Thread: Issues With Layout And Time Being Display

Currently doing an assignment for college that involves displaying multiple "clocks" on screen depending on how many cities are selected from a list.

I have most of it built I believe but I am having a couple of issues that I hope someone can give me advice on.

1. Having selected a couple of cities from the list, when I press the "+" button on the display they get added to the list horizontally. I am trying to get them to be added vertically. I believe I have set the layout to a grid layout with 1 column and a number of rows depending on how many cities are selected from the list so not sure why that is happening.

2. What I am trying to achieve is that when the "+" button is pressed, the panel that is going to contain the "clocks" is wipped clear and only the cities that I have selected are going to have their "clocks" displayed. Can you achieve this with a jpanel? I know I could do something like this with a jtextarea by setting the text to an empty string. Is there something similar for a jpanel?

3. When I have multiple clocks being displayed, only the last clock added updates its time. I want all the clocks that I have displayed to be ticking away when displayed. Can you point me in the right direction as to what I am leaving out of the code to achieve this?

I have though about building a clock interface for each of the cities in advance and setting them visible / invisible as needed but I want to be able to add cities to the list without having to also go and build a clock for that city.

Any help or advice would be much appreciated.

This is what I have done with my code so far...

import java.awt.*;  
import javax.swing.*;  
import java.awt.event.*;  
import javax.swing.event.*;  
import java.util.Date;  
import java.text.SimpleDateFormat;  
 
public class AssignmentV1 implements ActionListener/*,ListSelectionListener*/ 
{ 
    private String [] cities; 
    private JButton addBtn; 
    private JButton minusBtn; 
    private JList cityList; 
    private JPanel right; 
    private JPanel displayArea;
    private JPanel [] clockDisplay;
    private long currentTime;
    private long cityTime;
    private int hourDiff;
    private String cityName;
    private String timeInFormat;
    private JLabel time;
    private JPanel topRight;
    public AssignmentV1() 
    { 
        JFrame appWin = new JFrame("World Time");  
        appWin.setSize(400,400);  
        appWin.setLocationRelativeTo(null);  
        appWin.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
 
        Font preferredFont = new Font("OCR A EXTENDED",Font.BOLD,50);  
 
        Container contentPane =appWin.getContentPane();  
 
        displayArea = new JPanel();  
        displayArea.setLayout(new GridLayout(1,2));  
 
        JPanel left = new JPanel();  
        left.setLayout(new GridLayout(2,1));  
 
        JPanel topLeft = new JPanel();  
        topLeft.setLayout(new FlowLayout(FlowLayout.CENTER));  
        //adding of +/- buttons to display 
        addBtn = new JButton();  
        addBtn.setText("+");  
        addBtn.addActionListener(this);  
        topLeft.add(addBtn);  
        minusBtn = new JButton();  
        minusBtn.setText("-");
        minusBtn.addActionListener(this);  
        topLeft.add(minusBtn);  
        left.add(topLeft);  
 
        //adding of list of cities to a scrollpane to add to display    
        JPanel bottomLeft=new JPanel(); 
 
        setUpCities(); 
        cityList=new JList(cities);    
        cityList.setSelectedIndex(0); 
        cityList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION); 
        JScrollPane scrollableList = new JScrollPane(cityList);  
        bottomLeft.add(scrollableList);  
        left.add(bottomLeft);  
 
        right = new JPanel();
        topRight = new JPanel();
        clockDisplay = new JPanel[1];
        topRight.setLayout(new GridLayout(clockDisplay.length,1));
        for(int i=0;i<clockDisplay.length;i++)
        {
            clockDisplay[i]=new JPanel();
            cityName = cities[0].substring(0,cities[0].indexOf(","));
            hourDiff=Integer.parseInt(cities[0].substring(cities[0].indexOf(",")+1));
            currentTime = System.currentTimeMillis();
            cityTime = System.currentTimeMillis()+(1000*60*60*hourDiff);
            clockDisplay[i].setBorder(BorderFactory.createTitledBorder(cityName));
            time = new JLabel();
            time.setOpaque(true);
            timeInFormat = textAsTime(cityTime);
            time.setText(timeInFormat);
            clockDisplay[i].add(time);
            topRight.add(clockDisplay[i]);
        }
        right.add(topRight);
 
 
        displayArea.add(left);  
        displayArea.add(right);  
        contentPane.add(displayArea);   
        Timer t= new Timer(1000,this);
        t.start();
        appWin.setVisible(true);
 
