Added in API level 24

MathContext

---

Kotlin |Java

class MathContext : Serializable

kotlin.Any
↳	android.icu.math.MathContext

The MathContext immutable class encapsulates the settings understood by the operator methods of the BigDecimal class (and potentially other classes). Operator methods are those that effect an operation on a number or a pair of numbers.

The settings, which are not base-dependent, comprise:

1. digits: the number of digits (precision) to be used for an operation
2. form: the form of any exponent that results from the operation
3. lostDigits: whether checking for lost digits is enabled
4. roundingMode: the algorithm to be used for rounding.

When provided, a MathContext object supplies the settings for an operation directly.

When MathContext.DEFAULT is provided for a MathContext parameter then the default settings are used (9, SCIENTIFIC, false, ROUND_HALF_UP).

In the BigDecimal class, all methods which accept a MathContext object defaults) also have a version of the method which does not accept a MathContext parameter. These versions carry out unlimited precision fixed point arithmetic (as though the settings were (0, PLAIN, false, ROUND_HALF_UP).

The instance variables are shared with default access (so they are directly accessible to the BigDecimal class), but must never be changed.

The rounding mode constants have the same names and values as the constants of the same name in java.math.BigDecimal, to maintain compatibility with earlier versions of BigDecimal.

Summary

Constants
static Int	ENGINEERING Standard floating point notation (with engineering exponential format, where the power of ten is a multiple of 3).
static Int	PLAIN Plain (fixed point) notation, without any exponent.
static Int	ROUND_CEILING Rounding mode to round to a more positive number.
static Int	ROUND_DOWN Rounding mode to round towards zero.
static Int	ROUND_FLOOR Rounding mode to round to a more negative number.
static Int	ROUND_HALF_DOWN Rounding mode to round to nearest neighbor, where an equidistant value is rounded down.
static Int	ROUND_HALF_EVEN Rounding mode to round to nearest neighbor, where an equidistant value is rounded to the nearest even neighbor.
static Int	ROUND_HALF_UP Rounding mode to round to nearest neighbor, where an equidistant value is rounded up.
static Int	ROUND_UNNECESSARY Rounding mode to assert that no rounding is necessary.
static Int	ROUND_UP Rounding mode to round away from zero.
static Int	SCIENTIFIC Standard floating point notation (with scientific exponential format, where there is one digit before any decimal point).

Public constructors
MathContext(setdigits: Int) Constructs a new MathContext with a specified precision.
MathContext(setdigits: Int, setform: Int) Constructs a new MathContext with a specified precision and form.
MathContext(setdigits: Int, setform: Int, setlostdigits: Boolean) Constructs a new MathContext with a specified precision, form, and lostDigits setting.
MathContext(setdigits: Int, setform: Int, setlostdigits: Boolean, setroundingmode: Int) Constructs a new MathContext with a specified precision, form, lostDigits, and roundingMode setting.

Public methods
Int	getDigits() Returns the digits setting.
Int	getForm() Returns the form setting.
Boolean	getLostDigits() Returns the lostDigits setting.
Int	getRoundingMode() Returns the roundingMode setting.
String	toString() Returns the MathContext as a readable string.

Properties
static MathContext!	DEFAULT A MathContext object initialized to the default settings for general-purpose arithmetic.

Constants

ENGINEERING

Added in API level 24

static val ENGINEERING: Int

Standard floating point notation (with engineering exponential format, where the power of ten is a multiple of 3). Used as a setting to control the form of the result of a BigDecimal operation. A zero result in plain form may have a decimal part of one or more zeros.

Value: 2

See Also

• #PLAIN
• #SCIENTIFIC

PLAIN

Added in API level 24

static val PLAIN: Int

Plain (fixed point) notation, without any exponent. Used as a setting to control the form of the result of a BigDecimal operation. A zero result in plain form may have a decimal part of one or more zeros.

