ch09

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1 9 Chapter CHAPTER GOALS B I G J A V A

2 436 CHAPTER CONTENTS Syntax Syntax Common Error Syntax Advanced Topic Syntax Advanced Topic Common Error Random Fact public class DataSet // BankAccount public void add(bankaccount x) sum = sum + x.getbalance( ); if (count == 0 maximum.getbalance( ) < x.getbalance( )) maximum = x; count++; public BankAccount getmaximum( ) return maximum; private double sum; private BankAccount maximum; private int count;

3 Chapter public class DataSet // Coin public void add(coin x) sum = sum + x.getvalue( ); if (count == 0 maximum.getvalue( ) < x.getvalue( )) maximum = x; count++; public Coin getmaximum( ) return maximum; Chapter 09 private double sum; private Coin maximum; private int count; sum = sum + x.getmeasure( ); if (count == 0 maximum.getmeasure( ) < x.getmeasure( )) maximum = x; count++;

4 438 public interface Measurable double getmeasure( ); public class DataSet public void add(measurable x) sum = sum + x.getmeasure( ); if (count == 0 maximum.getmeasure( ) < x.getmeasure( )) maximum = x; count++; public Measurable getmaximum( ) return maximum; private double sum; private Measurable maximum; private int count;

5 Chapter class ClassName implements Measurable public double getmeasure( ) Chapter 09 public class BankAccount implements Measurable public double getmeasure( ) return balance; public class Coin implements Measurable public double getmeasure( ) return value;

6 /** 02 DataSet 03 */ 04 public class DataSetTest public static void main(string [ ] args)) DataSet bankdata =new DataSet( ); bankdata.add(new BankAccount(0)); 12 bankdata.add(new BankAccount(10000)); 13 bankdata.add(new BankAccount(2000)); System.out.println("Average balance =" 16 + bankdata.getaverage( )); 17 Measurable max =bankdata.getmaximum( ); 18 System.out.println("Highest balance =" 19 + max.getmeasure( )); DataSet coindata =new DataSet( ); coindata.add(new Coin(0.25,"quarter")); 24 coindata.add(new Coin(0.1,"dime")); 25 coindata.add(new Coin(0.05,"nickel")); System.out.println("Average coin value =" 28 + coindata.getaverage( )); 29 max =coindata.getmaximum( ); 30 System.out.println("Highest coin value =" 31 + max.getmeasure( )); 32 33

7 Chapter Chapter 09 public interface public interface Measurable double getmeasure( );

8 442 public class implements,, public class bankaccount implements Measurable // BankAccount public double getmeasure( ) // Common Error 9.1 public class BankAccount implements Measurable double getmeasure( ) // public return balance;

9 Chapter bankdata.add(new BankAccount(10000)); Chapter 09 BankAccount account = new BankAccount(10000); Measurable x = account; // OK Coin dime = new Coin(0.1, "dime"); x = dime; // OK x = new Rectangle(5, 10, 20, 30); //

10 444 DataSet coindata = new DataSet( ); coindata.add(new Coin(0.25, "quarter")); coindata.add(new Coin(0.1, "dime")); coindata.add(new Coin(0.05, "nickel")); Measurable max = coindata.getmaximum( ); String name = max.getname( ); // Coin maxcoin = (Coin)max; String name = maxcoin.getname( );

11 Chapter max instnaceof Coin if (max instance of Coin) Coin maxcoin = (Coin)max; instanceof Chapter 09 if (x instanceof Coin) Coin c = (Coin)x; ] Advanced Topic 9.1

12 446 public interface SwingConstants int NORTH = 1; int NORTHEAST = 2; int EAST = 3; 9.3 Measurable x; x = new BankAccount(10000); // OK x = new Coin(0.1, "dime"); // OK x = new Measurable( ); //

13 Chapter double m = x.getmeasure( ); Chapter 09 double m = x.getmeasure( ); account = new BankAccount( ); // BankAccount( ) account = new BankAccount(10000); // BankAccount(double)

14 public interface Measurer double measure(object anobject);

15 Chapter public void add(object x) sum = sum + measurer.measure(x); if (count == 0 measurer.measure(maximum) < measurer.measure(x)) maximum = x; count++; Chapter 09 class RectangleMeasurer implements Measurer public double measure(object anobject) Rectangle arectangle = (Rectangle)anObject; double area = arectangle.getwidth( ) * arectangle.getheight( ); return area; Rectangle arectangle = (Rectangle)anObject; Measurer m = new RectangleMeasurer( ); DataSet data = new DataSet(m);

16 450 data.add(new Rectangle(5, 10, 20, 30)); data.add(new Rectangle(10, 20, 30, 40));

17 Chapter public static void main(string[ ] args) class RectangleMeasurer implements Measurer Measurer m = new Rectanglemeasurer( ); DataSet data = new DataSet(m); Chapter /** */ 04 public class DataSet /** 07 mesurer ameasurer 09 */ 10 public DataSet(Measurer ameasurer) sum = 0; 13 count = 0; 14 maximum = null; 15 measurer = ameasurer; 16

18 /** 19 x 21 */ 22 public void add(object x) sum = sum + measurer.measure(x); 25 if (count == 0 26 measurer.measure(maximum)<measurer.measure(x)) 27 maximum = x; 28 count++; /** */ 35 public double getaverage( ) if (count ==0)return 0; 38 else return sum /count; /** */ 45 public Object getmaximum( ) return maximum; private double sum; 51 private Object maximum; 52 private int count; 53 private Measurer measurer; import java.awt.rectangle; 02