    } 
    public void actionPerformed(ActionEvent e)  
    {
        cityTime=cityTime+1000;
        timeInFormat=textAsTime(cityTime);
        time.setText(timeInFormat);
 
        Object [] obj = cityList.getSelectedValues();
        Object source=e.getSource();
        if(source==addBtn)
        {
            right.setLayout(new GridLayout(obj.length,1));
            clockDisplay = new JPanel[obj.length];
            topRight.setLayout(new GridLayout(obj.length,1));
            for(int i=0;i<obj.length;i++)
            {
                String temp = (String)obj[i];
                clockDisplay[i]=new JPanel();
                cityName = temp.substring(0,temp.indexOf(","));
                hourDiff=Integer.parseInt(temp.substring(temp.indexOf(",")+1));
                currentTime = System.currentTimeMillis();
                cityTime = System.currentTimeMillis()+(1000*60*60*hourDiff);
                clockDisplay[i].setBorder(BorderFactory.createTitledBorder(cityName));
                time = new JLabel();
                time.setOpaque(true);
                timeInFormat = textAsTime(cityTime);
                time.setText(timeInFormat);
                clockDisplay[i].add(time);
                topRight.add(clockDisplay[i]);
            }
            right.add(topRight);
        }
    }
    public void setUpCities() 
    { 
       cities = new String []{"Accra,0","Addis Abada,+3","Adelaide,+11","Algiers,-1","Almaty,+6","Amman,+3","Amsterdam,+1","Anadyr,+12","Anchorage,-8","Ankara,+2","London,0","Paris,+1"};         
    } 
    public String textAsTime(long currentTime)  
    {  
        long second = (currentTime / 1000) % 60; 
        long minute = (currentTime / (1000 * 60)) % 60; 
        long hour = (currentTime / (1000 * 60 * 60)) % 24; 
        return String.format("%02d:%02d:%02d",hour,minute,second);  
    }        
}

sorry, haven't created one yet, using BlueJ and just creating new instances of it

updated with a main method now...

import java.awt.*;  
import javax.swing.*;  
import java.awt.event.*;  
import javax.swing.event.*;  
import java.util.Date;  
import java.text.SimpleDateFormat;  
 
public class AssignmentV1 implements ActionListener/*,ListSelectionListener*/ 
{ 
    private String [] cities; 
    private JButton addBtn; 
    private JButton minusBtn; 
    private JList cityList; 
    private JPanel right; 
    private JPanel displayArea;
    private JPanel [] clockDisplay;
    private long currentTime;
    private long cityTime;
    private int hourDiff;
    private String cityName;
    private String timeInFormat;
    private JLabel time;
    private JPanel topRight;
    public AssignmentV1() 
    { 
        JFrame appWin = new JFrame("World Time");  
        appWin.setSize(400,400);  
        appWin.setLocationRelativeTo(null);  
        appWin.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
 
        Font preferredFont = new Font("OCR A EXTENDED",Font.BOLD,50);  
 
        Container contentPane =appWin.getContentPane();  
 
        displayArea = new JPanel();  
        displayArea.setLayout(new GridLayout(1,2));  
 
        JPanel left = new JPanel();  
        left.setLayout(new GridLayout(2,1));  
 
        JPanel topLeft = new JPanel();  
        topLeft.setLayout(new FlowLayout(FlowLayout.CENTER));  
        //adding of +/- buttons to display 
        addBtn = new JButton();  
        addBtn.setText("+");  
        addBtn.addActionListener(this);  
        topLeft.add(addBtn);  
        minusBtn = new JButton();  
        minusBtn.setText("-");
        minusBtn.addActionListener(this);  
        topLeft.add(minusBtn);  
        left.add(topLeft);  
 
        //adding of list of cities to a scrollpane to add to display    
        JPanel bottomLeft=new JPanel(); 
 
        setUpCities(); 
        cityList=new JList(cities);    
        cityList.setSelectedIndex(0); 
        cityList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION); 
        JScrollPane scrollableList = new JScrollPane(cityList);  
        bottomLeft.add(scrollableList);  
        left.add(bottomLeft);  
 
