Class BigDecimal
- All Implemented Interfaces:
Serializable,Comparable<BigDecimal>
BigDecimal consists of an arbitrary precision integer
unscaled value and a 32-bit
integer scale. If the
scale is zero or positive, the scale is the number of digits to
the right of the decimal point. If the scale is 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 ArithmeticException
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 deprecated; 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. 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. 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.
The different representations of the same numerical value are
called members of the same cohort. The natural order of BigDecimal
considers members of the same cohort to be equal to each other. In
contrast, the equals method requires both the
numerical value and representation to be the same for equality to
hold. The results of methods like scale and unscaledValue() will differ for numerically equal values with
different representations.
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 and square root) 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.
For methods and constructors with a MathContext
parameter, if the result is inexact but the rounding mode is UNNECESSARY, an
ArithmeticException will be thrown.
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() |
| Square root | radicand.scale()/2 |
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.
As a 32-bit integer, the set of values for the scale is large,
but bounded. If the scale of a result would exceed the range of a
32-bit integer, either by overflow or underflow, the operation may
throw an ArithmeticException.
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.
All methods and constructors for this class throw
NullPointerException when passed a null object
reference for any input parameter.
- API Note:
- Care should be exercised if
BigDecimalobjects are used as keys in aSortedMapor elements in aSortedSetsinceBigDecimal's natural ordering is inconsistent with equals. SeeComparable,SortedMaporSortedSetfor more information.Relation to IEEE 754 Decimal Arithmetic
Starting with its 2008 revision, the IEEE 754 Standard for Floating-point Arithmetic has covered decimal formats and operations. While there are broad similarities in the decimal arithmetic defined by IEEE 754 and by this class, there are notable differences as well. The fundamental similarity shared byBigDecimaland IEEE 754 decimal arithmetic is the conceptual operation of computing the mathematical infinitely precise real number value of an operation and then mapping that real number to a representable decimal floating-point value under a rounding policy. The rounding policy is called a rounding mode forBigDecimaland called a rounding-direction attribute in IEEE 754-2019. When the exact value is not representable, the rounding policy determines which of the two representable decimal values bracketing the exact value is selected as the computed result. The notion of a preferred scale/preferred exponent is also shared by both systems.For differences, IEEE 754 includes several kinds of values not modeled by
BigDecimalincluding negative zero, signed infinities, and NaN (not-a-number). IEEE 754 defines formats, which are parameterized by base (binary or decimal), number of digits of precision, and exponent range. A format determines the set of representable values. Most operations accept as input one or more values of a given format and produce a result in the same format. ABigDecimal's scale is equivalent to negating an IEEE 754 value's exponent.BigDecimalvalues do not have a format in the same sense; all values have the same possible range of scale/exponent and the unscaled value has arbitrary precision. Instead, for theBigDecimaloperations taking aMathContextparameter, if theMathContexthas a nonzero precision, the set of possible representable values for the result is determined by the precision of theMathContextargument. For example inBigDecimal, if a nonzero three-digit number and a nonzero four-digit number are multiplied together in the context of aMathContextobject having a precision of three, the result will have three digits (assuming no overflow or underflow, etc.).The rounding policies implemented by
BigDecimaloperations indicated by rounding modes are a proper superset of the IEEE 754 rounding-direction attributes.BigDecimalarithmetic will most resemble IEEE 754 decimal arithmetic if aMathContextcorresponding to an IEEE 754 decimal format, such as decimal64 or decimal128 is used to round all starting values and intermediate operations. The numerical values computed can differ if the exponent range of the IEEE 754 format being approximated is exceeded since aMathContextdoes not constrain the scale ofBigDecimalresults. Operations that would generate a NaN or exact infinity, such as dividing by zero, throw anArithmeticExceptioninBigDecimalarithmetic.Algorithmic Complexity
Operations onBigDecimalvalues have a range of algorithmic complexities; in general, those complexities are a function of both the size of the unscaled value as well as the size of the scale. For example, an exact multiply of twoBigDecimalvalues is subject to the same complexity constraints asBigIntegermultiply of the unscaled values. In contrast, aBigDecimalvalue with a compact representation likenew BigDecimal(1E-1000000000)has atoPlainString()result with over one billion characters.Operations may also allocate and compute on intermediate results, potentially those allocations may be as large as in proportion to the running time of the algorithm.
Users of
BigDecimalconcerned with bounding the running time or space of operations can screen outBigDecimalvalues with unscaled values or scales above a chosen magnitude. - Since:
- 1.1
- External Specifications
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final BigDecimalThe value 1, with a scale of 0.static final intDeprecated.static final intDeprecated.UseRoundingMode.DOWNinstead.static final intDeprecated.UseRoundingMode.FLOORinstead.static final intDeprecated.UseRoundingMode.HALF_DOWNinstead.static final intDeprecated.UseRoundingMode.HALF_EVENinstead.static final intDeprecated.UseRoundingMode.HALF_UPinstead.static final intDeprecated.UseRoundingMode.UNNECESSARYinstead.static final intDeprecated.UseRoundingMode.UPinstead.static final BigDecimalThe value 10, with a scale of 0.static final BigDecimalThe value 2, with a scale of 0.static final BigDecimalThe value 0, with a scale of 0. -
Constructor Summary
