enterprise computing_anna university

Enterprise Computing

Unit 1A Enterprise Foundations

Balasubba Raman Guruswamy

ReferenceTEXT BOOKS:

1. Paul J Perrone, Venkata S.R. Krishna R and Chaganti, "Building Java Enterprise Systems with J2EE", Techmedia , New Delhi, 2000

2. George Reese, “Database programming, with JDBC and Java" Second Edition, O’Reiliy Publishers , New Delhi, 2000

REFERENCE BOOKS:

3. Dustin R. Callaway - "Inside Servlets" - Addison Wesley Longman Inc, New Delhi, 2001

4. Tom Valesky - "Enterprise Java Beans" - Addison Wesley Longman Inc. New Delhi, 2000

5. Ed Roman-"Mastering EJB”-John Wiley & Sons, New Delhi, 2001

11 April 2023Enterprise Foundations

Enterprise Computing2

EC – Unit 1A - SyllabusEnterprise Architectural overview - Object oriented

software development for enterprise - Component Based software development for enterprise



Chapter 1,2 3 of Reference 1

What is Enterprise Computing?• What is an enterprise?

Next

Large organization such as multinational corporation,

university, hospital, research laboratory, or government

organization

Large organization such as multinational corporation,

university, hospital, research laboratory, or government

organization

Requires special computing solutions because of its size and complexity

Requires special computing solutions because of its size and complexity

Enterprise computingEnterprise computingUse of computers in networks that

encompass variety of operating systems, protocols, and network architectures

Enterprise computingEnterprise computingUse of computers in networks that

encompass variety of operating systems, protocols, and network architectures

Set out to accomplish certain goals

11 April 2023 4Enterprise Foundations


How does information flow within an enterprise? Enterprise manages large amounts of information over an extensive

geographical area and disparate groups of people

Next11 April 2023 5Enterprise Foundations


How are enterprises organized? Most are organized in a hierarchy

11 April 2023 6Enterprise Foundations


Main Components of EnterprisePursuit of the enterprise’s goals are essential for

– Survival of the enterprise– Growth of the enterprise

Physical resources & assets– Computing eqpt, manufacturing facilities, product

supplies, corporate accounts, etc

People & users– Customers, employees, contractors, partners

Enterprise information & Knowledge



Primary Objectives of the Enterprise

• Preserve & grow customer base• Growth & efficiency of employee base• Growth of partnership base• Growth & protection of resources / assets• Sensitivity to

– Changing customer base– Changes in resources / assets– Changes in information & knowledge



What is enterprise system architecture?

A method for managing your business or enterprise:

Decision making tool

Change management tool

Knowledgebase of your business or enterprise



In the Information Age…How do you manage the increasing complexity of

your enterprise?

How do you manage the increasing rate of change?

How do you meet the demands of your constituency (or customers) quicker and more efficiently?

When someone leaves your enterprise, do you retain their knowledge?



Why enterprise architecture?Provides a method for writing things down

(develop blueprints)Shows you the impact of “moving a wall”

(complexity and change)Provides the plan on how to “move the wall”

(change management)Helps you retain employee knowledge

(becomes knowledgebase of enterprise)

11 April 2023 Enterprise Foundations Enterprise Computing

11

If you don’t have an architecture, you change by trial and error (which is high risk)

Generic enterprise system architecture (1)• Enterprise Use Interfacing

– Means to present content to both web-based and standard applications-based users

• Enterprise Data Enabling– Means to access, store and manage enterprise info. And knowledge via

enterprise databases

• Distributed Enterprise Communication – Means to access info and applications through out a distributed enterprise

system

• Common Services for Distributed ….– Provides a set of common services used by distributed object communications

paradigms– Global services that permeate every aspect of a distributed enterprise system



Generic enterprise system architecture (2)• Enterprise Systems Assurance

Provides secure, reliable, available, maintainable and safe qualities of an enterprise system

