Appendix A. Service Oriented Architecture (SOA) overview 449
More responsive and faster time-to-market.
The ability to compose new services out of existing ones provides a distinct
advantage to an organization that has to be agile to respond to demanding
business needs. Leveraging existing components and services reduces the
time needed to go through the software development life cycle of gathering
requirements, performing design, development and testing. This leads to
rapid development of new business services and allows an organization to
respond quickly to changes and reduce the time-to-market.
Reduce cost and increase reuse.
With core business services exposed in a loosely coupled manner, they can
be more easily used and combined based on business needs. This means
less duplication of resources, more potential for reuse, and lower costs.
Be ready for what lies ahead.
SOA prepares businesses for the future. Business processes which comprise
of a series of business services can be more easily created, changed and
managed to meet the needs of the time. SOA provides the flexibility and
responsiveness that is critical to businesses to survive and thrive.
Like most technologies, SOA is not necessarily the answer to every business
problem. Where SOA is appropriate, migration to it is non-trivial. Rather than
migrating the entire enterprise to a service-oriented architecture overnight, the
recommended approach is to migrate an appropriate subset of business
functions as the business need arises or is anticipated.
A.2 Web services architecture
Web services is a relatively new technology that has received wide acceptance
as an important implementation of SOA. This is because Web services provides
a distributed computing approach for integrating extremely heterogeneous
applications over the Internet. The Web services specification is completely
independent of programming languages, operating systems, and hardware to
promote loose coupling between the service consumer and provider. The
technology is based on open technologies such as:
eXtensible Markup Language (XML)
Simple Object Access Protocol (SOAP)
Universal Description, Discovery and Integration (UDDI)
Web Services Description Language (WSDL)