ConstructorsConstructorDescriptionBigDecimal(char[] in) Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor.BigDecimal(char[] in, int offset, int len) Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor, while allowing a sub-array to be specified.BigDecimal(char[] in, int offset, int len, MathContext mc) Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor, while allowing a sub-array to be specified and with rounding according to the context settings.BigDecimal(char[] in, MathContext mc) Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor and with rounding according to the context settings.BigDecimal(double val) Translates adoubleinto aBigDecimalwhich is the exact decimal representation of thedouble's binary floating-point value.BigDecimal(double val, MathContext mc) Translates adoubleinto aBigDecimal, with rounding according to the context settings.BigDecimal(int val) Translates anintinto aBigDecimal.BigDecimal(int val, MathContext mc) Translates anintinto aBigDecimal, with rounding according to the context settings.BigDecimal(long val) Translates alonginto aBigDecimal.BigDecimal(long val, MathContext mc) Translates alonginto aBigDecimal, with rounding according to the context settings.BigDecimal(String val) Translates the string representation of aBigDecimalinto aBigDecimal.BigDecimal(String val, MathContext mc) Translates the string representation of aBigDecimalinto aBigDecimal, accepting the same strings as theBigDecimal(String)constructor, with rounding according to the context settings.BigDecimal(BigInteger val) Translates aBigIntegerinto aBigDecimal.BigDecimal(BigInteger unscaledVal, int scale) Translates aBigIntegerunscaled value and anintscale into aBigDecimal.BigDecimal(BigInteger unscaledVal, int scale, MathContext mc) Translates aBigIntegerunscaled value and anintscale into aBigDecimal, with rounding according to the context settings.BigDecimal(BigInteger val, MathContext mc) Translates aBigIntegerinto aBigDecimalrounding according to the context settings. -
Method Summary
Modifier and TypeMethodDescriptionabs()Returns aBigDecimalwhose value is the absolute value of thisBigDecimal, and whose scale isthis.scale().abs(MathContext mc) Returns aBigDecimalwhose value is the absolute value of thisBigDecimal, with rounding according to the context settings.add(BigDecimal augend) Returns aBigDecimalwhose value is(this + augend), and whose scale ismax(this.scale(), augend.scale()).add(BigDecimal augend, MathContext mc) Returns aBigDecimalwhose value is(this + augend), with rounding according to the context settings.byteConverts thisBigDecimalto abyte, checking for lost information.intcompareTo(BigDecimal val) Compares thisBigDecimalnumerically with the specifiedBigDecimal.divide(BigDecimal divisor) Returns aBigDecimalwhose 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) anArithmeticExceptionis thrown.divide(BigDecimal divisor, int roundingMode) Deprecated.The methoddivide(BigDecimal, RoundingMode)should be used in preference to this legacy method.divide(BigDecimal divisor, int scale, int roundingMode) Deprecated.The methoddivide(BigDecimal, int, RoundingMode)should be used in preference to this legacy method.divide(BigDecimal divisor, int scale, RoundingMode roundingMode) Returns aBigDecimalwhose value is(this / divisor), and whose scale is as specified.divide(BigDecimal divisor, MathContext mc) Returns aBigDecimalwhose value is(this / divisor), with rounding according to the context settings.divide(BigDecimal divisor, RoundingMode roundingMode) Returns aBigDecimalwhose value is(this / divisor), and whose scale isthis.scale().divideAndRemainder(BigDecimal divisor) Returns a two-elementBigDecimalarray containing the result ofdivideToIntegralValuefollowed by the result ofremainderon the two operands.divideAndRemainder(BigDecimal divisor, MathContext mc) Returns a two-elementBigDecimalarray containing the result ofdivideToIntegralValuefollowed by the result ofremainderon the two operands calculated with rounding according to the context settings.divideToIntegralValue(BigDecimal divisor) Returns aBigDecimalwhose value is the integer part of the quotient(this / divisor)rounded down.divideToIntegralValue(BigDecimal divisor, MathContext mc) Returns aBigDecimalwhose value is the integer part of(this / divisor).doubleConverts thisBigDecimalto adouble.booleanCompares thisBigDecimalwith the specifiedObjectfor equality.floatConverts thisBigDecimalto afloat.inthashCode()Returns the hash code for thisBigDecimal.intintValue()Converts thisBigDecimalto anint.intConverts thisBigDecimalto anint, checking for lost information.longConverts thisBigDecimalto along.longConverts thisBigDecimalto along, checking for lost information.max(BigDecimal val) Returns the maximum of thisBigDecimalandval.min(BigDecimal val) Returns the minimum of thisBigDecimalandval.movePointLeft(int n) Returns aBigDecimalwhich is equivalent to this one with the decimal point movednplaces to the left.movePointRight(int n) Returns aBigDecimalwhich is equivalent to this one with the decimal point movednplaces to the right.multiply(BigDecimal multiplicand) Returns aBigDecimalwhose value is(this × multiplicand), and whose scale is(this.scale() + multiplicand.scale()).multiply(BigDecimal multiplicand, MathContext mc) Returns aBigDecimalwhose value is(this × multiplicand), with rounding according to the context settings.negate()Returns aBigDecimalwhose value is(-this), and whose scale isthis.scale().negate(MathContext mc) Returns aBigDecimalwhose value is(-this), with rounding according to the context settings.plus()Returns aBigDecimalwhose value is(+this), and whose scale isthis.scale().plus(MathContext mc) Returns aBigDecimalwhose value is(+this), with rounding according to the context settings.pow(int n) Returns aBigDecimalwhose value is(thisn), The power is computed exactly, to unlimited precision.pow(int n, MathContext mc) Returns aBigDecimalwhose value is(thisn).intReturns the precision of thisBigDecimal.remainder(BigDecimal divisor) Returns aBigDecimalwhose value is(this % divisor).remainder(BigDecimal divisor, MathContext mc) Returns aBigDecimalwhose value is(this % divisor), with rounding according to the context settings.round(MathContext mc) Returns aBigDecimalrounded according to theMathContextsettings.intscale()Returns the scale of thisBigDecimal.scaleByPowerOfTen(int n) Returns a BigDecimal whose numerical value is equal to (this* 10n).setScale(int newScale) Returns aBigDecimalwhose scale is the specified value, and whose value is numerically equal to thisBigDecimal's.setScale(int newScale, int roundingMode) Deprecated.The methodsetScale(int, RoundingMode)should be used in preference to this legacy method.setScale(int newScale, RoundingMode roundingMode) Returns aBigDecimalwhose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal's unscaled value by the appropriate power of ten to maintain its overall value.shortConverts thisBigDecimalto ashort, checking for lost information.intsignum()Returns the signum function of thisBigDecimal.sqrt(MathContext mc) Returns an approximation to the square root ofthiswith rounding according to the context settings.Returns aBigDecimalwhich is numerically equal to this one but with any trailing zeros removed from the representation.subtract(BigDecimal