org.apache.velocity.tools.generic
Class MathTool

java.lang.Object
  |
  +--org.apache.velocity.tools.generic.MathTool

public class MathTool

extends java.lang.Object

Tool for performing floating point math in Velocity.

Several things should be noted here:

1. This class does not have methods that take primitives. This is simply because Velocity wraps all primitives for us automagically.
2. Most methods return Double wrappers which automatically render the decimal places even for whole numbers (e.g. new Double(1).toString() -> '1.0') This is intentional. This tool is for floating point arithmetic. Integer arithmetic is already supported in Velocity syntax. if you really need '1' instead of '1.0', just call intValue() on the result.
3. No null pointer, number format, or divide by zero exceptions are thrown here. This is because such exceptions thrown in template halt rendering. It should be sufficient debugging feedback that Velocity will render the reference literally. (e.g. $math.div(1, 0) renders as '$math.div(1, 0)')

Version:

$Revision: 1.2 $ $Date: 2003/05/28 00:17:15 $

Author:

Nathan Bubna

Constructor Summary

MathTool()


Method Summary

static java.lang.Double	abs(java.lang.Object num)
static java.lang.Double	add(java.lang.Object num1, java.lang.Object num2)
static java.lang.Double	div(java.lang.Object num1, java.lang.Object num2)
static java.lang.Double	getRandom()
static java.lang.Double	max(java.lang.Object num1, java.lang.Object num2)
static java.lang.Double	min(java.lang.Object num1, java.lang.Object num2)
static java.lang.Double	mul(java.lang.Object num1, java.lang.Object num2)
static java.lang.Double	pow(java.lang.Object num1, java.lang.Object num2)
static java.lang.Integer	random(java.lang.Object num1, java.lang.Object num2) This returns a random Integer within the specified range.
static java.lang.Double	roundTo(java.lang.Object decimals, java.lang.Object num) Rounds a number to the specified number of decimal places.
static java.lang.Integer	roundToInt(java.lang.Object num) Rounds a number to the nearest whole Integer
static java.lang.Double	sub(java.lang.Object num1, java.lang.Object num2)
static java.lang.Double	toDouble(java.lang.Object num) Converts an object with a numeric value into a Double Valid formats are Number or a String representation of a number
static java.lang.Integer	toInteger(java.lang.Object num) Converts an object with a numeric value into an Integer Valid formats are Number or a String representation of a number

Methods inherited from class java.lang.Object

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

Constructor Detail

MathTool

public MathTool()

Method Detail

add

public static java.lang.Double add(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the sum of the numbers or null if they're invalid

See Also:

toDouble(java.lang.Object)

sub

public static java.lang.Double sub(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the difference of the numbers or null if they're invalid

See Also:

toDouble(java.lang.Object)

mul

public static java.lang.Double mul(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the product of the numbers or null if they're invalid

See Also:

toDouble(java.lang.Object)

div

public static java.lang.Double div(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the quotient of the numbers or null if they're invalid

See Also:

toDouble(java.lang.Object)

pow

public static java.lang.Double pow(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the first number raised to the power of the second or null if they're invalid

See Also:

toDouble(java.lang.Object)

max

public static java.lang.Double max(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the largest of the numbers or null if they're invalid

See Also:

toDouble(java.lang.Object)

min

public static java.lang.Double min(java.lang.Object num1,
                                   java.lang.Object num2)

Parameters:

num1 - the first number

num2 - the second number

Returns:

the smallest of the numbers or null if they're invalid

See Also:

toDouble(java.lang.Object)

abs

public static java.lang.Double abs(java.lang.Object num)

Returns:

the absolute value of the number null if it's invalid

See Also:

toDouble(java.lang.Object)

toDouble

public static java.lang.Double toDouble(java.lang.Object num)

Converts an object with a numeric value into a Double Valid formats are Number or a String representation of a number

Parameters:

num - the number to be converted

Returns:

a Double representation of the number or null if it's invalid

toInteger

public static java.lang.Integer toInteger(java.lang.Object num)

Converts an object with a numeric value into an Integer Valid formats are Number or a String representation of a number

Parameters:

num - the number to be converted

Returns:

a Integer representation of the number or null if it's invalid

roundTo

public static java.lang.Double roundTo(java.lang.Object decimals,
                                       java.lang.Object num)

Rounds a number to the specified number of decimal places. This is particulary useful for simple display formatting. If you want to round an number to the nearest integer, it is better to use roundToInt(java.lang.Object), as that will return an Integer rather than a Double.

Parameters:

decimals - the number of decimal places

Returns:

the value rounded to the specified number of decimal places or null if it's invalid

See Also:

toDouble(java.lang.Object), toInteger(java.lang.Object)

roundToInt

public static java.lang.Integer roundToInt(java.lang.Object num)

Rounds a number to the nearest whole Integer

Parameters:

num - the number to round

Returns:

the number rounded to the nearest whole Integer or null if it's invalid

See Also:

toDouble(java.lang.Object)

getRandom

public static java.lang.Double getRandom()

Returns:

a pseudo-random Double greater than or equal to 0.0 and less than 1.0

See Also:

Math.random()

random

public static java.lang.Integer random(java.lang.Object num1,
                                       java.lang.Object num2)

This returns a random Integer within the specified range. The return Integer will have a value greater than or equal to the first number and less than the second number.

Parameters:

num1 - the first number

num2 - the second number

Returns:

a pseudo-random Integer greater than or equal to the first number and less than the second

See Also:

toInteger(java.lang.Object), Math.random()