Bài giảng Phát triển phần mềm phân tán - Bài 1: Introduction

21-Oct-16

Objectives

•

Upon completion of this lesson, students will be

able to

LESSON I. Introduction

–

Recall the basics of programming

Approach the object-oriented paradigm

Understand the Java background

Vu Thi Huong Giang

Install and use some basic tools for Java programming

SoICT (School of Information and

Communication Technology)

HUST (Hanoi University of Science

and Technology)

Content

I. Programming

•

Programming

Object-oriented paradigm

Java background

• Given a problem, how to:

–

Design an algorithm for solving it

–

Implement this algorithm as a computer program

Needs of programming languages and paradigms

Language: express the algorithm to a machine

–

Process of programming using Java technology

•

–

Java technology

–

Declarative language (I): what to do, what to store

Non declarative language (II): how to do, how to store

•

Basic tools for Java programming

–

WSDL

Fortran

I

BPEL

II

C/C++

Java

HTML

….

Cobol

Basic

PASCAL

SQL

Assembly

PROLOG

Machine code

….

I. Programming

•

Given a problem, how to:

• Given a problem, how to:

–

Design an algorithm for solving it

–

Design an algorithm for solving it

–

Implement this algorithm as a computer program

–

Implement this algorithm as a computer program

 Needs of programming languages and paradigms

Needs of programming languages and paradigms

•

Paradigm: comprise a set of concepts that are

used as patterns for programming

Each language realizes

one or more paradigms

Each paradigm consists

of a set of concepts

Languages

Paradigms

Concepts

Imperative

Functional

Logical

Imperative

Functional

Logical

First do this and next do that

WSDL

BPEL

Fortran

Class

Object

Method

Evaluate an expression and use the resulting

value for something

C/C++

Java

HTML

Cobol

….

Answer

a question via search for a solution

PASCAL

SQL

Send messages between objects to simulate

Basic

Object-oriented

….

Object-oriented

….

the temporal evolution of

phenomena

a

set of real world

Assembly

PROLOG

….

Machine code

….

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21-Oct-16

Object-oriented modeling

•

Object in the real world are related to

us and each other.

They can be modeled as software

objects

II. OBJECT-ORIENTED

PARADIGM

Car

Tom

House

Reality

Flower

Object-oriented modeling

Model

House _lives

1. Concepts

2. Principles

Car

drives

in

gets

Flower

Tom

Object

Class

•

Object in the real world is represented by:

•

A class specifies the common

attributes and methods of many

–

Attributes: information about theirs states

individual objects all of the same kind.

–

Methods: their behaviors related to theirs states.

•

Example

•

Class is used as the blueprint to create

objects

Object

State

Behavior

- Move forward

- Speedometer: How fast is it

moving?

- Stop

- Odometer: How many miles has - Reverse

it driven?

- ….

- Author: Who is the author?

- Pages number: How many

pages does it contain ?

-…

- Buy

- Borrow

- Count the number of

pages….

Example: class is

used as the blueprint

to create objects

Example

•

Objects of the real

work that are

unclassified

•

Organisms

Mammals

Humans

Pine tree

Gum tree

Pine tree

Gum tree

Shere Khan the tiger

Jumbo the elephant

Daisy the cow

Bugs bunny

Jane

John

Big Al

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21-Oct-16

Example: class is

used as the blueprint

to create objects

2. Principles

•

Organisms

•

Abstraction: Hide details

Encapsulation: Keep changes local

Modularity: Control the information ﬂows

Hierarchy: Order abstractions

Inheritance: Reuse codes

Pine tree

Gum tree

•

Mammals

•

Dangerous

mammals

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1. History

•

When and by whom?

• Why Java ?

III. JAVA BACKGROUND

–

was created in 1991 by

James Gosling, Patrick

Naughton, Chris Warth,

Ed Frank and Mike

Sheridan of Sun

–

Widely used.

Widely available.

Embraces full set of

modern abstractions.

–

Variety of automatic

checks for mistakes in

programs.

Microsystems.

•

Which motivation ?

– Need of a language,

which is independent

from platforms and

which could be

embedded in various

electronic devices such

as interactive TVs.

1. History

2. Process of programming using Java technology

3. Java technology

2. Process of programming using Java

technology

a. Java as programming

language

•

Platform independent and object-

oriented programming language

Run (anywhere)

Write (once)

Compile

Java source files

Java bytecode files

Program output

•

Able to create all kinds of applications

that can be created by any

Text

editor

Java

compiler

Java Virtual

Machine

conventional programming language.

MyProg.java

API

Platform

Programming

language

Java

(application, development and

deployment environment)

JVM + Java API

Java Virtual Machine

Hardware-based platform

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b. Java as platform: JVM + API

Development environment

•

JVM: interpretation for the Java bytecode,

ported onto various hardware-based

platforms.

•

Compiler

javac.exe

java.exe

jdb.exe

Java API: collection of packages of classes and

Interpreter

Debugger

interfaces providing useful functionalities

 These components work as

–

Development environment

Application environment and deployment

environment

Document

Generator

javadoc.exe

of Java applications

MyProg.java

API

•

Archiver

jar.exe

rt.jar

Java Virtual Machine

Class Library

Hardware-based platform

Application and deployment

environments

Classification of Java platform

•

Java SE (Java Platform, Standard Edition)

Aims at the development of a usual business application.

