A Model Driven Development Framework for Enterprise Web Services

Der Ausdruck Quality of Service (QoS) beschreibt die Güte eines erbrachten Dienstes. QoS beschreibt Eigenschaften wie Antwortzeit, Verfügbarkeit, den Grad der Nachrichten-Verschlüsselung oder den Durchsatz. QoS ist sowohl für Multi-Media Anwendungen (Audio- und Video-Übertragung) als auch für Geschäftsanwendungen wichtig. Die vorgelegte Arbeit konzentriert sich dabei auf das Feld der Geschäftsanwendungen. Solche Anwendungen arbeiten mit Transaktionen wie etwa dem Bestellen eines Produkts oder der Überweisung von Geld zwischen Konten. QoS Eigenschaften solcher Anwendungen sind beispielsweise die Anzahl an Transaktionen während eines Zeitintervalls, die maximale Anzahl gleichzeitig mit dem System arbeitender Nutzer, oder die zu erwartende Verfügbarkeit. Durch Middleware kann die Realisierung von Verteilung vor dem Programmierer verborgen werden. In einer idealen Welt würde Middleware dasselbe für QoS leisten. Das heißt, der Entwickler spezifiziert nur die gewünschte Dienstgüte und kümmert sich nicht darum, wie sie realisiert wird. Das ist so aber nicht möglich, denn die zu erbringende Dienstgüte hat massive Auswirkungen auf das Design einer Applikation. Daher muss QoS schon in der Design-Phase angegangen werden, was mit einer rein Middleware-gestützten Herangehensweise nicht möglich ist. Die vorgelegte Arbeit zeigt, wie dieses Problem durch einen modellgetriebenen Ansatz behoben werden kann. Die Entwicklung beginnt dann mit einem Plattform-unabhängigen Modell (PIM), welches das Verhalten und die QoS Eigenschaften der Applikation beschreibt. Dieses Modell wird automatisch durch eine Modell-Transformation in ein Plattform-spezifisches Modell (PSM) umgewandelt. Das PSM beschreibt das Design einer Implementierung für eine spezifische Plattform und berücksichtigt dabei die im PIM beschriebenen QoS-Eigenschaften. Um dieses Szenario in der Praxis anwenden zu können, müssen zwei Probleme gelöst werden: das Modellieren von QoS Eigenschaften und die Modell-Transformation. Gegenwärtig erfordert das Erstellen einer Modell-Transformation detailliertes Wissen über die Modellierungssprache und ihre Interna. Um das zu vereinfachen, wurde im Rahmen dieser Arbeit die visuelle Regelbasierte Transformationssprache Kafka entwickelt. Kafka und die zugehörigen Werkzeuge bauen auf Graphtransformations-Theorie auf. Kafka vereinfacht das Erstellen von Transformationen weil es auf der Notation des PIM und PSM aufbaut. Daher muss der Entwickler nichts von den Interna (etwa dem Meta-Modell) verstehen. Um PIMs von QoS-fähigen Applikationen zu erstellen, wurde die Modellierungssprache PIQML entwickelt, welche auf UML 2.0 Komponenten, Hierarchischen Nachrichten Sequenz Diagrammen (HMSCs) und einer neuen Meta-Modell Erweiterung für QoS Verträge basiert. Die vorgelegte Arbeit zeigt, wie PIQML Modelle auf verschiedene Zielplattformen (Programmiersprachen und Middleware Produkte) abgebildet werden können. Basierend auf PIQML und Kafka wurde das Werkzeug Kase entwickelt, welches das Editieren von PIQML Modellen (PIMs), UML Modellen (PSMs) und Kafka Transformationen integriert. Das Ergebnis ist eine integrierte Werkzeug-Kette für das modellgetriebene Entwickeln QoS-fähiger verteilter Applikationen.