subtrahend) Returns aBigDecimalwhose value is(this - subtrahend), and whose scale ismax(this.scale(), subtrahend.scale()).subtract(BigDecimal subtrahend, MathContext mc) Returns aBigDecimalwhose value is(this - subtrahend), with rounding according to the context settings.Converts thisBigDecimalto aBigInteger.Converts thisBigDecimalto aBigInteger, checking for lost information.Returns a string representation of thisBigDecimal, using engineering notation if an exponent is needed.Returns a string representation of thisBigDecimalwithout an exponent field.toString()Returns the string representation of thisBigDecimal, using scientific notation if an exponent is needed.ulp()Returns the size of an ulp, a unit in the last place, of thisBigDecimal.Returns aBigIntegerwhose value is the unscaled value of thisBigDecimal.static BigDecimalvalueOf(double val) Translates adoubleinto aBigDecimal, using thedouble's canonical string representation provided by theDouble.toString(double)method.static BigDecimalvalueOf(long val) Translates alongvalue into aBigDecimalwith a scale of zero.static BigDecimalvalueOf(long unscaledVal, int scale) Translates alongunscaled value and anintscale into aBigDecimal.Methods declared in class java.lang.Number
byteValue, shortValue
-
Field Details
-
ZERO
-
ONE
-
TWO
-
TEN
-
ROUND_UP
Deprecated.UseRoundingMode.UPinstead.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.- See Also:
-
ROUND_DOWN
Deprecated.UseRoundingMode.DOWNinstead.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.- See Also:
-
ROUND_CEILING
Deprecated.UseRoundingMode.CEILINGinstead.Rounding mode to round towards positive infinity. If theBigDecimalis positive, behaves as forROUND_UP; if negative, behaves as forROUND_DOWN. Note that this rounding mode never decreases the calculated value.- See Also:
-
ROUND_FLOOR
Deprecated.UseRoundingMode.FLOORinstead.Rounding mode to round towards negative infinity. If theBigDecimalis positive, behave as forROUND_DOWN; if negative, behave as forROUND_UP. Note that this rounding mode never increases the calculated value.- See Also:
-
ROUND_HALF_UP
Deprecated.UseRoundingMode.HALF_UPinstead.Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. Behaves as forROUND_UPif the discarded fraction is ≥ 0.5; otherwise, behaves as forROUND_DOWN. Note that this is the rounding mode that most of us were taught in grade school.- See Also:
-
ROUND_HALF_DOWN
Deprecated.UseRoundingMode.HALF_DOWNinstead.Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. Behaves as forROUND_UPif the discarded fraction is > 0.5; otherwise, behaves as forROUND_DOWN.- See Also:
-
ROUND_HALF_EVEN
Deprecated.UseRoundingMode.HALF_EVENinstead.Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. Behaves as forROUND_HALF_UPif the digit to the left of the discarded fraction is odd; behaves as forROUND_HALF_DOWNif it's even. Note that this is the rounding mode that minimizes cumulative error when applied repeatedly over a sequence of calculations.- See Also:
-
ROUND_UNNECESSARY
Deprecated.UseRoundingMode.UNNECESSARYinstead.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, anArithmeticExceptionis thrown.- See Also:
-
-
Constructor Details
-
BigDecimal
public BigDecimal(char[] in, int offset, int len) Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor, while allowing a sub-array to be specified.- Implementation Note:
- If the sequence of characters is already available
within a character array, using this constructor is faster than
converting the
chararray to string and using theBigDecimal(String)constructor. - Parameters:
in-chararray that is the source of characters.offset- first character in the array to inspect.len- number of characters to consider.- Throws:
NumberFormatException- ifinis not a valid representation of aBigDecimalor the defined subarray is not wholly withinin.- Since:
- 1.5
-
BigDecimal
Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor, while allowing a sub-array to be specified and with rounding according to the context settings.- Implementation Note:
- If the sequence of characters is already available
within a character array, using this constructor is faster than
converting the
chararray to string and using theBigDecimal(String)constructor. - Parameters:
in-chararray 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.- Throws:
NumberFormatException- ifinis not a valid representation of aBigDecimalor the defined subarray is not wholly withinin.- Since:
- 1.5
-
BigDecimal
public BigDecimal(char[] in) Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor.- Implementation Note:
- If the sequence of characters is already available
as a character array, using this constructor is faster than
converting the
chararray to string and using theBigDecimal(String)constructor. - Parameters:
in-chararray that is the source of characters.- Throws:
NumberFormatException- ifinis not a valid representation of aBigDecimal.- Since:
- 1.5
-
BigDecimal
Translates a character array representation of aBigDecimalinto aBigDecimal, accepting the same sequence of characters as theBigDecimal(String)constructor and with rounding according to the context settings.- Implementation Note:
- If the sequence of characters is already available
as a character array, using this constructor is faster than
converting the
chararray to string and using theBigDecimal(String)constructor. - Parameters:
in-chararray that is the source of characters.mc- the context to use.- Throws:
NumberFormatException- ifinis not a valid representation of aBigDecimal.- Since:
- 1.5
-
BigDecimal
Translates the string representation of aBigDecimalinto aBigDecimal. 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.More formally, the strings this constructor accepts are described by the following grammar:
- BigDecimalString:
- Signopt Significand Exponentopt
- Sign:
+-- Significand:
- IntegerPart
.FractionPartopt.FractionPart- IntegerPart
- IntegerPart:
- Digits
- FractionPart:
- Digits
- Exponent:
- ExponentIndicator SignedInteger
- ExponentIndicator:
eE- SignedInteger:
- Signopt Digits
- Digits:
- Digit
- Digits Digit
- Digit:
- any character for which
Character.isDigit(char)returnstrue, including 0, 1, 2 ...
The scale of the returned
BigDecimalwill 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 betweenInteger.MIN_VALUEandInteger.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 returnedBigDecimalis 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]
- API Note:
- For values other than
floatanddoubleNaN and ±Infinity, this constructor is compatible with the values returned byFloat.toString(float)andDouble.toString(double). This is generally the preferred way to convert afloatordoubleinto a BigDecimal, as it doesn't suffer from the unpredictability of theBigDecimal(double)constructor. - Parameters:
val- String representation ofBigDecimal.- Throws:
NumberFormatException- ifvalis not a valid representation of aBigDecimal.
