public class BigDecimal extends Number implements Comparable<BigDecimal>
Immutable, arbitrary-precision signed decimal numbers. A BigDecimal
consists of an arbitrary precision integer unscaled value and a 32-bit integer scale. If zero or positive, the scale is the number of digits to the right of the decimal point. If negative, the unscaled value of the number is multiplied by ten to the power of the negation of the scale. The value of the number represented by the BigDecimal
is therefore (unscaledValue × 10-scale)
.
The BigDecimal
class provides operations for arithmetic, scale manipulation, rounding, comparison, hashing, and format conversion. The toString()
method provides a canonical representation of a BigDecimal
.
The BigDecimal
class gives its user complete control over rounding behavior. If no rounding mode is specified and the exact result cannot be represented, an exception is thrown; otherwise, calculations can be carried out to a chosen precision and rounding mode by supplying an appropriate MathContext
object to the operation. In either case, eight rounding modes are provided for the control of rounding. Using the integer fields in this class (such as ROUND_HALF_UP
) to represent rounding mode is largely obsolete; the enumeration values of the RoundingMode
enum
, (such as RoundingMode.HALF_UP
) should be used instead.
When a MathContext
object is supplied with a precision setting of 0 (for example, MathContext.UNLIMITED
), arithmetic operations are exact, as are the arithmetic methods which take no MathContext
object. (This is the only behavior that was supported in releases prior to 5.) As a corollary of computing the exact result, the rounding mode setting of a MathContext
object with a precision setting of 0 is not used and thus irrelevant. In the case of divide, the exact quotient could have an infinitely long decimal expansion; for example, 1 divided by 3. If the quotient has a nonterminating decimal expansion and the operation is specified to return an exact result, an ArithmeticException
is thrown. Otherwise, the exact result of the division is returned, as done for other operations.
When the precision setting is not 0, the rules of BigDecimal
arithmetic are broadly compatible with selected modes of operation of the arithmetic defined in ANSI X3.274-1996 and ANSI X3.274-1996/AM 1-2000 (section 7.4). Unlike those standards, BigDecimal
includes many rounding modes, which were mandatory for division in BigDecimal
releases prior to 5. Any conflicts between these ANSI standards and the BigDecimal
specification are resolved in favor of BigDecimal
.
Since the same numerical value can have different representations (with different scales), the rules of arithmetic and rounding must specify both the numerical result and the scale used in the result's representation.
In general the rounding modes and precision setting determine how operations return results with a limited number of digits when the exact result has more digits (perhaps infinitely many in the case of division) than the number of digits returned. First, the total number of digits to return is specified by the MathContext
's precision
setting; this determines the result's precision. The digit count starts from the leftmost nonzero digit of the exact result. The rounding mode determines how any discarded trailing digits affect the returned result.
For all arithmetic operators , the operation is carried out as though an exact intermediate result were first calculated and then rounded to the number of digits specified by the precision setting (if necessary), using the selected rounding mode. If the exact result is not returned, some digit positions of the exact result are discarded. When rounding increases the magnitude of the returned result, it is possible for a new digit position to be created by a carry propagating to a leading "9" digit. For example, rounding the value 999.9 to three digits rounding up would be numerically equal to one thousand, represented as 100×101. In such cases, the new "1" is the leading digit position of the returned result.
Besides a logical exact result, each arithmetic operation has a preferred scale for representing a result. The preferred scale for each operation is listed in the table below.
Operation | Preferred Scale of Result |
---|---|
Add | max(addend.scale(), augend.scale()) |
Subtract | max(minuend.scale(), subtrahend.scale()) |
Multiply | multiplier.scale() + multiplicand.scale() |
Divide | dividend.scale() - divisor.scale() |
1/32
is 0.03125
. Before rounding, the scale of the logical exact intermediate result is the preferred scale for that operation. If the exact numerical result cannot be represented in precision
digits, rounding selects the set of digits to return and the scale of the result is reduced from the scale of the intermediate result to the least scale which can represent the precision
digits actually returned. If the exact result can be represented with at most precision
digits, the representation of the result with the scale closest to the preferred scale is returned. In particular, an exactly representable quotient may be represented in fewer than precision
digits by removing trailing zeros and decreasing the scale. For example, rounding to three digits using the floor rounding mode,
19/100 = 0.19 // integer=19, scale=2
but
21/110 = 0.190 // integer=190, scale=3
Note that for add, subtract, and multiply, the reduction in scale will equal the number of digit positions of the exact result which are discarded. If the rounding causes a carry propagation to create a new high-order digit position, an additional digit of the result is discarded than when no new digit position is created.
Other methods may have slightly different rounding semantics. For example, the result of the pow
method using the specified algorithm can occasionally differ from the rounded mathematical result by more than one unit in the last place, one ulp.
Two types of operations are provided for manipulating the scale of a BigDecimal
: scaling/rounding operations and decimal point motion operations. Scaling/rounding operations (setScale
and round
) return a BigDecimal
whose value is approximately (or exactly) equal to that of the operand, but whose scale or precision is the specified value; that is, they increase or decrease the precision of the stored number with minimal effect on its value. Decimal point motion operations (movePointLeft
and movePointRight
) return a BigDecimal
created from the operand by moving the decimal point a specified distance in the specified direction.
For the sake of brevity and clarity, pseudo-code is used throughout the descriptions of BigDecimal
methods. The pseudo-code expression (i + j)
is shorthand for "a BigDecimal
whose value is that of the BigDecimal
i
added to that of the BigDecimal
j
." The pseudo-code expression (i == j)
is shorthand for "true
if and only if the BigDecimal
i
represents the same value as the BigDecimal
j
." Other pseudo-code expressions are interpreted similarly. Square brackets are used to represent the particular BigInteger
and scale pair defining a BigDecimal
value; for example [19, 2] is the BigDecimal
numerically equal to 0.19 having a scale of 2.
