Tirumalesh_J2EE

7/31/2019 Tirumalesh_J2EE

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J2EE

Tirumalesh Reddy

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About This Presentation

SDLC

Application Server.

Web Server.

J2EE Architecture.

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Sowtware Development Life Cycle (SDLC)

WaterFall Methodology

Spiral

Agile

WaterFall Methodology

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Agile Processes

Requirements change.

Design evolves.

Documents are seldom current.

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Agile Methodology

1. Introduction to Agile Java Development

2. Agile Processes

3. Agile Modeling

4. Agile Development Environment Setup: Directory Structure, JDK, Ant and JUnit

Using Hibernate For Persistent Objects

5. Beyond The Basics


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What Is Agile Java Development? It CouldInclude

1. Agile Software Processes Iterative Development

Use an Agile method - Scrum, XP, etc.

2. Agile Architecture/Design Modeling

Incremental design with good enough models Use an agile method -Agile Model Driven Development (AMDD)

3. Agile Java Design/Development Simple design and coding!

Test-driven development (TDD)

Efficient frameworks and tools (Ant, JUnit, Hibernate, Spring, Eclipse)

Plain Old Java Objects (POJOs), whenever possible

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Term Agile Incorporates a Wide Range of Methods

AM - Agile Modeling

ASD - Adaptive Software Development

AUP - Agile Unified Process

Crystal

FDD - Feature Driven Development

DSDM - Dynamic Systems Development Method

Lean Software Development

Scrum

Xbreed

XP - eXtreme Programming

Others

Agility- All About Smaller Chunks (Shorter/Frequent

Cycles)

...

Iteration

0

Iteration

1

Iteration

n

Release 1

...

Release 2

Iteration

0

Iteration

1

Iteration

n

...

software software software software software software

Incrementally Build Software - Highest Priority Features First!

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Agile Method: Scrum

Simple process for product/project management

Product Backlog - List of known features/changes for product

Sprint - 1-month iterations (develop highest priority items)

Meetings

Sprint Planning Meeting Done at beginning of each sprint

(after planning, features moved from product backlog to sprint backlog)

Daily scrum meeting(short: 15 minutes)

Sprint review meeting

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Agile Method: Extreme Programming (XP)

Shorter and Frequent Cycles (smaller chunks!)

Release - Quarterly Cycles (set a theme)

Iteration- Weekly Cycles (e.g. aim for last day of week)

10-minute builds Continuous integration (multiple times per day; manual or automatic)

Incremental Design and Planning (defer investment till needed)

Development in small increments using Test-First development

Communications - Sit Together, Informative Workspace, on-site customer

Flow - sustainable pace versus rigid phases; velocity, continuousintegration

Others visit extremeprogramming.org

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Choices Of Release (High) Level Models

Model with a purpose -- shared understanding!

domain model user storiesUI prototype& flow map

architectureRelease

Level

Models

scope table,glossary, etc .

CRC cardsapplicationflow map

UMLdiagrams

databasemodel

Iteration

Level

Models

acceptancetests


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Sample Scope Table

Shared understanding: what's in and what's out

Scope Functionality

Include Time Expression will provi de the capability to enter, approve, and

pay for hours worked by employees.

Defer Time Expression will not calculate deductions from paychecks, such

as federal/state taxes and medical expenses.

Defer Time Expression will not track vacation or sick leave.

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Domain Model

Shared understanding: business concepts > key domain objects

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User Stories Or Use Cases

Shared understanding: features required of software

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XP Style User Story Card

Use Case: Login

Author

Anil Hemrajani

DescriptionThis processallows User to log into the System

Actors/Interfaces

FM TraderThe System

Trigger

User performs a Loginaction

Preconditions

N/A

Success/Basic Flow

1. The System displays the Login panelp rompting User for login details as specified inthe

2. User completes all required fields and performs a Submitaction.Failure/Alternative Flow

Invalid User ID and/or Password - The system notifies FM trader with the message Invalid UserID and/or Password . The system displays the Loginpanel to User with the contents of all fields

empty.

Use Case - Casual, Brief or Fully Dressed

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User Interface (UI) Prototype

Shared understanding: functionality, look-and-feel, etc.

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UI Flow Map (Storyboard)

Shared understanding: user interface navigation/flow

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High-Level Architecture Diagram

Shared understanding: technologies, scalability, security, reliability

BEA WebLogic Server

Objects managed by Spring IoC Container

HTTP JDBC

View

JSP/HTML

Controller

Spring

DispatcherServlet

Web

Browser

Model

Business objects,

Hibernate beans

Spring

Scheduler

RDBMS

(Oracle)


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Choices Of Iteration Level (Detailed) Models

domain model user storiesUI prototype& flow map

architectureRelease

Level

Models

scope table,glossary, etc.

