Lecture 01Enterprise Applications

Agenda The Post-PC era Enterprise Application Building Blocks Evolution of Enterprise Software

Reading Brown 1 Digital Lifestyle Enterprise Software

The Post-PC era

1960 1970 1980 1990 2000 2010

Mainframes

Mini computers

Personal Computers

Servers

Clusters

Cloud – utility computing

Laptops

Music player2G Cell phones

CONVERGE

DIVERGESmartphones

Tablets

Smart TV

Internet of things

Smartwatch

2000 2010

THE DIGITALDECADE

“[The Personal Computer] can become the 'Digital Hub'

of our emerging digital lifestyle, adding tremendous value

to our other devices.”- Steve Jobs, 2001 Keynote

introducing the iPod

THE DIGITALDECADE

2000 2010

THE DIGITAL DECADE

MUSIC

PICTURES

VOICESMARTPHONES

TV SHOWS

MOVIES

BOOKS

WHAT HAPPENEDAT THE END OF THEDIGITAL DECADE?

1981-2011 The era of the PC

THE PC IS JUST ADEVICE

2000 2010

iMac iPhoneMac OS 9.0.4500 MHz PowerPC G3 CPU, 128MB MemoryScreen - 786K pixelsStorage - 30GB Hard Drive

iOS 4.01 Ghz ARM A4 CPU, 512MB MemoryScreen - 614K pixelsStorage - 32GB Flash Drive

Source: Ars Technical Images: Apple

Digital LifestyleThe “mobile web” is just the web – there is only one web

d ig i ta l on l ine wor ld

Digital Online World

WorkMore

informationFocused

Digital Online World

BrowsingConsuming

content

CheckingMobileNow

ConsumingVideo

Information

The Post-PC Era The Personal Computer era is over– Rise of the network – APIs– Enterprise systems are accessible

by consumers– New devices, mobile phone,

ITV, game machines, MP3 players,...Source: (cc) 1998-2008Digibarn Computer Museum,

Source: Picture from Convergence Transforms Digital Home: Techno-Economic Impact

The Post-PC Era New Requirements– More users, more complicated software– Uptime, security and reliability– Scalability– Competition drives need for productivity– Leveraging investments – integration with

existing systems

Challenges in Computing

Software and integration of components and devices are the challenges ahead

Cloud computing and ubiquity Move to Service Oriented Architecture and APIs

1980 1990 2000

HardwareConnecting hardware

NetworkSoftware

Connectingsoftware

New Approch to SoftwareArchitecture

Which of the following statements is not true?

A) The challenge ahead is to connect softwareB) The PC is no longer a device for developmentC) Computing has moved to the cloudD) During the digital decade, the PC was the digital hub for all you devices

QUIZ

Which of the following statements is not true?

A) The challenge ahead is to connect softwareB) The PC is no longer a device for developmentC) Computing has moved to the cloudD) During the digital decade, the PC was the digital hub for all you devices

QUIZ

✔

Enterprise Application

Enterprise Applications Software running in corporate data centers Characteristics– Involve data, some times huge amounts– Concurrent data access, multiple users– Lot of user interface screens– Integration with other enterprise application– Use of middleware software, such as

databases, application servers, web servers– Operated by specialists – system operators

Examples B2C - Business to Consumer– E-commerce web sites such as Amazon, eBay– Commercial services like banking

B2B – Business to Consumer– Payroll, patient records, shipping tracking, cost

analysis, credit scoring, insurance, supply chain, accounting, customer service, and foreign exchange trading

Content– Stock quotes, sports results, email, blogs

Software as a Service (SaaS) “On-demand” software– Cloud computing

IT infrastructure demands– Communication: interacting with the software– Scalability: dealing with fluctuation– Dependability: available 24/7

Software as a Service Examples E-mail services Project management Blog services

What is not necessarily characteristic of enterprise software?

A) Has many concurrent users working on the same dataB) Integrates with other IT systemsC) Deploys some form of distribution strategyD) Is operated by specialists not by the users

QUIZ

What is not necessarily characteristic of enterprise software?

A) Has many concurrent users working on the same dataB) Integrates with other IT systemsC) Deploys some form of distribution strategyD) Is operated by specialists not by the users

