File	Doc	Category	Size	Date	Package
BigDecimal.java	API Doc	Java SE 6 API	142131	Tue Jun 10 00:25:40 BST 2008	java.math

BigDecimal

• java.lang.Object
  • java.lang.Number

Fields Summary
private volatile BigInteger	intVal The unscaled value of this BigDecimal, as returned by {@link #unscaledValue}.
private int	scale The scale of this BigDecimal, as returned by {@link #scale}.
private volatile transient int	precision The number of decimal digits in this BigDecimal, or 0 if the number of digits are not known (lookaside information). If nonzero, the value is guaranteed correct. Use the precision() method to obtain and set the value if it might be 0. This field is mutable until set nonzero.
private volatile transient String	stringCache Used to store the canonical string representation, if computed.
private static final long	INFLATED Sentinel value for {@link #intCompact} indicating the significand information is only available from {@code intVal}.
private transient long	intCompact If the absolute value of the significand of this BigDecimal is less than or equal to {@code Long.MAX_VALUE}, the value can be compactly stored in this field and used in computations.
private static final int	MAX_COMPACT_DIGITS
private static final int	MAX_BIGINT_BITS
private static final long	serialVersionUID
private static final BigDecimal[]	zeroThroughTen
public 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.
private static BigInteger	LONGMIN BigInteger equal to Long.MIN_VALUE.
private static BigInteger	LONGMAX BigInteger equal to Long.MAX_VALUE.
private static BigInteger[]	TENPOWERS
private static long[]	thresholds
private static int[]	ilogTable

Constructors Summary
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 {@link #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 . param in char array that is the source of characters. param offset first character in the array to inspect. param len number of characters to consider. throws NumberFormatException if in is not a valid representation of a BigDecimal or the defined subarray is not wholly within in. since 1.5 // Constructors // This is the primary string to BigDecimal constructor; all // incoming strings end up here; it uses explicit (inline) // parsing for speed and generates at most one intermediate // (temporary) object (a char[] array). // use array bounds checking to handle too-long, len == 0, // bad offset, etc. try { // handle the sign boolean isneg = false; // assume positive if (in[offset] == '-") { isneg = true; // leading minus means negative offset++; len--; } else if (in[offset] == '+") { // leading + allowed offset++; len--; } // should now be at numeric part of the significand int dotoff = -1; // '.' offset, -1 if none int cfirst = offset; // record start of integer long exp = 0; // exponent if (len > in.length) // protect against huge length throw new NumberFormatException(); char coeff[] = new char[len]; // integer significand array char c; // work for (; len > 0; offset++, len--) { c = in[offset]; if ((c >= '0" && c <= '9") || Character.isDigit(c)) { // have digit coeff[precision] = c; precision++; // count of digits continue; } if (c == '.") { // have dot if (dotoff >= 0) // two dots throw new NumberFormatException(); dotoff = offset; continue; } // exponent expected if ((c != 'e") && (c != 'E")) throw new NumberFormatException(); offset++; c = in[offset]; len--; boolean negexp = false; // optional sign if (c == '-" || c == '+") { negexp = (c == '-"); offset++; c = in[offset]; len--; } if (len <= 0) // no exponent digits throw new NumberFormatException(); // skip leading zeros in the exponent while (len > 10 && Character.digit(c, 10) == 0) { offset++; c = in[offset]; len--; } if (len > 10) // too many nonzero exponent digits throw new NumberFormatException(); // c now holds first digit of exponent for (;; len--) { int v; if (c >= '0" && c <= '9") { v = c - '0"; } else { v = Character.digit(c, 10); if (v < 0) // not a digit throw new NumberFormatException(); } exp = exp * 10 + v; if (len == 1) break; // that was final character offset++; c = in[offset]; } if (negexp) // apply sign exp = -exp; // Next test is required for backwards compatibility if ((int)exp != exp) // overflow throw new NumberFormatException(); break; // [saves a test] } // here when no characters left if (precision == 0) // no digits found throw new NumberFormatException(); if (dotoff >= 0) { // had dot; set scale scale = precision - (dotoff - cfirst); // [cannot overflow] } if (exp != 0) { // had significant exponent try { scale = checkScale(-exp + scale); // adjust } catch (ArithmeticException e) { throw new NumberFormatException("Scale out of range."); } } // Remove leading zeros from precision (digits count) int first = 0; for (; (coeff[first] == '0" || Character.digit(coeff[first], 10) == 0) && precision > 1; first++) precision--; // Set the significand .. // Copy significand to exact-sized array, with sign if // negative // Later use: BigInteger(coeff, first, precision) for // both cases, by allowing an extra char at the front of // coeff. char quick[]; if (!isneg) { quick = new char[precision]; System.arraycopy(coeff, first, quick, 0, precision); } else { quick = new char[precision+1]; quick[0] = '-"; System.arraycopy(coeff, first, quick, 1, precision); } if (precision <= MAX_COMPACT_DIGITS) intCompact = Long.parseLong(new String(quick)); else intVal = new BigInteger(quick); // System.out.println(" new: " +intVal+" ["+scale+"] "+precision); } catch (ArrayIndexOutOfBoundsException e) { throw new NumberFormatException(); } catch (NegativeArraySizeException e) { throw new NumberFormatException(); }
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. param val BigInteger value to be converted to BigDecimal. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 intVal = val; if (mc.precision > 0) roundThis(mc);
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). param unscaledVal unscaled value of the BigDecimal. param scale scale of the BigDecimal. // Negative scales are now allowed intVal = unscaledVal; this.scale = scale; if (unscaledVal.bitLength() <= MAX_BIGINT_BITS) { intCompact = unscaledVal.longValue(); }
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. param unscaledVal unscaled value of the BigDecimal. param scale scale of the BigDecimal. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 intVal = unscaledVal; this.scale = scale; if (mc.precision > 0) roundThis(mc);
public BigDecimal(int val) Translates an int into a BigDecimal. The scale of the BigDecimal is zero. param val int value to be converted to BigDecimal. since 1.5 intCompact = val;
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. param val int value to be converted to BigDecimal. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 intCompact = val; if (mc.precision > 0) roundThis(mc);
public BigDecimal(long val) Translates a long into a BigDecimal. The scale of the BigDecimal is zero. param val long value to be converted to BigDecimal. since 1.5 if (compactLong(val)) intCompact = val; else intVal = BigInteger.valueOf(val);
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. param val long value to be converted to BigDecimal. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 if (compactLong(val)) intCompact = val; else intVal = BigInteger.valueOf(val); if (mc.precision > 0) roundThis(mc);
private BigDecimal(long val, int scale) Trusted internal constructor this.intCompact = val; this.scale = scale;
private BigDecimal(BigInteger intVal, long val, int scale) Trusted internal constructor this.intVal = intVal; this.intCompact = val; this.scale = scale;
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 {@link #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 . param in char array that is the source of characters. param offset first character in the array to inspect. param len number of characters to consider.. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. throws NumberFormatException if in is not a valid representation of a BigDecimal or the defined subarray is not wholly within in. since 1.5 this(in, offset, len); if (mc.precision > 0) roundThis(mc);
public BigDecimal(char[] in) Translates a character array representation of a BigDecimal into a BigDecimal, accepting the same sequence of characters as the {@link #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 . param in char array that is the source of characters. throws NumberFormatException if in is not a valid representation of a BigDecimal. since 1.5 this(in, 0, in.length);
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 {@link #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 . param in char array that is the source of characters. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. throws NumberFormatException if in is not a valid representation of a BigDecimal. since 1.5 this(in, 0, in.length, mc);