-
BigDecimal
Translates the string representation of aBigDecimalinto aBigDecimal, accepting the same strings as theBigDecimal(String)constructor, with rounding according to the context settings.- Parameters:
val- string representation of aBigDecimal.mc- the context to use.- Throws:
NumberFormatException- ifvalis not a valid representation of a BigDecimal.- Since:
- 1.5
-
BigDecimal
public BigDecimal(double val) Translates adoubleinto aBigDecimalwhich is the exact decimal representation of thedouble's binary floating-point value. The scale of the returnedBigDecimalis the smallest value such that(10scale × val)is an integer.Notes:
-
The results of this constructor can be somewhat unpredictable.
One might assume that writing
new BigDecimal(0.1)in Java creates aBigDecimalwhich 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 adouble(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. -
The
Stringconstructor, on the other hand, is perfectly predictable: writingnew BigDecimal("0.1")creates aBigDecimalwhich 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. -
When a
doublemust be used as a source for aBigDecimal, note that this constructor provides an exact conversion; it does not give the same result as converting thedoubleto aStringusing theDouble.toString(double)method and then using theBigDecimal(String)constructor. To get that result, use thestaticvalueOf(double)method.
- Parameters:
val-doublevalue to be converted toBigDecimal.- Throws:
NumberFormatException- ifvalis infinite or NaN.
-
The results of this constructor can be somewhat unpredictable.
One might assume that writing
-
BigDecimal
Translates adoubleinto aBigDecimal, with rounding according to the context settings. The scale of theBigDecimalis 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.- Parameters:
val-doublevalue to be converted toBigDecimal.mc- the context to use.- Throws:
NumberFormatException- ifvalis infinite or NaN.- Since:
- 1.5
-
BigDecimal
Translates aBigIntegerinto aBigDecimal. The scale of theBigDecimalis zero.- Parameters:
val-BigIntegervalue to be converted toBigDecimal.
-
BigDecimal
Translates aBigIntegerinto aBigDecimalrounding according to the context settings. The scale of theBigDecimalis zero.- Parameters:
val-BigIntegervalue to be converted toBigDecimal.mc- the context to use.- Since:
- 1.5
-
BigDecimal
Translates aBigIntegerunscaled value and anintscale into aBigDecimal. The value of theBigDecimalis(unscaledVal × 10-scale).- Parameters:
unscaledVal- unscaled value of theBigDecimal.scale- scale of theBigDecimal.
-
BigDecimal
Translates aBigIntegerunscaled value and anintscale into aBigDecimal, with rounding according to the context settings. The value of theBigDecimalis(unscaledVal × 10-scale), rounded according to theprecisionand rounding mode settings.- Parameters:
unscaledVal- unscaled value of theBigDecimal.scale- scale of theBigDecimal.mc- the context to use.- Since:
- 1.5
-
BigDecimal
public BigDecimal(int val) Translates anintinto aBigDecimal. The scale of theBigDecimalis zero.- Parameters:
val-intvalue to be converted toBigDecimal.- Since:
- 1.5
-
BigDecimal
Translates anintinto aBigDecimal, with rounding according to the context settings. The scale of theBigDecimal, before any rounding, is zero.- Parameters:
val-intvalue to be converted toBigDecimal.mc- the context to use.- Since:
- 1.5
-
BigDecimal
public BigDecimal(long val) Translates alonginto aBigDecimal. The scale of theBigDecimalis zero.- Parameters:
val-longvalue to be converted toBigDecimal.- Since:
- 1.5
-
BigDecimal
Translates alonginto aBigDecimal, with rounding according to the context settings. The scale of theBigDecimal, before any rounding, is zero.- Parameters:
val-longvalue to be converted toBigDecimal.mc- the context to use.- Since:
- 1.5
-
-
Method Details
-
valueOf
Translates alongunscaled value and anintscale into aBigDecimal.- API Note:
- This static factory method is provided in preference
to a (
long,int) constructor because it allows for reuse of frequently usedBigDecimalvalues. - Parameters:
unscaledVal- unscaled value of theBigDecimal.scale- scale of theBigDecimal.- Returns:
- a
BigDecimalwhose value is(unscaledVal × 10-scale).
-
valueOf
Translates alongvalue into aBigDecimalwith a scale of zero.- API Note:
- This static factory method is provided in preference
to a (
long) constructor because it allows for reuse of frequently usedBigDecimalvalues. - Parameters:
val- value of theBigDecimal.- Returns:
- a
BigDecimalwhose value isval.
-
valueOf
Translates adoubleinto aBigDecimal, using thedouble's canonical string representation provided by theDouble.toString(double)method.- API Note:
- This is generally the preferred way to convert a
double(orfloat) into aBigDecimal, as the value returned is equal to that resulting from constructing aBigDecimalfrom the result of usingDouble.toString(double). - Parameters:
val-doubleto convert to aBigDecimal.- Returns:
- a
BigDecimalwhose value is equal to or approximately equal to the value ofval. - Throws:
NumberFormatException- ifvalis infinite or NaN.- Since:
- 1.5
-
add
Returns aBigDecimalwhose value is(this + augend), and whose scale ismax(this.scale(), augend.scale()).- Parameters:
augend- value to be added to thisBigDecimal.- Returns:
this + augend
-
add
Returns aBigDecimalwhose 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.- Parameters:
augend- value to be added to thisBigDecimal.mc- the context to use.- Returns:
this + augend, rounded as necessary.- Since:
- 1.5
-
subtract
Returns aBigDecimalwhose value is(this - subtrahend), and whose scale ismax(this.scale(), subtrahend.scale()).- Parameters:
subtrahend- value to be subtracted from thisBigDecimal.- Returns:
this - subtrahend
-
subtract
Returns aBigDecimalwhose value is(this - subtrahend), with rounding according to the context settings. Ifsubtrahendis zero then this, rounded if necessary, is used as the result. If this is zero then the result issubtrahend.negate(mc).- Parameters:
subtrahend- value to be subtracted from thisBigDecimal.mc- the context to use.- Returns:
this - subtrahend, rounded as necessary.- Since:
- 1.5
-
multiply
Returns aBigDecimalwhose value is(this × multiplicand), and whose scale is(this.scale() + multiplicand.scale()).- Parameters:
multiplicand- value to be multiplied by thisBigDecimal.- Returns:
this * multiplicand
-
multiply
Returns aBigDecimalwhose value is(this × multiplicand), with rounding according to the context settings.- Parameters:
multiplicand- value to be multiplied by thisBigDecimal.mc- the context to use.- Returns:
this * multiplicand, rounded as necessary.- Since:
- 1.5
-
divide
Deprecated.The methoddivide(BigDecimal, int, RoundingMode)should be used in preference to this legacy method.Returns aBigDecimalwhose 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.- Parameters:
divisor- value by which thisBigDecimalis to be divided.scale- scale of theBigDecimalquotient to be returned.roundingMode- rounding mode to apply.- Returns:
this / divisor- Throws:
ArithmeticException- ifdivisoris zero,roundingMode==ROUND_UNNECESSARYand the specified scale is insufficient to represent the result of the division exactly.IllegalArgumentException- ifroundingModedoes not represent a valid rounding mode.- See Also:
-
divide
Returns aBigDecimalwhose 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.- Parameters:
divisor- value by which thisBigDecimalis to be divided.scale- scale of theBigDecimalquotient to be returned.roundingMode- rounding mode to apply.- Returns:
this / divisor- Throws:
ArithmeticException- ifdivisoris zero,roundingMode==RoundingMode.UNNECESSARYand the specified scale is insufficient to represent the result of the division exactly.- Since:
- 1.5
-
divide
Deprecated.The methoddivide(BigDecimal, RoundingMode)should be used in preference to this legacy method.Returns aBigDecimalwhose value is(this / divisor), and whose scale isthis.scale(). If rounding must be performed to generate a result with the given scale, the specified rounding mode is applied.- Parameters:
divisor- value by which thisBigDecimalis to be divided.roundingMode- rounding mode to apply.- Returns:
this / divisor- Throws:
ArithmeticException- ifdivisor==0, orroundingMode==ROUND_UNNECESSARYandthis.scale()is insufficient to represent the result of the division exactly.IllegalArgumentException- ifroundingModedoes not represent a valid rounding mode.- See Also:
-
divide
Returns aBigDecimalwhose value is(this / divisor), and whose scale isthis.scale(). If rounding must be performed to generate a result with the given scale, the specified rounding mode is applied.- Parameters:
divisor- value by which thisBigDecimalis to be divided.roundingMode- rounding mode to apply.- Returns:
this / divisor- Throws:
ArithmeticException- ifdivisor==0, orroundingMode==RoundingMode.UNNECESSARYandthis.scale()is insufficient to represent the result of the division exactly.- Since:
- 1.5
-
divide
Returns aBigDecimalwhose 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) anArithmeticExceptionis thrown.- Parameters:
divisor- value by which thisBigDecimalis to be divided.- Returns:
this / divisor- Throws:
ArithmeticException- if the exact quotient does not have a terminating decimal expansion, including dividing by zero- Since:
- 1.5
-
divide
Returns aBigDecimalwhose value is(this / divisor), with rounding according to the context settings.- Parameters:
divisor- value by which thisBigDecimalis to be divided.mc- the context to use.- Returns:
this / divisor, rounded as necessary.- Throws:
ArithmeticException- if the result is inexact but the rounding mode isUNNECESSARYormc.precision == 0and the quotient has a non-terminating decimal expansion, including dividing by zero- Since:
- 1.5
-
divideToIntegralValue
Returns aBigDecimalwhose value is the integer part of the quotient(this / divisor)rounded down. The preferred scale of the result is(this.scale() - divisor.scale()).- Parameters:
divisor- value by which thisBigDecimalis to be divided.- Returns:
- The integer part of
this / divisor. - Throws:
ArithmeticException- ifdivisor==0- Since:
- 1.5
-
divideToIntegralValue
Returns aBigDecimalwhose 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()). AnArithmeticExceptionis thrown if the integer part of the exact quotient needs more thanmc.precisiondigits.- Parameters:
divisor- value by which thisBigDecimalis to be divided.mc- the context to use.- Returns:
- The integer part of
this / divisor. - Throws:
ArithmeticException- ifdivisor==0ArithmeticException- ifmc.precision> 0 and the result requires a precision of more thanmc.precisiondigits.- Since:
- 1.5
-
remainder
Returns aBigDecimalwhose 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).- Parameters:
divisor- value by which thisBigDecimalis to be divided.- Returns:
this % divisor.- Throws:
ArithmeticException- ifdivisor==0- Since:
- 1.5
-
remainder
Returns aBigDecimalwhose value is(this % divisor), with rounding according to the context settings. TheMathContextsettings affect the implicit divide used to compute the remainder. The remainder computation itself is by definition exact. Therefore, the remainder may contain more thanmc.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).- Parameters:
divisor- value by which thisBigDecimalis to be divided.mc- the context to use.- Returns:
this % divisor, rounded as necessary.- Throws:
ArithmeticException- ifdivisor==0ArithmeticException- if the result is inexact but the rounding mode isUNNECESSARY, ormc.precision> 0 and the result ofthis.divideToIntegralValue(divisor)would require a precision of more thanmc.precisiondigits.- Since:
- 1.5
- See Also:
-
divideAndRemainder
Returns a two-elementBigDecimalarray containing the result ofdivideToIntegralValuefollowed by the result ofremainderon the two operands.Note that if both the integer quotient and remainder are needed, this method is faster than using the
divideToIntegralValueandremaindermethods separately because the division need only be carried out once.- Parameters:
divisor- value by which thisBigDecimalis to be divided, and the remainder computed.- Returns:
- a two element
BigDecimalarray: the quotient (the result ofdivideToIntegralValue) is the initial element and the remainder is the final element. - Throws:
ArithmeticException- ifdivisor==0- Since:
- 1.5
- See Also:
-
divideAndRemainder
Returns a two-elementBigDecimalarray containing the result ofdivideToIntegralValuefollowed by the result ofremainderon 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
divideToIntegralValueandremaindermethods separately because the division need only be carried out once.- Parameters:
divisor- value by which thisBigDecimalis to be divided, and the remainder computed.mc- the context to use.- Returns:
- a two element
BigDecimalarray: the quotient (the result ofdivideToIntegralValue) is the initial element and the remainder is the final element. - Throws:
ArithmeticException- ifdivisor==0ArithmeticException- if the result is inexact but the rounding mode isUNNECESSARY, ormc.precision> 0 and the result ofthis.divideToIntegralValue(divisor)would require a precision of more thanmc.precisiondigits.- Since:
- 1.5
- See Also:
-
sqrt
Returns an approximation to the square root ofthiswith rounding according to the context settings.The preferred scale of the returned result is equal to
this.scale()/2. The value of the returned result is always within one ulp of the exact decimal value for the precision in question. If the rounding mode isHALF_UP,HALF_DOWN, orHALF_EVEN, the result is within one half an ulp of the exact decimal value.Special case:
- The square root of a number numerically equal to
ZEROis numerically equal toZEROwith a preferred scale according to the general rule above. In particular, forZERO,ZERO.sqrt(mc).equals(ZERO)is true with anyMathContextas an argument.
