BA Karlsruhe, Vorlesung Programmieren, „Threads“

DHBW Karlsruhe, Vorlesung Programmieren, „Threads“ (1)
Musterlösungen
Aufgabe 1 „Ampel” (Lösung 1)
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JApplet;
public class Ampel extends JApplet implements Runnable {
private Ampelphase[] phasen;
private Ampelphase aktuellePhase;
private Thread thread;
@Override public void init() {
phasen = new Ampelphase[4];
phasen[3] = new Ampelphase("Rotgelb", true, true, false, 1);
phasen[2] = new Ampelphase("Rot", true, false, false, 10, phasen[3]);
phasen[1] = new Ampelphase("Gelb", false, true, false, 2, phasen[2]);
phasen[0] = new Ampelphase("Grün", false, false, true, 10, phasen[1]);
phasen[3].setNext(phasen[0]);
aktuellePhase = phasen[0];
}
public void run() {
while (true)
try {
this.repaint();
Thread.sleep(aktuellePhase.getDuration() * 500);
aktuellePhase = aktuellePhase.getNext();
} catch (InterruptedException ex) {}
}
@Override public void stop() {
if (thread != null) thread = null;
}
@Override public void start() {
if (thread == null) {
thread = new Thread(this);
thread.start();
}
}
}
@Override public void paint(Graphics g) {
g.setColor(Color.BLACK);
g.fillRect(10, 10, 80, 195);
g.setColor(Color.WHITE);
g.fillOval(23, 23, 54, 54);
g.fillOval(23, 83, 54, 54);
g.fillOval(23, 143, 54, 54);
g.setColor(Color.RED);
if (aktuellePhase.isRed()) g.fillOval(25, 25, 50, 50);
g.setColor(Color.YELLOW);
if (aktuellePhase.isYellow()) g.fillOval(25, 85, 50, 50);
g.setColor(Color.GREEN);
if (aktuellePhase.isGreen()) g.fillOval(25, 145, 50, 50);
}

public class Ampelphase {
}
private String name;
private boolean red;
private boolean yellow;
private boolean green;
private int duration;
private Ampelphase next;
public Ampelphase(String name, boolean red, boolean yellow, boolean green,
int duration, Ampelphase next) {
this.name=name;
this.red=red;
this.yellow=yellow;
this.green=green;
this.duration=duration;
this.next=next;
}
public Ampelphase(String name, boolean red, boolean yellow, boolean green,
int duration) {
this.name=name;
this.red=red;
this.yellow=yellow;
this.green=green;
this.duration=duration;
this.next=null;
}
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public boolean isRed() { return red; }
public void setRed(boolean red) { this.red = red; }
public boolean isYellow() { return yellow; }
public void setYellow(boolean yellow) { this.yellow = yellow; }
public boolean isGreen() { return green; }
public void setGreen(boolean green) { this.green = green; }
public int getDuration() { return duration; }
public void setDuration(int duration) { this.duration = duration; }
public Ampelphase getNext() { return next; }
public void setNext(Ampelphase next) { this.next = next; }

Aufgabe 1 „Ampel” (Lösung 2 mit enum)
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JApplet;
public class Ampel extends JApplet implements Runnable {
}
private int state = 0;
private Thread thread;
@Override
public void run() {
while (true)
try {
state = (++state) % Ampelphase.values().length;
this.repaint();
Thread.sleep(Ampelphase.values()[state].getDuration() * 500);
} catch (InterruptedException ex) {}
}
@Override public void stop() {
if (thread != null) thread = null;
}
@Override public void start() {
if (thread == null) {
thread = new Thread(this);
thread.start();
}
}
@Override public void paint(Graphics g) {
Ampelphase a = Ampelphase.values()[state];
g.setColor(Color.BLACK);
g.fillRect(10, 10, 80, 195);
g.setColor(Color.WHITE);
g.fillOval(23, 23, 54, 54);
g.fillOval(23, 83, 54, 54);
g.fillOval(23, 143, 54, 54);
g.setColor(Color.RED);
if (a.isRed()) g.fillOval(25, 25, 50, 50);
g.setColor(Color.YELLOW);
if (a.isYellow()) g.fillOval(25, 85, 50, 50);
g.setColor(Color.GREEN);
if (a.isGreen()) g.fillOval(25, 145, 50, 50);
}