QUIZ

✔

Evolution of Enterprise Software

Evolution60 70 80 90 00

IBMMainframes

Limitedlayering orabstraction

IBM, DECMini-

computersUnix, VAX

“Dumb”terminals

Screens/DB

PC, Intel,DOS, Mac,

Unix, Windows

Client/ServerDB

WindowsInternet

HTTP

Web Browsers

WebApplications

DB

Windows,Linux

MacOS

Browsers,ServicesDomain

ApplicationsDB

Evolution60 70 80 90 00

IBMMainframes

Limitedlayering orabstraction

IBM, DECMini-

computersUnix, VAX

“Dumb”terminals

Screens/DB

PC, Intel,DOS, Mac,

Unix, Windows

Client/ServerDB

WindowsInternet

HTTP

Web Browsers

WebApplications

DB

Windows,Linux

MacOS

Browsers,ServicesDomain

ApplicationsDB

iOSAndroidHTML5

BrowsersAppsAPI

CloudNoSQL

10

Client-Server Two-layer systems– Thick client on PCs handle user interface and

connect to servers for data

Client-Server The client handles all computation –

domain logic (business logic)– Limited reusability– Versioning is a challenge

Move to Three Tiers Three Layers– Presentation Layer for the User Interface– Domain Layer for the domain logic– Data Source Layer for the data access

Enter the Web Layer The Web added new challenges

– The browser accesses strings of tags (HTML)– Move the logic from client to a web layer

– Web layer adds connectivity by HTTP protocols

Application Servers Domain Components are deployed on

Application Servers– Distributed Multi-tiered Applications– Example:

• Web Servers, Spring, EJB containers

Service Oriented Architecture Built software into independent services Use APIs such as SOAP to expose

functionalityWebBrowser

NativeApp

WebServer

SOAP

DomainLayer

HTTPSERVER

WebBrowser

SOAP

HTML SOAPClient

SOAP

Microservices Built software into (smaller) independent

services Use RESTful APIs with Json

WebBrowser

NativeApp

WebServer Domain

LayerREST

CMSRESTHTML

Client Types Native Applications – Apps – Usually use some OS GUI and APIs– Windows, Linux, MacOS, iOS, Andriod– Communication can be anything

Embedded– Run inside Web Browsers– Flash, Java Applets– Communication with XML using HTTP

Client Types Rich Internet Application (RIA)– JavaScript calls REST/SOAP services for data– HTML with XML/Json using Ajax/jQuery

HTML Presentation in Browsers– All functionality is server side– Simple HTML

Tiers vs. Layers Tier implies physical layer

– Example:• Client-server is two-tier system: client on one machine,

server on another

Layers do not need to run on separate machines– Layers can be on the same machine– Example:

• Web system with Web Layer, Domain Layer and Data Source Layer on the same machine, then the database on a separate machine

N-tier Web App Architecture Classic architecture

Which of the following statements is not true?

A) Versioning is only a challenge with client-service modelB) Layers need not be on a separate machinesC) Web servers can be used as application serversD) Scalability is achieved by duplicating the system

QUIZ

Which of the following statements is not true?

A) Versioning is only a challenge with client-service modelB) Layers need not be on a separate machinesC) Web servers can be used as application serversD) Scalability is achieved by duplicating the system

QUIZ

✔

Building Blocks

Building Enterprise Applications Building computer systems is hard– As the complexity of the system gets greater,

thetask of building the software gets exponentially harder

Building Enterprise Applications Building computer systems is hard

DesignPattern

Middleware

FrameworksOOProgramming

SoftwareArchitecture

Software Architecture Shared understanding of system’s design

by the expert developers on a project– Highest-level breakdown of a system into its

parts– Decisions that are hard to change

Architecture influences design of components, technology, performance and middleware

There are always options

Object Oriented Programming OO is key to development of systems– Design for reusability, flexibility and

performance

One of the biggest hurdles for developers– Each component should be simple with simple

task– Involves understanding of interaction of parts

“OO design is more important than specific technologies, such as J2EE. We should try to avoid letting our technology choices, such as J2EE, constrain our ability to use true OO design” – Rod Johnson “If the design is good, there is no code”

– Jónas Þór, Senior Betware developer

Design Patterns Design using known ideas– Design patterns are standard solutions to

common problems in software design– Systematic approach for problems that

reoccur in software development– Patterns have name and definitions - not

language dependant History– Landmark book from 1995: Design Patterns:

Elements of Reusable Object-Oriented Software Gang of Four (GoF)

Middleware Enterprise system are built on middleware

– Can cover a broad spectrum of software and generally sits between an application and an operating system

– For example, databases, application servers, web servers, messaging systems, transaction monitors

– “The plumbing” – the infrastructure Horizontal market

– Solves common problems – not specific business requirements

– Low-level system

Frameworks Frameworks define the support structure for how

to organize and build systems– Can improve productivity– We can use existing frameworks or build our own

Frameworks implement common problems– Developers extend and add their business requirements

Framework design– Use inheritance, inversion of control, interfaces and

helper classes– Implement design patterns

Which of the following statement is not true?

A) Design patterns are solutions to common problemsB) Object oriented programing is good for general problemsC) Frameworks are used to increase productivityD) Middleware can solve business related problems

QUIZ

Which of the following statement is not true?

A) Design patterns are solutions to common problemsB) Object oriented programing is good for general problemsC) Frameworks are used to increase productivityD) Middleware can solve business related problems

QUIZ

✔

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