org.apache.velocity.runtime.parser.node
Class MathUtils

java.lang.Object
  org.apache.velocity.runtime.parser.node.MathUtils

public abstract class MathUtils
extends Object

Utility-class for all arithmetic-operations.

All operations (+ - / *) return a Number which type is the type of the bigger argument.
Example:
add ( new Integer(10), new Integer(1)) will return an Integer-Object with the value 11
add ( new Long(10), new Integer(1)) will return an Long-Object with the value 11
add ( new Integer(10), new Float(1)) will return an Float-Object with the value 11

Overflow checking:
For integral values (byte, short, int) there is an implicit overflow correction (the next "bigger" type will be returned). For example, if you call add (new Integer (Integer.MAX_VALUE), 1) a Long-object will be returned with the correct value of Integer.MAX_VALUE+1.
In addition to that the methods multiply,add and substract implement overflow checks for long-values. That means that if an overflow occurs while working with long values a BigInteger will be returned.
For all other operations and types (such as Float and Double) there is no overflow checking.

Author:

Peter Romianowski

Field Summary

protected static int	BASE_BIGDECIMAL
protected static int	BASE_BIGINTEGER
protected static int	BASE_DOUBLE
protected static int	BASE_FLOAT
protected static int	BASE_LONG The constants are used to determine in which context we have to calculate.
protected static BigDecimal	DECIMAL_ZERO A BigDecimal representing the number 0
protected static Map	ints The Class-object is key, the maximum-value is the value
protected static List	typesBySize The "size" of the number-types - ascending.

Constructor Summary

MathUtils()

Method Summary

static Number	add(Number op1, Number op2) Add two numbers and return the correct value / type.
static int	compare(Number op1, Number op2) Compare two numbers.
static Number	divide(Number op1, Number op2) Divide two numbers.
static boolean	isInteger(Number n) Test, whether the given object is an integer value (Byte, Short, Integer, Long, BigInteger)
static boolean	isZero(Number n) Compare the given Number to 0.
static Number	modulo(Number op1, Number op2) Modulo two numbers.
static Number	multiply(Number op1, Number op2) Multiply two numbers and return the correct value / type.
static Number	subtract(Number op1, Number op2) Subtract two numbers and return the correct value / type.
static BigDecimal	toBigDecimal(Number n) Convert the given Number to a BigDecimal
static BigInteger	toBigInteger(Number n) Convert the given Number to a BigInteger
static Number	wrapPrimitive(long value, Class type) Wrap the given primitive into the given class if the value is in the range of the destination type.

Methods inherited from class java.lang.Object

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

Field Detail

DECIMAL_ZERO

protected static final BigDecimal DECIMAL_ZERO

A BigDecimal representing the number 0

BASE_LONG

protected static final int BASE_LONG

The constants are used to determine in which context we have to calculate.

See Also:

Constant Field Values

BASE_FLOAT

protected static final int BASE_FLOAT

See Also:

Constant Field Values

BASE_DOUBLE

protected static final int BASE_DOUBLE

See Also:

Constant Field Values

BASE_BIGINTEGER

protected static final int BASE_BIGINTEGER

See Also:

Constant Field Values

BASE_BIGDECIMAL

protected static final int BASE_BIGDECIMAL

See Also:

Constant Field Values

ints

protected static final Map ints

The Class-object is key, the maximum-value is the value

typesBySize

protected static final List typesBySize

The "size" of the number-types - ascending.

Constructor Detail

MathUtils

public MathUtils()

Method Detail

toBigDecimal

public static BigDecimal toBigDecimal(Number n)

Convert the given Number to a BigDecimal

Parameters:

n -

Returns:

The number as BigDecimal

toBigInteger

public static BigInteger toBigInteger(Number n)

Convert the given Number to a BigInteger

Parameters:

n -

Returns:

The number as BigInteger

isZero

public static boolean isZero(Number n)

Compare the given Number to 0.

Parameters:

n -

Returns:

True if number is 0.

isInteger

public static boolean isInteger(Number n)

Test, whether the given object is an integer value (Byte, Short, Integer, Long, BigInteger)

Parameters:

n -

Returns:

True if n is an integer.

wrapPrimitive

public static Number wrapPrimitive(long value,
                                   Class type)

Wrap the given primitive into the given class if the value is in the range of the destination type. If not the next bigger type will be chosen.

Parameters:

value -

type -

Returns:

Number object representing the primitive.

add

public static Number add(Number op1,
                         Number op2)

Add two numbers and return the correct value / type. Overflow detection is done for integer values (byte, short, int, long) only!

Parameters:

op1 -

op2 -

Returns:

Addition result.

subtract

public static Number subtract(Number op1,
                              Number op2)

Subtract two numbers and return the correct value / type. Overflow detection is done for integer values (byte, short, int, long) only!

Parameters:

op1 -

op2 -

Returns:

Subtraction result.

multiply

public static Number multiply(Number op1,
                              Number op2)

Multiply two numbers and return the correct value / type. Overflow detection is done for integer values (byte, short, int, long) only!

Parameters:

op1 -

op2 -

Returns:

Multiplication result.

divide

public static Number divide(Number op1,
                            Number op2)

Divide two numbers. The result will be returned as Integer-type if and only if both sides of the division operator are Integer-types. Otherwise a Float, Double, or BigDecimal will be returned.

Parameters:

op1 -

op2 -

Returns:

Division result.

modulo

public static Number modulo(Number op1,
                            Number op2)
                     throws ArithmeticException

Modulo two numbers.

Parameters:

op1 -

op2 -

Returns:

Modulo result.

Throws:

ArithmeticException - If at least one parameter is a BigDecimal

compare

public static int compare(Number op1,
                          Number op2)

Compare two numbers.

Parameters:

op1 -

op2 -

Returns:

1 if n1 > n2, -1 if n1 < n2 and 0 if equal.