List of Chapters
Chapter 14: Sharing Names among the Parts of a Java Program
In this chapter:
<![CDATA[
class SomeClass {
private int myField = 10;
public int getMyField() {
return myField;
}
public void setMyField(int myField) {
this.myField = myField;
}
}
class SomeOtherClass {
public static void main(String[] args) {
var someObject = new SomeClass();
System.out.println(someObject.getMyField());
}
}
]]>
<![CDATA[
package com.burdbrain.drawings;
import java.awt.Color;
import java.awt.Graphics;
public class Drawing {
public int x = 40, y = 40, width = 40, height = 40;
enum State {
GREEN, YELLOW, RED
}
State state = State.GREEN;
public void paint(Graphics g) {
switch (state) {
case GREEN -> {
showGreen(g, false);
showYellow(g, true);
state = State.YELLOW;
}
case YELLOW -> {
showYellow(g, false);
showRed(g, true);
state = State.RED;
}
case RED -> {
showRed(g, false);
showGreen(g, true);
state = State.GREEN;
}
}
}
void showGreen(Graphics g, boolean t) {
g.setColor(t ? Color.GREEN : Color.WHITE);
g.fillOval(x, y + 100, width, height);
}
void showYellow(Graphics g, boolean t) {
g.setColor(t ? Color.YELLOW : Color.WHITE);
g.fillOval(x, y + 50, width, height);
}
void showRed(Graphics g, boolean t) {
g.setColor(t ? Color.RED : Color.WHITE);
g.fillOval(x, y, width, height);
}
}
package com.burdbrain.frames;
import java.awt.Graphics;
import javax.swing.JFrame;
import com.burdbrain.drawings.Drawing;
public class ArtFrame extends JFrame {
private static final long serialVersionUID = 1L;
Drawing drawing;
public ArtFrame(Drawing drawing) {
this.drawing = drawing;
setTitle("Abstract Art");
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public void paint(Graphics g) {
drawing.paint(g);
}
}
import com.burdbrain.drawings.Drawing;
import com.burdbrain.frames.ArtFrame;
class ShowFrame {
public static void main(String[] args) {
var artFrame = new ArtFrame(new Drawing());
artFrame.setSize(60, 200);
artFrame.setVisible(true);
while (true) {
try {
Thread.sleep(10000);
artFrame.repaint();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
]]>
<![CDATA[
public class Book {
private String title;
private Author author;
public Book(String title, Author author) {
this.title = title;
this.author = author;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Author getAuthor() {
return author;
}
public void setAuthor(Author author) {
this.author = author;
}
}
import java.util.ArrayList;
public class Author {
private String name;
private ArrayList<Book> books = new ArrayList<>();
public Author(String name) {
this.name = name;
}
public void display() {
System.out.println(name);
for (Book book : books) {
System.out.println(book.getTitle());
}
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public ArrayList<Book> getBooks() {
return books;
}
public void setBooks(ArrayList<Book> books) {
this.books = books;
}
}
public class Main {
public static void main(String[] args) {
var dickens = new Author("Charles Dickens");
var greatExpectations = new Book("Great Expectations", dickens);
var taleOfTwoCities = new Book("Tale of Two Cities", dickens);
dickens.getBooks().add(greatExpectations);
dickens.getBooks().add(taleOfTwoCities);
dickens.display();
}
}
]]>
<![CDATA[
public enum Genre {
ROCK, POP, BLUES, CLASSICAL
}
import java.util.ArrayList;
public class Artist {
private String name;
private ArrayList<Item> items = new ArrayList<>();
public Artist(String name) {
super();
this.name = name;
}
public String getString() {
return name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public ArrayList<Item> getItems() {
return items;
}
public void add(Item item) {
items.add(item);
}
}
public class Item {
private String name;
private Artist artist;
public Item(String name, Artist artist) {
this.name = name;
this.artist = artist;
}
public String getString() {
return name + ", " + artist.getString() + "\n";
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Artist getArtist() {
return artist;
}
public void setArtist(Artist artist) {
this.artist = artist;
}
public String toString() {
return (name + " " + artist.getName());
}
}
public class Song extends Item {
private Genre genre;
public Song(String name, Artist artist, Genre genre) {
super(name, artist);
this.genre = genre;
}
public String getString() {
return
getName() + ", " + getArtist().getString() + ", " + genre + "\n";
}
public Genre getGenre() {
return genre;
}
public void setGenre(Genre genre) {
this.genre = genre;
}
@Override
public String toString() {
String string = super.toString() + " ";
string += genre;
return string;
}
}
import java.util.ArrayList;
public class Album extends Item {
private ArrayList<Song> songs = new ArrayList<>();
public Album(String name, Artist artist) {
super(name, artist);
}
public String getString() {
String string = getName() + "\n";
for (Song song : songs) {
string += " " + song.getString();
}
return string;
}
public ArrayList<Song> getSongs() {
return songs;
}
public void add(Song song) {
songs.add(song);
}
@Override
public String toString() {
String string = super.toString() + " ";
for (Song song : songs) {
string += song.toString() + " ";
}
return string;
}
}
import java.util.ArrayList;
public class Playlist {
private ArrayList<Item> items = new ArrayList<>();
public String getString() {
String string = "";
for (Item item : items) {
string += item.getString();
}
return string;
}
public void addItem(Item item) {
items.add(item);
}
public ArrayList<Item> getItems() {
return items;
}
public void setItems(ArrayList<Item> items) {
this.items = items;
}
}
public class SongsAndAlbumsTest {
public static void main(String[] args) {
var john = new Artist("Elton John");
Item rocketMan = new Item("Rocket Man", john);
var bach = new Artist("J.S. Bach");
var wellTemperedClavier =
new Song("Well Tempered Clavier", bach, Genre.CLASSICAL);
bach.add(wellTemperedClavier);
var tocataAndFugue =
new Song("Tocata and Fugue", bach, Genre.CLASSICAL);
bach.add(tocataAndFugue);
var joel = new Artist("Billy Joel");
var movinOut = new Song("Movin' Out", joel, Genre.POP);
joel.add(movinOut);
var justTheWayYouAre =
new Song("Just the Way You Are", joel, Genre.POP);
joel.add(justTheWayYouAre);
var stranger = new Album("The Stranger", joel);
stranger.add(movinOut);
stranger.add(justTheWayYouAre);
joel.add(stranger);
var playlist = new Playlist();
playlist.addItem(stranger);
playlist.addItem(rocketMan);
playlist.addItem(wellTemperedClavier);
playlist.addItem(tocataAndFugue);
System.out.println(playlist.getString());
}
}
]]>
<![CDATA[
package com.mypackage.things;
import com.yourpackage.stuff.Stuff;
import com.yourpackage.stuff.morestuff.MoreStuff;
public class Things {
protected int i = 0;
protected int j = 0;
int k = 0;
public static void main(String[] args) {
var stuff = new Stuff();
System.out.println(stuff.i);
var moreStuff = new MoreStuff();
System.out.println(moreStuff.i);
}
}
package com.yourpackage.stuff;
import com.yourpackage.stuff.morestuff.MoreStuff;
public class Stuff {
public int i = 0;
void aMethod() {
new MoreStuff().myMethod();
}
}
package com.yourpackage.stuff.morestuff;
import com.mypackage.things.Things;
public class MoreStuff extends Things {
public void myMethod() {
System.out.println(i);
}
}
package com.mypackage.things;
public class MoreThings extends Things {
public void anotherMethod() {
System.out.println(i);
System.out.println(j);
System.out.println(k);
}
}
]]>