Part 1. Understanding ESB functionality

An enterprise service bus (ESB) is a confusing topic in the modern world of IT. Sometimes it’s referred to as an architectural pattern, which describes a flexible and constructive way to approach integration challenges. The ESB seen as a pattern can and will be implemented with several different products, each excelling in its own domain like routing, transformation, security, and orchestration.

An ESB from an integration vendor perspective is a product offering that provides integration functionality, a developer toolset, and a management environment. These product offerings often have a background in the enterprise application integration (EAI) domain.

Another perspective of an ESB is as an important part of a service-oriented architecture (SOA). From the SOA perspective, an ESB can be used as an integration platform that enables existing IT assets and applications to be exposed as services. Because the ESB is based on open standards, the proprietary technology of legacy applications can be exposed as services based on open and modern technologies like web services and messaging.

In part 1, we will show the functionality an ESB can offer to solve integration challenges. We take a close look at open source ESBs and provide an overview of the open source ESBs currently available. We also introduce two open source ESBs, Mule and Apache ServiceMix, and show you how to set up a development environment to work with these ESBs and the examples in this book. Finally, we take a first look at how to implement integration functionality and message flows in Mule and ServiceMix.