Note: care should be exercised if BigDecimal
objects are used as keys in a SortedMap
or elements in a SortedSet
since BigDecimal
's natural ordering is inconsistent with equals. See Comparable
, SortedMap
or SortedSet
for more information.
All methods and constructors for this class throw NullPointerException
when passed a null
object reference for any input parameter.
BigInteger
, MathContext
, RoundingMode
, SortedMap
, SortedSet
, Serialized Formpublic static final BigDecimal ZERO
The value 0, with a scale of 0.
public static final BigDecimal ONE
The value 1, with a scale of 0.
public static final BigDecimal TEN
The value 10, with a scale of 0.
public static final int ROUND_UP
Rounding mode to round away from zero. Always increments the digit prior to a nonzero discarded fraction. Note that this rounding mode never decreases the magnitude of the calculated value.
public static final int ROUND_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.
public static final int ROUND_CEILING
Rounding mode to round towards positive infinity. If the BigDecimal
is positive, behaves as for ROUND_UP
; if negative, behaves as for ROUND_DOWN
. Note that this rounding mode never decreases the calculated value.
public static final int ROUND_FLOOR
Rounding mode to round towards negative infinity. If the BigDecimal
is positive, behave as for ROUND_DOWN
; if negative, behave as for ROUND_UP
. Note that this rounding mode never increases the calculated value.
public static final int ROUND_HALF_UP
Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. Behaves as for ROUND_UP
if the discarded fraction is ≥ 0.5; otherwise, behaves as for ROUND_DOWN
. Note that this is the rounding mode that most of us were taught in grade school.
public static final int ROUND_HALF_DOWN
Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. Behaves as for ROUND_UP
if the discarded fraction is > 0.5; otherwise, behaves as for ROUND_DOWN
.
public static final int ROUND_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 ROUND_HALF_UP
if the digit to the left of the discarded fraction is odd; behaves as for ROUND_HALF_DOWN
if it's even. Note that this is the rounding mode that minimizes cumulative error when applied repeatedly over a sequence of calculations.
public static final int ROUND_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.
public BigDecimal(char[] in, int offset, int len)
Translates a character array representation of a BigDecimal
into a BigDecimal
, accepting the same sequence of characters as the BigDecimal(String)
constructor, while allowing a sub-array to be specified.
Note that if the sequence of characters is already available within a character array, using this constructor is faster than converting the char
array to string and using the BigDecimal(String)
constructor .
in
- char
array that is the source of characters.offset
- first character in the array to inspect.len
- number of characters to consider.NumberFormatException
- if in
is not a valid representation of a BigDecimal
or the defined subarray is not wholly within in
.public BigDecimal(char[] in, int offset, int len, MathContext mc)
Translates a character array representation of a BigDecimal
into a BigDecimal
, accepting the same sequence of characters as the BigDecimal(String)
constructor, while allowing a sub-array to be specified and with rounding according to the context settings.
Note that if the sequence of characters is already available within a character array, using this constructor is faster than converting the char
array to string and using the BigDecimal(String)
constructor .
in
- char
array that is the source of characters.offset
- first character in the array to inspect.len
- number of characters to consider..mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.NumberFormatException
- if in
is not a valid representation of a BigDecimal
or the defined subarray is not wholly within in
.public BigDecimal(char[] in)
Translates a character array representation of a BigDecimal
into a BigDecimal
, accepting the same sequence of characters as the BigDecimal(String)
constructor.
Note that if the sequence of characters is already available as a character array, using this constructor is faster than converting the char
array to string and using the BigDecimal(String)
constructor .
in
- char
array that is the source of characters.NumberFormatException
- if in
is not a valid representation of a BigDecimal
.public BigDecimal(char[] in, MathContext mc)
Translates a character array representation of a BigDecimal
into a BigDecimal
, accepting the same sequence of characters as the BigDecimal(String)
constructor and with rounding according to the context settings.
Note that if the sequence of characters is already available as a character array, using this constructor is faster than converting the char
array to string and using the BigDecimal(String)
constructor .
in
- char
array that is the source of characters.mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.NumberFormatException
- if in
is not a valid representation of a BigDecimal
.public BigDecimal(String val)
Translates the string representation of a BigDecimal
into a BigDecimal
. The string representation consists of an optional sign, '+'
( '\u002B'
) or '-'
('\u002D'
), followed by a sequence of zero or more decimal digits ("the integer"), optionally followed by a fraction, optionally followed by an exponent.
The fraction consists of a decimal point followed by zero or more decimal digits. The string must contain at least one digit in either the integer or the fraction. The number formed by the sign, the integer and the fraction is referred to as the significand.
The exponent consists of the character 'e'
('\u0065'
) or 'E'
('\u0045'
) followed by one or more decimal digits. The value of the exponent must lie between -Integer.MAX_VALUE
(Integer.MIN_VALUE
+1) and Integer.MAX_VALUE
, inclusive.
More formally, the strings this constructor accepts are described by the following grammar:
+
-
.
FractionPartopt .
FractionPart e
E
Character.isDigit(char)
returns true
, including 0, 1, 2 ... The scale of the returned BigDecimal
will be the number of digits in the fraction, or zero if the string contains no decimal point, subject to adjustment for any exponent; if the string contains an exponent, the exponent is subtracted from the scale. The value of the resulting scale must lie between Integer.MIN_VALUE
and Integer.MAX_VALUE
, inclusive.
The character-to-digit mapping is provided by Character.digit(char, int)
set to convert to radix 10. The String may not contain any extraneous characters (whitespace, for example).
Examples:
The value of the returned BigDecimal
is equal to significand × 10 exponent. For each string on the left, the resulting representation [BigInteger
, scale
] is shown on the right.