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 -{@link Integer#MAX_VALUE} ({@link Integer#MIN_VALUE}+1) and {@link Integer#MAX_VALUE}, inclusive. 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: e E SignedInteger: Signopt Digits Digits: Digit Digits Digit Digit: any character for which {@link Character#isDigit} 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 {@link java.lang.Character#digit} 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 {@link Float#toString} and {@link Double#toString}. 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 {@link #BigDecimal(double)} constructor. param val String representation of BigDecimal. throws NumberFormatException if val is not a valid representation of a BigDecimal. this(val.toCharArray(), 0, val.length());
public BigDecimal(String val, MathContext mc) Translates the string representation of a BigDecimal into a BigDecimal, accepting the same strings as the {@link #BigDecimal(String)} constructor, with rounding according to the context settings. param val string representation of a BigDecimal. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. throws NumberFormatException if val is not a valid representation of a BigDecimal. since 1.5 this(val.toCharArray(), 0, val.length()); if (mc.precision > 0) roundThis(mc);
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: The results of this constructor can be somewhat unpredictable. One might assume that writing 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. The 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 {@linkplain #BigDecimal(String) String constructor} be used in preference to this one. When a 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 {@link Double#toString(double)} method and then using the {@link #BigDecimal(String)} constructor. To get that result, use the static {@link #valueOf(double)} method. param val double value to be converted to BigDecimal. throws NumberFormatException if val is infinite or NaN. if (Double.isInfinite(val) || Double.isNaN(val)) throw new NumberFormatException("Infinite or NaN"); // Translate the double into sign, exponent and significand, according // to the formulae in JLS, Section 20.10.22. long valBits = Double.doubleToLongBits(val); int sign = ((valBits >> 63)==0 ? 1 : -1); int exponent = (int) ((valBits >> 52) & 0x7ffL); long significand = (exponent==0 ? (valBits & ((1L<<52) - 1)) << 1 : (valBits & ((1L<<52) - 1)) | (1L<<52)); exponent -= 1075; // At this point, val == sign * significand * 2**exponent. /* * Special case zero to supress nonterminating normalization * and bogus scale calculation. */ if (significand == 0) { intVal = BigInteger.ZERO; intCompact = 0; precision = 1; return; } // Normalize while((significand & 1) == 0) { // i.e., significand is even significand >>= 1; exponent++; } // Calculate intVal and scale intVal = BigInteger.valueOf(sign*significand); if (exponent < 0) { intVal = intVal.multiply(BigInteger.valueOf(5).pow(-exponent)); scale = -exponent; } else if (exponent > 0) { intVal = intVal.multiply(BigInteger.valueOf(2).pow(exponent)); } if (intVal.bitLength() <= MAX_BIGINT_BITS) { intCompact = intVal.longValue(); }
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 {@link #BigDecimal(double)} constructor. param val double value to be converted to BigDecimal. param mc the context to use. throws ArithmeticException if the result is inexact but the RoundingMode is UNNECESSARY. throws NumberFormatException if val is infinite or NaN. since 1.5 this(val); if (mc.precision > 0) roundThis(mc);
public BigDecimal(BigInteger val) Translates a BigInteger into a BigDecimal. The scale of the BigDecimal is zero. param val BigInteger value to be converted to BigDecimal. intVal = val; if (val.bitLength() <= MAX_BIGINT_BITS) { intCompact = val.longValue(); }

Methods Summary
public java.math.BigDecimal	abs() Returns a BigDecimal whose value is the absolute value of this BigDecimal, and whose scale is this.scale(). return abs(this) return (signum() < 0 ? negate() : this);
public java.math.BigDecimal	abs(java.math.MathContext mc) Returns a BigDecimal whose value is the absolute value of this BigDecimal, with rounding according to the context settings. param mc the context to use. return abs(this), rounded as necessary. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 return (signum() < 0 ? negate(mc) : plus(mc));