Software development is a complex process and the information technology market is faced by many challenges. Among the challenges is the effect of technology "platforms" change (languages, operating-systems, interoperability solutions, architecture frameworks etc.). Model Driven Architecture (MDA) is a new development method as a positive effort from the Object Management Group (OMG) to overcome software development problems including but not limited to technology change. The philosophy of MDA regarding technology change is the separation of concerns. In MDA, structures and behaviors based on the business functions are abstracted and modeled in a Platform Independent Model (PIM). The implementation specific structures and behaviors are modeled in a Platform Specific Model (PSM). The PIM is then realized into the PSM through a mapping process to automatically generate the software. Current practice shows that MDA approach works quite well but, in most cases, behavioral models are used for other purposes like documentation rather than complementing the structural models to facilitate automatic software generation. This paper examines the issues and challenges when mapping behavior models between different abstraction layers, respectively PIM and PSM using state machine models. A general solution to one of those challenges is discussed and outlined using a case study.

Towards a Generation of Class Diagram from User Stories in Agile Methods

PurposeIn the last decade, web services have become a major technology to implement loosely coupled business processes and perform application integration. Through the use of context, a new generation of web services, namely context‐aware web services (CASs), is currently emerging as an important technology for building innovative context‐aware applications. Unfortunately, CASs are still difficult to build. Issues like lack of context provisioning management approach and lack of generic approach for formalizing the development process need to be solved in the first place for easy and effective development of CASs. The purpose of this paper is to investigate the techniques on developing CASs.Design/methodology/approachThe paper focuses on introducing a model‐driven platform, called ContextServ, and showcasing how to use this platform to rapidly develop a context‐aware web application, Smart Adelaide Guide. ContextServ adopts a model‐driven development (MDD) approach where a Unified Modeling Language (UML)‐based modeling language – ContextUML – is used to model web services and its context‐awareness features.FindingsThe paper presents novel techniques for efficient and effective development of CASs using a MDD approach. The ContextServ platform is the only one that provides a comprehensive software toolset that supports graphical modeling and automatic model transformation of CASs.Practical implicationsThe proposed approach has been validated in practice by developing various CASs. The experimental study demonstrates the efficiency and effectiveness of the approach.Originality/valueThe paper presents a novel platform called ContextServ, which offers a set of visual editing and automation tools for easy and fast generating and deploying CASs.

Only in software and in linguistics a model has the same nature as the thing it models. In software at least, this opens the possibility to automatically derive software from its model. This property is well known from any compiler writer (and others), but it was recently be made quite popular with an OMG initiative called the Model Driven Architecture (MDA). The model transformations allowing the engineers to more or less automatically go from platform-independent models (PIM) to platform-specific models (PSM) are increasingly seen as vital assets that must be managed with sound software engineering principles. We believe that transformations should be first-class models in the MDA world; we propose to adopt the object-oriented approach and to leverage the expressive power of UML as a metamodel defining the transformation language.

A constant goal of enterprises of all sizes is to align their business with IT. The major concern is to design the technology to support the desired performance goals and business values. In e-business collaborations, services are becoming the cornerstones for modeling the offerings of the involved parties. However, business concepts, like value offerings, typically cannot be linked to technology levels, such as SOA and Web services. Business value models, formulated in terms of economic values, have been recognized as the basis for eliciting the actors in a business scenario and their relationships. Recently, several business ontological frameworks have been proposed to facilitate the design of business value models. Aiming towards an MDA-aligned approach, in our study we consider business value models for creating a service-centric Computational Independent Model (CIM). By utilizing well-defined mappings, the model is further transformed into a UML-based system model at the Platform Independent Model (PIM) level, capturing both the static and behavioral specifications of elicited e-services.

Cloud computing, a more recent computing paradigm, has evolved from a variety of legacy technologies that include Service oriented Architecture (SOA) and Web services besides several others. The software services in a cloud must be developed based on the service-oriented approach, in order to derive their full potential and benefits. Since, SOA inherently nurtures interoperability; it will enhance the integration and interaction among the cloud software services. Also, leveraging the Model Driven Architecture (MDA) approach to develop individual cloud software services will result in services that are more robust, flexible and agile in the wake of ever changing technologies. This paper is an attempt by the authors to lay emphasis on the convergence of Cloud computing, SOA and MDA in development of optimum business solutions.KeywordsCloud computingCloud SaaSService Oriented Architecture (SOA)Model-Driven Architecture (MDA)Computation Independent Model (CIM)Platform Independent Model (PIM)Platform Specific Model (PSM)Interoperability

Recently, Peer-to-Peer (P2P) architecture is being used to explore better the computing power and bandwidth of networks than a client/server architecture. In order to support the creation of P2P applications, some frameworks were proposed such as JXTA. However, large systems using P2P architecture are complex to be developed, maintained and evolved. Model Driven Architecture (MDA) can support the management of the complexity in the software development process through transformations of Platform Independent Models (PIM) into Platform Specific Models (PSM). In this paper, we apply an MDA approach to allow the development of applications based on JXTA. The JXTA implementation in Java is used to demonstrate our approach. We propose a model transformation definition from an UML model to a Java+JXTA model. In order to validate our approach, we present two case studies.

