Question

• If anyone could give me some guidance for these questions. I know i'm chancing my arm but its worth a shot.... Thanks in advance
• • i.Write a private instance method cycleState() which takes no argument and returns no value. This method cycles the value of state, from 1 to 2, from 2 to 3, from 3 to 4 and from 4 back to 1 again. (Note that the value of 0 for state is not part of this cycle).
  • ii.Write a private instance method colourAllLights() which takes no argument and returns no value. This method uses the value of state to determine what colour each of the four lights should be set to, and sets their colours accordingly. This includes the initial state of 0.
  • iii.Add a line to the constructor to set the colours of all the lights initially. Make sure you make appropriate re-use of a method you’ve written.

This is the code so far:

public class TrafficSystem
{
// given instance variables for the four lights
private TrafficLight north;
private TrafficLight south;
private TrafficLight east;
private TrafficLight west;

public void colourLight(TrafficLight aLight, OUColour aColour) // as aLight is a TrafficLight variable and aColour is a OUColour varaiable
{
aLight.setColour(aColour);
}

private int state; //This is the state variable

public TrafficSystem (TrafficLight north,TrafficLight south,TrafficLight east,TrafficLight west) //This is the constructor which takes the four TrafficLight references for each direction
{
this.north=north;
this.south=south;
this.east=east;
this.west=west;
this.state=0; //sets state to 0
this.setPositions(); //calls the setPositions() to initiate the positions

}




private void setPositions() // provided method
{
north.setXPos(100);
north.setYPos(0);
south.setXPos(100);
south.setYPos(200);
west.setXPos(0);
west.setYPos(100);
east.setXPos(200);
east.setYPos(100);
}

/**
* Provided method without try catch or the checking for 0-4 state.
* Extra functionality is to be added to deal with non-integer
* or out of range inputs
*/
public void manualOverride()
{
// if (!go)
// {
int newState = Integer.parseInt(OUDialog.request("Please give the state you want to change to - between 0 and 4 inclusive"));
// state = newState;
// colourAllLights();
// }
}

/**
* causes execution to pause by time number of milliseconds
*/
public void delay(int time)
{
try
{
Thread.sleep(time);
}
catch (Exception e)
{
System.out.println(e);
}
}

}

Trafficlight class you wanted:

public class TrafficLight
{
private Circle light;

/**
* Constructor for objects of class TrafficLight
*/
public TrafficLight(Circle aCircle)
{
light = aCircle;
light.setColour(OUColour.RED);
light.setDiameter(50);
}

  

/**
* setColour just sets the colour of the light as told to
* 0 = red, 1 = green, 2 = orange
*/
public void setColour(OUColour colour)
{
light.setColour(colour);
}

/**
* setter for x position
*/
public void setXPos(int xPos)
{
light.setXPos(xPos);
}

/**
* setter for y position
*/
public void setYPos(int yPos)
{
light.setYPos(yPos);
}

and for the different states at the junctions i need:

cycling state	North and south	East and west
1	Green	Red
2	Orange	Red
3	Red	Green
4	Red	Orange
1	Green	Red

Answer 1

I have added code for all the 3 questions mentioned in the question. I have mentioned all the details in the comments.

Please find the code below:

TrafficSystem.java

public class TrafficSystem
{
    // given instance variables for the four lights
    private TrafficLight north;
    private TrafficLight south;
    private TrafficLight east;
    private TrafficLight west;

    //method cycleState to change the state
    private void cycleState(){
        //if state is less then 4 then go to the next state
        if(state<4){
            state++;
        }
        //else reset it to the 1
        else{
            state = 1;
        }
    }

    private void colourAllLights(){
        //based on the value of the state switch case would be executed
        switch(state){
            case 0:
                north.setColour(OUColour.RED);
                south.setColour(OUColour.RED);
                east.setColour(OUColour.RED);
                west.setColour(OUColour.RED);
                break;
            case 1:
                north.setColour(OUColour.GREEN);
                south.setColour(OUColour.GREEN);
                east.setColour(OUColour.RED);
                west.setColour(OUColour.RED);
                break;
            case 2:
                north.setColour(OUColour.ORANGE);
                south.setColour(OUColour.ORANGE);
                east.setColour(OUColour.RED);
                west.setColour(OUColour.RED);
                break;
            case 3:
                north.setColour(OUColour.RED);
                south.setColour(OUColour.RED);
                east.setColour(OUColour.GREEN);
                west.setColour(OUColour.GREEN);
                break;
            case 4:
                north.setColour(OUColour.RED);
                south.setColour(OUColour.RED);
                east.setColour(OUColour.ORANGE);
                west.setColour(OUColour.ORANGE);
                break;
        }
    }

    public void colourLight(TrafficLight aLight, OUColour aColour) // as aLight is a TrafficLight variable and aColour is a OUColour varaiable
    {
        aLight.setColour(aColour);
    }


    private int state; //This is the state variable


    public TrafficSystem (TrafficLight north,TrafficLight south,TrafficLight east,TrafficLight west) //This is the constructor which takes the four TrafficLight references for each direction
    {
        this.north=north;
        this.south=south;
        this.east=east;
        this.west=west;
        this.state=0; //sets state to 0
        //lies to set initially all the lights to RED
        this.north.setColour(OUColour.RED);
        this.south.setColour(OUColour.RED);
        this.east.setColour(OUColour.RED);
        this.west.setColour(OUColour.RED);
        this.setPositions(); //calls the setPositions() to initiate the positions

    }
    
    private void setPositions() // provided method
    {
        north.setXPos(100);
        north.setYPos(0);
        south.setXPos(100);
        south.setYPos(200);
        west.setXPos(0);
        west.setYPos(100);
        east.setXPos(200);
        east.setYPos(100);
    }

    /**
     * Provided method without try catch or the checking for 0-4 state.
     * Extra functionality is to be added to deal with non-integer
     * or out of range inputs
     */
    public void manualOverride()
    {
// if (!go)
// {
        int newState = Integer.parseInt(OUDialog.request("Please give the state you want to change to - between 0 and 4 inclusive"));
// state = newState;
// colourAllLights();
// }
    }

    /**
     * causes execution to pause by time number of milliseconds
     */
    public void delay(int time)
    {
        try
        {
            Thread.sleep(time);
        }
        catch (Exception e)
        {
            System.out.println(e);
        }
    }

}
I am assuming that you have your own class library where OUColour is implemented.