Package org.apache.velocity.runtime.parser.node

Class 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 ( Integer.valueOf(10), Integer.valueOf(1)) will return an Integer-Object with the value 11
    add ( Long.valueOf(10), Integer.valueOf(1)) will return an Long-Object with the value 11
    add ( Integer.valueOf(10), Float.valueOf(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 (Integer.valueOf(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.
    Since:
    1.5
    Author:
    Peter Romianowski

    • 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

    • 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.

      • findCalculationBase

        public static int findCalculationBase​(Number op)
        Find the Number-type to be used for a single number
        Parameters:
        op - operand
        Returns:
        constant indicating type of Number to use in calculations

      • 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.

      • 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.

      • negate

        public static Number negate​(Number op)
        Negate a number
        Parameters:
        op - n
        Returns:
        -n (unary negation of n)