Hi guys i am working on a java car park simulation which controls the entry and departures of cars using the parking lot, the coding so far is below, but when i compile it i get 8 error messages, i have attached the errors message on the page...if anyone can tell me where i am going wrong.
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import java.awt.*;
import java.applet.*;
/*********************CARPARK CONTROL*****************************/
class CarParkControl {
protected int spaces;
protected int capacity;
CarParkControl(int n) {
capacity = spaces = n;
}
void arrive() throws InterruptedException {
// to do
--spaces;
}
void depart() throws InterruptedException {
// to do
++spaces;
}
}
/*******************ARRIVALS************************/
class Arrivals implements Runnable {
CarParkControl carpark;
Arrivals(CarParkControl c) {
carpark = c;
}
public void run() {
try {
while(true) {
ThreadPanel.rotate(330);
carpark.arrive();
ThreadPanel.rotate(30);
}
} catch (InterruptedException e){}
}
}
/********************DEPARTURES*******************************/
class Departures implements Runnable {
CarParkControl carpark;
Departures(CarParkControl c) {
carpark = c;
}
public void run() {
try {
while(true) {
ThreadPanel.rotate(180);
carpark.depart();
ThreadPanel.rotate(180);
}
} catch (InterruptedException e){}
}
}
/****************************APPLET**************************/
public class CarPark extends Applet {
final static int Places = 4;
ThreadPanel arrivals;
ThreadPanel departures;
CarParkCanvas carDisplay;
public void init() {
super.init();
// Set up Display
arrivals = new ThreadPanel("Arrivals",Color.blue);
departures = new ThreadPanel("Departures",Color.yellow);
carDisplay = new CarParkCanvas("CarPark",Places,this);
GridBagLayout gridbag = new GridBagLayout();
setLayout(gridbag);
GridBagConstraints gc = new GridBagConstraints();
gc.anchor = GridBagConstraints.NORTH;
gridbag.setConstraints(carDisplay, gc);
gridbag.setConstraints(arrivals, gc);
gridbag.setConstraints(departures, gc);
add(arrivals);
add(carDisplay);
add(departures);
}
public void start() {
CarParkControl c = new DisplayCarPark(carDisplay,Places);
arrivals.start(new Arrivals(c));
departures.start(new Departures(c));
}
public void stop() {
arrivals.stop();
departures.stop();
}
}
/**************************************************************/
class DisplayCarPark extends CarParkControl {
CarParkCanvas disp;
boolean occupied[];
DisplayCarPark(CarParkCanvas disp,int size) {
super(size);
this.disp = disp;
occupied = new boolean[size];
for (int i=0; i<size; i++) occupied[i]=false;
}
private void display() {
disp.setvalue(spaces,occupied);
}
synchronized public void arrive() throws InterruptedException {
super.arrive();
occupied[place(false)]=true;
display();
Thread.sleep(400);
}
synchronized public void depart() throws InterruptedException {
super.depart();
occupied[place(true)]=false;
display();
}
private int place(boolean v) {
int start = ((int)(Math.random() * 1000))% capacity;
for (int i =0; i<capacity; i++) {
int j = (start + i) % capacity;
if(occupied[j] == v) return j;
}
return 0; //should never happen
}
}
/**************************************************************/
class CarParkCanvas extends Canvas {
String title;
int slots;
int spaces;
boolean occupied[];
Applet applet;
Image car;
Font f1 = new Font("Helvetica",Font.ITALIC+Font.BOLD,24);
Font f2 = new Font("TimesRoman",Font.BOLD,36);
CarParkCanvas(String title, int slots, Applet applet) {
super();
this.title=title;
this.slots=slots;
spaces = slots;
this.applet = applet;
this.occupied = new boolean[slots];
for (int i=0; i<slots; i++) occupied[i] = false;
resize(20+50*slots,150);
setBackground(Color.cyan);
MediaTracker mt;
mt = new MediaTracker(this);
car = applet.getImage(applet.getDocumentBase(), "image/car.gif");
mt.addImage(car, 0);
try {
mt.waitForID(0);
} catch (java.lang.InterruptedException e) {
System.out.println("Couldn't load car image");
}
}
public void setvalue(int spaces, boolean occupied[]){
this.spaces = spaces;
this.occupied = occupied;
repaint();
}
public void paint(Graphics g) {
update(g);
}
Image offscreen;
Dimension offscreensize;
Graphics offgraphics;
public synchronized void update(Graphics g){
Dimension d = size();
if ((offscreen == null) || (d.width != offscreensize.width)
|| (d.height != offscreensize.height)) {
offscreen = createImage(d.width, d.height);
offscreensize = d;
offgraphics = offscreen.getGraphics();
offgraphics.setFont(getFont());
}
offgraphics.setColor(getBackground());
offgraphics.fillRect(0, 0, d.width, d.height);
// Display the title
offgraphics.setColor(Color.black);
offgraphics.setFont(f1);
FontMetrics fm = offgraphics.getFontMetrics();
int w = fm.stringWidth(title);
int h = fm.getHeight();
int x = (size().width - w)/2;
int y = h;
offgraphics.drawString(title, x, y);
offgraphics.drawLine(x,y+3,x+w,y+3);
// CarPark Places
y = h+10;
offgraphics.setColor(Color.white);
offgraphics.fillRect(10,y,50*slots,100);
offgraphics.setColor(Color.black);
for(int i=0; i<slots; i++) {
offgraphics.drawRect(10+50*i,y,50,100);
}
offgraphics.setColor(Color.white);
for(int i=1; i<slots; i++) {
offgraphics.drawLine(10+50*i,y+60,10+50*i,y+99);
}
//arrival gate
if (spaces==0)
offgraphics.setColor(Color.black);
else
offgraphics.setColor(Color.white);
offgraphics.fillRect(8,y+60,5,39);
//departure gate
if (spaces==slots)
offgraphics.setColor(Color.black);
else
offgraphics.setColor(Color.white);
offgraphics.fillRect(8+50*slots,y+60,5,39);
//Display Cars
offgraphics.setColor(Color.blue);
for (int i=0; i<slots; i++) {
if (occupied[i])
offgraphics.drawImage(car,15+50*i,y+5,this);
}
g.drawImage(offscreen, 0, 0, null);
}
}---------------------------------------------------------------------------------------------------
any advice appreaciated...cheers
tc.