"0" [0,0] "0.00" [0,2] "123" [123,0] "-123" [-123,0] "1.23E3" [123,-1] "1.23E+3" [123,-1] "12.3E+7" [123,-6] "12.0" [120,1] "12.3" [123,1] "0.00123" [123,5] "-1.23E-12" [-123,14] "1234.5E-4" [12345,5] "0E+7" [0,-7] "-0" [0,0]
Note: For values other than float
and double
NaN and ±Infinity, this constructor is compatible with the values returned by Float.toString(float)
and Double.toString(double)
. This is generally the preferred way to convert a float
or double
into a BigDecimal, as it doesn't suffer from the unpredictability of the BigDecimal(double)
constructor.
val
- String representation of BigDecimal
.NumberFormatException
- if val
is not a valid representation of a BigDecimal
.public BigDecimal(String val, MathContext mc)
Translates the string representation of a BigDecimal
into a BigDecimal
, accepting the same strings as the BigDecimal(String)
constructor, with rounding according to the context settings.
val
- string representation of a BigDecimal
.mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.NumberFormatException
- if val
is not a valid representation of a BigDecimal.public BigDecimal(double val)
Translates a double
into a BigDecimal
which is the exact decimal representation of the double
's binary floating-point value. The scale of the returned BigDecimal
is the smallest value such that (10scale × val)
is an integer.
Notes:
new BigDecimal(0.1)
in Java creates a BigDecimal
which is exactly equal to 0.1 (an unscaled value of 1, with a scale of 1), but it is actually equal to 0.1000000000000000055511151231257827021181583404541015625. This is because 0.1 cannot be represented exactly as a double
(or, for that matter, as a binary fraction of any finite length). Thus, the value that is being passed in to the constructor is not exactly equal to 0.1, appearances notwithstanding. String
constructor, on the other hand, is perfectly predictable: writing new BigDecimal("0.1")
creates a BigDecimal
which is exactly equal to 0.1, as one would expect. Therefore, it is generally recommended that the String
constructor be used in preference to this one. double
must be used as a source for a BigDecimal
, note that this constructor provides an exact conversion; it does not give the same result as converting the double
to a String
using the Double.toString(double)
method and then using the BigDecimal(String)
constructor. To get that result, use the static
valueOf(double)
method. val
- double
value to be converted to BigDecimal
.NumberFormatException
- if val
is infinite or NaN.public BigDecimal(double val, MathContext mc)
Translates a double
into a BigDecimal
, with rounding according to the context settings. The scale of the BigDecimal
is the smallest value such that (10scale × val)
is an integer.
The results of this constructor can be somewhat unpredictable and its use is generally not recommended; see the notes under the BigDecimal(double)
constructor.
val
- double
value to be converted to BigDecimal
.mc
- the context to use.ArithmeticException
- if the result is inexact but the RoundingMode is UNNECESSARY.NumberFormatException
- if val
is infinite or NaN.public BigDecimal(BigInteger val)
Translates a BigInteger
into a BigDecimal
. The scale of the BigDecimal
is zero.
val
- BigInteger
value to be converted to BigDecimal
.public BigDecimal(BigInteger val, MathContext mc)
Translates a BigInteger
into a BigDecimal
rounding according to the context settings. The scale of the BigDecimal
is zero.
val
- BigInteger
value to be converted to BigDecimal
.mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal(BigInteger unscaledVal, int scale)
Translates a BigInteger
unscaled value and an int
scale into a BigDecimal
. The value of the BigDecimal
is (unscaledVal × 10-scale)
.
unscaledVal
- unscaled value of the BigDecimal
.scale
- scale of the BigDecimal
.public BigDecimal(BigInteger unscaledVal, int scale, MathContext mc)
Translates a BigInteger
unscaled value and an int
scale into a BigDecimal
, with rounding according to the context settings. The value of the BigDecimal
is (unscaledVal × 10-scale)
, rounded according to the precision
and rounding mode settings.
unscaledVal
- unscaled value of the BigDecimal
.scale
- scale of the BigDecimal
.mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal(int val)
Translates an int
into a BigDecimal
. The scale of the BigDecimal
is zero.
val
- int
value to be converted to BigDecimal
.public BigDecimal(int val, MathContext mc)
Translates an int
into a BigDecimal
, with rounding according to the context settings. The scale of the BigDecimal
, before any rounding, is zero.
val
- int
value to be converted to BigDecimal
.mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal(long val)
Translates a long
into a BigDecimal
. The scale of the BigDecimal
is zero.
val
- long
value to be converted to BigDecimal
.public BigDecimal(long val, MathContext mc)
Translates a long
into a BigDecimal
, with rounding according to the context settings. The scale of the BigDecimal
, before any rounding, is zero.
val
- long
value to be converted to BigDecimal
.mc
- the context to use.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public static BigDecimal valueOf(long unscaledVal, int scale)
Translates a long
unscaled value and an int
scale into a BigDecimal
. This "static factory method" is provided in preference to a (long
, int
) constructor because it allows for reuse of frequently used BigDecimal
values..
unscaledVal
- unscaled value of the BigDecimal
.scale
- scale of the BigDecimal
.BigDecimal
whose value is (unscaledVal × 10-scale)
.public static BigDecimal valueOf(long val)
Translates a long
value into a BigDecimal
with a scale of zero. This "static factory method" is provided in preference to a (long
) constructor because it allows for reuse of frequently used BigDecimal
values.
val
- value of the BigDecimal
.BigDecimal
whose value is val
.public static BigDecimal valueOf(double val)
Translates a double
into a BigDecimal
, using the double
's canonical string representation provided by the Double.toString(double)
method.
