This document describes how the Date Conversion and RGB Color conversion can be done in Java

public
class
DateUtil

{

  public
static Date stringToDate(String dateStr) throws ParseException

  {

    SimpleDateFormat
dateFormatter = new
SimpleDateFormat("yyyy-MM-dd");

    Date
date = null;

    if(dateStr
!= null)

    {

      date
= dateFormatter.parse(dateStr);

    }

    return
date;

  }

 

  public
static String
dateToString(Date date)

  {

    return
dateToString(date, "yyyy-MM-dd");

  }

 

  public
static String
dateToStringMMM(Date date)

  {

    return
dateToString(date, "dd-MMM-yyyy");

  }

  public
static String
dateTimeToString(Date date)

  {

    return
dateToString(date, "yyyy-MM-dd
HH:mm:ss"
);

  }

 

  public
static String
dateToString(Date date, String pattern)

  {

    SimpleDateFormat
dateFormatter = new
SimpleDateFormat(pattern);

    String
dateStr = null;

    if(date
!= null)

    {

      dateStr
= dateFormatter.format(date);

    }

    return
dateStr;

  }

 

  public
static Date
stringMMMToDate(String dateStr) throws
ParseException

  {

    SimpleDateFormat
dateFormatter = new
SimpleDateFormat("dd-MMM-yyyy");

    Date
date = null;

    if(dateStr
!= null)

    {

      date
= dateFormatter.parse(dateStr);

    }

    return
date;

  }

 

  public
static Date
findPreviousMonday(Calendar calendar)

  {

    switch(calendar.get(Calendar.DAY_OF_WEEK))

    {

      case
Calendar.TUESDAY:

        calendar.add(Calendar.DATE,
-1);

        break;

      case
Calendar.WEDNESDAY:

        calendar.add(Calendar.DATE,
-2);

        break;

      case
Calendar.THURSDAY:

        calendar.add(Calendar.DATE,
-3);

        break;

      case
Calendar.FRIDAY:

        calendar.add(Calendar.DATE,
-4);

        break;

      case
Calendar.SATURDAY:

        calendar.add(Calendar.DATE,
-5);

        break;

      case
Calendar.SUNDAY:

        calendar.add(Calendar.DATE,
-6);

    }

    return
calendar.getTime();

  }

}

RGB Color Utility in Java

This section describes how RGB Color can be manipulated in Java

public static String
intToHexString(int r1,
int g1,
int b1)

{

String ret = null;

if(r1>= 0 && r1 <= 255 &&
g1 >= 0 && g1 <= 255 &&
b1 >= 0 && b1 <= 255)

{

String red =Integer.toHexString(r1).toUpperCase();

String green =Integer.toHexString(g1).toUpperCase();

String blue =Integer.toHexString(b1).toUpperCase();

if(red.length() == 1)

{

red = "0"+red;

}

if (green.length() == 1)

{

green = "0"+green;

}

if(blue.length() == 1)

{

blue = "0"+blue;

}

ret = red+green+blue;

}

return ret;

}

public static int[] hexStringToInt(String color)

{

int[]
ret = new int[3];

if(color !=
null
&& color.length() == 6)

{

String red,green,blue;

red=color.substring(0,2);

green=color.substring(2,4);

blue=color.substring(4,6);

ret[0] = Integer.parseInt(red, 16);

ret[1] = Integer.parseInt(green, 16);

ret[2] = Integer.parseInt(blue, 16);

}

return ret;

}