1. Introduction to Service-Oriented Architectures (SOA)
B. Ramamurthy
CSE Department, University at Buffalo (UB)
Buffalo, NY 14260
2/24/2019
CSE507 Introduction 2008

2. Introduction
We landed man on the moon with approx. 32K of memory and with equally meager compute power….
What have we achieved with peta-bytes of storage, GHz of multi-core CPU speed, ever increasing network bandwidth, and the proliferation of applications at all levels?
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CSE507 Introduction 2008

3. Outline Evolution of Internet computing (How did we get here?)
Challenges (What is next?)
Service-enabling:
Service
Service-oriented architecture (SOA)
Principles and elements
Definitions
SOA roadmap and case study
Web Services (WS)
Alignment of business process model (BPM) to SOA
Motivation
SOA context
SOA Roadmap
SOA/BPM alignment
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CSE507 Introduction 2008

4. Topics for Discussion How did we get here?
State of computing and business
Effect of scientific advances on industries, information technology (IT), computing research, environment, society,… ?
Role of SOA and services
SOA principles (Ch.1)
Evolution of the service concept (Ch.2)
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CSE507 Introduction 2008

5. Evolution of Internet Computing
deep web
scale
web
Parallel
HPC
Semantic
discovery
??????
Automate (discovery)
Discover (intelligence)
Transact
Integrate
Interact
Inform
Publish
time
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CSE507 Introduction 2008

6. Evolution Industrial Business Automation Just-in-time
Advances in supply chain …
Business
Remote operations
Heterogeneity
Scale
Integration (application, data)
E-commerce
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CSE507 Introduction 2008

7. Evolution (contd.) Information technology Internet World-wide web Grid
Mobile and wireless
Devices
Software, platforms
Search engines
Tremendous advances
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8. Evolution (contd.) Computing research Environment
Programming languages
RISC vs. CISC architectures
Memory capacity
Computing power
Simple programObject Component…
Environment
Accessibility
Globalization (outsourcing, markets)
...
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CSE507 Introduction 2008

9. Evolution (contd.) Society IT users not exclusive to Computer Science
Digital media
ipod, iphone, idog,..
Youtube, myspace, social networking
Blogs,wikies, podcasts …
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CSE507 Introduction 2008

10. Beyond Search Engines: Enabling Information Technology and Scientific Applications
Simple Search (stateless)
TV/Remote
Financial: Build Portfolio
Medicine: plan treatment
Environment: Plan Forestation
Wireless device
Biotech: drug discovery
Complex multi-organizational applications
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CSE507 Introduction 2008

11. Challenges
Need transformative solutions such as the Internet and the Search
Alignment with the needs of the business / user / non-computer specialists / community and society
Need to address the scalability issue: large scale data, high performance computing, automation, response time, rapid prototyping, and rapid time to production
Need to effectively address (i) ever shortening cycle of obsolescence, (ii) heterogeneity and (iii) rapid changes in requirements
Service-enabling and service-oriented-architecture (SOA) combination is attempt at addressing these issues.
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CSE507 Introduction 2008

12. Pieces of the pie..
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13. SOA can align the pieces!!?
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CSE507 Introduction 2008

14. Missing pieces? Question (Homework assignment)
Are there any categories that I did not consider in the pie? Ex: government policies?
What should be the appropriate weight of each category? For example, consider the heavy weight given to IT in the picture on the right.
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CSE507 Introduction 2008

15. SOA Principles
Loosely coupled (service provider and service consumer are loosely coupled: why?)
Large scale: complex system with high level of heterogeneity and redundancies.
Decoupling of functionality and technology
Service contract and agreements
Discoverability
On demand composability of services: composite services concept
Agility: respond to changes quickly
Statelessness
Inherent interoperability
Standards
Simplicity
Reusability
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CSE507 Introduction 2008

16. Typical Enterprise Complex heterogeneous system: Stakeholders
Examples: CRM (Customer relationship management) system, insurance claims processing system
Stakeholders
Highly heterogeneous teams
Different political environments
CEO, IT projects, customers, operations
Different applications and middleware
Content and data with varying lifetime
Potentially large number of end users
Applications have to be rolled out to a large number of PCs, say,10000
Major changes and ongoing incremental optimization need to be handled efficiently in an agile manner.
An SOA addresses these needs.
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CSE507 Introduction 2008

17. Evolution of the service concept
A service is a meaningful activity that a computer program performs on request of another computer program.
Technical definition: A service a remotely accessible, self-contained application module.
From IBM,
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CSE507 Introduction 2008

18. Class, Component and Service
Class is a core concept is object-oriented architectures. An object is instantiated form a class.
Focus on client side, single address space programs.
Then came the component/container concept to improve scalability and deployability. Ex: EJBs.
Focus on server side business objects and separation of resources from code.
Service came into use when publishing, discoverability, on-demand operation among interacting enterprise became necessity.
Focus of enterprise level activities, contracts, negotiations, reservations, audits, etc.
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CSE507 Introduction 2008

19. Object-oriented programming
Encapsulation of data and function in a class, instances of a class is called an object
Objects communicate through messages (invoking methods)
Class represents a type from which another type can be derived resulting inheritance hierarchy.
Problem: level of abstraction and granularity exposed is fine to enable reuse.
Data and functions are tightly coupled.
Important contribution SOA: concept of interface
Service-orientation assumes that data and functionality are separated.
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CSE507 Introduction 2008