Note: This is generally the preferred way to convert a double
(or float
) into a BigDecimal
, as the value returned is equal to that resulting from constructing a BigDecimal
from the result of using Double.toString(double)
.
val
- double
to convert to a BigDecimal
.BigDecimal
whose value is equal to or approximately equal to the value of val
.NumberFormatException
- if val
is infinite or NaN.public BigDecimal add(BigDecimal augend)
Returns a BigDecimal
whose value is (this +
augend)
, and whose scale is max(this.scale(),
augend.scale())
.
augend
- value to be added to this BigDecimal
.this + augend
public BigDecimal add(BigDecimal augend, MathContext mc)
Returns a BigDecimal
whose value is (this + augend)
, with rounding according to the context settings. If either number is zero and the precision setting is nonzero then the other number, rounded if necessary, is used as the result.
augend
- value to be added to this BigDecimal
.mc
- the context to use.this + augend
, rounded as necessary.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal subtract(BigDecimal subtrahend)
Returns a BigDecimal
whose value is (this -
subtrahend)
, and whose scale is max(this.scale(),
subtrahend.scale())
.
subtrahend
- value to be subtracted from this BigDecimal
.this - subtrahend
public BigDecimal subtract(BigDecimal subtrahend, MathContext mc)
Returns a BigDecimal
whose value is (this - subtrahend)
, with rounding according to the context settings. If subtrahend
is zero then this, rounded if necessary, is used as the result. If this is zero then the result is subtrahend.negate(mc)
.
subtrahend
- value to be subtracted from this BigDecimal
.mc
- the context to use.this - subtrahend
, rounded as necessary.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal multiply(BigDecimal multiplicand)
Returns a BigDecimal
whose value is (this × multiplicand)
, and whose scale is (this.scale() +
multiplicand.scale())
.
multiplicand
- value to be multiplied by this BigDecimal
.this * multiplicand
public BigDecimal multiply(BigDecimal multiplicand, MathContext mc)
Returns a BigDecimal
whose value is (this × multiplicand)
, with rounding according to the context settings.
multiplicand
- value to be multiplied by this BigDecimal
.mc
- the context to use.this * multiplicand
, rounded as necessary.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal divide(BigDecimal divisor, int scale, int roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is as specified. If rounding must be performed to generate a result with the specified scale, the specified rounding mode is applied.
The new divide(BigDecimal, int, RoundingMode)
method should be used in preference to this legacy method.
divisor
- value by which this BigDecimal
is to be divided.scale
- scale of the BigDecimal
quotient to be returned.roundingMode
- rounding mode to apply.this / divisor
ArithmeticException
- if divisor
is zero, roundingMode==ROUND_UNNECESSARY
and the specified scale is insufficient to represent the result of the division exactly.IllegalArgumentException
- if roundingMode
does not represent a valid rounding mode.ROUND_UP
, ROUND_DOWN
, ROUND_CEILING
, ROUND_FLOOR
, ROUND_HALF_UP
, ROUND_HALF_DOWN
, ROUND_HALF_EVEN
, ROUND_UNNECESSARY
public BigDecimal divide(BigDecimal divisor, int scale, RoundingMode roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is as specified. If rounding must be performed to generate a result with the specified scale, the specified rounding mode is applied.
divisor
- value by which this BigDecimal
is to be divided.scale
- scale of the BigDecimal
quotient to be returned.roundingMode
- rounding mode to apply.this / divisor
ArithmeticException
- if divisor
is zero, roundingMode==RoundingMode.UNNECESSARY
and the specified scale is insufficient to represent the result of the division exactly.public BigDecimal divide(BigDecimal divisor, int roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is this.scale()
. If rounding must be performed to generate a result with the given scale, the specified rounding mode is applied.
The new divide(BigDecimal, RoundingMode)
method should be used in preference to this legacy method.
divisor
- value by which this BigDecimal
is to be divided.roundingMode
- rounding mode to apply.this / divisor
ArithmeticException
- if divisor==0
, or roundingMode==ROUND_UNNECESSARY
and this.scale()
is insufficient to represent the result of the division exactly.IllegalArgumentException
- if roundingMode
does not represent a valid rounding mode.ROUND_UP
, ROUND_DOWN
, ROUND_CEILING
, ROUND_FLOOR
, ROUND_HALF_UP
, ROUND_HALF_DOWN
, ROUND_HALF_EVEN
, ROUND_UNNECESSARY
public BigDecimal divide(BigDecimal divisor, RoundingMode roundingMode)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose scale is this.scale()
. If rounding must be performed to generate a result with the given scale, the specified rounding mode is applied.
divisor
- value by which this BigDecimal
is to be divided.roundingMode
- rounding mode to apply.this / divisor
ArithmeticException
- if divisor==0
, or roundingMode==RoundingMode.UNNECESSARY
and this.scale()
is insufficient to represent the result of the division exactly.public BigDecimal divide(BigDecimal divisor)
Returns a BigDecimal
whose value is (this /
divisor)
, and whose preferred scale is (this.scale() -
divisor.scale())
; if the exact quotient cannot be represented (because it has a non-terminating decimal expansion) an ArithmeticException
is thrown.
divisor
- value by which this BigDecimal
is to be divided.this / divisor
ArithmeticException
- if the exact quotient does not have a terminating decimal expansionpublic BigDecimal divide(BigDecimal divisor, MathContext mc)
Returns a BigDecimal
whose value is (this /
divisor)
, with rounding according to the context settings.
divisor
- value by which this BigDecimal
is to be divided.mc
- the context to use.this / divisor
, rounded as necessary.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
or mc.precision == 0
and the quotient has a non-terminating decimal expansion.public BigDecimal divideToIntegralValue(BigDecimal divisor)
Returns a BigDecimal
whose value is the integer part of the quotient (this / divisor)
rounded down. The preferred scale of the result is (this.scale() -
divisor.scale())
.
divisor
- value by which this BigDecimal
is to be divided.this / divisor
.ArithmeticException
- if divisor==0
public BigDecimal divideToIntegralValue(BigDecimal divisor, MathContext mc)
Returns a BigDecimal
whose value is the integer part of (this / divisor)
. Since the integer part of the exact quotient does not depend on the rounding mode, the rounding mode does not affect the values returned by this method. The preferred scale of the result is (this.scale() - divisor.scale())
. An ArithmeticException
is thrown if the integer part of the exact quotient needs more than mc.precision
digits.
divisor
- value by which this BigDecimal
is to be divided.mc
- the context to use.this / divisor
.ArithmeticException
- if divisor==0
ArithmeticException
- if mc.precision
> 0 and the result requires a precision of more than mc.precision
digits.public BigDecimal remainder(BigDecimal divisor)
Returns a BigDecimal
whose value is (this % divisor)
.