• Enterprise Web Enabling Provides for connectivity of the enterprise to the internet/web and for

generating Web-based presentation content

• Enterprise Applications Enabling – Provides for the middle tier of application logic management with

connectivity to legacy enterprise application logic– Provision of new enterprise application logic– Connectivity to distributed enterprise applications and embedded devices– Business-to-business connectivity with commerce partners



Object-Oriented Software Development



Elements of Object-oriented SoftwareStage 1: Assembly level programming – Data exposed to direct access by

assembly –language instructionsStage 2: Higher-level programming languages – Construction of programs in a

more natural and human-readable formStage 3: Code could be modularized by partitioning software into separately

compilable modules using compilers and linkage technologyStage 4: Software engineering practices helped encapsulate such modules

into functional units Stage 5: Object oriented programming – modularity of behaviour and

encapsulation of state – new programming paradigm

Class – Discrete module of code – has set of variables and methods Object – An instance of a class in memoryHandles – Reference to distributed object – Network address information

and an object IDPackage – collection of one or more objects which have cohesive logical

relation and offer specific service11 April 2023

Enterprise Foundations Enterprise Computing

16

Modeling the Real World A software system provides a solution to a problem in the

real world

Consists of two essential components:

Model: abstraction of a part of the real world

Algorithm: captures the computations involved in manipulating or processing the model


17

AlgorithmModel

Software system

Real world

Abstraction

Interpretation

How to Model Real World?Programming languages

– Tools to describe computer models

Programming modelsComputation-oriented model (50s ~ 60s)Data-oriented model (70 ~ 80s)Object-oriented model (90s ~ )

Balanced view between data and computationComponent Based Model (2000 ~ ..)


18

Why O-O Model?

• Possible to directly represent real world objects in the computer system


19

Software systemReal world

Data-oriented model

Software systemReal world

Object-oriented model

Iterative Development• Key characteristics

– Consists of a number of success iterations– Each iteration produces a working program– Build system incrementally Monolithic approach of waterfall model

• Benefits

– Facilitates and manage changes Minimize and prevent changes

• Examples

– Rational Unified Process (RUP) – Extreme Programming (XP)


20

Object-Oriented Development

• Approach

– Focuses on improving the maintainability and reusability of software systems through a set of techniques, notations, tools, and criteria.

• Activities

– Conceptualization– Object-oriented analysis and modeling– Object-oriented design– Implementation– Maintenance

11 April 2023Enterprise Foundations Enterprise Computing

21

OO Development Process Project Charter

Requirement Analysis

System Behavioral Analysis

System Interface Analysis

Preliminary System Design

Detailed Design



Implementation

Unit Test

Assembly

Thread Test

Configuration Specification

System Test

Deployment

Maintenance

Detailed Activities (1)• Project Charter

– Conceptualization– To establish the vision and core requirements of the software system to be

developed.• Requirement Analysis

– Perform analysis of expected system behaviour and system interfaces

– System behavioural Analysis• Use-case analysis – identification of primarily user-driven scenarios

• Use case – sequence of steps of each behaviour

• Actors in use case - Entities involved with realising the outcome of the use case

• Pre-condition – Initial state of the system before the beginning of the use case

• Post-condition – State of the system after the use case

– System Interface Analysis• Interfaces to and from the system need to be analyzed and modeled

• External system interfaces, legacy system interfaces, database models, User interfaces


23

Detailed Activities (2)• Object-oriented analysis and modeling

– Build models of the system’s desired behavior, using notations such as the Unified Modeling Language (UML)

– Capture the essential relevant aspects of the real world and to define the services to be provided and/or the problems to be solved

– Simplify reality to better understand the system to be developed

• Preliminary System Design– Transforming conceptual-analysis model and transforming for realizing

using COTS or custom software – Capture the primary design components – Conceptual design models – describe logical relations between concepts

and design constructs – class diagrams

• Detailed design– Create an architecture for implementation– Represented in terms of objects & classes and relationships among them– Package names, class names, core public methods, i/p, o/p parameters


