To be fully buzz word compliant, most IT plans today include composite applications, Web services and SOA. They are all related, and all are needed dliver a new level of business ability required to meet today’s global competitive challenges.

Composite applications combine new functionality with existing data and applications. The goal is to deliver new business solutions faster, to respond quickly to market changes or emerging opportunities. Previous attempts at rapid application development (RAD) could not deliver the level of business agility required for real time business. RAD just shortened the development process (but not always the deployment processes). The RAD applications were not necessarily easy to change or scale. While client/server systems enabled reuse of information, they did not enable reuse of business functionality.

True business agility requires leveraging what already exists, adding functionality as required, and optimizing business processes to reduce time and cost. This is changing the nature of application development from a standalone activity that focuses on the creation of new code to an activity that is centered on using existing applications as the basis for developing new business systems. Rather than creating a new customer database for an application, you can reuse the existing CRM system. Rather than creating code to determine the value of a customer, you can reuse the existing custom application on the mainframe. Rather than creating a user interface from scratch, you can reuse the portal interface. Achieving this new level of business agility requires the ability to quickly add new functionality or business processes while leveraging existing system and information assets. This is the goal of composite applications.

Composite applications, by definition, reuse existing IT assets. While a composite application may include sending or receiving information from a packaged and legacy application, reuse can be maximized through componentized business services, such as credit checking, mortgage calculation, or package tracking. This is the concept of a Service Oriented Architecture (SOA). In an SOA, discrete business functions are created as independent components with standard interfaces that can be accessed by other applications, services, or business processes regardless of the platform or programming language. These services can be flexibly combined to support different or changing business processes and functions. SOA is the underlying architecture supporting the creation of composite applications that can be quickly assembled from existing and new services.