Almost all developers know something about Object Oriented Programming (OOP) which has been a common way to build software for a long time.  But what is Service Oriented architecture?

In recent years, development moved from building centralized local systems to distributed systems which run on several places.  Each part of these systems are hosted somewhere and provide some services.  The idea of having services to answer to common needs through the web became serious and development technologies answered to this need by providing Web Services in their core, but day after day distributed systems became more common and the idea of Service Orientation (SO) was born.

Service Orientation is a complement to Object Orientation.  It means you will not kick Object Orientation out to use Service Orientation.  Service Orientation uses Object Orientation in its core, but there are some distributed scenarios that can be viewed by Object Orientation so you use Service Orientation to describe these scenarios.

In Service Orientation you think different and describe things via services and divide your system into smaller parts which run as services.  These services can communicate with others via messages.  In each service you can apply Object Orientation to accomplish goals of that service.  One important benefit of Service Orientation is here because you can use different technologies and platforms to design a service by using Object Orientation then use universal formats to build messages and start communication between different pieces of your system.

There are four principles in Service Orientation (you may see them as tenets on other resources):

·         Boundaries are explicit.

·         Services are autonomous.

·         Services share schema and contract, not class.

·         Service compatibility is determined based on policy.

You can read more about these fundamentals (they are important principles) on MSDN.

Generally, you have to change your point of view in Service Oriented design, but this should not change your view for Object Oriented Programming.  You should get enough experience to divide a system to logical independent services then choose appropriate platform to build each piece.  Thankfully, Microsoft helps you in all stages and you can use powerful Microsoft technologies to build your distributed software.

Service Oriented Architecture (SOA) is a concept beyond the scope of these tutorials.  I recommend you to read good books about Service Oriented Architecture to learn more about it.  Having a good understanding of this architecture is an important requirement to be success in this field.