I found a java code from this link.
and when I tried to run it the error class doesnt have a main method.I know this is a similiar post but I tried searching/trying for different solution but when I tried them they dont work. Below is the code
package trafficlight;
import javax.swing.*;
import java.awt.*;
public final class TrafficLight extends JPanel implements Runnable{
int redDuration, // Time (in seconds) for duration of red light
yellowDuration, // Time (in seconds) for duration of yellow light
greenDuration; // Time (in seconds) for duration of green light
PedestrianLight PL; // Associated coordinated pedestrian light
Color onLight; // To indicate which color light is on
int TLWidth = 0; // Width of traffic light
int TLHeight; // Height of traffic light
int xOrigin; // Coordinates of upper left-hand corner of
int yOrigin; // traffic light
int xLCoor; // x coordinate of lights
int yLCoor; // y coor of red light
int LDiam; // Diameter of each light
int interLSpace; // Space between lights
/*************************************
* Constructors
*************************************/
TrafficLight( PedestrianLight PL ) // One-parameter constructor
{
this.PL = PL;
onLight = Color.green;
redDuration = 15000; // Set red duration to 15 secs
yellowDuration = 5000; // Set yellow duration to 5 seconds
greenDuration = 15000; // Set green duration to 15 secs
}
TrafficLight( PedestrianLight PL,Color c ) // Two-parameter constructor
{
this.PL = PL;
setOnLight( c ); // Verify color setting
redDuration = 15000; // Set red duration to 15 secs
yellowDuration = 5000; // Set yellow duration to 5 seconds
greenDuration = 15000; // Set green duration to 15 secs
}
TrafficLight( PedestrianLight PL,int redDur,int yellowDur,int greenDur ){
this.PL = PL;
onLight = Color.green;
redDuration = 1000*redDur; // Duration params given in secs
yellowDuration = 1000*yellowDur; // Convert to milliseconds
greenDuration = 1000*greenDur;
}
/**************************************
* Setters and getters
* @return
**************************************/
public Color getOnLight()
{
return onLight;
}
public void setOnLight( Color c )
{
// Setters and constructors should insure that class variables
// are set to valid values.
if ( c == Color.red || c == Color.yellow || c == Color.green )
{
onLight = c;
}
else
{
System.out.println("TrafficLight.setOnLight: cannot set " +
"traffic light to color " + c +
"\nSetting color to default green.");
onLight = Color.green;
}
}
public void setColor( Color c ){
setOnLight( c );
repaint();
}
/************************************************
* Paint
************************************************/
@Override
public void paintComponent(Graphics g)
{
super.paintComponent( g ); // For background
System.out.println("Painting traffic light again");
if ( TLWidth == 0 ){
Dimension d = getSize(); // Get size of panel
System.out.println("d = " + d);
TLWidth = d.width/2; // Set width of traffic light
TLHeight = 3*d.height/4; // Set height of traffic light
xOrigin = (d.width - TLWidth)/2; // Center traffic light on panel
yOrigin = (d.height - TLHeight)/2;
LDiam = TLHeight/6; // Diameter of each light
xLCoor = xOrigin + (TLWidth - LDiam)/2; // x coordinate of lights
interLSpace = (TLHeight - 3*LDiam)/4; // Space between lights
yLCoor = yOrigin + interLSpace; // y coor of red light
}
Color colorSave = g.getColor(); // Save current color
//Draw outline of traffic light
g.setColor( Color.lightGray );
g.fill3DRect(xOrigin,yOrigin,TLWidth,TLHeight,true);
Color Red, Yellow, Green; // Colors to change light to
// Change the light
if ( onLight == Color.red ){
Red = turnOn( Color.red );
Yellow = turnOff( Color.yellow );
Green = turnOff( Color.green );
}
else if ( onLight == Color.yellow ){
Red = turnOff( Color.red );
Yellow = turnOn( Color.yellow );
Green = turnOff( Color.green );
}
else{
Red = turnOff( Color.red );
Yellow = turnOff( Color.yellow );
Green = turnOn( Color.green );
}
// Now color the lights. onLight is bright others are darkened.
g.setColor( Red );
g.fillOval(xLCoor,yLCoor,LDiam,LDiam);
g.setColor( Yellow );
g.fillOval(xLCoor,yLCoor+LDiam+interLSpace,LDiam,LDiam);
g.setColor( Green );
g.fillOval(xLCoor,yLCoor+2*LDiam+2*interLSpace,LDiam,LDiam);
// Now draw black outline around each light
g.setColor(Color.black);
// Red light
g.drawOval(xLCoor,yLCoor,LDiam,LDiam);
// Yellow light
g.drawOval(xLCoor,yLCoor+LDiam+interLSpace,LDiam,LDiam);
// Green light
g.drawOval(xLCoor,yLCoor+2*LDiam+2*interLSpace,LDiam,LDiam);
g.setColor(colorSave); // Restore original color
}
/************************************************
* Auxillary methods used by paintComponent
************************************************/
Color turnOn( Color c )
{ return c.brighter().brighter(); }
Color turnOff( Color c )
{ return c.darker().darker(); }
/************************************************
* run method as required by Runnable interface
************************************************/
@Override
public void run(){
System.out.println("Entering TrafficLight.run()");
long startTime;
PL.setMessage( "Don't Walk" );
while ( true )
{
setColor( Color.red ); // Change traffic light to red
try{
System.out.println( "TL.run() sleep for " + redDuration +
"milliseconds." );
Thread.sleep( redDuration );
}
catch ( InterruptedException e ) {}
startTime = System.currentTimeMillis();
setColor( Color.green ); // Change traffic light to green
PL.setMessage( "Walk" ); // Change ped light to "Walk"
try{ // Sleep for 2/3 green dur minus time
startTime += 2*greenDuration/3; // to change lights
Thread.sleep( Math.max( 0,startTime-System.currentTimeMillis() ) );
}
catch ( InterruptedException e ) {}
//PL.setMessage( "Don't Walk" ); // change ped light to "Don't Walk"
//PL.setFlashing( true ); // & start ped light flashing.
startTime = System.currentTimeMillis();
PL.setMessage( "Don't Walk",true ); //Atomize above two calls
try{
startTime += greenDuration/3; // Sleep 1/3 green duration
Thread.sleep( Math.max( 0,startTime-System.currentTimeMillis() ) );
}
catch ( InterruptedException e ) {}
startTime = System.currentTimeMillis();
PL.setFlashing( false ); // Chg ped light from flash to solid
setColor( Color.yellow ); // Change traffic light to yellow
try{
startTime += yellowDuration;
Thread.sleep( Math.max( 0,startTime-System.currentTimeMillis() ) );
}
catch ( InterruptedException e ) {}
}
}
private static class PedestrianLight {
public PedestrianLight() {
}
private void setFlashing(boolean b) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
private void setMessage(String dont_Walk, boolean b) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
private void setMessage(String walk) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
}