19 Chapter /** 04 Measurer 05 */ 06 public class DataSetTest public static void main(string [ ] args) class RectangleMeasurer implements Measurer public double measure(object anobject) Rectangle arectangle = (Rectangle)anObject; 15 double area = arectangle.getwidth( ) 16 * arectangle.getheight( ); 17 return area; Measurer m = new RectangleMeasurer( ); DataSet data = new DataSet(m); data.add(new Rectangle(5,10,20,30)); 26 data.add(new Rectangle(10,20,30,40)); 27 data.add(new Rectangle(20,30,5,10)); System.out.println("Average area =" 30 + data.getaverage( )); 31 Rectangle max = (Rectangle)data.getMaximum( ); 32 System.out.println("Maximum area =" + max); Chapter /** */ 04 public interface Measurer /** 07 anobject

20 454 the measure 10 */ 11 double measure(object anobject); 12 class OuterClassName method signature class InnerClassName methods fields class OuterClassName methods fields accessspecifier class InnerClassName methods fields public class Test public static void main(string[ ] args)

21 Chapter class RectangleMeasurer implements Measurer Advanced Topic 9.2 Chapter 09 Coin a Coin = new Coin(0.1, "dime"); data.add(acoin); data.add(new Coin(0.1, dime)); public static void main(string[ ] args) Measurer m = new Measurer( ) //

22 456 // public double measure(object anobject) Rectangle arectangle = (Rectangle)anObject; double area = arectangle.getwidth( ) * arectangle.getheight( ); return area; ; DataSet data = new DataSet(m); 9.5

23 Chapter public interface ActionListener void actionperformed(actionevent event); class MyListener implements ActionListener public void actionperformed(actionevent event) // Chapter 09 MyListener listener = new MyListener( ); Timer t = new Timer(interval, listener); t.start( ); Liftoff!

24 import java.awt.event.actionevent; 02 import java.awt.event.actionlistener; 03 import javax.swing.joptionpane; 04 import javax.swing.timer; /** */ 09 public class TimerTest public static void main(string[ ] args) class CountDown implements ActionListener public CountDown(int initialcount) count = initialcount; public void actionperformed(actionevent event) if (count >= 0) 23 System.out.println(count); 24 if (count == 0) 25 System.out.println("Liftoff!"); 26 count--; private int count; CountDown listener = new CountDown(10); final int DELAY = 1000;// Timer t = new Timer(DELAY,listener);

25 Chapter t.start( ); JOptionPane.showMessageDialog(null,"Quit?"); 39 System.exit(0); Chapter 09 Balance = Balance = Balance = Balance = public class TimerTest public static void main(string[ ] args) final BankAccount account = new BankAccount(1000); private static final double RATE = 5; class InterestAdder implements ActionListener

26 460 public void actionperformed(actionevent event) double interest = account.getbalance( ) * RATE / 100; account.deposit(interest); System.out.println(Balance = + account.getbalance( )); public static void main(string[ ] args) final BankAccount account = new BankAccount(1000); class InterestAdder implements ActionListener public void actionperformed(actionevent event) double interest = account.getbalance( ) * RATE / 100; // account

27 Chapter Chapter import java.awt.event.actionevent; 02 import java.awt.event.actionlistener; 03 import javax.swing.joptionpane; 04 import javax.swing.timer; /** */ 10 public class TimerTest public static void main(string [ ] args) final BankAccount account = new BankAccount(1000); class InterestAdder implements ActionListener public void actionperformed(actionevent event) double interest = account.getbalance( )

28 * RATE /100; 22 account.deposit(interest); 23 System.out.println("Balance = " 24 + account.getbalance( )); InterestAdder listener = new InterestAdder( ); final int DELAY =1000;// Timer t = new Timer(DELAY,listener); 32 t.start( ); JOptionPane.showMessageDialog(null,"Quit?"); 35 System.exit(0); private static final double RATE = 5; 39

29 Chapter Common Error 9.1 class MyAction implements ActionListener public void actionperformed( ) // ActionEvent Chapter 09 public void actionperformed(actionevent event) public void actionperformed( ) Random Fact 9.1

30 464

31 Chapter Chapter 09

32 466 java.awt.event.actionevent java.awt.event.actionlistener actionperformed javax.swing.timer start C c = ;

33 Chapter I i = ; J j = ; c = i; // 1 j = c; // 2 i = j; // 3 C c = new C( ); I i = c; // 1 J j = (J)i; // 2 C d = (C)i; // 3 Chapter 09 Sandwich sub = new Sandwich( ); Edible e = sub; // 1 Rectangle cerealbox = new Rectangle(5, 10, 20, 30); Edible f = cerealbox; // 2 f = (Edible)cerealBox; // 3 sub = e; // 4 sub = (Sandwich)e; // 5 sub = (Sandwich)cerealBox; // 6

34 468 Rectangle getbounds( ) Shape s = ; Rectangle r = s.getbounds( );

35 Chapter public class T public void m(final int x, int y) int a; final int b; class C implements I public void f( ) Chapter 09 final int c; private int t;

36 470 public interface Filter boolean accept(object x); public interface Drawable void draw(graphics2d g2);

37 Chapter Date now = new Date( ); System.out.println(now); Chapter 09 public interface InputReader String readline(string prompt) throws IOException; public Coin readcoin(inputreader reader)

38 472

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