1. IDE (Integrated Development Environment)
5/6/2019
IDE (Integrated Development Environment)
A customized plain text editor
Compiler
Loader
Debugging tool
vi (or emacs)
javac hello.java
java hello
......
JDK (Java Development Kit) = IDE+JRE
Eclipse = IDE
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IT 179

2. ProblemsSolutions cycle
Customers
System analyst, Project leader
Problems
Senior Programmers
Syntax
Semantics
(human)
Algorithms
Programmers
Programs in JAVA
(or any high level Programming Language)
compiler
Assembly
IDE
(computers) VM
Assembler
Machine code
linker
Results
5/6/2019
IT 179

3. How much effort in solving a problem
After ITK 168
This is a basic requirement. We need to reduce this portion
6 month from now
After ITK 179
This is more important and difficult;
data structures,
algorithm analysis
5/6/2019
IT 179

4. Procedure- v. Object- oriented
To solve a program is:
To find a way to manipulate data --
We design procedures
Procedure-Oriented Programming
Statements + functions  programs
To find objects to model the problem –
We choose data (object)
Object-Oriented Programming
Classes + Objects  programs
(interfaces, methods, attributes…)
5/6/2019
IT 179

5. Robot Class name Attributes Constructor Services, methods
int street
int avenue
Direction direction
ThingBag backbag
...
Robot(City aCity, int aStreet, int aAvenue, Direction aDir)
void move()
void turnLeft()
void pickThing()
void putThing()
Class name
Attributes
Constructor
Services, methods
UML class diagram for Robot
5/6/2019
IT 179

6. Modeling what? Modeling Robots in a City with Software Classes. Robot
int street
int avenue
Direction direction
ThingBag backbag
...
Robot(City aCity, int aStreet, int aAvenue, Direction aDir)
void move()
void turnLeft()
void pickThing()
void putThing()
City
String name
int stree_No
int ave_No
...
....
City( )
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IT 179

7. class defined in the package
Anatomy of a Java Program
class defined in the package
import javax.swing.JOptionPane;
public class time{
public static void main(String args[]){
int x,y,z;
String X,Y;
X = JOptionPane.showInputDialog("Input x");
Y = JOptionPane.showInputDialog("Input y");
x = Integer.parseInt(X);
y = Integer.parseInt(Y);
z = x*y;
JOptionPane.showMessageDialog(
null,
x + " * " + y + " = " + z,
"The product of " + x + " and " + y,
JOptionPane.PLAIN_MESSAGE );
System.exit(0); }
Variable declaration
classes
methods
arguments
5/6/2019
IT 179

8. Task: deliver X from (1,2) to (3,1) and step away
import becker.robot.*;
public class DeliverX{
public static void main(String args[]){
// set up Initial situation
City A = new City();
Thing X = new Thing(A,1,2);
Robot karel = new Robot(A,0,0,
Direction.East);
// direct the robot
karel.move();
karel.turnLeft(); karel.turnLeft();
karel.turnLeft();
karel.pickThing();
karek.move(); karel.move();
karel.move(); karel.putThing(); } 1 2 3 4 X 1 2 3 4
named Karel
5/6/2019
IT 179

9. Anatomy of a Java Program
import becker.robot.*;
public class DeliverX{
public static void main(String args[]){
// set up Initial situation
City A = new City();
Thing X = new Thing(A,1,2);
Robot karel = new Robot(A,0,0,Direction.East);
// direct the robot
karel.move();
karel.turnLeft(); karel.turnLeft();
karel.turnLeft();
karel.pickThing();
karek.move(); karel.move();
karel.move(); karel.putThing(); }
5/6/2019
IT 179

10. Package: collection of classes
// Java API: Java Application Programming Interface
// (java., javax.)
// GUI: Graphical User Interface //
// using swing package, JOptionPane class
// showMessageDialog method
import javax.swing.JOptionPane;
public class TestPane{
public static void main(String args[]){
JOptionPane.showMessageDialog(
null,
"Welcome\nTo\nswing\nPackage");
System.exit(0); }
5/6/2019
IT 179