CRC cardsapplicationflow map

UMLdiagrams

databasemodel

Iteration

Level

Models

acceptancetests

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Iteration Level Details - Acceptance Tests & Active

Stakeholders

Sign In

The employee id can be up to 6 characters. The password

must be between 8 and 10 characters.

Only valid users can sign in.

Timesheet List

Only a user's personal timesheets can be accessed.

Enter Hours

Hours must contain numeric data.

Daily hours cannot exceed 16 hours. Weekly hours cannot

exceed 96 hours.

Hours must be billed to a department.

Hours can be entered as two decimal places.

Employees can only view and edit their own timesheets.

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Exploring Classes Using CRC Cards

Class Name (Noun)

Responsibilities (obligations

of this class, such as business

methods, exception handling,

security methods,

attributes/variables).

Collaborators (other

classes required to

provide a complete

solution to a high-level

requirement)

TimesheetManager

Fetches timesheet(s) from

database

Saves timesheet to database

Timesheet

Timesheet

Knows of period ending date

Knows of time

Knows of department code

domain model

Timesheet List screen

First, let's reflect on what we know,domain model, UI and architecture

Second, let's explore classes on CRCcards using both as input models

TimesheetListController

Controller (in MVC) for

displaying a list of timesheets.

TimesheetManager

free-form architecture

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Application Flow Map (Home Grown A rtifact)

Complementary to class diagrams and CRC cards

Can be extended using CRUD columns

Story Tag View Controller Class Collaborators TablesImpacted

Timesheet

List

timesheetlist TimeSheetListController TimesheetManager Timesheet

Enter

Hours

enterhours EnterHoursController TimesheetManager Timesheet

Department

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UML Class and Package Diagrams

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Focus Is On Working Software vs. Comprehensive Documentation

Physical Models

CRC cards

applicationflow map

UMLdiagrams

databasemodel

acceptancetests

Conceptual Models

user stories

architecture

problem

statement

domain model

scopetable

glossary

UI prototype& flow map

Implementation

Data Base Code Base

THE FINAL AND LASTING ARTIFAC TS!

UIprototypes Model in Small Increments

Depict Models Simply

Discard temporary models

Prove it with code

- agilemodeling.com


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Shifting Some Upfront Design to Refactoring

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Shifting Some Upfront Design T o Refactoring (Continuous Design)

Refactoring is not a new concept; the term is relatively new

refactoring.com

Refactoring is a disciplined technique for restructuring an existing body of

code, altering its internal structure without changing its external behavior.

- Martin Fowler

Over 100 refactoring techniques; for example:

Extract superclass

Extract interface

Move class

Move method

Application Server

What is an App Server?

Serves up web pages

Provides a container model for applications

Provides services for applications

Adheres to a specification controlled by industry

Distributes requests across multiple physical servers

Provides management and/or development tools

Eg :

Weblogic (8.1, 9.2, 10[11g])

Websphere(IBM)

Tomcat

Web Server

Acomputer that delivers (serves up) Web pages. Every Web serverhas an IP address and possibly a domain name. For example, if you

enter the URL http://www.egen.com/index.html in your browser,this sends a request to the server whose domain name is egen.com.The server then fetches the page named index.html and sends it toyour browser. Any computer can be turned into a Web server byinstalling server software and connecting the machine to theInternet. There are many Web server software applications ,including public domain software from NCSA and Apache.

Let's use Egen as an example. You decide to visit Egen by typing its

URL -- http://www.egen.com -- into your Web browser. Through anInternet connection, your browser initiates a connection to the Web

server that is storing the Egen files by first converting the domain

name into an IP address (through a domain name service) and thenlocating the server that is storing the information for that IP address

(also see Understanding IP Addressing).

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J2EE Architecture and Components
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Containers Services

Containers are the interface between a component and the low-

level platform-specificfunctionality that supports the component.

Before it can be executed, a web, enterprise bean, or application

client component must be assembled into a Java EE module and

deployed into its container.

Container Types Container Types

Java EE server: The runtime portion of a Java EE product. A

Java EE server provides EJB and web containers.

Enterprise JavaBeans (EJB) container:Manages the

execution of enterprise beans for Java

Web container: Manages the execution of web pages,

servlets, and some EJB components for Java EE applications.

Web components and their container run on the Java EE server.

Application client container: Manages the execution of

application client components. Application clients and their

container run on the client.

Applet container:Manages the execution of applets. Consists

of a web browser and Java Plug-in running on the client together.

EJB Container Web Container


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Packaging Applications

JAR(Java Archive)

WAR(Web Archive)

EAR(Enterprise Archive)

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