The remainder is given by this.subtract(this.divideToIntegralValue(divisor).multiply(divisor))
. Note that this is not the modulo operation (the result can be negative).
divisor
- value by which this BigDecimal
is to be divided.this % divisor
.ArithmeticException
- if divisor==0
public BigDecimal remainder(BigDecimal divisor, MathContext mc)
Returns a BigDecimal
whose value is (this %
divisor)
, with rounding according to the context settings. The MathContext
settings affect the implicit divide used to compute the remainder. The remainder computation itself is by definition exact. Therefore, the remainder may contain more than mc.getPrecision()
digits.
The remainder is given by this.subtract(this.divideToIntegralValue(divisor,
mc).multiply(divisor))
. Note that this is not the modulo operation (the result can be negative).
divisor
- value by which this BigDecimal
is to be divided.mc
- the context to use.this % divisor
, rounded as necessary.ArithmeticException
- if divisor==0
ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
, or mc.precision
> 0 and the result of this.divideToIntgralValue(divisor)
would require a precision of more than mc.precision
digits.divideToIntegralValue(java.math.BigDecimal, java.math.MathContext)
public BigDecimal[] divideAndRemainder(BigDecimal divisor)
Returns a two-element BigDecimal
array containing the result of divideToIntegralValue
followed by the result of remainder
on the two operands.
Note that if both the integer quotient and remainder are needed, this method is faster than using the divideToIntegralValue
and remainder
methods separately because the division need only be carried out once.
divisor
- value by which this BigDecimal
is to be divided, and the remainder computed.BigDecimal
array: the quotient (the result of divideToIntegralValue
) is the initial element and the remainder is the final element.ArithmeticException
- if divisor==0
divideToIntegralValue(java.math.BigDecimal, java.math.MathContext)
, remainder(java.math.BigDecimal, java.math.MathContext)
public BigDecimal[] divideAndRemainder(BigDecimal divisor, MathContext mc)
Returns a two-element BigDecimal
array containing the result of divideToIntegralValue
followed by the result of remainder
on the two operands calculated with rounding according to the context settings.
Note that if both the integer quotient and remainder are needed, this method is faster than using the divideToIntegralValue
and remainder
methods separately because the division need only be carried out once.
divisor
- value by which this BigDecimal
is to be divided, and the remainder computed.mc
- the context to use.BigDecimal
array: the quotient (the result of divideToIntegralValue
) is the initial element and the remainder is the final element.ArithmeticException
- if divisor==0
ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
, or mc.precision
> 0 and the result of this.divideToIntgralValue(divisor)
would require a precision of more than mc.precision
digits.divideToIntegralValue(java.math.BigDecimal, java.math.MathContext)
, remainder(java.math.BigDecimal, java.math.MathContext)
public BigDecimal pow(int n)
Returns a BigDecimal
whose value is (thisn)
, The power is computed exactly, to unlimited precision.
The parameter n
must be in the range 0 through 999999999, inclusive. ZERO.pow(0)
returns ONE
. Note that future releases may expand the allowable exponent range of this method.
n
- power to raise this BigDecimal
to.thisn
ArithmeticException
- if n
is out of range.public BigDecimal pow(int n, MathContext mc)
Returns a BigDecimal
whose value is (thisn)
. The current implementation uses the core algorithm defined in ANSI standard X3.274-1996 with rounding according to the context settings. In general, the returned numerical value is within two ulps of the exact numerical value for the chosen precision. Note that future releases may use a different algorithm with a decreased allowable error bound and increased allowable exponent range.
The X3.274-1996 algorithm is:
ArithmeticException
exception is thrown if abs(n) > 999999999
mc.precision == 0
and n < 0
mc.precision > 0
and n
has more than mc.precision
decimal digits n
is zero, ONE
is returned even if this
is zero, otherwise n
is positive, the result is calculated via the repeated squaring technique into a single accumulator. The individual multiplications with the accumulator use the same math context settings as in mc
except for a precision increased to mc.precision + elength + 1
where elength
is the number of decimal digits in n
. n
is negative, the result is calculated as if n
were positive; this value is then divided into one using the working precision specified above. n
- power to raise this BigDecimal
to.mc
- the context to use.thisn
using the ANSI standard X3.274-1996 algorithmArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
, or n
is out of range.public BigDecimal abs()
Returns a BigDecimal
whose value is the absolute value of this BigDecimal
, and whose scale is this.scale()
.
abs(this)
public BigDecimal abs(MathContext mc)
Returns a BigDecimal
whose value is the absolute value of this BigDecimal
, with rounding according to the context settings.
mc
- the context to use.abs(this)
, rounded as necessary.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal negate()
Returns a BigDecimal
whose value is (-this)
, and whose scale is this.scale()
.
-this
.public BigDecimal negate(MathContext mc)
Returns a BigDecimal
whose value is (-this)
, with rounding according to the context settings.
mc
- the context to use.-this
, rounded as necessary.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.public BigDecimal plus()
Returns a BigDecimal
whose value is (+this)
, and whose scale is this.scale()
.