        right = new JPanel();
        topRight = new JPanel();
        clockDisplay = new JPanel[1];
        topRight.setLayout(new GridLayout(clockDisplay.length,1));
        for(int i=0;i<clockDisplay.length;i++)
        {
            clockDisplay[i]=new JPanel();
            cityName = cities[0].substring(0,cities[0].indexOf(","));
            hourDiff=Integer.parseInt(cities[0].substring(cities[0].indexOf(",")+1));
            currentTime = System.currentTimeMillis();
            cityTime = System.currentTimeMillis()+(1000*60*60*hourDiff);
            clockDisplay[i].setBorder(BorderFactory.createTitledBorder(cityName));
            time = new JLabel();
            time.setOpaque(true);
            timeInFormat = textAsTime(cityTime);
            time.setText(timeInFormat);
            clockDisplay[i].add(time);
            topRight.add(clockDisplay[i]);
        }
        right.add(topRight);
 
 
        displayArea.add(left);  
        displayArea.add(right);  
        contentPane.add(displayArea);   
        Timer t= new Timer(1000,this);
        t.start();
        appWin.setVisible(true);
 
    } 
    public void actionPerformed(ActionEvent e)  
    {
        cityTime=cityTime+1000;
        timeInFormat=textAsTime(cityTime);
        time.setText(timeInFormat);
 
        Object [] obj = cityList.getSelectedValues();
        Object source=e.getSource();
        if(source==addBtn)
        {
            right.setLayout(new GridLayout(obj.length,1));
            clockDisplay = new JPanel[obj.length];
            topRight.setLayout(new GridLayout(obj.length,1));
            for(int i=0;i<obj.length;i++)
            {
                String temp = (String)obj[i];
                clockDisplay[i]=new JPanel();
                cityName = temp.substring(0,temp.indexOf(","));
                hourDiff=Integer.parseInt(temp.substring(temp.indexOf(",")+1));
                currentTime = System.currentTimeMillis();
                cityTime = System.currentTimeMillis()+(1000*60*60*hourDiff);
                clockDisplay[i].setBorder(BorderFactory.createTitledBorder(cityName));
                time = new JLabel();
                time.setOpaque(true);
                timeInFormat = textAsTime(cityTime);
                time.setText(timeInFormat);
                clockDisplay[i].add(time);
                topRight.add(clockDisplay[i]);
            }
            right.add(topRight);
        }
    }
    public void setUpCities() 
    { 
       cities = new String []{"Accra,0","Addis Abada,+3","Adelaide,+11","Algiers,-1","Almaty,+6","Amman,+3","Amsterdam,+1","Anadyr,+12","Anchorage,-8","Ankara,+2","London,0","Paris,+1"};         
    } 
    public String textAsTime(long currentTime)  
    {  
        long second = (currentTime / 1000) % 60; 
        long minute = (currentTime / (1000 * 60)) % 60; 
        long hour = (currentTime / (1000 * 60 * 60)) % 24; 
        return String.format("%02d:%02d:%02d",hour,minute,second);  
    }
    public static void main(String [] args)
    {
        new AssignmentV1();
    }
}

at the moment they are not.
are you suggesting about adding the individual times to a list as they are generated in the actionPerformed method?
and then perform the an update on them ie (+1000 milliseconds)
I will try that and see if helps.
Thanks

I was using it so that I could use the same reference to the array for when I had multiple selections.

I have moved the creation of the lists to the constructor, I am thinking that I will also need a list of the strings that are going to be inserted into the labels, that way I can update them when I update the time of the selected cities, would this be correct?

sorry for not responding, thank you very much for your help.
I have added another arraylist of JLabels that will hold all the jlabels as they are created in the for loop in the actionPerformed method.

import java.awt.*;
import java.util.ArrayList; 
import javax.swing.*;  
import java.awt.event.*;  
import javax.swing.event.*;  
import java.util.Date;  
import java.text.SimpleDateFormat;  
 
public class AssignmentV1 implements ActionListener/*,ListSelectionListener*/ 
{ 
    private String [] cities; 
    private JButton addBtn; 
    private JButton minusBtn; 
    private JList cityList; 
    private JPanel right; 
    private JPanel displayArea;
    private JPanel [] clockDisplay;
    private long currentTime;
    private long cityTime;
    private int hourDiff;
    private String cityName;
    private String timeInFormat;
    private JLabel time;
    private JPanel topRight;
    private ArrayList<String> cityNamesList;
    private ArrayList<Long> cityTimes;
    private ArrayList<JLabel> cityLabels;
    public AssignmentV1() 
    { 
        JFrame appWin = new JFrame("World Time");  
        appWin.setSize(400,400);  
        appWin.setLocationRelativeTo(null);  
        appWin.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  
 
        Font preferredFont = new Font("OCR A EXTENDED",Font.BOLD,50);  
 