24

Detailed Activities (3)• Implementation

– Implement the design by using an object-oriented programming language– Involves custom code writing, integrating with COTS

• Unit Test– Testing at class and package level– Performed during implementation of a particular class & collection of classes

• Assembly– Identify a subset of the entire system behaviour, along with the code

– Assemble individual elements into discrete elements of behaviour

– Integrate the code with a target platform and environment in mind

• Thread Test– Demonstrating that the assembled classes interoperate– Test threads of behaviour on assembled elements – provides incremental

assurance



Detailed Activities (4)• Configuration Management

– Define COTS and custom software configurations and versions– Should include instruction for building and deploying the software

• System Test– Test fully assembled and configured system– Load testing, system security testing, performance testing

• Deployment– Deploy the system as per the configuration specification– Deployment environment should closely resemble system test

environment• Maintenance

– Manage post delivery evolution effectively– Maintain operational software for bug fixes and upgrades– Time to repair should be minimum and ease with which upgrades are

deployed should be maximized



O-O Processes (e.g., RUP)


27

Classes

• A class represent a concept.• A class encapsulates state (attributes) and behavior (operations).• Each attribute has a type.• Each operation has a signature.• The class name is the only mandatory information.

zone2pricegetZones()getPrice()

TariffSchedule

Table zone2priceEnumeration getZones()Price getPrice(Zone)

TariffSchedule

Name

Attributes

Operations

Signature

TariffSchedule

UML (Unified Modeling Language)– An emerging standard for modeling object-oriented

software– Resulted from the convergence of notations from three

leading object-oriented methods• OMT (James Rumbaugh)• OOSE (Ivar Jacobson)• Booch (Grady Booch)

• Goal of UML – Provide a standard notation for use by all object-oriented methods and to select & integrate the best elements of precursor notations

• Commercial tools: Rational (IBM),Together (Borland), Visual Architect (business processes, BCD)

• Open Source tools: ArgoUML, StarUML, Umbrello

• Commercial and Opensource: PoseidonUML (Gentleware)11 April 2023 29

Introduction - UML OBJECT ORIENTED SOFTWARE ENGINEERING

UML Diagrams

11 April 2023Introduction - UML

OBJECT ORIENTED SOFTWARE ENGINEERING

30

UML Diagrams• Use case diagrams

– Describe the functional behavior of the system as seen by the user.

• Class diagrams– Describe the static structure of the system: Objects,

Attributes, and Associations.• Sequence diagrams

– Describe the dynamic behavior between actors and the system and between objects of the system.

• Statechart diagrams– Describe the dynamic behavior of an individual object as a

finite state machine.• Activity diagrams

– Model the dynamic behavior of a system, in particular the workflow, i.e. a flowchart.

11 April 2023 31Introduction - UML


Use Case Diagrams

WatchUser WatchRepairPerson

ReadTime

SetTime

ChangeBattery

Actor

Use case

Package

SimpleWatch

Use case diagrams represent the functionality of the system from user’s point of view



Class Diagrams

• Class diagrams represent the structure of the system.• Class diagrams are used

– during requirements analysis to model problem domain concepts

– during system design to model subsystems and interfaces– during object design to model classes.

Enumeration getZones()Price getPrice(Zone)

TariffSchedule

* *

Tripzone:Zoneprice:Price



Class Diagrams

Batteryload()

1

2

Timenow()

PushButtonstatepush()release()

1

1

1

1

1

2

blinkIdxblinkSeconds()blinkMinutes()blinkHours()stopBlinking()referesh()

LCDDisplay

SimpleWatch

Class

AssociationMultiplicity

Attributes

Operations

Class diagrams represent the structure of the system



Dynamic Behaviour DiagramsScenario diagram is used to design modelling

view to indicate dynamic behaviour between object instances

Sequence diagram



Sequence DiagramObject

MessageActivation

blinkHours()

blinkMinutes()

incrementMinutes()

refresh()

commitNewTime()

stopBlinking()

pressButton1()

pressButton2()

pressButtons1And2()

pressButton1()

:WatchUser:Time:LCDDisplay:SimpleWatch



Sequence diagrams represent the behavior of a system as messages (“interactions”) between different objects

button1&2Pressed

button1&2Pressed

button1Pressed

button2Pressed

button2Pressed

button2Pressed

button1Pressed

button1&2Pressed IncrementMinutes

IncrementHours

BlinkHours

BlinkSeconds

BlinkMinutes

IncrementSeconds

StopBlinking

Statechart DiagramsState

Initial state

Final state

Transition

Event



Represent behavior of a single object with interesting dynamic behavior.