- Parameters:
mc- the context to use.- Returns:
- the square root of
this. - Throws:
ArithmeticException- ifthisis less than zero.ArithmeticException- if an exact result is requested (mc.getPrecision()==0) and there is no finite decimal expansion of the exact resultArithmeticException- if(mc.getRoundingMode()==RoundingMode.UNNECESSARY) and the exact result cannot fit inmc.getPrecision()digits.- Since:
- 9
- See Also:
- The square root of a number numerically equal to
-
pow
Returns aBigDecimalwhose value is(thisn), The power is computed exactly, to unlimited precision.The parameter
nmust be in the range 0 through 999999999, inclusive.ZERO.pow(0)returnsONE. Note that future releases may expand the allowable exponent range of this method.- Parameters:
n- power to raise thisBigDecimalto.- Returns:
thisn- Throws:
ArithmeticException- ifnis out of range.- Since:
- 1.5
-
pow
Returns aBigDecimalwhose 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:
- An
ArithmeticExceptionexception is thrown ifabs(n) > 999999999mc.precision == 0andn < 0mc.precision > 0andnhas more thanmc.precisiondecimal digits
- if
nis zero,ONEis returned even ifthisis zero, otherwise- if
nis 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 inmcexcept for a precision increased tomc.precision + elength + 1whereelengthis the number of decimal digits inn. - if
nis negative, the result is calculated as ifnwere positive; this value is then divided into one using the working precision specified above. - The final value from either the positive or negative case is then rounded to the destination precision.
- if
- Parameters:
n- power to raise thisBigDecimalto.mc- the context to use.- Returns:
thisnusing the ANSI standard X3.274-1996 algorithm- Throws:
ArithmeticException- if the result is inexact but the rounding mode isUNNECESSARY, ornis out of range.- Since:
- 1.5
- An
-
abs
Returns aBigDecimalwhose value is the absolute value of thisBigDecimal, and whose scale isthis.scale().- Returns:
abs(this)
-
abs
Returns aBigDecimalwhose value is the absolute value of thisBigDecimal, with rounding according to the context settings.- Parameters:
mc- the context to use.- Returns:
abs(this), rounded as necessary.- Since:
- 1.5
-
negate
Returns aBigDecimalwhose value is(-this), and whose scale isthis.scale().- Returns:
-this.
-
negate
Returns aBigDecimalwhose value is(-this), with rounding according to the context settings.- Parameters:
mc- the context to use.- Returns:
-this, rounded as necessary.- Since:
- 1.5
-
plus
Returns aBigDecimalwhose value is(+this), and whose scale isthis.scale().This method, which simply returns this
BigDecimalis included for symmetry with the unary minus methodnegate().- Returns:
this.- Since:
- 1.5
- See Also:
-
plus
Returns aBigDecimalwhose value is(+this), with rounding according to the context settings.The effect of this method is identical to that of the
round(MathContext)method.- Parameters:
mc- the context to use.- Returns:
this, rounded as necessary. A zero result will have a scale of 0.- Since:
- 1.5
- See Also:
-
signum
public int signum()Returns the signum function of thisBigDecimal.- Returns:
- -1, 0, or 1 as the value of this
BigDecimalis negative, zero, or positive.
-
scale
public int scale()Returns the scale of thisBigDecimal. 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-3means the unscaled value is multiplied by 1000.- Returns:
- the scale of this
BigDecimal.
-
precision
public int precision()Returns the precision of thisBigDecimal. (The precision is the number of digits in the unscaled value.)The precision of a zero value is 1.
- Returns:
- the precision of this
BigDecimal. - Since:
- 1.5
-
unscaledValue
Returns aBigIntegerwhose value is the unscaled value of thisBigDecimal. (Computes(this * 10this.scale()).)- Returns:
- the unscaled value of this
BigDecimal. - Since:
- 1.2
-
round
Returns aBigDecimalrounded according to theMathContextsettings. 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.- Parameters:
mc- the context to use.- Returns:
- a
BigDecimalrounded according to theMathContextsettings. - Since:
- 1.5
- See Also:
-
setScale
Returns aBigDecimalwhose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal'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.- API Note:
- 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
setXmutate fieldX. Instead,setScalereturns an object with the proper scale; the returned object may or may not be newly allocated. - Parameters:
newScale- scale of theBigDecimalvalue to be returned.roundingMode- The rounding mode to apply.- Returns:
- a
BigDecimalwhose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal's unscaled value by the appropriate power of ten to maintain its overall value. - Throws:
ArithmeticException- ifroundingMode==UNNECESSARYand the specified scaling operation would require rounding.- Since:
- 1.5
- See Also:
-
setScale
Deprecated.The methodsetScale(int, RoundingMode)should be used in preference to this legacy method.Returns aBigDecimalwhose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal'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.- API Note:
- 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
setXmutate fieldX. Instead,setScalereturns an object with the proper scale; the returned object may or may not be newly allocated. - Parameters:
newScale- scale of theBigDecimalvalue to be returned.roundingMode- The rounding mode to apply.- Returns:
- a
BigDecimalwhose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal's unscaled value by the appropriate power of ten to maintain its overall value. - Throws:
ArithmeticException- ifroundingMode==ROUND_UNNECESSARYand the specified scaling operation would require rounding.IllegalArgumentException- ifroundingModedoes not represent a valid rounding mode.- See Also:
-
setScale
Returns aBigDecimalwhose scale is the specified value, and whose value is numerically equal to thisBigDecimal's. Throws anArithmeticExceptionif this is not possible.This call is typically used to increase the scale, in which case it is guaranteed that there exists a
BigDecimalof the specified scale and the correct value. The call can also be used to reduce the scale if the caller knows that theBigDecimalhas 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.- API Note:
- Since
BigDecimalobjects are immutable, calls of this method do not result in the original object being modified, contrary to the usual convention of having methods namedsetXmutate fieldX. Instead,setScalereturns an object with the proper scale; the returned object may or may not be newly allocated. - Parameters:
newScale- scale of theBigDecimalvalue to be returned.- Returns:
- a
BigDecimalwhose scale is the specified value, and whose unscaled value is determined by multiplying or dividing thisBigDecimal's unscaled value by the appropriate power of ten to maintain its overall value. - Throws:
ArithmeticException- if the specified scaling operation would require rounding.- See Also:
-
movePointLeft
Returns aBigDecimalwhich is equivalent to this one with the decimal point movednplaces to the left. Ifnis non-negative, the call merely addsnto the scale. Ifnis negative, the call is equivalent tomovePointRight(-n). TheBigDecimalreturned by this call has value(this × 10-n)and scalemax(this.scale()+n, 0).- Parameters:
n- number of places to move the decimal point to the left.- Returns:
- a
BigDecimalwhich is equivalent to this one with the decimal point movednplaces to the left. - Throws:
ArithmeticException- if scale overflows.
