GeezerVison

All Implemented Interfaces:

Serializable, Comparable<RoundingMode>

public enum RoundingMode
extends Enum<RoundingMode>

Since:

1.5

See Also:

BigDecimal, MathContext

• Enum Constant Summary

  Enum Constants 

  Enum Constant	Description
  CEILING	Rounding mode to round towards positive infinity.
  DOWN	Rounding mode to round towards zero.
  FLOOR	Rounding mode to round towards negative infinity.
  HALF_DOWN	Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
  HALF_EVEN	Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor.
  HALF_UP	Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
  UNNECESSARY	Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary.
  UP	Rounding mode to round away from zero.

• Method Summary

  All Methods Static Methods Concrete Methods 

  Modifier and Type	Method	Description
  static RoundingMode	valueOf(int rm)	Returns the RoundingMode object corresponding to a legacy integer rounding mode constant in BigDecimal.
  static RoundingMode	valueOf(String name)	Returns the enum constant of this type with the specified name.
  static RoundingMode[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

  • Methods inherited from class java.lang.Enum

    clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

  • Methods inherited from class java.lang.Object

    getClass, notify, notifyAll, wait, wait, wait

• Enum Constant Detail

  • UP

    public static final RoundingMode UP

    Rounding mode to round away from zero. Always increments the digit prior to a non-zero discarded fraction. Note that this rounding mode never decreases the magnitude of the calculated value.

    Example:

    Rounding mode UP Examples

    Input Number	Input rounded to one digit with UP rounding
    5.5	6
    2.5	3
    1.6	2
    1.1	2
    1.0	1
    -1.0	-1
    -1.1	-2
    -1.6	-2
    -2.5	-3
    -5.5	-6

  • DOWN

    public static final RoundingMode DOWN

    Rounding mode to round towards zero. Never increments the digit prior to a discarded fraction (i.e., truncates). Note that this rounding mode never increases the magnitude of the calculated value.

    Example:

    Rounding mode DOWN Examples

    Input Number	Input rounded to one digit with DOWN rounding
    5.5	5
    2.5	2
    1.6	1
    1.1	1
    1.0	1
    -1.0	-1
    -1.1	-1
    -1.6	-1
    -2.5	-2
    -5.5	-5

  • CEILING

    public static final RoundingMode CEILING

    Rounding mode to round towards positive infinity. If the result is positive, behaves as for RoundingMode.UP; if negative, behaves as for RoundingMode.DOWN. Note that this rounding mode never decreases the calculated value.

    Example:

    Rounding mode CEILING Examples

    Input Number	Input rounded to one digit with CEILING rounding
    5.5	6
    2.5	3
    1.6	2
    1.1	2
    1.0	1
    -1.0	-1
    -1.1	-1
    -1.6	-1
    -2.5	-2
    -5.5	-5

  • FLOOR

    public static final RoundingMode FLOOR

    Rounding mode to round towards negative infinity. If the result is positive, behave as for RoundingMode.DOWN; if negative, behave as for RoundingMode.UP. Note that this rounding mode never increases the calculated value.

    Example:

    Rounding mode FLOOR Examples

    Input Number	Input rounded to one digit with FLOOR rounding
    5.5	5
    2.5	2
    1.6	1
    1.1	1
    1.0	1
    -1.0	-1
    -1.1	-2
    -1.6	-2
    -2.5	-3
    -5.5	-6

  • HALF_UP

    public static final RoundingMode HALF_UP

    Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. Behaves as for RoundingMode.UP if the discarded fraction is ≥ 0.5; otherwise, behaves as for RoundingMode.DOWN. Note that this is the rounding mode commonly taught at school.

    Example:

    Rounding mode HALF_UP Examples

    Input Number	Input rounded to one digit with HALF_UP rounding
    5.5	6
    2.5	3
    1.6	2
    1.1	1
    1.0	1
    -1.0	-1
    -1.1	-1
    -1.6	-2
    -2.5	-3
    -5.5	-6

  • HALF_DOWN

    public static final RoundingMode HALF_DOWN

    Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. Behaves as for RoundingMode.UP if the discarded fraction is > 0.5; otherwise, behaves as for RoundingMode.DOWN.

    Example:

    Rounding mode HALF_DOWN Examples

    Input Number	Input rounded to one digit with HALF_DOWN rounding
    5.5	5
    2.5	2
    1.6	2
    1.1	1
    1.0	1
    -1.0	-1
    -1.1	-1
    -1.6	-2
    -2.5	-2
    -5.5	-5

  • HALF_EVEN

    public static final RoundingMode HALF_EVEN

    Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. Behaves as for RoundingMode.HALF_UP if the digit to the left of the discarded fraction is odd; behaves as for RoundingMode.HALF_DOWN if it's even. Note that this is the rounding mode that statistically minimizes cumulative error when applied repeatedly over a sequence of calculations. It is sometimes known as "Banker's rounding," and is chiefly used in the USA. This rounding mode is analogous to the rounding policy used for float and double arithmetic in Java.

    Example:

    Rounding mode HALF_EVEN Examples

    Input Number	Input rounded to one digit with HALF_EVEN rounding
    5.5	6
    2.5	2
    1.6	2
    1.1	1
    1.0	1
    -1.0	-1
    -1.1	-1
    -1.6	-2
    -2.5	-2
    -5.5	-6

  • UNNECESSARY

    public static final RoundingMode UNNECESSARY

    Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary. If this rounding mode is specified on an operation that yields an inexact result, an ArithmeticException is thrown.

    Example:

    Rounding mode UNNECESSARY Examples

    Input Number	Input rounded to one digit with UNNECESSARY rounding
    5.5	throw ArithmeticException
    2.5	throw ArithmeticException
    1.6	throw ArithmeticException
    1.1	throw ArithmeticException
    1.0	1
    -1.0	-1
    -1.1	throw ArithmeticException
    -1.6	throw ArithmeticException
    -2.5	throw ArithmeticException
    -5.5	throw ArithmeticException

• Method Detail

  • values

    public static RoundingMode[] values()

    Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

    for (RoundingMode c : RoundingMode.values())
        System.out.println(c);
    

    Returns:

    an array containing the constants of this enum type, in the order they are declared

  • valueOf

    public static RoundingMode valueOf(String name)

    Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

    Parameters:

    name - the name of the enum constant to be returned.

    Returns:

    the enum constant with the specified name

    Throws:

    IllegalArgumentException - if this enum type has no constant with the specified name

    NullPointerException - if the argument is null

  • valueOf

    public static RoundingMode valueOf(int rm)

    Returns the RoundingMode object corresponding to a legacy integer rounding mode constant in BigDecimal.

    Parameters:

    rm - legacy integer rounding mode to convert

    Returns:

    RoundingMode corresponding to the given integer.

    Throws:

    IllegalArgumentException - integer is out of range