Component based software development


38

Enterprise Components

OO SoftwareClasses – Encapsulate fine-grained concepts of a

problem and solutionObjects - Instances of classes created during the

runtime operation of the system

ComponentsCoarser-grained means to encapsulate problemsRepresent a logical collection of one or more fine-

grained classes Can be more directly produced from analyses and

design models11 April 2023


39

Component models• A component model is a definition of standards for

component implementation, documentation and deployment

• Examples of component models– EJB model (Enterprise Java Beans)– COM+ model (.NET model)– Corba Component Model

The component model specifies how interfaces should be defined and the elements that should be included in an interface definition



Elements of a component model



Component model

InterfacesUsage

informationDeployment

and use

Interfacedefinition

Specificinterfaces

Composition

Namingconvention

Meta-dataaccess

Customisation

Packaging

Documentation

Evolutionsupport

Middleware supportComponent models are the basis for middleware that provides

support for executing components

Component model implementations provide:

– Platform services that allow components written according to the model to communicate

– Horizontal services that are application-independent services used by different components

To use services provided by a model, components are deployed in a container. This is a set of interfaces used to access the service implementations



Component interfacesInterfaces in a component model is primary contract between

component and other code entities. Other code entities may be containers, application code, other components, other component models, ....

Provides interface– Defines the services that are provided by the component

to other components.Requires interface

– Defines the services that specifies what services must be made available for the component to execute as specified.



Component interfaces



Provides interfaceRequires interface

ComponentDefines the servicesfrom the component’senvironment that ituses

Defines the servicesthat are providedby the componentto other components

Component Interface typesComponent APIs• Defines a set of standard interfaces that applications can use to tap the services

of a component

Design Patterns• A set of classes, interfaces and their relationships that provide a common

design solution to a common problem classification

Component SPIs• Defines a set of standard interfaces that the provider of service adheres to and

implements

Component-to-Container interfaces• Defines the interface to a container environment assumed by a component

Container-to-Component interfaces• Defines the interface to a component assumed by a container



Component Development Process



Development

Analysis

Design

Implementation

Integration

Test

Evaluation

Find

Select

Adapt

Integrate

Test

Component evaluation System Development

Requirements must be :

captured analyzed defined

Component must be designed : implemented verified validated delivered

Component Development Process (1) Project Charter

Analysis Pattern Identification

External Component Interface Analysis

System Component Interface Analysis

Component Model Technology Identification

Component Identification

Component Selection



During Requirement Analysis

During Preliminary System Design

Component Development Process (2)



Component Design Adaptation (During Detailed Design)

Component Implementation Specialisation

Component Test (During Unit Test)

Component Assembly (During Assembly)

Module Test (During Thread Test)

Component Configuration Specification

System Test

Deployment

Maintenance

Detailed Activities (1)• Project Charter

– Conceptualization– To establish the vision and core requirements of the software system to be

developed.

