Browsing by Subject "Aspect-Oriented Software Development"

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Open Access
Aspect-oriented evolution of legacy information systems
(2004) Satıroğlu, Yasemin
A legacy information system is an old system that typically has been developed several years ago, and remains in operation within an organization. Since the software requirements change, legacy systems must be evolved accordingly. Various approaches such as wrapping, migration and redevelopment have been proposed to maintain legacy information systems. Unfortunately, these approaches have not explicitly considered the concerns that are difficult to capture in single components, and tend to crosscut many components. Examples of such crosscutting concerns include distribution, synchronization, persistence, security, logging and real-time behavior. The crosscutting property of concerns seriously complicates the maintenance of legacy systems because the code of the system needs to be changed at multiple places, and conventional maintenance techniques fall short to do this effectively. Aspect-Oriented Software Development (AOSD) provides explicit mechanisms for coping with these crosscutting concerns. However, current AOSD approaches have primarily focused on coping with crosscutting concerns in software systems that are developed from scratch. Hereby, the crosscutting concerns are implemented as aspects at the beginning, hence localized in single modules. In this way the implementation and maintenance of crosscutting concerns can be prepared to a large extent so that the maintenance of these systems will be easier later on. Unfortunately, legacy systems impose harsher requirements, because crosscutting concerns in legacy systems are neither explicitly identified nor have been prepared before. We provide a systematic process for analyzing the impact of crosscutting concerns on legacy systems. The process, which is called Aspectual Legacy Analysis Process (ALAP), consists of three sub-processes, Feasibility Analysis, Aspectual Analysis and Maintenance Analysis. All the three sub-processes consist of a set of heuristic rules and the corresponding control. Feasibility Analysis, which consists of two phases, describes rules for categorizing legacy systems, in the first phase; and describes the rules for evaluating legacy systems with respect to the ability to implement static crosscutting and ability to implement dynamic crosscutting, in the second phase. The rules of the first phase are based on the categories of legacy systems that we have defined after a thorough study to legacy information systems, and the rules of the second phase are based on our discussion of these categories with respect to crosscutting implementation. Once the legacy system has been categorized and evaluated with respect to crosscutting implementation, the Aspectual Analysis sub-process describes rules for identifying and specifying aspects in legacy systems. Based on the results of the Feasibility Analysis and Aspectual Analysis sub-processes, the Maintenance Analysis describes the rules for the selection of the appropriate legacy maintenance approach. ALAP has been implemented in the Aspectual Legacy Analysis Tool (ALAT), which implements the rules of the three sub-processes and as such helps to support the legacy maintainer in analyzing the legacy system and identifying the appropriate maintenance approach.
Open Access
A tool framework for developing context-sensitive user assistance systems using model-driven aspect weaving
(2012) Açar, Murat
User assistance systems act as a guide for the users of software products. These systems aim to guarantee a successful user experience by helping in performing tasks. Early on, off-line user manuals were mostly the mediums of user assistance, and technically, they were independent of the systems they belong to. The upward trend in user assistance systems is that the provision of assistance is automated through some attached mechanisms to the software systems. There have been numerous proposals introducing fresh and novel methods for the purpose of automated user assistance. Specifically, embedded user assistance consists of instructional or conceptual information that appears within a software application window. It includes embedded help that appear within the application, field labels, and page overviews. The overall objective of this thesis is to reveal the state of the art advances in user assistance systems, and to propose a tool framework for developing contextsensitive user assistance systems. Firstly, we conducted two systematic literature reviews for both automated and embedded user assistance systems. The systematic literature reviews are required for acquiring solid background on embedded user assistance systems as well as for exploring the main obstacles to automated user assistance systems. The research findings are presented in parallel with the work published in the literature, and we aim at revealing a variety of techniques used for automated and embedded user assistance. The systematic reviews are conducted by a multiphase study selection process under a lot of articles obtained by dedicated search strategies. Since there has been no study to systematically undertake the state of user assistance systems, our work has a pioneering value of contents providing a road-map of current trends for further researchers in the field of user assistance. Having analyzed the results of systematic reviews, we conducted a survey of help authoring tools that revealed the lack of generalized context-sensitive user assistance solutions. Also, the utilization of methods, algorithms and tools differs from domain to domain, being rather scattered. We aimed at developing embedded context-sensitive user assistance systems, which is not trivial and has to meet several challenges. Unfortunately, user-assistance concerns such as help content and related weaving information cannot be easily localized in single modules and as such tend to crosscut multiple modules. The reuse of user assistance tools for different applications is required because developing custom-based user assistance for each separate application is laborious. Consequently, the obstacles related to the development of context-sensitive user assistance systems have brought out the idea of a tool framework for this purpose. To address these issues we developed an aspect-oriented tool framework Assistant-Pro that can be used to develop context-sensitive embedded user assistance for multiple applications. The framework provides tools for defining the process model, defining guidance related to process steps, and modularizing and weaving help concerns in the target application for which user guidance needs to be provided. The tool has been originally developed and validated in the context of Aselsan, a large Turkish defense electronics company.