Proposed Technology Projects and Service-Oriented Architecture - Essay Example

Proposed Technology Projects In the past few years, “.com” establishments have flooded the information superhighway and there is a common objective to change the way consumers shop. The advantage brought about by e-business is obvious. The cost of running a business can be driven down significantly because location is no longer a concern, with the added advantage of not having to demonstrate physical products and to keep large quantities of unsold stock. Consumers, on the other hand, are reluctant to change the way they shop for many reasons Fong (2000). To be successful in the competitive market of e-business, a well-structured web site becomes an essential trading tool. The web site itself can be very complex, depending on its functions, features, and more importantly, the level of security provided to customers. The worst scenario is to make the web site unnecessarily complicated that yields to undesired consequences such as incurring extra costs and making troubleshooting much more difficult. This is a consequence of not having a well-documented plan in place. Web Services A Web service is a software system planned to maintain interoperable interaction between computers over a network." Web services are Web APIs that can be accessed over a network, for instance, Internet. Web services are a collection of tools that can be used in a number of ways. RPC is a style of Web services which provides a dispersed utility call interface that is well-known to several developers. Normally, the fundamental component of RPC Web services is the WSDL operation. Web services are also used to apply a design according to Service-oriented architecture (SOA) models, in this situation the basic unit of communication is a message, instead of an operation. Representational state transfer is also a web service which effort to follow HTTP and related protocols by limiting the interface to a set of well-known, standard operations such as Get, Put, Delete. This web service uses WSDL to express SOAP messaging over HTTP, which defines the operations. Service Oriented Architecture (SOA) Service Oriented Architecture is an architectural approach that leads all features of developing and using business processes, put together as services, all the way through their lifecycle, in addition to defining and provisioning the Information Technology infrastructure that permits different applications to exchange data and contribute in business processes loosely coupled from the operating systems and programming languages underlying those applications. SOA corresponds to an infrastructure in which functionality is decomposed into dissimilar services, which can be dispersed over a network and can be joint together and reused to generate business applications. These services correspond with each other by passing data from one service to another, or by coordinating an activity between two or more services. Organizations are required to put together existing systems in order to apply information technology support for business processes that cover all present and forthcoming projects requirements required to run the business continuous. A range of designs can be used to this end, varying from rigid point-to-point electronic data interchange communications to Web auctions. By bringing up to date technologies, such as Internet-enabling EDI-based systems, organizations can formulate their Information Technology systems accessible to internal or external customers; but the resulting systems have not confirmed to be elastic sufficient to meet business demands. An elastic, consistent infrastructure is required to better support the connection of various applications and the sharing of data. SOA is one such infrastructure. It combines business processes by configuring large applications as an unplanned collection of smaller modules called services. These applications can be used by different groups of people both inside and outside the organizations, and new applications developed from a mix of services from the global pool exhibit greater flexibility and uniformity. Building all applications from the same group of services makes accomplishing this objective much easier and more deployable to partner companies. Workflow Management Systems Workflow Management Systems allow organizations to define and control the various activities associated with a business process. In addition, many management systems also allow a business the opportunity to measure and analyze the execution of the process so that continuous improvements can be made. Such improvements may be short-term (e.g. reallocation of tasks to better balance the workload at any point in time) or long-term (e.g. redefining portions of the workflow process to avoid bottlenecks in the future). Most workflow systems also combine with other systems used by the organization: document management systems, databases, e-mail, office automation products, GIS (Geographic Information Systems), production applications, etc. This integration provides structure to a process which employs a number of otherwise independent systems. Why particular project has been chosen With the emergence of service-oriented architectures (SOAs), workflow management systems are being used to create applications from service compositions. Because service compositions may extend across platforms, domains, and virtual organisations, classical implementations of workflow management systems must be extended to address interoperability and reliability. In particular, there is a need to define interoperable and scalable communication mechanisms to support workflows over loosely-coupled environments and to provide support for runtime verification to increase user confidence in workflow behavior. With the emphasis on increasing resource usage across organisations and the emergence of Web Services (WS) technologies, SO is rising as the main alternative to the development of distributed, loosely-coupled software. The term SO refers to the level of abstraction in which functionality is specified. In particular, SO is an approach for analysis, design, and development of modules that support principles such as reusability, loose coupling, abstraction, and separation of concerns (Erl, 2005). The more familiar term SOA is used to describe “the policies, practices, and frameworks that enable application functionality to be provided and consumed as sets of services” (Sprott and Wilkes, 2004). Application developers from business and scientific domains are using WS to implement systems based on the SOA paradigm. Web service technologies provide the necessary mechanisms to expose shareable resources (service-oriented modules that provide data and functionality) over the network and allow the resources to be consumed by users across heterogeneous platforms, enhancing interaction across organisations. As the number of shareable