Question

public class CalendarUtil

{

    private Calendar cal = null;

    public String getRemId()

    {

        cal = Calendar.getInstance();

        return "" + cal.get(Calendar.DATE) + (cal.get(Calendar.MONTH)+1) +        cal.get(Calendar.YEAR);

    }        
}

How can we auto generate ID on a button click that will contain the concatenation of date,month,year and a 3 digit counter starting form 000 and display it in a textfield? for eg:- 28122012001, 28122012002, etc and so on. Code that i have been trying is as above

Answer 1

I think two static fieds can do it.

private static String lastUsedDatePrefix;
private static int counter;

If you want to nenerate a new ID, check if the dateprefix is the same as stored in lastUsedDatePrefix if yes, increment counter else set counter=0 and set lastUsedDatePrefixto actual date.

Untested implementation:

public class CalendarUtil{
    private static String lastUsedDatePrefix = "";
    private static int counter = 0;

    public String getRemId(){
        final String datePrefix = new SimpleDateFormat("ddMMyyy").format(new Date());
        if (lastUsedDatePrefix.equals(datePrefix)) {
            CalendarUtil.counter++;
        }
        else{
            CalendarUtil.lastUsedDatePrefix = datePrefix;
            CalendarUtil.counter = 0;
        }
        final String counterSuffix = ((100 <= CalendarUtil.counter) ? ""
                : (10 <= CalendarUtil.counter) ? "0" : "00")
                + CalendarUtil.counter;
        return datePrefix + counterSuffix;
     }   
}