This method, which simply returns this BigDecimal
is included for symmetry with the unary minus method negate()
.
this
.negate()
public BigDecimal plus(MathContext mc)
Returns a BigDecimal
whose value is (+this)
, with rounding according to the context settings.
The effect of this method is identical to that of the round(MathContext)
method.
mc
- the context to use.this
, rounded as necessary. A zero result will have a scale of 0.ArithmeticException
- if the result is inexact but the rounding mode is UNNECESSARY
.round(MathContext)
public int signum()
Returns the signum function of this BigDecimal
.
BigDecimal
is negative, zero, or positive.public int scale()
Returns the scale of this BigDecimal
. If zero or positive, the scale is the number of digits to the right of the decimal point. If negative, the unscaled value of the number is multiplied by ten to the power of the negation of the scale. For example, a scale of -3
means the unscaled value is multiplied by 1000.
BigDecimal
.public int precision()
Returns the precision of this BigDecimal
. (The precision is the number of digits in the unscaled value.)
The precision of a zero value is 1.
BigDecimal
.public BigInteger unscaledValue()
Returns a BigInteger
whose value is the unscaled value of this BigDecimal
. (Computes (this * 10this.scale())
.)
BigDecimal
.public BigDecimal round(MathContext mc)
Returns a BigDecimal
rounded according to the MathContext
settings. If the precision setting is 0 then no rounding takes place.
The effect of this method is identical to that of the plus(MathContext)
method.
mc
- the context to use.BigDecimal
rounded according to the MathContext
settings.ArithmeticException
- if the rounding mode is UNNECESSARY
and the BigDecimal
operation would require rounding.plus(MathContext)
public BigDecimal setScale(int newScale, RoundingMode roundingMode)
Returns a BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing this BigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value. If the scale is reduced by the operation, the unscaled value must be divided (rather than multiplied), and the value may be changed; in this case, the specified rounding mode is applied to the division.
Note that since BigDecimal objects are immutable, calls of this method do not result in the original object being modified, contrary to the usual convention of having methods named setX
mutate field X
. Instead, setScale
returns an object with the proper scale; the returned object may or may not be newly allocated.
newScale
- scale of the BigDecimal
value to be returned.roundingMode
- The rounding mode to apply.BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing this BigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value.ArithmeticException
- if roundingMode==UNNECESSARY
and the specified scaling operation would require rounding.RoundingMode
public BigDecimal setScale(int newScale, int roundingMode)
Returns a BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing this BigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value. If the scale is reduced by the operation, the unscaled value must be divided (rather than multiplied), and the value may be changed; in this case, the specified rounding mode is applied to the division.
Note that since BigDecimal objects are immutable, calls of this method do not result in the original object being modified, contrary to the usual convention of having methods named setX
mutate field X
. Instead, setScale
returns an object with the proper scale; the returned object may or may not be newly allocated.
The new setScale(int, RoundingMode)
method should be used in preference to this legacy method.
newScale
- scale of the BigDecimal
value to be returned.roundingMode
- The rounding mode to apply.BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing this BigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value.ArithmeticException
- if roundingMode==ROUND_UNNECESSARY
and the specified scaling operation would require rounding.IllegalArgumentException
- if roundingMode
does not represent a valid rounding mode.ROUND_UP
, ROUND_DOWN
, ROUND_CEILING
, ROUND_FLOOR
, ROUND_HALF_UP
, ROUND_HALF_DOWN
, ROUND_HALF_EVEN
, ROUND_UNNECESSARY
public BigDecimal setScale(int newScale)
Returns a BigDecimal
whose scale is the specified value, and whose value is numerically equal to this BigDecimal
's. Throws an ArithmeticException
if this is not possible.
This call is typically used to increase the scale, in which case it is guaranteed that there exists a BigDecimal
of the specified scale and the correct value. The call can also be used to reduce the scale if the caller knows that the BigDecimal
has sufficiently many zeros at the end of its fractional part (i.e., factors of ten in its integer value) to allow for the rescaling without changing its value.
This method returns the same result as the two-argument versions of setScale
, but saves the caller the trouble of specifying a rounding mode in cases where it is irrelevant.
Note that since BigDecimal
objects are immutable, calls of this method do not result in the original object being modified, contrary to the usual convention of having methods named setX
mutate field X
. Instead, setScale
returns an object with the proper scale; the returned object may or may not be newly allocated.
newScale
- scale of the BigDecimal
value to be returned.BigDecimal
whose scale is the specified value, and whose unscaled value is determined by multiplying or dividing this BigDecimal
's unscaled value by the appropriate power of ten to maintain its overall value.ArithmeticException
- if the specified scaling operation would require rounding.setScale(int, int)
, setScale(int, RoundingMode)
public BigDecimal movePointLeft(int n)
Returns a BigDecimal
which is equivalent to this one with the decimal point moved n
places to the left. If n
is non-negative, the call merely adds n
to the scale. If n
is negative, the call is equivalent to movePointRight(-n)
. The BigDecimal
returned by this call has value (this × 10-n)
and scale max(this.scale()+n,
0)
.
n
- number of places to move the decimal point to the left.BigDecimal
which is equivalent to this one with the decimal point moved n
places to the left.ArithmeticException
- if scale overflows.public BigDecimal movePointRight(int n)
Returns a BigDecimal
which is equivalent to this one with the decimal point moved n
places to the right. If n
is non-negative, the call merely subtracts n
from the scale. If n
is negative, the call is equivalent to movePointLeft(-n)
. The BigDecimal
returned by this call has value (this × 10n)
and scale max(this.scale()-n,
0)
.
n
- number of places to move the decimal point to the right.BigDecimal
which is equivalent to this one with the decimal point moved n
places to the right.ArithmeticException
- if scale overflows.public BigDecimal scaleByPowerOfTen(int n)
Returns a BigDecimal whose numerical value is equal to (this
* 10n). The scale of the result is (this.scale() - n)
.
n
- the exponent power of ten to scale bythis
* 10n)ArithmeticException
- if the scale would be outside the range of a 32-bit integer.public BigDecimal stripTrailingZeros()
Returns a BigDecimal
which is numerically equal to this one but with any trailing zeros removed from the representation. For example, stripping the trailing zeros from the BigDecimal
value 600.0
, which has [BigInteger
, scale
] components equals to [6000, 1], yields 6E2
with [BigInteger
, scale
] components equals to [6, -2]. If this BigDecimal is numerically equal to zero, then BigDecimal.ZERO
is returned.
