Copyright IBM Corporation 2005. All rights reserved. Page 1 of 15 A standards-based approach to application integration An introduction to IBM’s WebSphere ESB product Jim MacNair Senior Consulting IT Specialist [email protected] IBM Corporation 2005. All rights reserved. Page 2 of 15 IBM WebSphere® Enterprise Service Bus (WebSphere ESB) V6.0.1 product is a component based integration platform built on a uniform programming model and a uniform data representation model. WebSphere ESB provides a flexible connectivity infrastructure designed to help you integrate applications and services as part of your service oriented architecture (SOA). An SOA separates implementation from interfaces. WebSphere ESB powers an SOA by separating the connectivity details from the interfaces, so that you can focus on your core business. WebSphere® ESB V6.0.1 takes a new approach to application integration. It is based on industry standards and runs in a common J2EE environment, WebSphere® Application Server Network Deployment V6. WebSphere® ESB is based on the Service Component Architecture (SCA), introduced in the WebSphere® Process Server V6.0 product. The SCA includes both the development of services and the connectivity of services into larger composite business processes, using an easy to use graphical tooling environment. The WebSphere® Process Server product offers the infrastructure for the implementation and composition of services. The WebSphere® Application Server Network Deployment V6 product delivers the basic transport functions. The WebSphere ESB product offers capabilities to intelligently connect services. With WebSphere® ESB you can connect services faster and change existing connections more easily. A flexible and manageable approach to an SOA A Service Oriented Architecture (SOA) is a means of integrating an enterprise. It allows enterprises to increase their flexibility and supports the reuse of existing assets. Services are composed into integrated processes, without the need to write or modify programs. By connecting through an ESB, the individual services can be loosely coupled. The services can be separately maintained, managed and enhanced without requiring two or more integrated applications to be changed at the same time. An ESB offers a flexible and manageable approach to support the implementation of a Service Oriented Architecture.Copyright IBM Corporation 2005. All rights reserved. Page 3 of 15 What is an Enterprise Service Bus? An Enterprise Service Bus (ESB) is a flexible connectivity infrastructure for integrating application and services. There is a core set of functions that is included in most definitions. The core functions are: • Route messages between service requestors and service providers • Convert transport protocol between requestor and provider • Transforms message formats between requestor and provider • Distributes business events The ESB must provide JMS messaging and Web services communications. Industry standards Industry standards are an important characteristic of any Enterprise Service Bus. These standards are popular because they can provide the wide interoperability necessary for services on a variety of platforms and environments to work together. Standards can provide application portability between different implementations of a standard. Which standards are most relevant to an ESB? There is a long list of standards that could apply to an Enterprise Service Bus (ESB). However, the following standards are likely to be the most relevant to an ESB. • XML • XSLT/XPath • Web services (WS-*) • JAX-RPC and JSR-109 • JMS • SOAP • WSDL • UDDI XML is a standard, platform independent method of representing data. The combination of XSLT and XPath provide a standard method for the identification and transformation of XML data.Copyright IBM Corporation 2005. All rights reserved. Page 4 of 15 If XML provides a standard representation of data, then the Web services standards provide a standard way of accessing the data. There are a variety of Web services standards that are relevant, including the WS-I specification and the WS-Security specification. The JAX-RPC and JSR-109 protocols provide a standard method of invoking a web service. WebSphere Application Server V6 provides strong support for relevant Web services standards. SOAP, Web Services Definition Language (WSDL) and UDDI provide important standards for the interoperability and platform independence of services. JMS provides a common messaging application programming interface for the Java programming environment. A messaging infrastructure can provide the benefits of loose coupling and reliable communications. While industry standards are an important part of an ESB, it is possible to draw some erroneous conclusions based on misunderstandings of what industry standards do and do not cover. Do standards mean that my choice of vendor is not important? The best way to keep up with current and emerging standards is to choose a vendor like IBM who is committed to standards. You cannot buy industry standards. Rather, you must buy a solution (product) that implements a standard from a vendor. It is the vendor who implements the standards and who must stay current with new and evolving standards. A vendor’s commitment to invest in standards now and in the future is more important than a typical point in time comparison. It is easy to think that the choice of vendor is not important, since applications can easily be moved to a different vendor’s product in the future. Standards are often aimed at interoperability rather than portability. A robust and complete product offering requires more than the implementation of a list of standards. Many applications that use industry standards are not easily portable. Standards do not cover non-functional requirements such as performance, scalability and availability. These can vary widely among products that support a particular standard.Copyright IBM Corporation 2005. All rights reserved. Page 5 of 15 An architected approach to integration The WebSphere ESB product uses an architected approach to integrate applications. IBM developed this architecture to allow tooling that simplifies and quickens development and that shortens the associated learning curves of all of the underlying