Service Oriented Architecture (SOA) Prof. Wenwen Li School of Geographical Sciences and Urban Planning 5644 Coor Hall

Outline 1. Concepts 2. Architecture of SOA 3. SOA & Web Service 4. Without & with SOA 5. Advantages & limitations of SOA 6. Summary

Concepts Web services Web services is an approach way to communicate data by integrating multiple applications through XML (Extensible Markup Language), SOAP (Simple Object Access Protocol), WSDL (Web Service Definition Language) and UDDI (Universal Description, Discovery and Integration). XML labels the data resources SOAP transfers the data resources WSDL describes the available services UDDI is used for listing what services are available. Differences between stand-alone service & web service? Differences between client/server & web service?

Concepts Web services

Concepts Definitions of SOA OpenGroup definition*: Service-Oriented Architecture (SOA) is an architectural style that supports service-orientation. Service-orientation is a way of thinking in terms of services and service-based development and the outcomes of services. OASIS definition**: Service-Oriented Architecture (SOA) is a paradigm for organizing and utilizing distributed capabilities that may be under the control of different ownership domains. It provides a uniform means to offer, discover, interact with and use capabilities to produce desired effects consistent with measurable preconditions and expectations. * **

Concepts Characteristics of SOA Follows open standards Reusability Interoperability Good extensibility Autonomous operation Dynamic operation Functionally composability Loose coupling

Architecture of SOA Architecture

Architecture of SOA Architecture *

Architecture of SOA Key components of SOA Services Service Description Advertising and Discovery Specification of associated data model Service contracts

Architecture of SOA Key standards and technologies of SOA Extensible Markup Language (XML): a markup language that defines a set of rules for encoding documents in a format which is both human-readable and machine-readable.* Web service Simple Object Access protocol (SOAP): a protocol specification for exchanging structured information in the implementation of web services in computer networks. It uses XML Information Set for its message format, and relies on other application layer protocols, most notably Hypertext Transfer Protocol (HTTP) or Simple Mail Transfer Protocol (SMTP), for message negotiation and transmission.** * **

Architecture of SOA Key standards and technologies of SOA Web Services Description Language (WSDL): an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information. The operations and messages are described abstractly, and then bound to a concrete network protocol and message format to define an endpoint.* Universal Description, Discovery and Integration (UDDI): a platform- independent, XML-based registry by which businesses worldwide can list themselves on the Internet, and a mechanism to register and locate web service applications.** * **

Architecture of SOA Workflow of SOA

SOA & Web service SOA is not Web service. Both SOA and Web service are built by similar theories. Web service defines the relationship of applications in Web environment. SOA defines an architecture to make Web service work better. Web service focuses on data resources provider and user. SOA focuses on services.

SOA & Web service

Without and with SOA *

Advantages & limitations of SOA Benefits of SOA* Service reusability Easy maintainability Greater reliability Location independence Improved scalability and availability Improved software quality Platform independence Increased productivity *

Advantages & limitations of SOA Limitations of SOA* Increased overload Complex service management High investment cost Security issue in loosely coupled environment Efficiency for XML based structure Service registry and repository Retrieval on services and interfaces *

Summary SOA facilitates the rapid development of from web application: SOA reduces the difficulties in communicating when the systems are complex, SOA changes the users’ role in web service: Users can receive the services without knowing the complex logic behind. The users can be service providers in SOA. SOA plays an essential role in cloud computing and grid computing The architecture of SOA is difficult to construct for the present requirement and further demand. The context of implementation has an important impact on SOA architecture.

Summary What is SOA? Characteristics Architecture Key components Key standards and technologies Workflow SOA vs. Web service With and Without SOA Advantages and limitations