•

Java programs run on any machine

where the Java runtime environment

(JRE) is installed.

–

Java EE (Java Platform, Enterprise Edition) and

GlassFish

•

2 main deployment environments:

–

Aims at the development of a decentralized application in a

multistory layer in Internet/Intranet.

–

The JRE supplied by the Java Software

Development Kit (JDK 7)

•

Java ME (Java Platform, Micro Edition)

Aims at the development of an embedded application such

as the cellular phone, the portable terminal, and the

microchip, etc.

–

The Java technology interpreter and

runtime environment supplied by

commercial web browsers.

•

JavaCard

–

Aims at the development of smart card applications.

Etc.

1. Java SE + text editor + console

•

Java platform standard edition

IV. BASIC TOOLS FOR

JAVA PROGRAMMING

–

Download the Java SE Development Kit 7 (JDK) at:

–

http://www.oracle.com/technetwork/java/javase/downlo

ads/index.html

–

Don’t forget to update the PATH / CLASSPATH

environment variables

•

Text editor: Notepad, Notepad++, Wordpad, etc.

Console: for typing Java command line and

getting results.

1. Java SE + text editor + console

2. IDE (Eclipse)

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Exercise: first Java program using text

editor + console

Exercise: first Java program using text

editor + console

•

Compile this file by javac command

> dir

SayHello.java

> javac SayHello.java

Verify if a .class file is produced or not

> dir

SayHello.java

SayHello.class

Run the class file using java command

> java SayHello

Chao!

•

Use your text editor (e.g Notepad) to create this

code and save it in the file named SayHello.java

public class SayHello {

// The program starts here

public static void main (String[] args) {

// print "Chao!" on the screen

System.out.println ("Chao!");

}

2. Eclipse (Juno 4.2)

Screen composition of Eclipse

available at: http://www.eclipse.org/downloads/

•

Open source Java IDE

Features:

compile

and run

–

Extension of functions through plug-ins

–

Enhanced development assistance functions: Code

assistance, automatic build function, refactoring,

debugger, etc.

Perspective

•

Basics:

–

Workbench: desktop development environment, each

Editor

contains one or more Perspectives

–

Perspectives: Contain views and editors, menus and tool

bars

Console

Lab: Create – Compile – Run a Java

Program with Eclipse

Creating a simple application

•

Select File -> New -> Java Project ->. Fill in the Project

Name as javaproject

•

Starting screen

–

Under Contents, select Create new project in workspace

–

Under Project Layout , choose Create separate source and output

folders

–

Click Finish

•

Create a SayHello class by selecting File -> New -> Class.

This will bring up a New Java Class window.

–

Fill in javaproject /src as Source folder.

Fill in firstpackage as Package.

Use SayHello as the Name.

Select public static void main ... .

Click Finish.

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Creating a simple application

Edit the code

•

Delete the comment lines and insert a line so

that the main method looks like this:

public static void main(String[] args) {

// Print Chao! on the screen

System.out.println ("Chao!");

}

Compile and Run

Quiz

•

Right click on SayHello and choose Run As ->

Java Application

A Save and Launch window may pop up.

1. Java program is termed “Write once, run

everywhere”. Explain.

2. Give an example of class and objects in the real

world.

3. Write a program named MyFavouriteBook to

display the information about the book you love

(title, author, language) and why you love it.

–

If it does, select Always save resources before launching

(so this does not pop up again) and click OK.

•

You should see the output in the Console window

at the bottom of the screen.

4. Using javac and java command to compile and

run it

5. Using Eclipse to create a project FirstLecture,

them compile and run it.

Solution

Quiz 3-4: Solution

public class MyFavouriteBook

{

Quiz 1

Quiz 2

public static void main(String[] args)

{

•

A Java program can be

written on any device, for

example a PC.

Then, it is compiled into a

standard byte code and be

expected to run on any

device such as cell phone,

mainframe without any

adjustments, if these

•

Consider your marker pen.

System.out.println("My favourite book");

System.out.println("Title: Pride and Prejudice");

System.out.println("Author: Jane Austen");

System.out.println("Language: English");

Each marker pen contains

the same components, so

we can say that each

marker pen was

manufactured from the

same blueprint.

Your marker pen (a specific

pen object) is an instance of

a class of objects known as

marker pens. You can easily

describe the state and

•

System.out.println("Why do

I love it ? I don't know.");

}

•

devices are equipped with a

Java virtual machine (JVM)

behavior of a marker pen.

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21-Oct-16

Quiz 5: Solution

Review

•

Programming

Language

–

Paradigm

•

Object-oriented paradigm

–

Object: state + behavior

Class: blueprint for creating objects

Principles: abstraction, encapsulation, hierarchy,

modularity, inheritance

•

Java background:

–

Language: Java

–

Platform: JVM + API

Basic tools for Java programming

–

Platform +Text editor + console

–

Platform + IDE

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Bài giảng Phát triển phần mềm phân tán - Bài 1: Introduction - Vũ Thị Hương Giang