Class EasyFormat

java.lang.Object

EasyFormat

public class EasyFormat
extends java.lang.Object

This class provides easy to use formatting methods. They can be particularly useful for setting up tables with fixed width columns or formatting decimal numbers to a fixed number of decimal places. While Java does have some formatting classes (Format, DateFormat, SimpleDataFormat, MessageFormat, NumberFormat, ChoiceFormat, and DecimalFormat) they are not always easy to understand and use especially when setting up tables.

This clsss includes methods for for

• Formatting Strings, booleans, and ints to a fixed length.
• Formatting doubles to a fixed number of decimal places and optionally a fixed length. Another method allows users to specify the format for doubles.
• Internally rounding a double number to a fixed number of decimal places.

When formatting a String, boolean, int, or double to a fixed lenght, the value is right justified by padding with blanks on the left. Values are never chopped if their length is already longer than the specified length. All the methods are static so it is never necessary to create a new EasyFormat object.

The roundTo(number, numDecimalPlaces) function was modeled after the ROUND(number,num_digits) function in Excel. 'num' is the number of decimal places to which x is rounded. If num < 0, then the number is rounded to the left of the decimal point. For example, roundTo(12345.6,-2) = 12300. roundTo returns a double. Occasionally roundTo does not produce the desired result for printed output. This method is intended for situations where internal rounding of numbers is needed in order to continue calculations.

When the only purpose of rounding is to produce a formatted string to be printed, the format(number, numDecimalPlaces) function is a better choice. It works about the same way roundTo works as long as the number of decimal places is greater to or equal to 0.

Constructor Summary

Constructors

Constructor and Description
EasyFormat()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	format(boolean value, int length) Returns the boolean value right justified in a string of the specified length.
static java.lang.String	format(double x, int numOfDecimals) Returns a string with the double rounded to numOfDecimals decimal places.
static java.lang.String	format(double x, int length, int numOfDecimals) Returns a string of the specified length with the double rounded to numOfDecimals decimal places.
static java.lang.String	format(double x, java.lang.String pattern) Formats a double according to the supplied pattern.
static java.lang.String	format(int number, int length) Returns the int number right justified in a string of the specified length.
static java.lang.String	format(java.lang.String str, int length) Returns the String str right justified in a string of the specified length.
static void	main(java.lang.String[] args) A simple test program.
static double	roundTo(double x, int num) Rounds x to num decimal places.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EasyFormat

public EasyFormat()

Method Detail

roundTo

public static double roundTo(double x,
                             int num)

Rounds x to num decimal places. If num is less than 0, then it rounds x left of the decimal. For example, roundTo(56892.5,-3) = 57000.0.

Parameters:

x - - the number to be rounded.

num - - the number of decimal places. If num < 0, it rounds to the number of digits left of the decimal

format

public static java.lang.String format(double x,
                                      int numOfDecimals)

Returns a string with the double rounded to numOfDecimals decimal places. It includes the needed digits left of the decimal and includes "," as appropriate. The decimal point is included if numOfDecimals > 0. It always includes the specified number of decimal places right of the decimal, even if 0's are needed to pad the string.

Returns "?" if the first parameter is Double.NaN or Double.POSITIVE_INFINITY and "-?" if the parameter is Double.NEGATIVE_INFINITY.

Examples:
format(12.34, -1) = "12"
format(12.34, 0) = "12"
format(12.34, 1) = "12.3"
format(12.34, 5) = "12.34000"
format(-.00012345, 3) = "-.000"
format(12345.111, -2) = "12,345"
format(12345, 2) = "12,345.00"

Parameters:

x - - the number to be rounded.

numOfDecimals - - the number of decimal places. If num < 0, it rounds to the nearest integer.

format

public static java.lang.String format(double x,
                                      int length,
                                      int numOfDecimals)

Returns a string of the specified length with the double rounded to numOfDecimals decimal places. It includes the needed digits left of the decimal and includes "," as appropriate. The decimal point is included if numOfDecimals > 0. It always includes the specified number of decimal places right of the decimal, even if 0's are needed to pad the string. The result is padded on the left with blanks, if needed, to achieve the desired length. If the number is too long to fit in the specified length, the returned string will be longer than the specified length.

Returns a string containing "?" if the first parameter is Double.NaN or Double.POSITIVE_INFINITY and "-?" if the parameter is Double.NEGATIVE_INFINITY.

Examples:
format(12.34, 4, -1) = " 12"
format(12.34, 4, 0) = " 12"
format(12.34, 4, 1) = "12.3"
format(12.34, 4, 5) = "12.34000" (the string is longer than specified)
format(-.00012345, 6, 3) = " -.000"
format(12345.111, 8, -2) = " 12,345"
format(12345, 10, 2) = " 12,345.00"

Parameters:

x - - the number to be rounded.

numOfDecimals - - the number of decimal places. If num < 0, it rounds to the nearest integer.

format

public static java.lang.String format(java.lang.String str,
                                      int length)

Returns the String str right justified in a string of the specified length. If the length parameter is less or equal to the length of the str, it just returns the string.

Parameters:

str - - the String to be formatted.

length - - the desired length of the resulting string.

Returns:

- a String of the specified length containing the String right justified.

format

public static java.lang.String format(int number,
                                      int length)

Returns the int number right justified in a string of the specified length. If the length parameter is less or equal to the length of the int, it just returns the string with the number.

Parameters:

number - - the int number to be formatted.

length - - the desired length of the resulting string.

Returns:

- a String of the specified length containing the number right justified.

format

public static java.lang.String format(boolean value,
                                      int length)

Returns the boolean value right justified in a string of the specified length. If the length parameter is less or equal to the length of the boolean, it just returns the string with the boolean value

Parameters:

value - - the boolean value to be formatted.

length - - the desired length of the resulting string.

Returns:

- a String of the specified length containing the boolean value right justified.

format

public static java.lang.String format(double x,
                                      java.lang.String pattern)

Formats a double according to the supplied pattern. See DecimalFormat in the JavaDocs for a complete listing of pattern symbols. Some typical formats include:
",###" - round to an integer, no decimal point, use commas
",###.##" - round to two decimal places which are omitted if not needed, " use commas
"#.00" - round to two decimal places, show both decimal places, no commas.

Parameters:

x - - the number to be rounded

pattern - - the formatting pattern

main

public static void main(java.lang.String[] args)

A simple test program.