Value: 0

See Also

• #ENGINEERING
• #SCIENTIFIC

ROUND_CEILING

Added in API level 24

static val ROUND_CEILING: Int

Rounding mode to round to a more positive number. Used as a setting to control the rounding mode used during a BigDecimal operation.

If any of the discarded digits are non-zero then the result should be rounded towards the next more positive digit.

Value: 2

ROUND_DOWN

Added in API level 24

static val ROUND_DOWN: Int

Rounding mode to round towards zero. Used as a setting to control the rounding mode used during a BigDecimal operation.

All discarded digits are ignored (truncated). The result is neither incremented nor decremented.

Value: 1

ROUND_FLOOR

Added in API level 24

static val ROUND_FLOOR: Int

Rounding mode to round to a more negative number. Used as a setting to control the rounding mode used during a BigDecimal operation.

If any of the discarded digits are non-zero then the result should be rounded towards the next more negative digit.

Value: 3

ROUND_HALF_DOWN

Added in API level 24

static val ROUND_HALF_DOWN: Int

Rounding mode to round to nearest neighbor, where an equidistant value is rounded down. Used as a setting to control the rounding mode used during a BigDecimal operation.

If the discarded digits represent greater than half (0.5 times) the value of a one in the next position then the result should be rounded up (away from zero). Otherwise the discarded digits are ignored.

Value: 5

ROUND_HALF_EVEN

Added in API level 24

static val ROUND_HALF_EVEN: Int

Rounding mode to round to nearest neighbor, where an equidistant value is rounded to the nearest even neighbor. Used as a setting to control the rounding mode used during a BigDecimal operation.

If the discarded digits represent greater than half (0.5 times) the value of a one in the next position then the result should be rounded up (away from zero). If they represent less than half, then the result should be rounded down.

Otherwise (they represent exactly half) the result is rounded down if its rightmost digit is even, or rounded up if its rightmost digit is odd (to make an even digit).

Value: 6

ROUND_HALF_UP

Added in API level 24

static val ROUND_HALF_UP: Int

Rounding mode to round to nearest neighbor, where an equidistant value is rounded up. Used as a setting to control the rounding mode used during a BigDecimal operation.

If the discarded digits represent greater than or equal to half (0.5 times) the value of a one in the next position then the result should be rounded up (away from zero). Otherwise the discarded digits are ignored.

Value: 4

ROUND_UNNECESSARY

Added in API level 24

static val ROUND_UNNECESSARY: Int

Rounding mode to assert that no rounding is necessary. Used as a setting to control the rounding mode used during a BigDecimal operation.

Rounding (potential loss of information) is not permitted. If any of the discarded digits are non-zero then an ArithmeticException should be thrown.

Value: 7

ROUND_UP

Added in API level 24

static val ROUND_UP: Int

Rounding mode to round away from zero. Used as a setting to control the rounding mode used during a BigDecimal operation.

If any of the discarded digits are non-zero then the result will be rounded up (away from zero).

Value: 0

SCIENTIFIC

Added in API level 24

static val SCIENTIFIC: Int

Standard floating point notation (with scientific exponential format, where there is one digit before any decimal point). Used as a setting to control the form of the result of a BigDecimal operation. A zero result in plain form may have a decimal part of one or more zeros.

Value: 1

See Also

• #ENGINEERING
• #PLAIN

Public constructors

MathContext

Added in API level 24

MathContext(setdigits: Int)

Constructs a new MathContext with a specified precision. The other settings are set to the default values (see DEFAULT). An IllegalArgumentException is thrown if the setdigits parameter is out of range (<0 or >999999999).

Parameters
setdigits	Int: The int digits setting for this MathContext.

Exceptions
java.lang.IllegalArgumentException	parameter out of range.

MathContext

Added in API level 24

MathContext(
    setdigits: Int, 
    setform: Int)

Constructs a new MathContext with a specified precision and form. The other settings are set to the default values (see DEFAULT). An IllegalArgumentException is thrown if the setdigits parameter is out of range (<0 or >999999999), or if the value given for the setform parameter is not one of the appropriate constants.

