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 math in Velocity.

Some things should be noted here:

• This class does not have methods that take primitives. This is simply because Velocity wraps all primitives for us automagically.
• 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)')

 Example toolbox.xml config (if you want to use this with VelocityView):
 <tool>
   <key>math</key>
   <scope>application</scope>
   <class>org.apache.velocity.tools.generic.MathTool</class>
 </tool>
 

Version:

$Revision: 1.7.2.1 $ $Date: 2004/05/17 17:09:43 $

Author:

Nathan Bubna

Constructor Summary

MathTool()

Method Summary

java.lang.Number	abs(java.lang.Object num)
java.lang.Number	add(java.lang.Object num1, java.lang.Object num2)
java.lang.Integer	ceil(java.lang.Object num)
java.lang.Number	div(java.lang.Object num1, java.lang.Object num2)
java.lang.Integer	floor(java.lang.Object num)
java.lang.Double	getRandom()
protected java.lang.Number	matchType(java.lang.Number in, double out)
protected java.lang.Number	matchType(java.lang.Number in1, java.lang.Number in2, double out) Takes the original argument(s) and returns the resulting value as an instance of the best matching type (Integer, Long, or Double).
java.lang.Number	max(java.lang.Object num1, java.lang.Object num2)
java.lang.Number	min(java.lang.Object num1, java.lang.Object num2)
java.lang.Number	mul(java.lang.Object num1, java.lang.Object num2)
protected java.lang.Number	parseNumber(java.lang.String value) Converts an object into a Number (if it can) This is used as the base for all numeric parsing methods.
java.lang.Number	pow(java.lang.Object num1, java.lang.Object num2)
java.lang.Number	random(java.lang.Object num1, java.lang.Object num2) This returns a random Number within the specified range.
java.lang.Integer	round(java.lang.Object num) Rounds a number to the nearest whole Integer
java.lang.Double	roundTo(java.lang.Object decimals, java.lang.Object num) Rounds a number to the specified number of decimal places.
java.lang.Integer	roundToInt(java.lang.Object num) Deprecated. This will be removed in VelocityTools 1.2. Use #round(Object num) instead.
java.lang.Number	sub(java.lang.Object num1, java.lang.Object num2)
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
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
java.lang.Number	toNumber(java.lang.Object num) Converts an object with a numeric value into a Number 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 java.lang.Number 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:

toNumber(java.lang.Object)

sub

public java.lang.Number 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:

toNumber(java.lang.Object)

mul

public java.lang.Number 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:

toNumber(java.lang.Object)

div

public java.lang.Number 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:

toNumber(java.lang.Object)

pow

public java.lang.Number 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:

toNumber(java.lang.Object)

max

public java.lang.Number 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:

toNumber(java.lang.Object)

min

public java.lang.Number 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:

toNumber(java.lang.Object)

abs

public java.lang.Number abs(java.lang.Object num)

Parameters:

num - the number

Returns:

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

See Also:

toDouble(java.lang.Object)

ceil

public java.lang.Integer ceil(java.lang.Object num)

Parameters:

num - the number

Returns:

the smallest integer that is not less than the given number

floor

public java.lang.Integer floor(java.lang.Object num)

Parameters:

num - the number

Returns:

the integer portion of the number

round

public java.lang.Integer round(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:

Math.rint(double)

roundTo

public 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 round(java.lang.Object), as that will return an Integer rather than a Double.

Parameters:

decimals - the number of decimal places

num - the number to round

Returns:

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

See Also:

toNumber(java.lang.Object)

roundToInt

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

Deprecated. This will be removed in VelocityTools 1.2. Use #round(Object num) instead.

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 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 java.lang.Number random(java.lang.Object num1,
                               java.lang.Object num2)

This returns a random Number within the specified range. The returned value will be greater than or equal to the first number and less than the second number. If both arguments are whole numbers then the returned number will also be, otherwise a Double will be returned.

Parameters:

num1 - the first number

num2 - the second number

Returns:

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

See Also:

Math.random()

toInteger

public 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

toDouble

public 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

toNumber

public java.lang.Number toNumber(java.lang.Object num)

Converts an object with a numeric value into a Number Valid formats are Number or a String representation of a number. Note that this does not handle localized number formats. Use the NumberTool to handle such conversions.

Parameters:

num - the number to be converted

Returns:

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

matchType

protected java.lang.Number matchType(java.lang.Number in,
                                     double out)

See Also:

matchType(Number,Number,double)

matchType

protected java.lang.Number matchType(java.lang.Number in1,
                                     java.lang.Number in2,
                                     double out)

Takes the original argument(s) and returns the resulting value as an instance of the best matching type (Integer, Long, or Double). If either an argument or the result is not an integer (i.e. has no decimal when rendered) the result will be returned as a Double. If not and the result is < -2147483648 or > 2147483647, then a Long will be returned. Otherwise, an Integer will be returned.

parseNumber

protected java.lang.Number parseNumber(java.lang.String value)
                                throws java.lang.NumberFormatException

Converts an object into a Number (if it can) This is used as the base for all numeric parsing methods. So, sub-classes can override to allow for customized number parsing. (e.g. for i18n, fractions, compound numbers, bigger numbers, etc.)

Parameters:

value - the string to be parsed

Returns:

the value as a Number

Throws:

java.lang.NumberFormatException