers utilize a set of design patterns to foster reusability and better software design. Recently, mobile applications (apps) have become a mainstay of modern computing, as well as, a challenging domain for software engineers. This is because mobile apps now target more critical domains such as health, banking, m-payments, and even military to mention just a few. Android is a very popular mobile platform, and has managed to take over the majority of mobile market. It is true that there are comprehensive studies in the area of design patterns detection in several object-oriented languages such as Java, C# and C++. However, little studies target design patterns in Android apps. As a step toward helping to measure and explore the application of design patterns in Android apps, we introduce PatRoid, an automated framework for detecting design patterns. PatRoid is a model-based approach that is able to detect design patterns laying inside Android apps source code. The model is based on a graph isomorphism approach, where design patterns are divided into sub-patterns that can be aggregated to formulate design patterns. We have conducted a preliminary evaluation and the results show that PatRoid can detect all of the 23 GoF design patterns.

This research aims to improve the maintainability and readability of a skin disease detection application through the implementation of clean code and design patterns. SkinPal, an image analysis application, faces several issues in its backend API, particularly in the maintenance and development process. The research began with a domain case analysis, followed by an assessment of existing maintainability and readability problems. Afterwards, clean code principles were mapped and used as the basis for the refactoring process using design patterns. Lastly, the evaluation phase is used to measure the improvements. Several issues were identified in the backend code, including the merging of business logic with data access, unclear variable names, and code duplication. A total of 10 classes and 18 functions had low maintainability scores, and most of the functions were difficult to read. The refactoring process successfully improved the maintainability to a high level, from an average score of 39.61 to 99.62, confirming a major enhancement in code quality compared to previous studies. In terms of readability, only one of six developers encountered difficulties in understanding the refactored code. Overall, the implementation of clean code and design patterns successfully improved maintainability and readability in SkinPal's backend.

Design patterns are known as a way for software designers to communicate about design. There are various descriptions, structures and behaviors on the solution for a design problem in a design pattern. However, there is not much visual aid on the internal workings of a design pattern in a visual design modeling tool. Currently, it is difficult to determine the pattern role and the variant of interaction groups of a design pattern in an UML diagram as the design pattern information is not represented in the interaction diagram. There is a need to have a consistent way to define the pattern role participating in a design pattern interaction and whether there is a variant in each interaction group. This paper proposes to extend the UML sequence diagram via UML profile to allow designers to define and visualize the pattern roles and the different types of interaction groups for a design pattern. An example of the approach is then applied to the observer design pattern. The benefit of the extension enables tool support on cataloging and retrieval of design patterns' structural and behavioral information as well as variant in a visual design modeling tool.

Reuse is one of the core principles in professional software engineering. Design patterns provide a reusable solution for common design problems. But their implementations are generally not reusable as they are often well tailored to a specific context. We introduce a concept, that facilitates the reuse of their implementations by defining an abstract design pattern definition that can be instantiated with specialized design decisions. This approach is a meta-level Builder constructing design patterns as first-class citizens. It simplifies the application of design patterns by providing a pattern library and still being able to adjust it to the concrete context.

Developing and testing mobile agent-based applications are complex tasks that demand appropriate support to cope with mobility as well as usual distributed applications issues. Development approaches have already been proposed, and the use of design patterns has proved to be essential to increase productivity and feasibility. However, testing of mobile agent-based applications has not been extensively investigated. The use of test patterns seems to be a promising approach to test these applications in a cost-effective way. Aiming to promote the use of design patterns together with test patterns, we present an approach to identifying test patterns related to mobile agent design patterns. We also propose a documentation template and an implementation strategy.

Design pattern-based model transformation supported by QVT