Common Principles of SOA

8 common principles of SOA are as follows :

1.Reusability

Reuse is very important within service-orientation, so that it becomes a core part of that service and design processes. Non-proprietary service technology has provided

the opportunity to maximize the reuse potential of multi-purpose logic on desire level.Services are designed to potential and frequent reuse when available and required.

2.Formal Contract

Services express their purpose and capabilities via a service contract. To define service and terms of information exchange formal contract is the best way. Contract design including that services functionality, how data types and data models are defined, and how policies lies confidential. There is a constant focus on ensuring that service contracts are optimized, granular, and standardized to ensure that the outcome should be consistent and reliable.

3. Loose Coupling

Coupling defines a connection or relationship between two things. A measure of coupling is comparable to a level of dependency.

The principle of Loose Coupling promotes the independent design and evolution of a logic for a service and implementation . There are many types of coupling involved in the design of a service, each of which can impact the content and granularity of its contract.

Figure : Coupling represents a core design consideration that spans both intra and inter-service design.

4. Abstract underlying logic

Abstraction ties into many aspects of service-orientation. This principle emphasizes the need to hide as much of the underlying details of a service as possible.

Various forms of meta data come into the picture when we are going to assess appropriate abstraction levels. The extent of abstraction applied can affect service contract granularity and can further influence the ultimate cost and effort for run the service.

5. Composability

The ability to compose services is a main requirement for achieving some of the most fundamental goals of SOA.

Composibility allows logic that will help to create new service at different levels of granuality and that will be capable of participating as effective composition members. The principle of Service Composability addresses this requirement by ensuring that a variety of considerations are taken into account.

6. Service are Autonomous

The logic of this principle fully based on explicit boundaries and the principle of this service supports the extent to which other design principles can be effectively realized in real world production environments that increase a service’s reliability and behavioral predictability. And all the services within this explicit boundaries are control by them and these are independent from other service.

7. Stateless

Every service should be able to remain loosely coupled and there is no need to manage state information .Service should be design such that its statelessness maximized.Services are therefore ideally designed to remain stateful only when required.

8.Discoverable

Services should always be discoverable and also should be such that it is easily understood by humans and also service requesters so that the logic can be used.