BigDecimal
with any trailing zeros removed.public int compareTo(BigDecimal val)
Compares this BigDecimal
with the specified BigDecimal
. Two BigDecimal
objects that are equal in value but have a different scale (like 2.0 and 2.00) are considered equal by this method. This method is provided in preference to individual methods for each of the six boolean comparison operators (<, ==, >, >=, !=, <=). The suggested idiom for performing these comparisons is: (x.compareTo(y)
<op> 0)
, where <op> is one of the six comparison operators.
compareTo
in interface Comparable<BigDecimal>
val
- BigDecimal
to which this BigDecimal
is to be compared.BigDecimal
is numerically less than, equal to, or greater than val
.public boolean equals(Object x)
Compares this BigDecimal
with the specified Object
for equality. Unlike compareTo
, this method considers two BigDecimal
objects equal only if they are equal in value and scale (thus 2.0 is not equal to 2.00 when compared by this method).
equals
in class Object
x
- Object
to which this BigDecimal
is to be compared.true
if and only if the specified Object
is a BigDecimal
whose value and scale are equal to this BigDecimal
's.compareTo(java.math.BigDecimal)
, hashCode()
public BigDecimal min(BigDecimal val)
Returns the minimum of this BigDecimal
and val
.
val
- value with which the minimum is to be computed.BigDecimal
whose value is the lesser of this BigDecimal
and val
. If they are equal, as defined by the compareTo
method, this
is returned.compareTo(java.math.BigDecimal)
public BigDecimal max(BigDecimal val)
Returns the maximum of this BigDecimal
and val
.
val
- value with which the maximum is to be computed.BigDecimal
whose value is the greater of this BigDecimal
and val
. If they are equal, as defined by the compareTo
method, this
is returned.compareTo(java.math.BigDecimal)
public int hashCode()
Returns the hash code for this BigDecimal
. Note that two BigDecimal
objects that are numerically equal but differ in scale (like 2.0 and 2.00) will generally not have the same hash code.
hashCode
in class Object
BigDecimal
.equals(Object)
public String toString()
Returns the string representation of this BigDecimal
, using scientific notation if an exponent is needed.
A standard canonical string form of the BigDecimal
is created as though by the following steps: first, the absolute value of the unscaled value of the BigDecimal
is converted to a string in base ten using the characters '0'
through '9'
with no leading zeros (except if its value is zero, in which case a single '0'
character is used).
Next, an adjusted exponent is calculated; this is the negated scale, plus the number of characters in the converted unscaled value, less one. That is, -scale+(ulength-1)
, where ulength
is the length of the absolute value of the unscaled value in decimal digits (its precision).
If the scale is greater than or equal to zero and the adjusted exponent is greater than or equal to -6
, the number will be converted to a character form without using exponential notation. In this case, if the scale is zero then no decimal point is added and if the scale is positive a decimal point will be inserted with the scale specifying the number of characters to the right of the decimal point. '0'
characters are added to the left of the converted unscaled value as necessary. If no character precedes the decimal point after this insertion then a conventional '0'
character is prefixed.
Otherwise (that is, if the scale is negative, or the adjusted exponent is less than -6
), the number will be converted to a character form using exponential notation. In this case, if the converted BigInteger
has more than one digit a decimal point is inserted after the first digit. An exponent in character form is then suffixed to the converted unscaled value (perhaps with inserted decimal point); this comprises the letter 'E'
followed immediately by the adjusted exponent converted to a character form. The latter is in base ten, using the characters '0'
through '9'
with no leading zeros, and is always prefixed by a sign character '-'
('\u002D'
) if the adjusted exponent is negative, '+'
('\u002B'
) otherwise).
Finally, the entire string is prefixed by a minus sign character '-'
('\u002D'
) if the unscaled value is less than zero. No sign character is prefixed if the unscaled value is zero or positive.
Examples:
For each representation [unscaled value, scale] on the left, the resulting string is shown on the right.
[123,0] "123" [-123,0] "-123" [123,-1] "1.23E+3" [123,-3] "1.23E+5" [123,1] "12.3" [123,5] "0.00123" [123,10] "1.23E-8" [-123,12] "-1.23E-10"Notes:
BigDecimal
values and the result of this conversion. That is, every distinguishable BigDecimal
value (unscaled value and scale) has a unique string representation as a result of using toString
. If that string representation is converted back to a BigDecimal
using the BigDecimal(String)
constructor, then the original value will be recovered. NumberFormat
class and its subclasses. toEngineeringString()
method may be used for presenting numbers with exponents in engineering notation, and the setScale
method may be used for rounding a BigDecimal
so it has a known number of digits after the decimal point. Character.forDigit
is used. toString
in class Object
BigDecimal
.Character.forDigit(int, int)
, BigDecimal(java.lang.String)
public String toEngineeringString()
Returns a string representation of this BigDecimal
, using engineering notation if an exponent is needed.
