Mohsen Asadi

Combining service-orientation and software product line engineering: A systematic mapping study

Context: Service-Orientation (SO) is a rapidly emerging paradigm for the design and development of adaptive and dynamic software systems. Software Product Line Engineering (SPLE) has also gained attention as a promising and successful software reuse development paradigm over the last decade and proven to provide effective solutions to deal with managing the growing complexity of software systems. Objective: This study aims at characterizing and identifying the existing research on employing and leveraging SO and SPLE. Method: We conducted a systematic mapping study to identify and analyze related literature. We identified 81 primary studies, dated from 2000-2011 and classified them with respect to research focus, types of research and contribution. Result: The mapping synthesizes the available evidence about combining the synergy points and integration of SO and SPLE. The analysis shows that the majority of studies focus on service variability modeling and adaptive systems by employing SPLE principles and approaches. In particular, SPLE approaches, especially feature-oriented approaches for variability modeling, have been applied to the design and development of service-oriented systems. While SO is employed in software product line contexts for the realization of product lines to reconcile the flexibility, scalability and dynamism in product derivations thereby creating dynamic software product lines. Conclusion: Our study summarizes and characterizes the SO and SPLE topics researchers have investigated over the past decade and identifies promising research directions as due to the synergy generated by integrating methods and techniques from these two areas.

A quality aggregation model for service-oriented software product lines based on variability and composition patterns

Quality evaluation is a challenging task in monolithic software systems. It is even more complex when it comes to Service-Oriented Software Product Lines (SOSPL), as it needs to analyze the attributes of a family of SOA systems. In SOSPL, variability can be planned and managed at the architectural level to develop a software product with the same set of functionalities but different degrees of non-functional quality attribute satisfaction. Therefore, architectural quality evaluation becomes crucial due to the fact that it allows for the examination of whether or not the final product satisfies and guarantees all the ranges of quality requirements within the envisioned scope. This paper addresses the open research problem of aggregating QoS attribute ranges with respect to architectural variability. Previous solutions for quality aggregation do not consider architectural variability for composite services. Our approach introduces variability patterns that can possibly occur at the architectural level of an SOSPL. We propose an aggregation model for QoS computation which takes both variability and composition patterns into account.

Goal-Oriented Test Case Selection and Prioritization for Product Line Feature Models

The software product line engineering paradigm is amongst the widely used means for capturing and handling the commonalities and variabilities of the many applications of a target domain. The large number of possible products and complex interactions between software product line features makes the effective testing of them a challenge. To conquer the time and space complexity involved with testing a product line, an intuitive approach is the reduction of the test space. In this paper, we propose an approach to reduce the product line test space. We introduce a goal-oriented approach for the selection of the most desirable features from the product line. Such an approach allows us to identify the features that are more important and need to be tested more comprehensively from the perspective of the domain stakeholders. The more important features and the configurations that contain them will be given priority over the less important configurations, hence providing a hybrid test case reduction and prioritization strategy for testing software product lines.

Toward automated feature model configuration with optimizing non-functional requirements

Abstract Context A software product line is a family of software systems that share some common features but also have significant variabilities. A feature model is a variability modeling artifact, which represents differences among software products with respect to the variability relationships among their features. Having a feature model along with a reference model developed in the domain engineering lifecycle, a concrete product of the family is derived by binding the variation points in the feature model (called configuration process) and by instantiating the reference model. Objective In this work we address the feature model configuration problem and propose a framework to automatically select suitable features that satisfy both the functional and non-functional preferences and constraints of stakeholders. Additionally, interdependencies between various non-functional properties are taken into account in the framework. Method The proposed framework combines Analytical Hierarchy Process (AHP) and Fuzzy Cognitive Maps (FCM) to compute the non-functional properties weights based on stakeholders’ preferences and interdependencies between non-functional properties. Afterwards, Hierarchical Task Network (HTN) planning is applied to find the optimal feature model configuration. Result Our approach improves state-of-art of feature model configuration by considering positive or negative impacts of the features on non-functional properties, the stakeholders’ preferences, and non-functional interdependencies. The approach presented in this paper extends earlier work presented in [1] from several distinct perspectives including mechanisms handling interdependencies between non-functional properties, proposing a novel tooling architecture, and offering visualization and interaction techniques for representing functional and non-functional aspects of feature models. Conclusion our experiments show the scalability of our configuration approach when considering both functional and non-functional requirements of stakeholders.

Development and configuration of service-oriented systems families

Software Product Lines (SPLs) are families of software systems which share a common sets of feature and are developed through common set of core assets in order to promotes software reusability, mass customization, reducing cost, time-to-market and improving the quality of the product. SPLs are sets (i.e., families) of software applications developed as a whole for a specific business domain. Particular applications are derived from software families by selecting the desired features through configuration process. Traditionally, SPLs are implemented with systematically developed components, shared by members of the SPLs and reused every time a new application is derived. In this paper, we propose an approach to the development and configuration of Service-Oriented SPLs in which services are used as reusable assets and building blocks of implementation. Our proposed approach also suggests prioritization of family features according to stakeholders non-functional requirements (NFRs) and preferences. Priorities of NFRs are used to filter the most important features of the family, which is performed by Stratified Analytic Hierarchical Process (S-AHP). The priorities also are used further for the selection of appropriate services implementation for business processes realizing features. We apply Mixed Integer Linear Programming to find the optimal service selection within the constraints boundaries specified by stakeholders.