public java.math.BigDecimal	add(java.math.BigDecimal augend) Returns a BigDecimal whose value is (this + augend), and whose scale is max(this.scale(), augend.scale()). param augend value to be added to this BigDecimal. return this + augend BigDecimal arg[] = {this, augend}; matchScale(arg); long x = arg[0].intCompact; long y = arg[1].intCompact; // Might be able to do a more clever check incorporating the // inflated check into the overflow computation. if (x != INFLATED && y != INFLATED) { long sum = x + y; /* * If the sum is not an overflowed value, continue to use * the compact representation. if either of x or y is * INFLATED, the sum should also be regarded as an * overflow. See "Hacker's Delight" section 2-12 for * explanation of the overflow test. */ if ( (((sum ^ x) & (sum ^ y)) >> 63) == 0L ) // not overflowed return BigDecimal.valueOf(sum, arg[0].scale); } return new BigDecimal(arg[0].inflate().intVal.add(arg[1].inflate().intVal), arg[0].scale);
public java.math.BigDecimal	add(java.math.BigDecimal augend, java.math.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. param augend value to be added to this BigDecimal. param mc the context to use. return this + augend, rounded as necessary. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 if (mc.precision == 0) return add(augend); BigDecimal lhs = this; // Could optimize if values are compact this.inflate(); augend.inflate(); // If either number is zero then the other number, rounded and // scaled if necessary, is used as the result. { boolean lhsIsZero = lhs.signum() == 0; boolean augendIsZero = augend.signum() == 0; if (lhsIsZero || augendIsZero) { int preferredScale = Math.max(lhs.scale(), augend.scale()); BigDecimal result; // Could use a factory for zero instead of a new object if (lhsIsZero && augendIsZero) return new BigDecimal(BigInteger.ZERO, 0, preferredScale); result = lhsIsZero ? augend.doRound(mc) : lhs.doRound(mc); if (result.scale() == preferredScale) return result; else if (result.scale() > preferredScale) return new BigDecimal(result.intVal, result.intCompact, result.scale). stripZerosToMatchScale(preferredScale); else { // result.scale < preferredScale int precisionDiff = mc.precision - result.precision(); int scaleDiff = preferredScale - result.scale(); if (precisionDiff >= scaleDiff) return result.setScale(preferredScale); // can achieve target scale else return result.setScale(result.scale() + precisionDiff); } } } long padding = (long)lhs.scale - augend.scale; if (padding != 0) { // scales differ; alignment needed BigDecimal arg[] = preAlign(lhs, augend, padding, mc); matchScale(arg); lhs = arg[0]; augend = arg[1]; } return new BigDecimal(lhs.inflate().intVal.add(augend.inflate().intVal), lhs.scale).doRound(mc);
private java.math.BigDecimal	audit() Check internal invariants of this BigDecimal. These invariants include: The object must be initialized; either intCompact must not be INFLATED or intVal is non-null. Both of these conditions may be true. If both intCompact and intVal and set, their values must be consistent. If precision is nonzero, it must have the right value. // Check precision if (precision > 0) { if (precision != digitLength()) { print("audit", this); throw new AssertionError("precision mismatch"); } } if (intCompact == INFLATED) { if (intVal == null) { print("audit", this); throw new AssertionError("null intVal"); } } else { if (intVal != null) { long val = intVal.longValue(); if (val != intCompact) { print("audit", this); throw new AssertionError("Inconsistent state, intCompact=" + intCompact + "\t intVal=" + val); } } } return this;
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. return this BigDecimal converted to a byte. throws ArithmeticException if this has a nonzero fractional part, or will not fit in a byte. since 1.5 long num; num = this.longValueExact(); // will check decimal part if ((byte)num != num) throw new java.lang.ArithmeticException("Overflow"); return (byte)num;
private int	checkScale(long val) Check a scale for Underflow or Overflow. If this BigDecimal is uninitialized or initialized and nonzero, throw an exception if the scale is out of range. If this is zero, saturate the scale to the extreme value of the right sign if the scale is out of range. param val The new scale. throws ArithmeticException (overflow or underflow) if the new scale is out of range. return validated scale as an int. if ((int)val != val) { if ((this.intCompact != INFLATED && this.intCompact != 0) || (this.intVal != null && this.signum() != 0) || (this.intVal == null && this.intCompact == INFLATED) ) { if (val > Integer.MAX_VALUE) throw new ArithmeticException("Underflow"); if (val < Integer.MIN_VALUE) throw new ArithmeticException("Overflow"); } else { return (val > Integer.MAX_VALUE)?Integer.MAX_VALUE:Integer.MIN_VALUE; } } return (int)val;
