1. Esempio: Tombola!

2. Random numbers package java.util; Random(long seed)
Creates a new random number generator using a single long seed
public int nextInt(int n)
Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

3. Banco package tombola; import java.util.*; public class Banco {
Random generatore;
Set numeriUsciti;
final int MAXNUM = 9;
public Banco() {
generatore = new Random(System.currentTimeMillis()/101);
numeriUsciti = new HashSet(); }

4. Banco int getNextNumber() { boolean isNew = false; int num = 0; do {
num = generatore.nextInt(MAXNUM) + 1;
isNew = numeriUsciti.add(new Integer(num));
System.out.println(num + " " + isNew); }
while (!isNew);
return num;

5. Banco private void test() { while (numeriUsciti.size() < MAXNUM) {
this.getNextNumber(); }
Iterator iter=numeriUsciti.iterator();
while (iter.hasNext()) {
System.out.println(iter.next());
public static void main(String[] args) {
Banco banco1 = new Banco();
banco1.test();

6. Banco 1 true 2 true 1 false 7 true 6 true 8 true 8 false 7 false4 8 6 1 3 7 5

7. Player package tombola; import java.util.*; public class Player {
Collection cartella;
Collection cartellaOriginale;
final int MAXNUM=9;
final int NCELLS=3;
String nome=null;
Player(String nome){this.nome=nome;}

8. Player void creaNuovaCartella(){
Random generatore = new Random(System.currentTimeMillis()/27);
cartella=new HashSet();
for (int i=1; i<=NCELLS; i++) {
boolean creatoNuovoNumero=false;
do {
int x=generatore.nextInt(MAXNUM)+1;
creatoNuovoNumero=cartella.add(new Integer(x));
} while (!creatoNuovoNumero); }
cartellaOriginale=new HashSet();
cartellaOriginale.addAll(cartella);

9. Player public boolean checkNumber(int x) {
boolean presente=cartella.remove(new Integer(x));
if (presente) {
System.out.println(nome+" ha il numero "+x); }
return presente;
public boolean isFinished() {
if (cartella.isEmpty()) {
System.out.println(nome+" ha finito!");
System.out.println("Aveva la seguente cartella:");
Iterator iter=cartellaOriginale.iterator();
while (iter.hasNext()) {
System.out.println(iter.next());
return true;
} else return false;

10. Player private void test() { this.creaNuovaCartella();
// elimina i numeri
for (int i=1; i<MAXNUM; i++) {
boolean res=checkNumber(i);
System.out.println(i+" "+res);
if (isFinished()) break; }
public static void main(String[] args) {
Player player1 = new Player("GIOVANNI");
player1.test();

11. Player C:\bin\JBuilderX\jdk1.4\bin\javaw tombola.Player
GIOVANNI ha il numero 1
1 true
2 false
GIOVANNI ha il numero 3
3 true
GIOVANNI ha il numero 4
4 true
GIOVANNI ha finito!
Aveva la seguente cartella: 4 1 3

12. Gioco public class Gioco { public Gioco() { Banco b1=new Banco();
Player p=new Player("Pippo");
p.creaNuovaCartella();
while (true) {
int x=b1.getNextNumber();
System.out.println("Numero estratto :"+x);
p.checkNumber(x);
if (p.hasFinished()) break; }
public static void main(String[] args) {
Gioco gioco1 = new Gioco();

13. Gioco Numero estratto :2
Pippo ha il numero 2
1 false
2 false
7 false
3 false
5 false
4 true
Numero estratto :4
Pippo ha il numero 4
Pippo ha finito!
Aveva la seguente cartella: 2 4 8
C:\bin\JBuilderX\jdk1.4\bin\javaw tombola.Gioco
3 true
Numero estratto :3
1 true
Numero estratto :1
3 false
5 true
Numero estratto :5
7 true
Numero estratto :7
8 true
Numero estratto :8
Pippo ha il numero 8
7 false
2 true

14. Gioco
Esercizio:
Modificare il codice aggiungendo altri giocatori

15. Javadoc

16. Input
/**
* Returns an Image object that can then be painted on the screen.
* The url argument must specify an absolute URL}. The name
* argument is a specifier that is relative to the url argument.
* <p>
* This method always returns immediately, whether or not the
* image exists. When this applet attempts to draw the image on
* the screen, the data will be loaded. The graphics primitives
* that draw the image will incrementally paint on the screen. *
url an absolute URL giving the base location of the image
name the location of the image, relative to the url argument
the image at the specified URL
Image */
public Image getImage(URL url, String name) {
try { return getImage(new URL(url, name));
} catch (MalformedURLException e) { return null; } }

17. Output getImage public Image getImage(URL url, String name)
Returns an Image object that can then be painted on the screen. The url argument must specify an absolute URL. The name argument is a specifier that is relative to the url argument. This method always returns immediately, whether or not the image exists. When this applet attempts to draw the image on the screen, the data will be loaded. The graphics primitives that draw the image will incrementally paint on the screen.
Parameters:
url - an absolute URL giving the base location of the image
name - the location of the image, relative to the url argument
Returns:
the image at the specified URL
See Also:
Image

18. Tags Include tags in the following order:
@author (classes and interfaces only, required)
@version (classes and interfaces only, required.)
@param (methods and constructors only)
@return (methods only)
@exception is a synonym added in Javadoc 1.2)
@see (additional references)
@since (since what version/ since when is it available?)
@serial
@deprecated (why is deprecated, since when, what to use)

19. Documentation generation
To generate the html documentation, run javadoc followed by the list of source files, which the documentation is to be generated for, in the command prompt (i.e. javadoc [files]).
javadoc also provides additional options which can be entered as switches following the javadoc command (i.e. javadoc [options] [files]).

20. javadoc options Here are some basic javadoc options:
-author - generated documentation will include a author section
-classpath [path] - specifies path to search for referenced .class files.
-classpathlist [path];[path];...;[path] - specifies a list locations (separated by ";") to search for referenced .class files.
-d [path] - specifies where generated documentation will be saved.
-private - generated documentation will include private fields and methods (only public and protected ones are included by default).
-sourcepath [path] - specifies path to search for .java files to generate documentation form.
-sourcepathlist [path];[path];...;[path] - specifies a list locations (separated by ";") to search for .java files to generate documentation form.
-version - generated documentation will include a version section

21. Examples
Basic example that generates and saves documentation to the current directory (c:\MyWork) from A.java and B.java in current directory and all .java files in c:\OtherWork\.
c:\MyWork> javadoc A.java B.java c:\OtherWork\*.java 
More complex example with the generated documentation showing version information and private members from all .java files in c:\MySource\ and c:\YourSource\ which references files in c:\MyLib and saves it to c:\MyDoc.
c:\> javadoc -version -private -d c:\MyDoc
-sourcepathlist c:\MySource;c:\YourSource\
-classpath c:\MyLib

22. More info
The javadoc tool does not directly document anonymous classes -- that is, their declarations and doc comments are ignored. If you want to document an anonymous class, the proper way to do so is in a doc comment of its outer class

23. Gioco
Esercizio:
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