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BPM Web Services-Oriented Architecture:A Critical Technology
Web Services-Oriented Architecture:A Critical Technology
By: Ashish Deshpande
May. 24, 2002 12:00 AM
The Web has always been service-oriented. Services such as auctions or ticket-buying services are available today to general Web users. Essentially, what the Web did for interactions between business functions and their users, Web services will do for interactions between functions spread out across multiple business units or even across multiple businesses. Because of this, a number of organizations are trying to design and build a Web service-oriented architecture (WSOA). The good news is that most of them are already on the right path to getting there. This next wave of application development is a natural extension of the move toward component-based standards such as J2EE and COM. Web services are unique in that they rely entirely on Internet-standard technologies. (Note: Web services rely on existing standards such as XML messaging [SOAP], Internet standard transport [HTTP, FTP, SMTP], and emerging standards such as WSDL, UDDI, and WSFL.) They build on distributed, component-oriented environments, rather than throwing them away and starting from scratch. The biggest departure from component-based development (CBD) is that a WSOA is likely to be very process-centric as opposed to the program-centric applications of the earlier waves of application development. That's because organizations will use Web services to provide access to higher-level business functions rather than to their components or legacy systems. For example, car rental agencies want to expose the process of renting a car or checking on its status, and not the inventory system or the order entry system that implements parts of those business functions. Similarly, an insurance company wants to expose the process of renewing an insurance policy or checking the status of a claim, instead of providing access to the legacy systems or databases that contain the required information. A critical enabling technology is business process integration (BPI). BPI extends integration capabilities by providing a graphical interface that enables business users to model business processes that are core to an organization's operations. BPI allows the use of functionality from existing applications, regardless of the technology with which the applications were developed. BPI also handles issues such as load balancing, fault-tolerance, and scalability, so business processes can be executed at any time by as many customers and partners as necessary. Essentially, BPI enables organizations to create an internal WSOA that lets them effectively leverage their existing investments and take advantage of Web services. Basic to the WSOA paradigm is the shift away from the traditional approach of building customized systems to focusing on the business process. Organizations have heavy investments in existing systems, applications, and people. A WSOA built on the foundations of BPI provides a practical approach to delivering business value while preserving existing investments. BPI enables the WSOA to evolve incrementally and forces it to stay closely aligned with business drivers. It provides an alternative to the endless treadmill of application rewrites and custom coding.
Building a WSOA
With a WSOA, the focus on the business process enables a much higher level of application development than in the past. It's also more closely tied to business requirements than technical requirements. For this potential to be realized, the BPI technology must enable processes to be quickly and dynamically created from functionality in multiple, preexisting, back-end systems that are incompatible. It must allow deployment of those processes to a robust execution engine. Finally, it must facilitate the exposure of these processes or various parts or combinations of these processes via the Internet-standard technologies of Web services. Newer, emerging BPI products enable model-driven visual definition and automation of business processes. Using a sophisticated modeling environment, organizations can define business processes and leverage a powerful connectivity framework that includes numerous point-and-click wizards for interacting with existing legacy business systems as well as newer component-based systems, including J2EE, COM, and Web services themselves. Some even provide a high-performance, high-availability engine for deploying and executing these business processes in an extremely reliable manner. Any such process, portions of the process, or groups of these processes may be exposed to the outside world in the form of Web services.
Building a WSOA with BPI
The WSOA is built in layers using existing technology. Below is a description of the layers and then an overview of the combined work at the end.
Components
In a WSOA the components may utilize the same Internet-standard technologies of Web services. The required back-end functionality may be accessed via SOAP messages sent over a messaging layer such as MQSeries. However, this is not required and may not add any business value, particularly since some BPI products can already communicate with a variety of back-end systems to automate the business process. As Figure 1 shows, the most convenient way to access each component is different. BPI technology allows each component to be created using the most appropriate technology for that platform. However, it doesn't preclude the creation of internal Web services to expose the functionality in each back-end system. By and large, most organizations are already well down the path toward componentizing using one or more technologies. BPI technology can leverage these efforts and build on top of existing component strategies to enable the WSOA.
Services
BPI technology allows business analysts to rapidly model business processes that combine components to create the above services. Typically, the process model is very rich and includes support for business rules, data transformations, and automatic error-handling. It doesn't require all components to be created using one particular standard such as EJB, COM, or XML. The process can mix and match components created using incompatible technologies.
Service Manager
A BPI engine can provide a very high-performance, scalable, robust execution environment for internal as well as collaborative business processes. The engine is equally capable of executing long-running processes that may run for weeks as well as short-running straightthrough processes that are fully automated and may run for a few milliseconds.
Client Access
Figure 4 shows a complete WSOA built around BPI technology for the service manager. The WSOA builds upon the existing technologies that are already deployed within numerous organizations. The business processes that define the operation of the business can be easily modeled - business users who understand the processes can do this work. Similarly, collaborative business processes between business partners can be modeled within this environment. These processes can be fully automated or they can retain the necessary elements of human interaction depending on business needs. The process metamodel is rich enough to support all the requirements of short-running, fully automated processes or long-running human-interactive processes. The variety of applications and technologies typical of most organizations can be incrementally incorporated into the integration via wizards, tools, and adapters provided by the same modeling environment. The business process models are then deployed to an execution engine that automates all the issues normally associated with complex, distributed systems, including performance, scalability, load balancing, and fault tolerance. The engine provides access to the business process models through a wide variety of client protocols. Typically, the system can be easily administered from a single, centralized location using nothing more than a Web browser. A powerful, sophisticated security infrastructure, based on existing corporate and Internet security standards guarantees secure access to the business functionality embodied in the exposed business processes and ensures that access is provided only to authorized entities. Finally, the modeling environment provides a single, unified graphical user interface that business users and developers alike can use to do their work and share among those users. This reduces training issues and costs associated with deploying multiple tools.
Summary
To effectively implement Web services, many organizations are already designing and building a WSOA. Fortunately, this new wave of application development is a natural extension of component-based standards and architectures like J2EE and COM. Web services are built on the distributed, component-oriented environment that is already in place at many organizations. A critical enabling technology for implementing a services architecture is business process integration. BPI lets organizations create an internal WSOA that allows them to effectively leverage their existing investments and take advantage of Web services. A WSOA built on the foundations of BPI provides a practical approach to delivering business value while preserving existing investments in people and systems. This is because BPI enables the WSOA to evolve incrementally and provides a seamless alternative to endless rewrites and custom coding. Reader Feedback: Page 1 of 1
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