        Container contentPane =appWin.getContentPane();  
 
        displayArea = new JPanel();  
        displayArea.setLayout(new GridLayout(1,2));  
 
        JPanel left = new JPanel();  
        left.setLayout(new GridLayout(2,1));  
 
        JPanel topLeft = new JPanel();  
        topLeft.setLayout(new FlowLayout(FlowLayout.CENTER));  
        //adding of +/- buttons to display 
        addBtn = new JButton();  
        addBtn.setText("+");  
        addBtn.addActionListener(this);  
        topLeft.add(addBtn);  
        minusBtn = new JButton();  
        minusBtn.setText("-");
        minusBtn.addActionListener(this);  
        topLeft.add(minusBtn);  
        left.add(topLeft);  
 
        //adding of list of cities to a scrollpane to add to display    
        JPanel bottomLeft=new JPanel(); 
 
        setUpCities(); 
        cityList=new JList(cities);    
        cityList.setSelectedIndex(0); 
        cityList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION); 
        JScrollPane scrollableList = new JScrollPane(cityList);  
        bottomLeft.add(scrollableList);  
        left.add(bottomLeft);  
 
        right = new JPanel();
        topRight = new JPanel();
        clockDisplay = new JPanel[1];
        topRight.setLayout(new GridLayout(clockDisplay.length,1));
        for(int i=0;i<clockDisplay.length;i++)
        {
            clockDisplay[i]=new JPanel();
            cityName = cities[i].substring(0,cities[i].indexOf(","));
            hourDiff=Integer.parseInt(cities[i].substring(cities[i].indexOf(",")+1));
            currentTime = System.currentTimeMillis();
            cityTime = System.currentTimeMillis()+(1000*60*60*hourDiff);
            clockDisplay[i].setBorder(BorderFactory.createTitledBorder(cityName));
            time = new JLabel();
            time.setOpaque(true);
            timeInFormat = textAsTime(cityTime);
            time.setText(timeInFormat);
 
            clockDisplay[i].add(time);
            topRight.add(clockDisplay[i]);
        }
        right.add(topRight);
 
 
        displayArea.add(left);  
        displayArea.add(right);  
        contentPane.add(displayArea);   
        Timer t= new Timer(1000,this);
        t.start();
        appWin.setVisible(true);
 
    } 
    public void actionPerformed(ActionEvent e)  
    {
        cityTime = cityTime+1000;
        timeInFormat=textAsTime(cityTime);
        time.setText(timeInFormat);
        cityNamesList = new ArrayList<String>();
        cityTimes = new ArrayList<Long>();
        cityLabels= new ArrayList<JLabel>();
 
        Object [] obj = cityList.getSelectedValues();
        Object source=e.getSource();
        if(source==addBtn)
        {
            topRight.removeAll();
            right.setLayout(new GridLayout(obj.length,1));
            clockDisplay = new JPanel[obj.length];
            topRight.setLayout(new GridLayout(obj.length,1));
            ArrayList<String> cityNamesList = new ArrayList<String>();
            ArrayList<Long> cityTimes = new ArrayList<Long>();
            for(int i=0;i<obj.length;i++)
            {
                String temp = (String)obj[i];
                clockDisplay[i]=new JPanel();
                cityName = temp.substring(0,temp.indexOf(","));
                cityNamesList.add(cityName);
                hourDiff=Integer.parseInt(temp.substring(temp.indexOf(",")+1));
                currentTime = System.currentTimeMillis();
                cityTime = System.currentTimeMillis()+(1000*60*60*hourDiff);
                cityTimes.add(cityTime);
                clockDisplay[i].setBorder(BorderFactory.createTitledBorder(cityName));
                time = new JLabel();
                time.setOpaque(true);
                timeInFormat = textAsTime(cityTime);
                time.setText(timeInFormat);
                cityLabels.add(time);
                clockDisplay[i].add(time);
                topRight.add(clockDisplay[i]);
            }
            right.add(topRight);            
        }
    }
    public void setUpCities() 
    { 
       cities = new String []{"Accra,0","Addis Abada,+3","Adelaide,+11","Algiers,-1","Almaty,+6","Amman,+3","Amsterdam,+1","Anadyr,+12","Anchorage,-8","Ankara,+2","London,0","Paris,+1"};         
    } 
    public String textAsTime(long currentTime)  
    {  
        long second = (currentTime / 1000) % 60; 
        long minute = (currentTime / (1000 * 60)) % 60; 
        long hour = (currentTime / (1000 * 60 * 60)) % 24; 
        return String.format("%02d:%02d:%02d",hour,minute,second);  
    }
    public static void main(String [] args)
    {
        new AssignmentV1();
    }
    //public long tick(long cityTime)
    //{
 
    //}
}

With regard to the class that you suggested in your previous post, I am not sure that I fully understand what you are suggesting. Is it to create a class that references the three array lists that I have created that contain the data associated with the time display? If it is I am not sure how to go about creating that. Could you give me some guidance on it?

thanks for your help with this question. I did not fully understand what you were suggesting so I went back to the professor for guidance and it turns out that many people were in the same question. I have since got a much clearer understanding of how to approach this question.

