Service-Oriented Architecture ( SOA ) represents a new and evolving model for building distributed applications. Services are distributed components that provide well-defined interface that process and deliver XML messages. A service-based approach makes sense for building solutions that cross organizational, departmental, and corporate domain boundaries. A business with multiple systems and applications on different platforms can use SOA to build a loosely coupled integration solution that implements unified workflows .
Overview of Service-Oriented Architecture
The concept of services is familiar to anyone who shops online at an e-commerce web site. Once you place your order, you have to supply your credit card information, which is typically authorized and charged by an outside service vendor. Once the order has been committed, the e-commerce company coordinates with a shipping service vendor to deliver your purchase. E-commerce applications provide a perfect illustration of the need for an SOA. if the credit card billing component is offline or unresponsive, you do not want the sales order process to fail. Instead, you want the order to be collected and the billing operation to proceed at a later time. Figure 1-1 provides a conceptual workflow for an e-commerce business that uses multiple services to process orders.