-
movePointRight
Returns aBigDecimalwhich is equivalent to this one with the decimal point movednplaces to the right. Ifnis non-negative, the call merely subtractsnfrom the scale. Ifnis negative, the call is equivalent tomovePointLeft(-n). TheBigDecimalreturned by this call has value(this × 10n)and scalemax(this.scale()-n, 0).- Parameters:
n- number of places to move the decimal point to the right.- Returns:
- a
BigDecimalwhich is equivalent to this one with the decimal point movednplaces to the right. - Throws:
ArithmeticException- if scale overflows.
-
scaleByPowerOfTen
Returns a BigDecimal whose numerical value is equal to (this* 10n). The scale of the result is(this.scale() - n).- Parameters:
n- the exponent power of ten to scale by- Returns:
- a BigDecimal whose numerical value is equal to
(
this* 10n) - Throws:
ArithmeticException- if the scale would be outside the range of a 32-bit integer.- Since:
- 1.5
-
stripTrailingZeros
Returns aBigDecimalwhich is numerically equal to this one but with any trailing zeros removed from the representation. For example, stripping the trailing zeros from theBigDecimalvalue600.0, which has [BigInteger,scale] components equal to [6000, 1], yields6E2with [BigInteger,scale] components equal to [6, -2]. If this BigDecimal is numerically equal to zero, thenBigDecimal.ZEROis returned.- Returns:
- a numerically equal
BigDecimalwith any trailing zeros removed. - Throws:
ArithmeticException- if scale overflows.- Since:
- 1.5
-
compareTo
Compares thisBigDecimalnumerically with the specifiedBigDecimal. TwoBigDecimalobjects that are equal in value but have a different scale (like 2.0 and 2.00) are considered equal by this method. Such values are in the same cohort. 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.- Specified by:
compareToin interfaceComparable<BigDecimal>- API Note:
- Note: this class has a natural ordering that is inconsistent with equals.
The behavior of comparing the result of this method for
equality to 0 is analogous to checking the numerical equality of
doublevalues. - Parameters:
val-BigDecimalto which thisBigDecimalis to be compared.- Returns:
- -1, 0, or 1 as this
BigDecimalis numerically less than, equal to, or greater thanval.
-
equals
Compares thisBigDecimalwith the specifiedObjectfor equality. UnlikecompareTo, this method considers twoBigDecimalobjects equal only if they are equal in value and scale. Therefore 2.0 is not equal to 2.00 when compared by this method since the former has [BigInteger,scale] components equal to [20, 1] while the latter has components equal to [200, 2].- Overrides:
equalsin classObject- API Note:
- One example that shows how 2.0 and 2.00 are not
substitutable for each other under some arithmetic operations
are the two expressions:
new BigDecimal("2.0" ).divide(BigDecimal.valueOf(3), HALF_UP)which evaluates to 0.7 and
new BigDecimal("2.00").divide(BigDecimal.valueOf(3), HALF_UP)which evaluates to 0.67. The behavior of this method is analogous to checking the representation equivalence ofdoublevalues. - Parameters:
x-Objectto which thisBigDecimalis to be compared.- Returns:
trueif and only if the specifiedObjectis aBigDecimalwhose value and scale are equal to thisBigDecimal's.- See Also:
-
min
Returns the minimum of thisBigDecimalandval.- Parameters:
val- value with which the minimum is to be computed.- Returns:
- the
BigDecimalwhose value is the lesser of thisBigDecimalandval. If they are equal, as defined by thecompareTomethod,thisis returned. - See Also:
-
max
Returns the maximum of thisBigDecimalandval.- Parameters:
val- value with which the maximum is to be computed.- Returns:
- the
BigDecimalwhose value is the greater of thisBigDecimalandval. If they are equal, as defined by thecompareTomethod,thisis returned. - See Also:
-
hashCode
public int hashCode()Returns the hash code for thisBigDecimal. The hash code is computed as a function of the unscaled value and the scale of thisBigDecimal. -
toString
Returns the string representation of thisBigDecimal, using scientific notation if an exponent is needed.A standard canonical string form of the
BigDecimalis created as though by the following steps: first, the absolute value of the unscaled value of theBigDecimalis 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), whereulengthis 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 convertedBigIntegerhas 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:- There is a one-to-one mapping between the distinguishable
BigDecimalvalues and the result of this conversion. That is, every distinguishableBigDecimalvalue (unscaled value and scale) has a unique string representation as a result of usingtoString. If that string representation is converted back to aBigDecimalusing theBigDecimal(String)constructor, then the original value will be recovered. - The string produced for a given number is always the same;
it is not affected by locale. This means that it can be used
as a canonical string representation for exchanging decimal
data, or as a key for a Hashtable, etc. Locale-sensitive
number formatting and parsing is handled by the
NumberFormatclass and its subclasses. - The
toEngineeringString()method may be used for presenting numbers with exponents in engineering notation, and thesetScalemethod may be used for rounding aBigDecimalso it has a known number of digits after the decimal point. - The digit-to-character mapping provided by
Character.forDigitis used.