Originally Posted by digitalsystems

thanks for your help with this question. I did not fully understand what you were suggesting so I went back to the professor for guidance and it turns out that many people were in the same question. I have since got a much clearer understanding of how to approach this question.

I think I have spoken too soon in saying that I have completed this. I have split the code into four different classes as per what my lecturer suggested.

I have one remaining problem that I would be very grateful if anyone could give me guidance on.

In the clockModel class, when I click on the "-" button (to remove a "clock" from the display) I am trying to see if the selected city is in the arraylist cityNames (created when in the addToDisplayMethod) and if it is to remove the associated jtextfield. I have got to the stage where I can check and see if the selected item is contained in the arraylist cityNames but I do not know how I can get at the associated jtextfield.

Is it possible to check if the string that is the title of the jtextfield is the same as the text of the selected city? Or is there a different way that I should approch this?

Thank you.

import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.*;
import java.util.*;
public class ClockModel {
    private long timeInSeconds;
    private JList cityList; 
    ClockView view;
    private JPanel right;
    private ArrayList<Integer> hourDiffs;
    private ArrayList<String> cityNames;
    private JTextField worldClock[];
    private int hourDiff;
    private String cityName;
    public ClockModel(long startTimeInSeconds) {
        this.timeInSeconds = System.currentTimeMillis()/1000;
        view = new ClockView(this);
        this.cityList = view.cityList;
        this.right = view.right;
        this.hourDiffs = view.hourDiffs;
        this.cityNames = view.cityNames;
        this.worldClock = view.worldClock;
        this.hourDiff = view.hourDiff;
        this.cityName = view.cityName;
 
    }
    public ClockModel() {
        this(0);
    }
    public void tick() {
        timeInSeconds++;
        view.update(worldClock,hourDiffs);
    }
    public long currentTime() {
        return timeInSeconds;
    }
    public void addToDisplay()
    {
        Border lineBorder = BorderFactory.createLineBorder(Color.BLACK,1);
        Font font = new Font("Bradley Hand ITC", Font.BOLD, 24);
        view.right.removeAll();
        cityNames = new ArrayList<String>();
        hourDiffs = new ArrayList<Integer>();
        Object [] obj = view.cityList.getSelectedValues();
        worldClock = new JTextField[obj.length];
        for(int i=0;i<obj.length;i++)
        {
           String temp = (String)obj[i];
           cityName = temp.substring(0,temp.indexOf(","));
           hourDiff=Integer.parseInt(temp.substring(temp.indexOf(",")+1));
           worldClock[i]=new JTextField(8);
           worldClock[i].setFont(font);
           worldClock[i].setEditable(false);
           worldClock[i].setFocusable(false);
           worldClock[i].setBorder(BorderFactory.createTitledBorder(lineBorder,cityName));
           cityNames.add(cityName);
           right.add(worldClock[i]);
 
           hourDiffs.add(hourDiff);
        }
        view.update(worldClock,hourDiffs);   
    }  
    public void removeFromDisplay()
    {
        Object [] obj = view.cityList.getSelectedValues();
        //ArrayList<String> deleteList = new ArrayList<String>();
        for(int i=0;i<obj.length;i++)
        {
           String temp = (String)obj[i];
           cityName = temp.substring(0,temp.indexOf(","));
           hourDiff=Integer.parseInt(temp.substring(temp.indexOf(",")+1));
           if(cityNames.contains(cityName))
           {
              //deleteList.add(cityName);
              //right.remove(worldClock[i]);
           }
        }
    }
}

import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.*;
import java.util.*;
 
 
public class ClockView {
    JTextField worldClock[];
    private ClockModel model;
    JList cityList;
    JPanel right;
    private String [] cities;
    ArrayList<Integer> hourDiffs;
    ArrayList<String> cityNames;
    int hourDiff;
    String cityName;
    AddRemoveButton addBtn;
    AddRemoveButton minusBtn;
    public ClockView(ClockModel model) {
        JFrame clockFace = new JFrame("World Clock");
        clockFace.setSize(600,600);
        clockFace.setLocationRelativeTo(null);
        clockFace.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
        Container contentPane = clockFace.getContentPane();
 
