| Integration capabilities of the bus are implemented as separate services. Specialized integration services, which can be extended and augmented using a service interface, provide the integration capabilities that allow applications to easily interoperate (Figure 6-9). Examples of such services include: A specialized transformation service, with the sole responsibility of applying an XSLT stylesheet to convert an in-flight XML message from one dialect of XML to another A content-based routing service, which applies an XPath expression to look contextually into the nodes of the XML documents as they pass through the service and make determinations on where to send the message next An XML logging service, which extracts a copy of an XML message as it travels through a portion of a business process and logs it for auditing and tracking purposes
Chapter 8 explores more examples in a case study that uses custom services for EDI translators and SAP adapters. Figure 6-9. Integration capabilities of the bus can be augmented and extended through specialized integration services that use a common service interface Because these integration capabilities are themselves implemented as services, they can be independently deployed anywhere within the network. The result is precise deployment of integration capabilities at specific locations, which can then be scaled independently as required. It also means that services can easily be upgraded, moved, replaced, or replicated without affecting the applications that they cooperate with. |