Object Oriented Paradigm

1
Object Oriented Paradigm

• An evolutionary path

2
Programming At Its Infancy

• A program is a single block of procedural code
• Disadvantages
• Reusability is practically nil.
• Programming Complexity is high.
• Software cannot not evolve gracefully as changes
  in one part of the software can have unwanted
  side-effects.

3
Software Development- The Structured Approach

• Top-down design followed by bottom-up programming
• Top-down decomposition driven by functional
  criteria
• Architecture reflects system functions

4
The Structured Approach - Advantages

• Modularization implies
• Reduction in software complexity
• Increased reusability
• Reduction in unwanted side-effects as much of the
  effect is confined to the module being changed.

5
The Structured Approach - Disadvantages

• Produces satisfactory results only when functions
  have been identified properly and remain
  unchanged through time.
• Software structure is induced by functions. Thus
  evolution of these functions may imply important
  structural modifications.
• Guarantees only limited modularizations thereby
  rendering subsequent modifications difficult and
  filled with side-effects.

6
Software Development - The Object Oriented
Approach

• A paradigm shift from a function-centric approach
  to an object-centric approach to software
  development.
• Structure induced by players (which constitute
  the more static part of the system) rather than
  by functions (the dynamic and evolving part of
  the system).
• Doesnt replace the structured approach builds
  on top of it.
• Further modularization achieved through the
  decoupling of the system into independent objects.

7
Object Oriented Approach - Advantages

• Models the real world more closely.
• Is easier to maintain because its structure is
  inherently decoupled.
• Leads to reuse which in turn leads to faster
  software development and higher quality programs.

8
Object Oriented Paradigm Key Features

• Abstraction
• Encapsulation
• Inheritance
• Polymorphism

9
Changing Scenario

• Emergence of networks Can the capabilities of
  networks be exploited to create an application
  that is distributed over the network? YES
• Increasing software complexity Can a software
  be assembled from a collection of pre-built,
  plug-and-play software components much in the
  same way as a hardware is created? YES
• HOW?

10
Component Technology

• A software component is defined as an
  independent, binary piece of code that can
  connect at run-time with other software
  components to provide the desired functionality.

11
Component Technology - Goals

• Basic Interoperability A software component
  developed by one developer should be able to
  interoperate with other components
• Versioning It should be possible to upgrade a
  component without need to upgrade the entire
  software
• Language Independence Components written in
  different languages should be able to communicate
• Cross-process Interoperability Two software
  components running in two different process
  spaces should be interoperable
• Cross-network Interoperability Two software
  components running in two different machines
  connected over the network should be interoperable

12
Component Technology Industry Initiatives

• Microsofts COM
• OMGs CORBA
• SUNs Java Beans / EJBs

13
Component Technology

• Microsofts COM
• OMGs CORBA
• Java Beans / EJBs

14
COM Key Features

• Component Object Model (COM)
• A component communication protocol by Microsoft
• OS (Windows) dependent
• Language independent
• Provides a standard way of accessing all kinds of
  software services be it in a library (DLL), in
  another process (EXE) or in another machine
  (DCOM)

15
Component Technology

• Microsofts COM
• OMGs CORBA
• Java Beans / EJBs

16
CORBA Specification

• A specification defined by Object Management
  Group (OMG)
• Non-profit organization
• Engaged in promoting vendor-independent solution
  using Object Technology
• Language independent
• OS independent

17
Component Technology

• Microsofts COM
• OMGs CORBA
• Java Beans / EJBs

18
JB/EJB Specifications

• Java Beans (JB), Enterprise Java Beans (EJB)
• Expounded by Sun Microsystems
• Language Dependent
• Built around Java Language
• Java specification Controlled by Sun
  Microsystems
• OS Independent

19
Component Technology Common Features

• All the three technologies built on Protocols
  that guide the inter-Process communication among
  processes on same or different systems
• Adopt the key features of the object-oriented
  paradigm
• Interface is everything

20
Component based approach to software development

• Software is developed as a collection of
  collaborating components
• Collaboration may be intra-process, inter-process
  or inter-network
• Individual components may be written in
  multiple-languages (in case of COM)
• Components may be ported to multiple platforms
  (in case of JB/EJB)

21
Component Based Approach to Software Development

• Disadvantages of current technologies
• Limited language independence
• JB/EJB components limited to Java
• COM components support language independence but
  require a conscious effort
• Interacting components must comply to the same
  standard
• JB/EJB components can interact only with other
  JB/EJB components
• Similarly with COM

22
COM Components Drawbacks

• Allow only limited language independence
• Allow inheritance only if both parent child
  components are written in the same language
• Can be accessed only by COM compliant components
• Create DLL Hell

23
Web Services

• An application delivered as a service that can be
  integrated with other Web services using the
  ubiquitous Internet Standards (HTTP, XML, SOAP
  protocols).
• Can be implemented using full feature set of any
  language, object model or platform.
• Can be consumed by applications implemented in
  any language for any platform
• Built on and an extension of COM Technology
• Abstraction scaled up to higher level
• Group of components, capable of delivering a
  meaningful service, is seen as a reusable unit
• The service is extended through Contract
  (comparable to Interface in Component)
• The Contract is published by provider on web

24
.NET Framework

• The Microsoft .NET Framework is a new platform
  for building integrated, internet-based,
  service-oriented applications to meet the needs
  of applications that gather information from, and
  interact with, a wide variety of sources,
  regardless of the platforms or languages in use.

25
.NET Framework - Objectives

• Use the Right Language for the Right Job Cross
  Language Integration
• Execute on many platforms Platform Independence
• Run Once, Run Always The end of DLL Hell

26
.NET Framework Enabling Features

• Standardisation of language Architecture
• Common data Types, Sys_Lib etc.
• Common Language Runtime (CLR)
• Comparable to Java Virtual Machine but capable of
  handling multiple languages
• Microsoft Intermediate Language (MSIL)
• Comparable to byte code of Java
• CLR MSIL enable JIT compilation on any platform
  that supports CLR

27
Software Development using the .NET Framework

• Develop applications as a collection of
  collaborating components or web services that are
  portable across platforms and can interact across
  language boundaries
• Strengthened by open protocol of accessibility
  like http, xml etc
• Web Services assisted by .NET
• Platform language independence

28
HailStorm a user-centric web service

• .Net based Web Services
• The first paid web-service from Microsoft
• Based on Microsoft Passport user Authentication
• Domain Personal Information Management
• Helps you manage and protect your information and
  interaction across all applications and devices
• Strengthened by Authentication, authorization and
  access period

29
Hailstorm Services

• myAddress
• myProfile
• myContacts
• myLocation
• myNotifications
• MyInbox
• myCalendar
• myDocuments

• myApplicationsettings
• myFavouritewebsites
• myWallet
• myDevices
• myServices
• myUsage

30
SoftwareDevelopment using Hailstorm

• Use HailStorm services in your applications for
  user authentication, routing notifications to the
  users of your applications

31
Future

• High Independence at Low level
• Easy Integration at middle level
• Total Convergence at Application level
• Any where Any Time
• Any Language Any OS
• Any Device
• Thanx