Soa 6 service architecture components
- 1. Service Oriented Architecture: 6 SOA Components Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. SOA Defined : “Service orientation” • “SOA is a conceptual business architecture where business functionality, or application logic, is made available to SOA users, or consumers, as shared, reusable services on an IT network. • “Services” in an SOA are modules of business or application functionality with exposed interfaces, and are invoked by messages.”
- 3. SOA: Business Perspective • The “business oriented” definitions of SOA is about analyzing the business to identify business areas and business processes. • Followed by defining services to represent these “areas” . • Services expose their capabilities through message interfaces. • The services can then be choreographed or orchestrated to realize the business processes. • The goal of SOA is to increase the alignment between business and IT and achieve business agility – the ability to respond to changes quickly and efficiency.
- 4. SOA: Technology Perspective • Service Oriented Architecture as an architectural style for building systems based on interacting coarse grained autonomous components called services. • Each service expose processes and behavior through contracts, which are composed of messages at discoverable addresses called endpoints. • Services’ behavior is governed by policies which are set externally to the service itself.
- 6. Service • The central pillar of SOA is the service. • “a facility supplying some public demand”. • A Service should provide a high cohesion and distinct function. • Services should be coarse grained pieces of logic. • A Service should implement at least all the functionality promised by the contracts it exposes. • Service autonomy means the services should be self- sufficient, at least to some extent, and manifest self healing properties
- 7. Service contract • The collection of all the messages supported by the Service is collectively known as the service's contract. • The contract can be unilateral, meaning a closed set of messages the service chooses to provide. • A contract might also be multilateral or bilateral, that is, between a predefined group of parties. • The contract can be considered the interface of the Service akin to interfaces of object in object oriented languages.
- 8. End Point • The Endpoint is an address, a URI, a specific place where the service can be found and consumed. • A specific contract can be exposed at a specific endpoint.
- 9. Messages • The unit of communication in SOA is the message. • Messages can come in different forms and shapes, for instance, http GET messages (part of the REST style) ,SOAP messages, JMS messages and even SMTP messages are all valid message forms. • The differentiator between a message and other forms of communication such as plain RPC, is that messages have both a header and a body.
- 10. Policy • One important differentiator between Object Orientation and SOA is the existence of policy. • If an interface or contract in SOA lingo, separates specification from implementation. • Policy separates dynamic specification from static/semantic specification. • Policy represents the conditions for the semantic specification availability for service consumers. • The unique aspects of policy are that it can be updated in run-time and that it is externalized from the business logic. • The Policy specify dynamic properties like security (encryption, authentication, Id etc.) , auditing, SLA etc.
- 11. Service Consumer • A service consumer is any software that interacts with a service by exchanging messages with the service. • Consumers can be either client applications or other "neighboring” services their only requirement is that they bind to an SOA contract.
- 12. SOA Interfaces for SOAD • SOA has a lot of emphasis on interface. – Starting from the messages which are the parts of the interface, – the contract which is the collection of the messages, – the endpoint where the contract is delivered – and the policy which governs the behavior of the endpoint. – Thus SOA has a total of four different components that deal with the interface – The focus on interfaces is what gives SOA the ability to create loose coupling, composable components, reuse and achieve the various design goals.
- 13. Assignment • 1. Discuss in detail the components of Service Oriented Architecture