        JPanel displayArea = new JPanel(new GridLayout(1,2));
 
        JPanel left = new JPanel(new GridLayout(2,1));
        JPanel topLeft = new JPanel(new FlowLayout());
 
        AddRemoveButton addBtn = new AddRemoveButton("+",model);
        topLeft.add(addBtn);
        AddRemoveButton minusBtn = new AddRemoveButton("-",model);
        topLeft.add(minusBtn);
        left.add(topLeft);
 
 
        JPanel bottomLeft = new JPanel();
        setUpCities();
        cityList=new JList(cities);
        int selectedIndex = 3;
        cityList.setSelectedIndex(selectedIndex);
        cityList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        int currentIndex=cityList.getSelectedIndex();
        JScrollPane scrollableList = new JScrollPane(cityList); 
        bottomLeft.add(scrollableList); 
        left.add(bottomLeft);
 
        right = new JPanel(new FlowLayout());
 
        Border lineBorder = BorderFactory.createLineBorder(Color.BLACK,1);
        Font font = new Font("Bradley Hand ITC", Font.BOLD, 24);
 
        worldClock = new JTextField[1];
        worldClock[0]=new JTextField(8);
        worldClock[0].setFont(font);
        worldClock[0].setEditable(false);
        worldClock[0].setFocusable(false);
        worldClock[0].setHorizontalAlignment(JTextField.CENTER);
        cityName = cities[selectedIndex].substring(0,cities[selectedIndex].indexOf(","));
        cityNames = new ArrayList<String>();
        cityNames.add(cityName);
        worldClock[0].setBorder(BorderFactory.createTitledBorder(lineBorder,cityName));
        right.add(worldClock[0]);
        hourDiff=Integer.parseInt(cities[selectedIndex].substring(cities[selectedIndex].indexOf(",")+1));
        hourDiffs = new ArrayList<Integer>();
        hourDiffs.add(hourDiff);
 
        displayArea.add(left);
        displayArea.add(right);
        contentPane.add(displayArea);
 
        this.model = model;
        new ClockController(model);
 
        update(worldClock,hourDiffs);
        clockFace.setVisible(true);
    }
 
    public void update(JTextField [] worldClock, ArrayList<Integer> hourDiffs) 
    {
        for(int i=0;i<worldClock.length;i++)
        {
            worldClock[i].setText(secondsAsTimeText(model.currentTime()+((hourDiffs.get(i))*60*60)));
        }
    }
 
    public String secondsAsTimeText(long timeInSeconds) {
        long hours, minutes, seconds ;
        minutes = timeInSeconds / 60;
        seconds = timeInSeconds % 60;
        hours = minutes / 60;
        hours = hours%24;
        minutes = minutes % 60;
        return String.format("%02d:%02d:%02d",hours,minutes,seconds);
    }
    public void setUpCities()
    {
       cities = new String []{"Accra,0","Addis Abada,+3","Adelaide,+11","Algiers,-1","Almaty,+6","Amman,+3","Amsterdam,+1","Anadyr,+12","Anchorage,-8","Ankara,+2","London,0","Paris,+1"};        
    }
}

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.Timer;
 
public class ClockController implements ActionListener {
    private ClockModel model;
 
    public ClockController(ClockModel model)
    {
        this.model = model;
        Timer timer = new Timer(1000,this);
        timer.start();
    }
 
    public void actionPerformed(ActionEvent event)
    {
        model.tick();
    }
}

import javax.swing.*;
import java.awt.event.*;
public class AddRemoveButton extends JButton implements ActionListener
{
    private ClockModel model;
    private ClockView view;
    private String buttonText;
    //private AddRemoveButton addBtn;
    //private AddRemoveButton minusBtn;
    public AddRemoveButton(String buttonText, ClockModel model)
    {
        super(buttonText);
        addActionListener(this);
        this.model=model;
        this.buttonText = buttonText;
        //this.addBtn = view.addBtn;
        //this.minusBtn = view.minusBtn;
    }
    public void actionPerformed(ActionEvent e)
    {
        Object source = e.getSource();
        if(buttonText=="+")
        {
            model.addToDisplay();
        }
        else
        model.removeFromDisplay();
    }
}