• During OO Requirement Analysis– Analysis Pattern Identification

• Common problems described as system behaviours that can be used to map to design patterns

– External component Interface Analysis

• Component models, standard component interfaces & specific component interfaces are identified

– System Component Interface Analysis

• Standard component model interfaces are identified


49

Detailed Activities (2)• During OO Preliminary System Design

– Component Model Technology Identification

• Technology and tools used to design the system

– Component Identification

• In terms of the interfaces and technology they must support

– Component Selection• COTS components evaluated for fitness and applicability for use

• Components developed in other projects

• Component qualified for functional support, quality, technology support, desgree of customization required and supported

• Component Design Adaptation (During OO Detailed Design)

– Easy-to-use customisation interface – Descripter file or set of design-time attributes


50

Detailed Activities (3) Component Implementation Specialisation

May need modification in code, extending existing code via subclassing

Component Test (During OO Unit Test)

Unit testing

Component Assembly (During OO Assembly)

Assembled into individual modules that can be separately tested. Modules have their own customisation descripters

Module Test (During OO Thread Test)

Behaviour of an individual module, serving as an assembly of components, is tested and verified



Detailed Activities (4) Component Configuration Specification

– Specification of configuration using component descriptors. Component modules are then configured into a cohesive application

System Test– Involves testing a cohesive application as per a particular component

configuration

Deployment– Deploy the system as per the configuration specification– Deployment environment should closely resemble system test environment

Maintenance– Components swapped out for replacement with other component

implementations with less time spent on repair– Enhances system availability for the user base



Component development for reuse

• Components developed for a specific application usually have to be generalised to make them reusable

• A component is most likely to be reusable if it associated with a stable domain abstraction (business object)

• For example, in a hospital stable domain abstractions are associated with the fundamental purpose - nurses, patients, treatments, etc



Design PatternsRequirement analysis -> Analysis patterns -> Generate common analysis models -

> Common design patterns

A design pattern is a description or template for solving a problem that can be used in many different situations

Design patterns can speed up the development process by providing tested, proven development paradigms. Reusing design patterns helps to prevent subtle issues that can cause major problems and improves code readability for coders and architects familiar with the patterns.

Design pattern is defined in terms of : Intended Use Common problem it intends to solve A design structure of classes/interfaces and their relationships, participating

and collaborating objects Expected solution results Implementation considerations



Types of Design Patterns (1)• Adapter Pattern

Used to adapt the implementation of one class’s interface to support a new underlying implementation. Adapter could also be thought of as a “wrapper”

• Factory PatternGeneral framework for creating new object instances.

Defines an interface for creating objects, but lets subclasses decide which classes to instantiate.

• Singleton PatternProvides a means to ensure that only one object instance of a

class is created and referenced by clients accessing that class

Encapsulated “just-in-time initialization” or “initialization on first use”.



Types of Design Patterns (2)• MVC Pattern

Standards for Model, View & Control aspects are separately encapsulated

• Strategy PatternEncapsulates interchangeable underlying

algorithms / policies and provide the same interface for accessing such algorithms / policies

• Command PatternEncapsulate a command for performing

some operation



Types of Design Patterns (3)• Subject-Observer pattern

Encapsulate subject of some event that is to be observed.

Define a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.

• Proxy PatternProxy provides a surrogate or place holder to

provide access to an object.A check or bank draft is a proxy for funds in an account. A check

can be used in place of cash for making purchases and ultimately controls access to cash in the issuer’s account.

• Composite PatternContains one or more composite objects

• Anti-PatternCommon design patterns to be avoided during

development



Auctioneer starts the bidding & “observes” when a paddle is raised to accept the bid. Acceptance of the bid changes the bid price which is broadcast to all of the bidders in the form of a new bid.

EC – SAQ - Unit1A1. What is an enterprise?2. Enumerate the main

components of enterprise?3. List the primary objectives of

an enterprise.4. What is enterprise computing?5. What is enterprise

architecture?6. Give the generic enterprise

system architecture.7. What are the two essential

components of a software system?

8. Define class & class package in OOD.



9. What is class diagram?10. What is Dynamic Behaviour

diagram?11. What are the various

component model interface classifications?

12. List the common design patterns.

EC – LAQ - Unit1A

1. Why enterprise system architecture is needed in organisations?

2. Give the generic enterprise system architecture.3. Describe object-oriented development process from charter

to maintenance.4. Describe Component based software development.5. Describe the design patterns in distributed object

architectures.



enterprise computing_anna university

Documents