Parameters
setdigits	Int: The int digits setting for this MathContext.
setform	Int: The int form setting for this MathContext.

Exceptions
java.lang.IllegalArgumentException	parameter out of range.

MathContext

Added in API level 24

MathContext(
    setdigits: Int, 
    setform: Int, 
    setlostdigits: Boolean)

Constructs a new MathContext with a specified precision, form, and lostDigits setting. The roundingMode setting is set to its default value (see DEFAULT). An IllegalArgumentException is thrown if the setdigits parameter is out of range (<0 or >999999999), or if the value given for the setform parameter is not one of the appropriate constants.

Parameters
setdigits	Int: The int digits setting for this MathContext.
setform	Int: The int form setting for this MathContext.
setlostdigits	Boolean: The boolean lostDigits setting for this MathContext.

Exceptions
java.lang.IllegalArgumentException	parameter out of range.

MathContext

Added in API level 24

MathContext(
    setdigits: Int, 
    setform: Int, 
    setlostdigits: Boolean, 
    setroundingmode: Int)

Constructs a new MathContext with a specified precision, form, lostDigits, and roundingMode setting. An IllegalArgumentException is thrown if the setdigits parameter is out of range (<0 or >999999999), or if the value given for the setform or setroundingmode parameters is not one of the appropriate constants.

Parameters
setdigits	Int: The int digits setting for this MathContext.
setform	Int: The int form setting for this MathContext.
setlostdigits	Boolean: The boolean lostDigits setting for this MathContext.
setroundingmode	Int: The int roundingMode setting for this MathContext.

Exceptions
java.lang.IllegalArgumentException	parameter out of range.

Public methods

getDigits

Added in API level 24

fun getDigits(): Int

Returns the digits setting. This value is always non-negative.

Return
Int	an int which is the value of the digits setting

getForm

Added in API level 24

fun getForm(): Int

Returns the form setting. This will be one of ENGINEERING, PLAIN, or SCIENTIFIC.

Return
Int	an int which is the value of the form setting

getLostDigits

Added in API level 24

fun getLostDigits(): Boolean

Returns the lostDigits setting. This will be either true (enabled) or false (disabled).

Return
Boolean	a boolean which is the value of the lostDigits setting

getRoundingMode

Added in API level 24

fun getRoundingMode(): Int

Returns the roundingMode setting. This will be one of ROUND_CEILING, ROUND_DOWN, ROUND_FLOOR, ROUND_HALF_DOWN, ROUND_HALF_EVEN, ROUND_HALF_UP, ROUND_UNNECESSARY, or ROUND_UP.

Return
Int	an int which is the value of the roundingMode setting

toString

Added in API level 24

fun toString(): String

Returns the MathContext as a readable string. The String returned represents the settings of the MathContext object as four blank-delimited words separated by a single blank and with no leading or trailing blanks, as follows:

1. digits=, immediately followed by the value of the digits setting as a numeric word.
2. form=, immediately followed by the value of the form setting as an uppercase word (one of SCIENTIFIC, PLAIN, or ENGINEERING).
3. lostDigits=, immediately followed by the value of the lostDigits setting (1 if enabled, 0 if disabled).
4. roundingMode=, immediately followed by the value of the roundingMode setting as a word. This word will be the same as the name of the corresponding public constant.

For example:
digits=9 form=SCIENTIFIC lostDigits=0 roundingMode=ROUND_HALF_UP

Additional words may be appended to the result of toString in the future if more properties are added to the class.

Return
String	a String representing the context settings.

Properties

DEFAULT

Added in API level 24

static val DEFAULT: MathContext!

A MathContext object initialized to the default settings for general-purpose arithmetic. That is, digits=9 form=SCIENTIFIC lostDigits=false roundingMode=ROUND_HALF_UP.

See Also

• #SCIENTIFIC
• #ROUND_HALF_UP