Nowadays, a Service Oriented Architecture (SOA) seems to be one of the most promising paradigms for leveraging enterprise information systems. SOA creates opportunities for enterprises to provide value added service tailored for on demand enterprise collaboration. With the emergence and rapid development of Web services technologies, SOA is being paid increasing attention and has become widespread. In spite of the popularity of SOA, a standardized framework for modeling and implementing business services are still in progress. For the purpose of supporting these service-oriented solutions, we adopt a model driven development approach. This paper outlines the Contextual Service Oriented Modeling and Analysis (CSOMA) methodology and presents UML profiles for the PIM level service-oriented architectural modeling, as well as its corresponding meta-models. The proposed PIM (Platform Independent Model) describes the business SOA at a high level of abstraction regardless of techniques involved in the application employment. In addition, all essential service-specific concerns required for delivering quality and context-aware service are covered. Some of the advantages of this approach are that it is generic and thus not closely allied with Web service technology as well as specifically treating the service adaptability during the design stage.

Manufacturing companies today face an increasingly dynamic environment. Development of production planning systems requires approaches that offer flexibility in development of solutions. Applying the UML (Unified Modeling Language) and MDA (Model Driven Architecture) paradigm can ensure compatibility between applications developed on different platforms. The MDA approach to software development becomes an obvious choice. In this approach, the models drive the process of software development. These models are defined at different levels of abstraction to represent various aspects of the system. The transformation of models from one level of abstraction to another, or the transformation of models to executable code is performed by using automated transformation tools. The strength of MDA lies in the fact that it is based on widely used industry standards for visualizing, storing and exchanging software designs and models. The models in MDA are abstracted at three different levels – the Computation Independent Model (CIM), the Platform Independent Model (PIM) and the Platform Specific Model (PSM). The key to the success of MDA lies in automated or semi-automated model-to-model and model-to-code transformations. In this paper, we examine how a platform-independent model of an MRP-based production planning system can be created using MDA approach, from which several platform-specific systems can be achieved, as required.

Transformations’ Study Between Requirements Models and Business Process Models in MDA Approach

Model driven architecture (MDA), which takes platform independent modeling and platform specific transforming as its core technologies, is a software development method and standards system using modeling newly issued by OMG. It analyzes the basic theorem of ROSE, and point out deficiency the model transformation from PIM to PSM. This paper presents a vision of mapping method from PIM to PSM based on XMI/XML platform, using UML. UML profile and MOF makes up PIM and designs theorem of transformation through XMI.