public enum Ampelphase {
}
GRUEN("Grün",false,false,true,10),
GELB("Gelb",false,true,false,2),
ROT("Rot",true,false,false,10),
GELBROT("Gelbrot",true,true,false,1);
private String name;
private boolean red;
private boolean yellow;
private boolean green;
private int duration;
Ampelphase(String name, boolean red, boolean yellow,
boolean green, int duration) {
this.name=name;
this.red=red;
this.yellow=yellow;
this.green=green;
this.duration=duration;
}
public String getName() { return name; }
public void setName(String name) { this.name = name; }
public boolean isRed() { return red; }
public void setRed(boolean red) { this.red = red; }
public boolean isYellow() { return yellow; }
public void setYellow(boolean yellow) { this.yellow = yellow; }
public boolean isGreen() { return green; }
public void setGreen(boolean green) { this.green = green; }
public int getDuration() { return duration; }
public void setDuration(int duration) { this.duration = duration; }

Aufgabe 2 „Tanzende Schrift” (Lösung A)
import javax.swing.JApplet;
import java.awt.*;
public class Schrift extends JApplet implements Runnable {
}
int red, green, blue, x, y;
int sleep = 50;
String text = "Mein Name";
Thread t;
@Override
public void init() {
red = (int) (Math.random()*256);
green = (int) (Math.random()*256);
blue = (int) (Math.random()*256);
x = this.getWidth() / 3;
y = this.getHeight() / 2;
t = new Thread(this);
t.start();
}
public void run() {
while (true) {
try {
x = newRandomN(x,0,this.getWidth()-200,6);
y = newRandomN(y,24,this.getHeight(),6);
repaint();
Thread.sleep(sleep);
} catch (InterruptedException ex) { }
}
}
@Override
public void paint(Graphics g) {
g.setColor(Color.WHITE); // vorherigen Fensterinhalt löschen
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setFont(new Font("Arial",Font.BOLD,30));
for (int i=0;i

Aufgabe 2 „Tanzende Schrift” (Lösung B)
import javax.swing.JApplet;
import java.awt.*;
public class TanzendeSchrift extends JApplet implements Runnable {
static Color[] Palette = {Color.black, Color.blue, Color.cyan, Color.darkGray,
Color.gray, Color.green, Color.magenta, Color.orange, Color.pink,
Color.red, Color.white, Color.yellow
};
Thread thread;
@Override
public void start() {
if (thread == null) {
setSize(220, 100);
thread = new Thread(this, "Schrift");
thread.start();
}
}
public void run() {
while (thread != null)
try {
repaint();
Thread.sleep(200);
} catch (InterruptedException e) { }
}
@Override
public void paint(Graphics g) {
g.setColor(Color.WHITE); // vorherigen Fensterinhalt löschen
g.fillRect(0, 0, this.getWidth(), this.getHeight());
char text[] = "Tanzende Schrift".toCharArray();
g.setFont(new Font("Helvetica", Font.BOLD, 20));
FontMetrics m = g.getFontMetrics();
int height = m.getHeight() + 5;
int width = m.charWidth(text[0]);
for (int i = 1; i < text.length; i++)
if (m.charWidth(text[i]) > width)
width = m.charWidth(text[i]);
for (int i = 0; i < text.length; i++) {
int start = (int) Math.round(20 * Math.random());
g.setColor(Palette[start % Palette.length]);
g.drawChars(text, i, 1, i * width, height + start);
}
}
}
@Override
public void stop() {
if (thread != null) {
thread = null;
}
}