Need help adding AM/PM to my clock program

Question

Hi everyone
I would be grateful if you could help me adding AM/PM to my clockDisplay program, been trying but i'm not very familiar with Java.
Thanks
I have used 2 classes:
NumberDisplay and ClockDisplay
the clock automatically convert hours after 12 noon such as 14:34 to 02:34 so all i need is to add PM and AM accordingly.
NumberDisplay classs:
public class NumberDisplay
    private int limit;
    private int value;
    public NumberDisplay(int rollOverLimit)
        limit = rollOverLimit;
        value = 0;
    public int getValue()
        return value;
    public String getDisplayValue()
        if(value < 10)
            return "0" + value;
        else
            return "" + value;
    public void setValue(int replacementValue)
        if((replacementValue >= 0) && (replacementValue < limit))
            value = replacementValue;
        else if ( (replacementValue>=limit) && (replacementValue>=0) )
           value=replacementValue-12;
    public void increment()
        value = (value + 1) % limit;
}ClockDisplay class:
public class ClockDisplay
    private NumberDisplay hours;
    private NumberDisplay minutes;
    private String displayString;    // simulates the actual display
    public ClockDisplay()
        hours = new NumberDisplay(12);
        minutes = new NumberDisplay(60);
        updateDisplay();
    public ClockDisplay(int hour, int minute)
        hours = new NumberDisplay(12);
        minutes = new NumberDisplay(60);
        setTime(hour, minute);
    public void timeTick()
        minutes.increment();
        if(minutes.getValue() == 0) {
            hours.increment();
        updateDisplay();
    public void setTime(int hour, int minute)
        hours.setValue(hour);
        minutes.setValue(minute);
         updateDisplay(); 
    public String getTime()
        return displayString;
    private void updateDisplay()
        displayString = hours.getDisplayValue() + ":" +
                        minutes.getDisplayValue();
}As you see value=replacementValue-12; do the job.
i tried do this:
if(hours.setValue(hour)>=12)
updateDisplayPm();
else
updateDisplay();
and for
private void updateDisplayPm()
displayString = hours.getDisplayValue() + ":" +
                        minutes.getDisplayValue() + "PM";but it didnt work.
so should iwrite if statemnt in NumberDisplay class and refer it to ClockDisplay or i can do something in clockDisplay.
Looking forward to hear from you
thanks

Answer 1

solved
public class NumberDisplay
    private int limit;
    private int value;
    private boolean isam;
    public NumberDisplay(int rollOverLimit)
        limit = rollOverLimit;
        value = 0;
    public int getValue()
        return value;
      public boolean getAm()
             return isam;
    public String getDisplayValue()
        if(value < 10)
            return "0" + value;
        else
            return "" + value;
    public void setValue(int replacementValue)
        if((replacementValue >= 0) && (replacementValue < limit))
            value = replacementValue;
            isam=true;
        else if ( (replacementValue>=limit) && (replacementValue>=0) )
           value=replacementValue-12;
           isam=false;
    public void increment()
        value = (value + 1) % limit;
public class ClockDisplay
    private NumberDisplay hours;
    private NumberDisplay minutes;
    private String displayString;    // simulates the actual display
    private NumberDisplay amCheck;
    public ClockDisplay()
        hours = new NumberDisplay(12);
        minutes = new NumberDisplay(60);
        updateDisplay();
    public ClockDisplay(int hour, int minute)
        hours = new NumberDisplay(12);
        minutes = new NumberDisplay(60);
        setTime(hour, minute);
    public void timeTick()
        minutes.increment();
        if(minutes.getValue() == 0) {
            hours.increment();
        updateDisplay();
    public void setTime(int hour, int minute)
        hours.setValue(hour);
        minutes.setValue(minute);
       updateDisplay(); 
    public String getTime()
        return displayString;
    private void updateDisplay()
        if(hours.getAm())
        displayString = hours.getDisplayValue() + ":" +  minutes.getDisplayValue() + "AM";
        else
         displayString = hours.getDisplayValue() + ":" +  minutes.getDisplayValue() + " PM";
}