Principles of SOA

Principles of SOA

 1) Services are reusable

                Services are designed in such a way that they should be reused in future,

so that activities concerned with development of redundant services can be minimised

reuse can of inter-application interoperability, composition, creation of cross cutting

or utility services, more generic the service is more the reuse.

2)Services are share a formal contract

                A formal contract need to be shared between the service requestors and the service providers, these contracts explain the how a service may go about accomplishing a particular task. These contracts define service endpoint, operation, input & output supported by each operation, rules and characteristics of a service.

3)Services are loosely coupled

                If services to be composed with others so as to develop a inter application or cross cutting applications these services need to be loosely coupled with each other, services should interact with each other with some predefined parameters but should be independent of each other.

4)Services abstract underlying logic

                Services act as black boxes hiding details from outside world but exposes only those that need for services  to communicate with each other  

5)Services are composable

                If we need to develop some cross cutting applications then services should be able to be composed with others services ,this is another form of reuse.

6)Services are autonomous

                The logic the service provides is confined within a boundary and service has control only within the boundary. Types of autonomy

  1) Service-level autonomy.

  2)Pure autonomy.        

7)Services are stateless

                If we want services to be loosely-coupled then they should not maintain any state information.

8)Services are discoverable

                To implement the principle of reuse services need to discovered in its first place, this also avoids creation  of redundant logic