20. Distributed Computing
Important challenge is find abstractions for both remoteness and actual service task at the same time.
Simple interfaces such a telnet, rlogin emerged for remoting.
Distributed Computing Environment (DCE), Common Object Request Broker Architecture (CORBA) emerged as middleware.
“interoperability” was an important goal.
IDL Interface definition language came into existence..
IDL is a predecessor of WSDL
Heavy weight infrastructure resulted in discovery of the light weight XML solution.
XML, SOAP over HTTP, WS emerged.
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CSE507 Introduction 2008

21. Business Computing File systems to main frames
Emergence of new paradigms such as Enterprise Resource Planning (ERP) and Supply Chain Management (SCM) placed complex requirements on the computing machines and applications.
This was followed by huge compute (IT) demands for Enterprise Application Integration (EAI) and Enterprise Data Integration (EDI).
An appealing characteristic of SOA is that it aligns these business entities by directly mapping them to services, thus enabling an enterprise integration on the business level, not on the technical level.
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CSE507 Introduction 2008

22. SOA and WS
A Service-Oriented Architecture (SOA) is a design model for linking computational resources, data and applications to perform services and deliver results to service consumers.
Web Service (WS) standard provides a platform-independent method for messaging-based interaction of applications.
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CSE507 Introduction 2008

23. Topics for Discussion
Webservices and Service Oriented Architectures (SOA)
XML (eXtensible Markup Language)
SOAP (Simple Object Access Protocol)
WS (Web Services)
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CSE507 Introduction 2008

24. Web Services and SOA
Web Services is a technology that allows for applications to communicate with each other in a standard format.
A Web Service exposes an interface that can be accessed through XML messaging.
A Web service uses XML based protocol to describe an operation or the data exchange with another web service. Ex: SOAP
A group of web services collaborating accomplish the tasks of an application. The architecture of such an application is called Service-Oriented Architecture (SOA).
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CSE507 Introduction 2008

25. SOA in Real World: Report in InfoWorld, May 2, 2005 Issue 18
State of Massachusetts uses SOA to deliver healthcare services. With HTML web application it had no control of look and feel and handling many hospitals. With SOAP based messaging they can easily handle different systems, billing systems, medical records systems etc. Use Microsoft-based systems.
Countrywide financial simplifies lending: IBM Websphere based SOA is used to deliver services.
Guardian Life Insurance uses SOA: IBM websphere based services. Uses EJB for business logic.
British Telecom uses combination of BEA systems and Microsoft’s Connected Services Framework. Billing backend and operational support for the organization are web services. Legacy systems are enabled as web services.
Amazon.com provides WS API for developers to implement applications leveraging their architecture and data.
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CSE507 Introduction 2008

26. XML
XML is a markup language, developed by W3C (World Wide Web Consortium), mainly to overcome the limitations of HTML.
But it took a life of its own and has become a very popular part of distributed systems.
We will examine its definition, associated specifications (DTD, XSLT etc.), Java APIs available to process XML, protocols and services based on XML, and the role XML plays in a distributed computing environment.
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CSE507 Introduction 2008

27. First Look at XML It has no predefined tags. It is stricter.
Such as in HTML
Domains may specify their own set of standard tags
It is stricter.
Most html document have errors and the browser have to built to take care of these.
On the other hand XML has a strict syntax.
There is a notion of validity and
A notion of well-formed.
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CSE507 Introduction 2008

28. An Example: Memo
See the two documents enclosed: one in html and the other in XML formats.
Observe the meaningful tags in XML.
Compare it to a class definition: it looks like a class with data definitions and accessors (tags).
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CSE507 Introduction 2008

29. Memo.html vs memo.xml
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="content-type"
content="text/html; charset=ISO ">
<title>memo.html</title>
</head>
<body>
<h3>Hello World</h3>
Bina<br>
CSE507 SOA and WS Students <br>
Wake up everyone<br>
BR<br>
<br>
</body>
</html>
<?xml version="1.0" ?>
  <!DOCTYPE memo (View Source for full doctype...)>
- <memo>
  <header>Hello World</header>
  <from>bina</from>
  <to>CSE507 SOA and WS Students</to>
  <body>Wake up everyone</body>
  <sign>br</sign>
  </memo>
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CSE507 Introduction 2008

30. XML to SOAP
Simple xml can facilitate sending message to receive information.
The message could be operations to be performed on objects.
Simple Object Access Protocol (SOAP)
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CSE507 Introduction 2008

31. SOAP Request
<soap:Envelope xmlns:soap="
<soap:Body>
<getProductDetails xmlns="
<productId>827635</productId>
</getProductDetails>
</soap:Body>
</soap:Envelope>
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CSE507 Introduction 2008

32. SOAP Reply
<soap:Envelope xmlns:soap="
<soap:Body>
<getProductDetailsResponse xmlns="
<getProductDetailsResult>
<productName>Toptimate 3-Piece Set</productName>
<productId>827635</productId>
<description>3-Piece luggage set. Black Polyester.</description>
<price>96.50</price>
<inStock>true</inStock>
</getProductDetailsResult>
</getProductDetailsResponse>
</soap:Body>
</soap:Envelope>
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CSE507 Introduction 2008

33. SOAPWeb Services (WS)SOA
Read this paper:
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CSE507 Introduction 2008

34. Service Oriented Architectures
Lets look at some success stories.
Amazon.com has is data collection available web services developers.
See these URLs:
Amazon.com E-Commerce Service (ECS)
A cool application
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CSE507 Introduction 2008

35. Summary We had a first look at SOA
We looked at foundational concepts supporting web services: XML, SOAP, WSDL and Web Services standards.
2/24/2019
CSE507 Introduction 2008