1. Turning Software into a Service By Mark Turner, David Budgen and Pearl Brereton

2. Two MajorThemes The promotion of Software as a service (SaaS)The promotion of Software as a service (SaaS) The proposal a change to the way software development is created through Service compositionThe proposal a change to the way software development is created through Service composition

3. Quick Definitions SaaSSaaS –Software provided by a third party from a remote location. –One instance servicing many users. –It focuses on separating possession and ownership from software use Service CompositionService Composition –The construction of software from many smaller components provided by several providers at remote locations

4. Services Offered Translation Services Available Translation Services Available (Broker) Service Composition Example Alice Company Properties Info Negotiation And Purchasing - Scribe -TS2 - TS3 - TS4 - LTS1 - ES-Trans - LTS3 Unknown to Alice

5. Benefits Services can change when the business changes dynamicallyServices can change when the business changes dynamically –i.e. scribe broker discovers new service Example shows two examples of service discovery and two stages of service negotiationExample shows two examples of service discovery and two stages of service negotiation a service is only concerned with issues around the sub services it is subscribed toa service is only concerned with issues around the sub services it is subscribed to

6. Service Models Supplier’s Software Application Service Service Transportation Layer (using forms such as.net or J2EE) Layer 1 Layer 2 Layer 1 Layer 2 Layer 3 Service Layer (Applications created on demand from smaller services) Service Integration Layer Service Transportation Layer Current Supply Led Model Proposed Demand Led Model

7. Integration Layer The key to the integration layer are divided into the following sub layers.The key to the integration layer are divided into the following sub layers. –Service description –Service discovery –Service negotiation –Service delivery –Service composition

8. Integration Layer- Service Description Current service description methods do not describe function semantically.Current service description methods do not describe function semantically. WSDL is the standard protocol for describing services but it does not have a feature for describing the functions negotiable parameters such as cost, duration, contract, termination rules, etc.WSDL is the standard protocol for describing services but it does not have a feature for describing the functions negotiable parameters such as cost, duration, contract, termination rules, etc. The Agent Markup Language for Services (DAML-S now called OWL-S) is a markup language for describing the properties and capabilities of Web services in unambiguous, computer-interpretable form.The Agent Markup Language for Services (DAML-S now called OWL-S) is a markup language for describing the properties and capabilities of Web services in unambiguous, computer-interpretable form. This is an important protocol to this model because it is the only protocol that describes a service in this detail.This is an important protocol to this model because it is the only protocol that describes a service in this detail.

9. Integration Layer- Service Discovery This service allows a client to identify potential service providers that offer a function that meets their needs and that are prepared to negotiate within some acceptable bounds.This service allows a client to identify potential service providers that offer a function that meets their needs and that are prepared to negotiate within some acceptable bounds. Although UDDI is the standard for discovering services it does not allow for services to be discovered using its semantic description.Although UDDI is the standard for discovering services it does not allow for services to be discovered using its semantic description. This semantic description ties in with the need for Service description have semantic descriptions of the functions.This semantic description ties in with the need for Service description have semantic descriptions of the functions.

10. Integration Layer- Service Negotiation This deals with clients and service providers negotiating on the terms and conditions of the client using the providers service.This deals with clients and service providers negotiating on the terms and conditions of the client using the providers service. Only ebXML allows for automatic negotiation and contractingOnly ebXML allows for automatic negotiation and contracting

11. Integration Layer- Service Delivery This service addresses the need for checking to see if the negotiated terms were filled and withheld during its use.This service addresses the need for checking to see if the negotiated terms were filled and withheld during its use. Were all conditions and provisions meet?Were all conditions and provisions meet? Using ebXML’s has a contract and CPA document that monitors transactions and terminates the process if the contract is broken.Using ebXML’s has a contract and CPA document that monitors transactions and terminates the process if the contract is broken.

12. Integration Layer- Service Composition By using the protocols at various layers of the model web services are automatic composed and bound.By using the protocols at various layers of the model web services are automatic composed and bound. The Business Process Modeling Language or the Business Process Execution Language for web services can be used to model the control and data flows between services that were bound.The Business Process Modeling Language or the Business Process Execution Language for web services can be used to model the control and data flows between services that were bound.

13. Proposed Web Services Stack Framework. ebXML SpecsSemantic WebExtend WSDL

14. Conclusion The important layers deal with the coordination of many smaller services to compose the main service that will fill a required need.The important layers deal with the coordination of many smaller services to compose the main service that will fill a required need. Although the model seems complicated we must be remembered is that the model is trying to accomplish these takes dynamically in real time as the request for the service is realized.Although the model seems complicated we must be remembered is that the model is trying to accomplish these takes dynamically in real time as the request for the service is realized.