Development and validation of customized process models

Abstract Configurable reference process models encompass common and variable processes of organizations from different business domains. These reference process models are designed and reused to guide and derive customized business processes according to the requirements of stakeholders. The customization process is generally initiated by a configuration step, selecting a subset of the reference process model. Configuration is followed by a customization step, which assumes adapting or extending the configured business process based on the specific or unforeseen requirements. Hence, it is crucial to validate the correctness and compliance of the final customized business process with respect to the patterns and business constraints that are specified in the reference model. In this paper, we firstly introduce a technique to develop a customized process model and then present a set of identified inconsistency patterns that may happen during the configuration of a reference model and the customization of configured process models. Furthermore, we describe our proposed approach including formal representations and algorithms that provide logical reasoning and enable automatic inconsistency detection by leveraging description logic. In order to explore the scalability of the approach, we designed the experiments with various process models sizes and inconsistency distributions. The results of the experiments revealed the scalability of our approach with large size process models (500 activities).

Goal-oriented modeling and verification of feature-oriented product lines

Goal models represent requirements and intentions of a software system. They play an important role in the development life cycle of software product lines (SPLs). In the domain engineering phase, goal models guide the development of variability in SPLs by providing the rationale for the variability, while they are used for the configuration of SPLs in the application engineering phase. However, variability in SPLs, which is represented by feature models, usually has design and implementation-induced constraints. When those constraints are not aligned with variability in goal models, the configuration with goal models becomes error prone. To remedy this problem, we propose a description logic (DL)-based approach to represent both models and their relations in a common DL knowledge base. Moreover, we apply reasoning to detect inconsistencies in the variability of goal and feature models. A formal proof is provided to demonstrate the correctness of the reasoning approach. An empirical evaluation shows computational tractability of the inconsistency detection.

The effects of visualization and interaction techniques on feature model configuration

A Software Product Line is a set of software systems of a domain, which share some common features but also have significant variability. A feature model is a variability modeling artifact which represents differences among software products with respect to variability relationships among their features. Having a feature model along with a reference model developed in the domain engineering lifecycle, a concrete product of the family is derived by selecting features in the feature model (referred to as the configuration process) and by instantiating the reference model. However, feature model configuration can be a cumbersome task because: 1) feature models may consist of a large number of features, which are hard to comprehend and maintain; and 2) many factors including technical limitations, implementation costs, stakeholders’ requirements and expectations must be considered in the configuration process. Recognizing these issues, a significant amount of research efforts has been dedicated to different aspects of feature model configuration such as automating the configuration process. Several approaches have been proposed to alleviate the feature model configuration challenges through applying visualization and interaction techniques. However, there have been limited empirical insights available into the impact of visualization and interaction techniques on the feature model configuration process. In this paper, we present a set of visualization and interaction interventions for representing and configuring feature models, which are then empirically validated to measure the impact of the proposed interventions. An empirical study was conducted by following the principles of control experiments in software engineering and by applying the well-known software quality standard ISO 9126 to operationalize the variables investigated in the experiment. The results of the empirical study revealed that the employed visualization and interaction interventions significantly improved completion time of comprehension and changing of the feature model configuration. Additionally, according to results, the proposed interventions are easy-to-use and easy-to-learn for the participants.

Deriving variability patterns in software product lines by ontological considerations

Variability modeling is widely used in software product line engineering to support reusability. Specifically, it is used in the derivation of concrete software products from a reusable solution within a family of products. To help manage variability, several modeling languages have been proposed for representing variability within a family of products. The study and evaluation of languages to model variability has so far focused on practical aspects of such languages. Less attention has been paid to more theoretical approaches to the analysis of variability modeling languages. In developing such approaches it would be of particular interest to explore the ability of variability modeling to represent the information about the real world (application) domain for which the product family is designed. In information systems research, evaluation of expressiveness of conceptual modeling languages has been done based on ontological theories. This paper describes a framework for general analysis of types of variability based on Bunges ontology and derives a variability framework which is used to evaluate variability modeling languages.

Developing Families of Method-Oriented Architecture

The method engineering paradigm is motivated by the need for software development methods suitable for specific situations and requirements of organizations in general and projects in particular. Assembly-based method engineering, as one of the prominent approaches in method engineering, creates project-specific methods by (re-)using method components, specified with method processes and products, and stored in method repositories. This paper tries to address the two challenges of assembly-based method engineering related to more effective: i) publication and sharing of method components; and ii) management of variability in software methods, which have many commonalties. In order to address these two challenges, we propose the concept of Families of Method-Oriented Architectures. This concept is built on top of the principles of service-oriented architectures and software product lines.