Web Services Service Oriented Architecture (SOA)

About service oriented architecture SOA:

• SOA is not a solution, it is a practice.
• At a high level, SOA is formed out of three core components:
• Service Provider (Service)
• Service Consumer (Consumer)
• Services Directory (enabled by Broker)

• The service provider offers business processes in the form of services.
• The services offered by the provider are called by the consumer to achieve certain sets of business goals.
• The process of services being provided and consumed is achieved by using directory services that lie between the provider and the consumer, in the form of broker.

Objective of using SOA

Loose coupling: The business process being decomposed into independent services will help in bringing down the ependencies on a single process. This in turn will help in faster processing time.
Platform-neutrality: XML-based message information flow enhances the capability to achieve platform neutrality. These XML messages are based on agreed XML schema, eliminating the need to set up other messaging standards that can differ across platforms
Standards: The message flow across the enterprise is in the form of globally accepted standards. The service only has to depend on the service descriptions without worrying about the target standards and removing the dependencies.
Re-usability: The business logic being divided into smaller logical units, the services can easily be re-used. These enhance the utilization of SOA-based solution, which has a cascading affect on service delivery and execution.
Scalability: Again, as the business processes are decomposed into smaller units, adding new business logic is easy to accomplish. The new logic could either be added as an extended unit of the current service, or it can also be constructed as a new service.
Top-down: In a top-down approach, the business use cases are created, which gives the specifications for the creation of services. This would ensure that the functional units are decomposed into smaller processes and then developed.
Bottom-up: Using the bottom-up approach, the current systems within the organization are studied, and suitable business processes are identified for conversion to services.
The Service provider: The provider comes into action when the service is invoked. Once the service is invoked, the provider will execute the business logic. Messaging will depend upon the business logic, in case the consumer expects a message after the execution of business process, the provider will send out the reply.
The Service Consumer: The consumer would send out a message to the provider in order to access the service. This is the requester. It would either be done directly by a service-to-service call or through the directory services. Services required for processing are identified by their service descriptions.
The same service can act as the provider as well as the requester of the service. But this is seldom seen in practice.

The Service Handler: The service handler acts as a collaboration agent between the provider and the consumer. The handler contains the realization logic, which will search the appropriate service provided and bind it to the consumer request.

end of service oriented architecture SOA.

Have fun!