resources increases and as service consumer applications grow in complexity, there is a need to define formal venues for connecting services and supporting interoperability of interfaces among services. Workflow technology is one approach that has been pursued to address the problems of composition and interoperability of services. A workflow specifies a group of activities and their order of execution with respect to each other, where an activity is considered an atomic unit of work (van der Aalst et al., 2003). In a scientific setting, a workflow usually is driven by data flow, and activities represent automated services, e.g. a dataset transformation module. In other words, an activity is triggered by data streams flowing as input and the activity requires limited or no user interaction. Workflow management systems provide functionality to access reusable modules, support specification of workflows, and manage workflow execution. Implementing a workflow management system that hosts effective workflows over service-oriented modules presents the following challenges: maintaining the interoperability goals of SO allowing users with limited technical background to compose workflows from independent, third-party modules giving users the confidence that the workflow execution results in the intended behaviour. Relation to previous strategy Workflow management systems provide functionality to access reusable modules, support specification of workflows, and manage workflow execution. Systems like the Kepler Scientific workflow management system (Ludäscher, 2005) provide a stand-alone module that incorporates all of the aforementioned functionality. Other systems like the IBM Domino suite (Lotus Development Corporation, 1999) extend the basic setting to a client-server environment. In a stand-alone environment, the user downloads and installs the management system on his or her local platform. The client-server environment, on the other hand, consists of a central framework that is hosted on a high-end server platform. The central framework is responsible for maintaining the workflow specifications, executing the workflow activities, and maintaining their state. Users connect to the central framework through client or web applications in order to create a workflow specification and monitor its execution. Because different users can connect to a single central management system, the client-server setting has the additional benefit of enhancing team collaboration for the management and execution of workflows. The client-server setting is well-suited for domains where multiple-user interaction is a key feature, while the stand-alone environment facilitates experimentation on a controlled, local environment, a feature that is desirable in a scientific domain. The range of reusable modules that may be involved in the workflow is limited by the connectivity interfaces that the workflow management system supports. Typically, a workflow management system utilizes a registry of available modules that the user can plug into a workflow. The registry may be internal or external. Maintaining an internal registry of modules provides the benefits of assuring that a module is compatible with the workflow framework and that the framework has sufficient information about the module’s interface to guarantee interoperability with other registered modules. In other words, if a module does not meet the interface requirements of the workflow management system, then the module cannot be included in the internal registry. For example, the Kepler system includes an internal library of ‘actors’ that provide the functionality that can be plugged into Kepler workflows. An external registry presents an alternative that is more aligned to SO. The registry presents clients with a description of the functionality provided by a given module and the interface requirements imposed by that module. This description serves as a contract between the module and the client of the module. Also, it allows third-party modules to be added to the registry without restrictions imposed by the workflow management system. In the case of an external registry, interoperability between modules is achieved through standardization of communication protocols. How and why particular software or hardware technologies can be used to implement the product Different web technologies along with the integration of different programming tools can be used to implement this product. Web services require sophisticated web technology and the implementation of workflow management system needs some programming effort. Also an expensive hardware setup is required to support this very complex software system. Figure 1 shows an implementation of a workflow management system that includes an internal registry of modules and provides monitoring capabilities for the execution of workflows. In this example, the user implements a workflow specification by selecting references to Web Services A and B (WSA and WSB, respectively) from the internal registry. Once workflow execution starts, WSA and WSB are instantiated through proxy stubs that are hosted on the workflow management system (cf. Platform 1). The proxy stubs are responsible for bridging communication between Platform 1 and Web Service A and Web Service B, which are remotely hosted on Platforms 2 and 3 respectively. Since the workflow management system is the sole initiator of workflow services, all communication of control and production data is routed through it. As a result, WSA and WSB never interact directly with each other. Figure 1: Diagram of the purpose system References Leonardo Salayandia and Ann Q. Gates “Towards a workflow management system for service oriented modules”. Intl J. Simulation and Process Modelling. Erl, T. (2005) “Service Oriented Architecture: Concepts, Techniques, and Design,” Prentice-Hall, Englewood Cliffs, New Jersey. Sprott, D. and Wilkes, L. (2004) ‘Understanding Service-Oriented Architecture’, Microsoft Architect Journal, January, Microsoft Corporation, Microsoft Developer Network, January 2004, http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnmaj/html/aj1soa.asp. van der Aalst, W., ter Hofstede, A., Kiepuszewski, B. and Barros, A. (2003) ‘Workflow patterns’, Distributed and Parallel Databases, Vol. 14, No. 3, July, pp.5–51. Ludäscher, B., Altintas, I., Berkley, C., Higgins, D., Jaeger, E., Jones, M., Lee, E.A., Tao, J. and Zhao, Y. (2005) ‘Scientific workflow management and the Kepler system’, Concurrency and Computation: Practice and Experience, Special Issue on Workflow in Grid Systems, John Wiley & Sons Ltd., Vol. 18, No. 10, pp.1039–1065. Lotus Development Corporation (1999) Domino Workflow Automating Real-World Business Processes, white paper, September, ftp://ftp.lotus.com/pub/lotusweb/eibu/dominoworkflow.pdf. Center of Technology in Government University at Albany / SUNY, “An Introduction to Workflow Management System”. Read More