- There is a one-to-one mapping between the distinguishable
-
toEngineeringString
Returns a string representation of thisBigDecimal, using engineering notation if an exponent is needed.Returns a string that represents the
BigDecimalas described in thetoString()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 oftoString(), the output of this method is not guaranteed to recover the same [integer, scale] pair of thisBigDecimalif the output string is converting back to aBigDecimalusing 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.- Returns:
- string representation of this
BigDecimal, using engineering notation if an exponent is needed. - Since:
- 1.5
-
toPlainString
Returns a string representation of thisBigDecimalwithout 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 thisBigDecimalwill necessarily be recovered; the representation of the newBigDecimalmay have a different scale. In particular, if thisBigDecimalhas 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 thetoStringmethod in 1.4 and earlier releases.)- Returns:
- a string representation of this
BigDecimalwithout an exponent field. - Since:
- 1.5
- See Also:
-
toBigInteger
Converts thisBigDecimalto aBigInteger. This conversion is analogous to the narrowing primitive conversion fromdoubletolongas defined in The Java Language Specification: any fractional part of thisBigDecimalwill be discarded. Note that this conversion can lose information about the precision of theBigDecimalvalue.To have an exception thrown if the conversion is inexact (in other words if a nonzero fractional part is discarded), use the
toBigIntegerExact()method.- Returns:
- this
BigDecimalconverted to aBigInteger. - See Java Language Specification:
-
5.1.3 Narrowing Primitive Conversion
-
toBigIntegerExact
Converts thisBigDecimalto aBigInteger, checking for lost information. An exception is thrown if thisBigDecimalhas a nonzero fractional part.- Returns:
- this
BigDecimalconverted to aBigInteger. - Throws:
ArithmeticException- ifthishas a nonzero fractional part.- Since:
- 1.5
-
longValue
public long longValue()Converts thisBigDecimalto along. This conversion is analogous to the narrowing primitive conversion fromdoubletoshortas defined in The Java Language Specification: any fractional part of thisBigDecimalwill be discarded, and if the resulting "BigInteger" is too big to fit in along, only the low-order 64 bits are returned. Note that this conversion can lose information about the overall magnitude and precision of thisBigDecimalvalue as well as return a result with the opposite sign.- Specified by:
longValuein classNumber- Returns:
- this
BigDecimalconverted to along. - See Java Language Specification:
-
5.1.3 Narrowing Primitive Conversion
-
longValueExact
public long longValueExact()Converts thisBigDecimalto along, checking for lost information. If thisBigDecimalhas a nonzero fractional part or is out of the possible range for alongresult then anArithmeticExceptionis thrown.- Returns:
- this
BigDecimalconverted to along. - Throws:
ArithmeticException- ifthishas a nonzero fractional part, or will not fit in along.- Since:
- 1.5
-
intValue
public int intValue()Converts thisBigDecimalto anint. This conversion is analogous to the narrowing primitive conversion fromdoubletoshortas defined in The Java Language Specification: any fractional part of thisBigDecimalwill be discarded, and if the resulting "BigInteger" is too big to fit in anint, only the low-order 32 bits are returned. Note that this conversion can lose information about the overall magnitude and precision of thisBigDecimalvalue as well as return a result with the opposite sign.- Specified by:
intValuein classNumber- Returns:
- this
BigDecimalconverted to anint. - See Java Language Specification:
-
5.1.3 Narrowing Primitive Conversion
-
intValueExact
public int intValueExact()Converts thisBigDecimalto anint, checking for lost information. If thisBigDecimalhas a nonzero fractional part or is out of the possible range for anintresult then anArithmeticExceptionis thrown.- Returns:
- this
BigDecimalconverted to anint. - Throws:
ArithmeticException- ifthishas a nonzero fractional part, or will not fit in anint.- Since:
- 1.5
-
shortValueExact
public short shortValueExact()Converts thisBigDecimalto ashort, checking for lost information. If thisBigDecimalhas a nonzero fractional part or is out of the possible range for ashortresult then anArithmeticExceptionis thrown.- Returns:
- this
BigDecimalconverted to ashort. - Throws:
ArithmeticException- ifthishas a nonzero fractional part, or will not fit in ashort.- Since:
- 1.5
-
byteValueExact
public byte byteValueExact()Converts thisBigDecimalto abyte, checking for lost information. If thisBigDecimalhas a nonzero fractional part or is out of the possible range for abyteresult then anArithmeticExceptionis thrown.- Returns:
- this
BigDecimalconverted to abyte. - Throws:
ArithmeticException- ifthishas a nonzero fractional part, or will not fit in abyte.- Since:
- 1.5
-
floatValue
public float floatValue()Converts thisBigDecimalto afloat. This conversion is similar to the narrowing primitive conversion fromdoubletofloatas defined in The Java Language Specification: if thisBigDecimalhas too great a magnitude to represent as afloat, it will be converted toFloat.NEGATIVE_INFINITYorFloat.POSITIVE_INFINITYas appropriate. Note that even when the return value is finite, this conversion can lose information about the precision of theBigDecimalvalue.- Specified by:
floatValuein classNumber- Returns:
- this
BigDecimalconverted to afloat. - See Java Language Specification:
-
5.1.3 Narrowing Primitive Conversion
-
doubleValue
public double doubleValue()Converts thisBigDecimalto adouble. This conversion is similar to the narrowing primitive conversion fromdoubletofloatas defined in The Java Language Specification: if thisBigDecimalhas too great a magnitude represent as adouble, it will be converted toDouble.NEGATIVE_INFINITYorDouble.POSITIVE_INFINITYas appropriate. Note that even when the return value is finite, this conversion can lose information about the precision of theBigDecimalvalue.- Specified by:
doubleValuein classNumber- Returns:
- this
BigDecimalconverted to adouble. - See Java Language Specification:
-
5.1.3 Narrowing Primitive Conversion
-
ulp
Returns the size of an ulp, a unit in the last place, of thisBigDecimal. An ulp of a nonzeroBigDecimalvalue is the positive distance between this value and theBigDecimalvalue next larger in magnitude with the same number of digits. An ulp of a zero value is numerically equal to 1 with the scale ofthis. The result is stored with the same scale asthisso the result for zero and nonzero values is equal to[1, this.scale()].- Returns:
- the size of an ulp of
this - Since:
- 1.5
-
RoundingMode.CEILINGinstead.