Returns a string that represents the BigDecimal
as described in the toString()
method, except that if exponential notation is used, the power of ten is adjusted to be a multiple of three (engineering notation) such that the integer part of nonzero values will be in the range 1 through 999. If exponential notation is used for zero values, a decimal point and one or two fractional zero digits are used so that the scale of the zero value is preserved. Note that unlike the output of toString()
, the output of this method is not guaranteed to recover the same [integer, scale] pair of this BigDecimal
if the output string is converting back to a BigDecimal
using the string constructor. The result of this method meets the weaker constraint of always producing a numerically equal result from applying the string constructor to the method's output.
BigDecimal
, using engineering notation if an exponent is needed.public String toPlainString()
Returns a string representation of this BigDecimal
without an exponent field. For values with a positive scale, the number of digits to the right of the decimal point is used to indicate scale. For values with a zero or negative scale, the resulting string is generated as if the value were converted to a numerically equal value with zero scale and as if all the trailing zeros of the zero scale value were present in the result. The entire string is prefixed by a minus sign character '-' ('\u002D'
) if the unscaled value is less than zero. No sign character is prefixed if the unscaled value is zero or positive. Note that if the result of this method is passed to the string constructor, only the numerical value of this BigDecimal
will necessarily be recovered; the representation of the new BigDecimal
may have a different scale. In particular, if this BigDecimal
has a negative scale, the string resulting from this method will have a scale of zero when processed by the string constructor. (This method behaves analogously to the toString
method in 1.4 and earlier releases.)
BigDecimal
without an exponent field.toString()
, toEngineeringString()
public BigInteger toBigInteger()
Converts this BigDecimal
to a BigInteger
. This conversion is analogous to the narrowing primitive conversion from double
to long
as defined in section 5.1.3 of The Java™ Language Specification: any fractional part of this BigDecimal
will be discarded. Note that this conversion can lose information about the precision of the BigDecimal
value.
To have an exception thrown if the conversion is inexact (in other words if a nonzero fractional part is discarded), use the toBigIntegerExact()
method.
BigDecimal
converted to a BigInteger
.public BigInteger toBigIntegerExact()
Converts this BigDecimal
to a BigInteger
, checking for lost information. An exception is thrown if this BigDecimal
has a nonzero fractional part.
BigDecimal
converted to a BigInteger
.ArithmeticException
- if this
has a nonzero fractional part.public long longValue()
Converts this BigDecimal
to a long
. This conversion is analogous to the narrowing primitive conversion from double
to short
as defined in section 5.1.3 of The Java™ Language Specification: any fractional part of this BigDecimal
will be discarded, and if the resulting "BigInteger
" is too big to fit in a long
, only the low-order 64 bits are returned. Note that this conversion can lose information about the overall magnitude and precision of this BigDecimal
value as well as return a result with the opposite sign.
public long longValueExact()
Converts this BigDecimal
to a long
, checking for lost information. If this BigDecimal
has a nonzero fractional part or is out of the possible range for a long
result then an ArithmeticException
is thrown.
BigDecimal
converted to a long
.ArithmeticException
- if this
has a nonzero fractional part, or will not fit in a long
.public int intValue()
Converts this BigDecimal
to an int
. This conversion is analogous to the narrowing primitive conversion from double
to short
as defined in section 5.1.3 of The Java™ Language Specification: any fractional part of this BigDecimal
will be discarded, and if the resulting "BigInteger
" is too big to fit in an int
, only the low-order 32 bits are returned. Note that this conversion can lose information about the overall magnitude and precision of this BigDecimal
value as well as return a result with the opposite sign.
public int intValueExact()
Converts this BigDecimal
to an int
, checking for lost information. If this BigDecimal
has a nonzero fractional part or is out of the possible range for an int
result then an ArithmeticException
is thrown.
BigDecimal
converted to an int
.ArithmeticException
- if this
has a nonzero fractional part, or will not fit in an int
.public short shortValueExact()
Converts this BigDecimal
to a short
, checking for lost information. If this BigDecimal
has a nonzero fractional part or is out of the possible range for a short
result then an ArithmeticException
is thrown.
BigDecimal
converted to a short
.ArithmeticException
- if this
has a nonzero fractional part, or will not fit in a short
.public byte byteValueExact()
Converts this BigDecimal
to a byte
, checking for lost information. If this BigDecimal
has a nonzero fractional part or is out of the possible range for a byte
result then an ArithmeticException
is thrown.
BigDecimal
converted to a byte
.ArithmeticException
- if this
has a nonzero fractional part, or will not fit in a byte
.public float floatValue()
Converts this BigDecimal
to a float
. This conversion is similar to the narrowing primitive conversion from double
to float
as defined in section 5.1.3 of The Java™ Language Specification: if this BigDecimal
has too great a magnitude to represent as a float
, it will be converted to Float.NEGATIVE_INFINITY
or Float.POSITIVE_INFINITY
as appropriate. Note that even when the return value is finite, this conversion can lose information about the precision of the BigDecimal
value.
floatValue
in class Number
BigDecimal
converted to a float
.public double doubleValue()
Converts this BigDecimal
to a double
. This conversion is similar to the narrowing primitive conversion from double
to float
as defined in section 5.1.3 of The Java™ Language Specification: if this BigDecimal
has too great a magnitude represent as a double
, it will be converted to Double.NEGATIVE_INFINITY
or Double.POSITIVE_INFINITY
as appropriate. Note that even when the return value is finite, this conversion can lose information about the precision of the BigDecimal
value.
doubleValue
in class Number
BigDecimal
converted to a double
.public BigDecimal ulp()
Returns the size of an ulp, a unit in the last place, of this BigDecimal
. An ulp of a nonzero BigDecimal
value is the positive distance between this value and the BigDecimal
value next larger in magnitude with the same number of digits. An ulp of a zero value is numerically equal to 1 with the scale of this
. The result is stored with the same scale as this
so the result for zero and nonzero values is equal to [1,
this.scale()]
.
this
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