11. A Java Program: // Text-printing program. public class Welcome1 {
// main method begins execution of Java application
public static void main( String args[] ) {
System.out.println( "Welcome to Java Programming!" );
} // end method main
} // end class Welcome1
/*********************************************************
*(C) Copyright by * * *
**********************************************************/
5/6/2019
IT 179

12. Reusing Codes Composition A class has another class, “has a” relation
Inheritance
A class has another class, “has a” relation
A car has an engine
A class inherits another class, “is a” relation
An SUV is a car
5/6/2019
IT 179

13. Composition: has a A DeliverX has a main,
The main has a City, Thing, and a Robot
import becker.robot.*;
public class DeliverX{
public static void main(String args[]){
// set up Initial situation
City A = new City();
Thing X = new Thing(A,1,2);
Robot karel = new Robot(A,0,0,
Direction.East);
...... }
5/6/2019
IT 179

14. Composition: has a
A BankAccount has a Client, has a List of BankTransaction
public class BankAccount {
private Client client;
private List<BankTransaction> transactions;
// other fields
... }
5/6/2019
IT 179

15. Classes: A class is a concept of something Vehicle
4 wheels, seats, engine, windows, color……
accelerate, start, stop, turn, lock,
Truck
…………
Sedan
…………
Focus
…………
Matrix
…………
SUV
…………
5/6/2019
IT 179

16. Inheritance: From membership point of view
A SUV is a vehicle, but a vehicle may not be a SUV
Any SUV is a
Vehicle
Vehicle
SUV
Base concept
Honda Pilot
Derived concept
Java
Object
Number
Base class
Integer
Double
Derived class
5/6/2019
IT 179

17. Inheritance: From functionality point of view
All vehicle can do, SUV can too
The SUV has every
properties and
function of the
Vehicle
SUV
Vehicle
Derived class
Base class
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IT 179

18. UML (Unified Modeling Language) Diagram
Vehicle
SUV
Truck
Sedan
Honda Pilot
Focus
Matrix
Matrix XRS
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IT 179

19. my_a is invisible to B = A - my_a: int +get_a():int B B - my_b: int
+get_b():int B
- my_b: int
+get_a():int
+get_b():int =
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IT 179

20. Base class (superclass) & Derived class (extended subclass)
// A is a base class
public class A {
private int my_a;
Public A(int a) {
my_a = a; }
public int get_a() {
return my_a;
// B is a derived class
Public class B extends A {
private int b;
public B(int a, int b) {
super(a);
this.b = b; }
public int get_b() {
return b;
A a = new A(2);
B b = new B(3,7);
I = a.get_a();
J = b.get_a();
K = b.get_b();
B inherits A’s functions and
variables.
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IT 179

21. An enhanced robot = Robot ExperimentRobot ExperimentRobot int street
int avenue
Direction direction
ThingBag backback
Robot(City aCity, int aStreet, int anAvenue,
Direction aDir)
void move()
void turnLeft()
void pickThing()
void putThing()
An enhanced robot
ExperimentRobot
int street
int avenue
Direction direction
ThingBag backback
ExperimentRobot(City aCity, int aStreet,
int anAvenue, Direction aDir)
void move()
void turnLeft()
void pickThing()
void putThing()
void turnAround();
void turnRight();
void move3();
ExperimentRobot
ExperimentRobot(City aCity, int aStreet,
int anAvenue, Direction aDir)
void turnAround();
void turnRight();
void move3(); =
5/6/2019
IT 179

22. Selection sort algorithm in Java
public static class SelectionSort {
public void sort(int a[]) {
for (int i = 0; i<a.length-1; i++) { // select one for a[i]
int j = min(a,i);
exchange(a,i,j); }
// select the minimum between a[s] to the end
private int min(int a[], int s) {int m = s;
for (int i=s; i<a.length;i++)
if (a[i] < a[m]) m=i;
return m;
private void exchange(int[] a, int i, int j) {
int temp = a[i];
a[i] = a[j];
a[j] = temp;
} // end of SelectionSort
5/6/2019
IT 179