THE Internet, along with its related technologies, has created an interconnected world in which information flows easily and tasks are processed collaboratively. To make service-oriented applications more robust, Web services must be examined from a transactional perspective. By transactional, we mean first defining the actions that guide the execution of Web services when failures arise and then the states that permit claiming the success of this execution following the handling of these failures. A variety of transactional models are reported in the database community. Some of these models can be leveraged and enhanced in response to Web services characteristics while others are not suitable for Web services due to the dynamic nature of Web services, the long-running execution scenarios that Web services take part in, and the successful execution of Web services despite other peers’ failure. Today’s service-oriented applications require advanced transactional models that guarantee integrity and continuity of business processes despite the dynamic nature of the features of the environments hosting the execution of these applications. This special section sheds light on the latest advances in the fields of Web services and transactional models in order to better address advanced research on and experience with transactional Web services. Four papers out of 19 submissions were selected for inclusion in this special section. Each submission was subject to a double-review process by at least three peer reviewers. In the first paper, entitled “Event-Based Design and Runtime Verification of Composite Service Transactional Behavior,” Gaaloul et al. propose an event-driven approach to validate the transactional behavior of Web services taking part in compositions. A composition life cycle consists of four phases, namely, design, execution, monitoring, and reengineering. The verification of this behavior throughout this life cycle is done either at design time to validate recovery mechanisms’ consistency or after runtime to detect execution deviations and repair design errors, and, therefore, formally ensure the execution reliability of Web services. In addition, this verification is based on the Event Calculus formalism, which offers a sound definition for this reliability. In the second paper, entitled “FACTS: A Framework for Fault-Tolerant Composition of Transactional Web Services,” Liu et al. note that delivering reliable compositions over unreliable Web services is challenging. To address this challenge, Liu et al. identify a set of high-level exception handling strategies and a new taxonomy of transactional Web services to devise a fault-tolerant mechanism that combines exception handling and transaction techniques. In addition, Liu et al. devise two modules, known as specification and verification, to assist service designers in constructing fault handling logic conveniently and correctly. This logic is automatically injected into WS-BPEL. In the third paper, entitled “Rule-Based Coordination of Distributed Web Service Transactions,” von Riegen et al. study the distributed transactional activity control problem in the context of service choreographies. In such a context, many participants are allowed to work together to achieve a global, common goal, and the initiator of a process is not always the one who is able to commit or cancel a transaction. Von Riegen et al. introduce a framework that allows autonomous coordination of dynamic processes. This framework extends WSBusinessActivity to strengthen the role of the coordinator. Predicate rules are developed to let participants cancel or complete a process and help the coordinators decide on the completion processes and the confirmation or cancellation of the participants’ works. In the fourth paper, entitled “TQoS: Transactional and QoS-Aware Selection Algorithm for Automatic Web Service Composition,” El Haddad et al. focus on the issues of selecting and composing Web services. A design-time selection algorithm is proposed in which transactional and QoS requirements are both integrated into the selection process. This algorithm is based on the notion of risk that indicates if execution outcomes can either be compensated for or not. Two risk levels of execution in a transactional system are considered: Risk 0, meaning that if the execution is successful, the obtained outcomes can be compensated for by the user, and Risk 1, meaning that the system does not guarantee successful execution, but if it achieves it, the outcomes cannot be compensated for by the user. We hope this special section inspires researchers to develop new transactional models that would guarantee service-oriented applications integrity and continuity. 30 IEEE TRANSACTIONS ON SERVICES COMPUTING, VOL. 3, NO. 1, JANUARY-MARCH 2010

Computer software is key part of information system (IS). One of the main targets of Model-Driven Software Engineering (MDSE) is the increase in productivity and reliability offered by automatically generating code from models. However, the practical adoption of code generation remains relatively slow and limited to niche applications. A potential is to develop automated code generation and automatic model transformation. To answer the challenge, this paper proposes, based on the practicable formal methods (PAR method), the methodology for implementing formal model-driven engineering (FMDE), then to develop platform of code generation based on FMDE, called PAR Platform. We call PAR method and PAR platform as PAR. PAR consists of requirement modeling language SNL (meta-model), algorithm modeling language Radl, abstract program modeling language Apla, a set of rules for the model transformation and a set of automatic transformation tools. The tools can implement several transformations from requirement to algorithm models, then to abstract program models and finally to executable programs. The goal of the transformations is to generate executable program. There are two kinds of applications of PAR platform. One is automatic generation of many nontrivial algorithms and programs. Another is, according to FMDE, development of several safety-critical information systems.

Several difficulties commonly arise during the software development process. Among them are the lengthy technical process of developing a system, the limited number and technical capabilities of human resources, the possibility of bugs and errors during the testing and implementation phase, dynamic and frequently changing user requirements, and the need for a system that supports multi-platforms. Rapid application development (RAD) is the software development life cycle (SDLC) that emphasizes the production of a prototype in a short amount of time (30-90 days). This study discovered that implementing a model-driven architecture (MDA) approach into the RAD method can accelerate the model design and prototyping stages. The goal is to accelerate the SDLC process. It took roughly five weeks to construct the system by applying all of the RAD stages. This time frame does not include iteration and the cutover procedure. During the prototype test, there were no errors with the create, read, update, and delete (CRUD) procedure. It was demonstrated that automatic transformation in MDA can shorten the RAD phases for designing the model and developing an early prototype, reduce code errors in standard processes like CRUD, and construct a system that supports multi-platform.