Advanced Web Technologies Lecture # 5 By: Faraz Ahmed

Quiz #1 0 What are design patterns? Explain 1 in detail. 0 What are web services? 0 List and explain 4 verbs used in HTTP.

Service Oriented Architecture 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. ~ OASIS

SOA (contd.) 0 Need for orchestration 0 Need to find services and utilize them in an autonomous way. 0 A repository? 0 Simple, abstract interface

Features 0 Reusable logic is divided into services 0 Services abstract underlying logic 0 Services are composable 0 Services are autonomous 0 Services share a formal contract 0 Services are loosely coupled 0 Services are stateless 0 Services are discoverable

SOA Myth 1 An application using webservices is a SOA application

SOA Myth 2 “If you understand Web services you won’t have a problem building SOA.”

SQA Myth 3 “Once you go SOA, everything becomes interoperable.”

Federated DBMS 0 A single ‘wrapper’ on autonomous databases. 0 The inputs are decomposed and sent to individual databases. 0 The output results are merged into a single result set 0 Can be loosely coupled (schema of individuals known) or tightly coupled.

SOA Life Cycle 0 Expose : relevant services 0 Compose : into complicated services 0 Consume: new services into projects

Service Oriented Stack

Business Processes are a collection of services They can be a service as well!

Service Oriented Stack Policies: Rules and conditions under which service made available to consumers.

Service Oriented Stack Transaction is the set of attributes that might be applied to a group of services to deliver a consistent result

Benefits 0 Reuse of legacy IT assets 0 Reduce cost and increase reuse 0 Rapidly respond to market changes 0 Implementation is hidden from consumers 0 Smaller projects (services) are more agile 0 Simplified testing 0 Easier to integrate

Basic Web services 0 Point to point web services are often rigid. Cannot sustain changes 0 You end up with spaghetti style communication between web services 0 Multiple protocols and hence multiple adapters. Increase costs.

Enterprise Service Bus 0 Performs virtualization

Enterprise Service Bus

HTML Presentation Oriented Faraz Ahmed Advanced Web Applications SZABIST, Karachi RESULT 0 Faraz Ahmed 0 Advanced Web Applications 0 SZABIST, Karachi

XML Content Oriented Faraz Ahmed AWT SZABIST

XML 0 Definition of self-describing data in worldwide standardized, non-proprietary format 0 Structured data and knowledge exchange for enterprises in various industries 0 Integration of information from different sources (into uniform documents)

Assignment #2 0 Create a RESTful webservice. 0 Create a SOA web application 0 Tools: ASP.NET, C# or VB.NET, WCF or simple WS-* 0 Submission date: next class after midterm