1. 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
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2. 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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3. 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
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4. 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.turnLeft(); karel.turnLeft();
karel.turnLeft();
karel.move();
karel.pickThing();
karek.move();
karel.putThing(); } 1 2 3 4 X 1 2 3 4
named Karel
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5. 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(); }
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6. 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); }
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7. class defined in the package
A Java program
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); }
class defined in the package
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8. 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 * * *
**********************************************************/
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9. 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
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10. 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);
...... }
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11. 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
... }
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12. 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
…………
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13. 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
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14. 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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15. UML (Unified Modeling Language) Diagram
Vehicle
SUV
Truck
Sedan
Honda Pilot
Focus
Matrix
Matrix XRS
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16. 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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17. 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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18. 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(); =
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