Soa 2 principles of soa
- 1. Service Oriented Architecture SOA: 2 SOA Principles Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. SOA Principles • Standardized Service Contracts • Loose Coupling • Abstraction • Reusability • Autonomy • Statelessness • Discoverability • Composability
- 3. Standardized Service Contracts • “Services within the same service inventory are in compliance with the same contract design standards." • Services use service contract to – Express their purpose – Express their capabilities • Use formal, standardized service contracts • Focus on the areas of – Functional expression – Data representation – Policy
- 4. Loose Coupling • “Service contracts impose low consumer coupling requirements and are themselves decoupled from their surrounding environment." • Create specific types of relationships within and outside of service boundaries with a constant emphasis on reducing (“loosening”) dependencies between – Service contract – Service implementation – Service consumers
- 5. Abstraction • “Service contracts only contain essential information and information about services is limited to what is published in service contracts” • Avoid the proliferation of unnecessary service information, meta-data. • Hide as much of the underlying details of a service as possible. – Enables and preserves the loosely coupled relationships – Plays a significant role in the positioning and design of service compositions
- 6. Reusability • “Services contain and express agnostic logic and can be positioned as reusable enterprise resources." • Reusable services have the following characteristics: – Defined by an agnostic functional context – Logic is highly generic – Has a generic and extensible contract – Can be accessed concurrently
- 7. Autonomy • "Services exercise a high level of control over their underlying runtime execution environment." • Represents the ability of a service to carry out its logic independently of outside influences • To achieve this, services must be more isolated • Primary benefits – Increased reliability – Behavioral predictability
- 8. Statelessness • "Services minimize resource consumption by deferring the management of state information when necessary." • Incorporate state management deferral extensions within a service design • Goals – Increase service scalability – Support design of agnostic logic and improve service reuse
- 9. Discoverability • Services are supplemented with communicative meta data by which they can be effectively discovered and interpreted." • Service contracts contain appropriate meta data for discovery which also communicates purpose and capabilities to humans • Store meta data in a service registry or profile documents
- 10. Composability • "Services are effective composition participants, regardless of the size and complexity of the composition." • Ensures services are able to participate in multiple compositions to solve multiple larger problems • Related to Reusability principle • Service execution should efficient in that individual processing should be highly tuned • Flexible service contracts to allow different types of data exchange requirements for similar functions