private static boolean	compactLong(long val) return (val != Long.MIN_VALUE);
public int	compareTo(java.math.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. param val BigDecimal to which this BigDecimal is to be compared. return -1, 0, or 1 as this BigDecimal is numerically less than, equal to, or greater than val. if (this.scale == val.scale && this.intCompact != INFLATED && val.intCompact != INFLATED) return longCompareTo(this.intCompact, val.intCompact); // Optimization: would run fine without the next three lines int sigDiff = signum() - val.signum(); if (sigDiff != 0) return (sigDiff > 0 ? 1 : -1); // If the (adjusted) exponents are different we do not need to // expensively match scales and compare the significands int aethis = this.precision() - this.scale; // [-1] int aeval = val.precision() - val.scale; // [-1] if (aethis < aeval) return -this.signum(); else if (aethis > aeval) return this.signum(); // Scale and compare intVals BigDecimal arg[] = {this, val}; matchScale(arg); if (arg[0].intCompact != INFLATED && arg[1].intCompact != INFLATED) return longCompareTo(arg[0].intCompact, arg[1].intCompact); return arg[0].inflate().intVal.compareTo(arg[1].inflate().intVal);
private int	digitLength() Returns the length of this BigDecimal, in decimal digits. Notes: This is performance-critical; most operations where a context is supplied will need at least one call to this method. This should be a method on BigInteger; the call to this method in precision() can then be replaced with the term: intVal.digitLength(). It could also be called precision() in BigInteger. Better still -- the precision lookaside could be moved to BigInteger, too. This could/should use MutableBigIntegers directly for the reduction loop. return the length of the unscaled value, in decimal digits if (intCompact != INFLATED && Math.abs(intCompact) <= Integer.MAX_VALUE) return intLength(Math.abs((int)intCompact)); if (signum() == 0) // 0 is one decimal digit return 1; this.inflate(); // we have a nonzero magnitude BigInteger work = intVal; int digits = 0; // counter for (;work.mag.length>1;) { // here when more than one integer in the magnitude; divide // by a billion (reduce by 9 digits) and try again work = work.divide(TENPOWERS[9]); digits += 9; if (work.signum() == 0) // the division was exact return digits; // (a power of a billion) } // down to a simple nonzero integer digits += intLength(work.mag[0]); // System.out.println("digitLength... "+this+" -> "+digits); return digits;
public java.math.BigDecimal	divide(java.math.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 {@link #divide(BigDecimal, int, RoundingMode)} method should be used in preference to this legacy method. param divisor value by which this BigDecimal is to be divided. param scale scale of the BigDecimal quotient to be returned. param roundingMode rounding mode to apply. return this / divisor throws ArithmeticException if divisor is zero, roundingMode==ROUND_UNNECESSARY and the specified scale is insufficient to represent the result of the division exactly. throws IllegalArgumentException if roundingMode does not represent a valid rounding mode. see #ROUND_UP see #ROUND_DOWN see #ROUND_CEILING see #ROUND_FLOOR see #ROUND_HALF_UP see #ROUND_HALF_DOWN see #ROUND_HALF_EVEN see #ROUND_UNNECESSARY /* * IMPLEMENTATION NOTE: This method *must* return a new object * since dropDigits uses divide to generate a value whose * scale is then modified. */ if (roundingMode < ROUND_UP || roundingMode > ROUND_UNNECESSARY) throw new IllegalArgumentException("Invalid rounding mode"); /* * Rescale dividend or divisor (whichever can be "upscaled" to * produce correctly scaled quotient). * Take care to detect out-of-range scales */ BigDecimal dividend; if (checkScale((long)scale + divisor.scale) >= this.scale) { dividend = this.setScale(scale + divisor.scale); } else { dividend = this; divisor = divisor.setScale(checkScale((long)this.scale - scale)); } boolean compact = dividend.intCompact != INFLATED && divisor.intCompact != INFLATED; long div = INFLATED; long rem = INFLATED;; BigInteger q=null, r=null; if (compact) { div = dividend.intCompact / divisor.intCompact; rem = dividend.intCompact % divisor.intCompact; } else { // Do the division and return result if it's exact. BigInteger i[] = dividend.inflate().intVal.divideAndRemainder(divisor.inflate().intVal); q = i[0]; r = i[1]; } // Check for exact result if (compact) { if (rem == 0) return new BigDecimal(div, scale); } else { if (r.signum() == 0) return new BigDecimal(q, scale); } if (roundingMode == ROUND_UNNECESSARY) // Rounding prohibited throw new ArithmeticException("Rounding necessary"); /* Round as appropriate */ int signum = dividend.signum() * divisor.signum(); // Sign of result boolean increment; if (roundingMode == ROUND_UP) { // Away from zero increment = true; } else if (roundingMode == ROUND_DOWN) { // Towards zero increment = false; } else if (roundingMode == ROUND_CEILING) { // Towards +infinity increment = (signum > 0); } else if (roundingMode == ROUND_FLOOR) { // Towards -infinity increment = (signum < 0); } else { // Remaining modes based on nearest-neighbor determination int cmpFracHalf; if (compact) { cmpFracHalf = longCompareTo(Math.abs(2*rem), Math.abs(divisor.intCompact)); } else { // add(r) here is faster than multiply(2) or shiftLeft(1) cmpFracHalf= r.add(r).abs().compareTo(divisor.intVal.abs()); } if (cmpFracHalf < 0) { // We're closer to higher digit increment = false; } else if (cmpFracHalf > 0) { // We're closer to lower digit increment = true; } else { // We're dead-center if (roundingMode == ROUND_HALF_UP) increment = true; else if (roundingMode == ROUND_HALF_DOWN) increment = false; else { // roundingMode == ROUND_HALF_EVEN if (compact) increment = (div & 1L) != 0L; else increment = q.testBit(0); // true iff q is odd } } } if (compact) { if (increment) div += signum; // guaranteed not to overflow return new BigDecimal(div, scale); } else { return (increment ? new BigDecimal(q.add(BigInteger.valueOf(signum)), scale) : new BigDecimal(q, scale)); }
public java.math.BigDecimal	divide(java.math.BigDecimal divisor, int scale, java.math.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. param divisor value by which this BigDecimal is to be divided. param scale scale of the BigDecimal quotient to be returned. param roundingMode rounding mode to apply. return this / divisor throws ArithmeticException if divisor is zero, roundingMode==RoundingMode.UNNECESSARY and the specified scale is insufficient to represent the result of the division exactly. since 1.5 return divide(divisor, scale, roundingMode.oldMode);
public java.math.BigDecimal	divide(java.math.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 {@link #divide(BigDecimal, RoundingMode)} method should be used in preference to this legacy method. param divisor value by which this BigDecimal is to be divided. param roundingMode rounding mode to apply. return this / divisor throws ArithmeticException if divisor==0, or roundingMode==ROUND_UNNECESSARY and this.scale() is insufficient to represent the result of the division exactly. throws IllegalArgumentException if roundingMode does not represent a valid rounding mode. see #ROUND_UP see #ROUND_DOWN see #ROUND_CEILING see #ROUND_FLOOR see #ROUND_HALF_UP see #ROUND_HALF_DOWN see #ROUND_HALF_EVEN see #ROUND_UNNECESSARY return this.divide(divisor, scale, roundingMode);
public java.math.BigDecimal	divide(java.math.BigDecimal divisor, java.math.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. param divisor value by which this BigDecimal is to be divided. param roundingMode rounding mode to apply. return this / divisor throws ArithmeticException if divisor==0, or roundingMode==RoundingMode.UNNECESSARY and this.scale() is insufficient to represent the result of the division exactly. since 1.5 return this.divide(divisor, scale, roundingMode.oldMode);
public java.math.BigDecimal	divide(java.math.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. param divisor value by which this BigDecimal is to be divided. throws ArithmeticException if the exact quotient does not have a terminating decimal expansion return this / divisor since 1.5 author Joseph D. Darcy /* * Handle zero cases first. */ if (divisor.signum() == 0) { // x/0 if (this.signum() == 0) // 0/0 throw new ArithmeticException("Division undefined"); // NaN throw new ArithmeticException("Division by zero"); } // Calculate preferred scale int preferredScale = (int)Math.max(Math.min((long)this.scale() - divisor.scale(), Integer.MAX_VALUE), Integer.MIN_VALUE); if (this.signum() == 0) // 0/y return new BigDecimal(0, preferredScale); else { this.inflate(); divisor.inflate(); /* * If the quotient this/divisor has a terminating decimal * expansion, the expansion can have no more than * (a.precision() + ceil(10*b.precision)/3) digits. * Therefore, create a MathContext object with this * precision and do a divide with the UNNECESSARY rounding * mode. */ MathContext mc = new MathContext( (int)Math.min(this.precision() + (long)Math.ceil(10.0*divisor.precision()/3.0), Integer.MAX_VALUE), RoundingMode.UNNECESSARY); BigDecimal quotient; try { quotient = this.divide(divisor, mc); } catch (ArithmeticException e) { throw new ArithmeticException("Non-terminating decimal expansion; " + "no exact representable decimal result."); } int quotientScale = quotient.scale(); // divide(BigDecimal, mc) tries to adjust the quotient to // the desired one by removing trailing zeros; since the // exact divide method does not have an explicit digit // limit, we can add zeros too. if (preferredScale > quotientScale) return quotient.setScale(preferredScale); return quotient; }
public java.math.BigDecimal	divide(java.math.BigDecimal divisor, java.math.MathContext mc) Returns a BigDecimal whose value is (this / divisor), with rounding according to the context settings. param divisor value by which this BigDecimal is to be divided. param mc the context to use. return this / divisor, rounded as necessary. throws 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. since 1.5 if (mc.precision == 0) return divide(divisor); BigDecimal lhs = this.inflate(); // left-hand-side BigDecimal rhs = divisor.inflate(); // right-hand-side BigDecimal result; // work long preferredScale = (long)lhs.scale() - rhs.scale(); // Now calculate the answer. We use the existing // divide-and-round method, but as this rounds to scale we have // to normalize the values here to achieve the desired result. // For x/y we first handle y=0 and x=0, and then normalize x and // y to give x' and y' with the following constraints: // (a) 0.1 <= x' < 1 // (b) x' <= y' < 10*x' // Dividing x'/y' with the required scale set to mc.precision then // will give a result in the range 0.1 to 1 rounded to exactly // the right number of digits (except in the case of a result of // 1.000... which can arise when x=y, or when rounding overflows // The 1.000... case will reduce properly to 1. if (rhs.signum() == 0) { // x/0 if (lhs.signum() == 0) // 0/0 throw new ArithmeticException("Division undefined"); // NaN throw new ArithmeticException("Division by zero"); } if (lhs.signum() == 0) // 0/y return new BigDecimal(BigInteger.ZERO, (int)Math.max(Math.min(preferredScale, Integer.MAX_VALUE), Integer.MIN_VALUE)); BigDecimal xprime = new BigDecimal(lhs.intVal.abs(), lhs.precision()); BigDecimal yprime = new BigDecimal(rhs.intVal.abs(), rhs.precision()); // xprime and yprime are now both in range 0.1 through 0.999... if (mc.roundingMode == RoundingMode.CEILING || mc.roundingMode == RoundingMode.FLOOR) { // The floor (round toward negative infinity) and ceil // (round toward positive infinity) rounding modes are not // invariant under a sign flip. If xprime/yprime has a // different sign than lhs/rhs, the rounding mode must be // changed. if ((xprime.signum() != lhs.signum()) ^ (yprime.signum() != rhs.signum())) { mc = new MathContext(mc.precision, (mc.roundingMode==RoundingMode.CEILING)? RoundingMode.FLOOR:RoundingMode.CEILING); } } if (xprime.compareTo(yprime) > 0) // satisfy constraint (b) yprime.scale -= 1; // [that is, yprime *= 10] result = xprime.divide(yprime, mc.precision, mc.roundingMode.oldMode); // correct the scale of the result... result.scale = checkScale((long)yprime.scale - xprime.scale - (rhs.scale - lhs.scale) + mc.precision); // apply the sign if (lhs.signum() != rhs.signum()) result = result.negate(); // doRound, here, only affects 1000000000 case. result = result.doRound(mc); if (result.multiply(divisor).compareTo(this) == 0) { // Apply preferred scale rules for exact quotients return result.stripZerosToMatchScale(preferredScale); } else { return result; }
public java.math.BigDecimal[]	divideAndRemainder(java.math.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. param divisor value by which this BigDecimal is to be divided, and the remainder computed. return a two element BigDecimal array: the quotient (the result of divideToIntegralValue) is the initial element and the remainder is the final element. throws ArithmeticException if divisor==0 see #divideToIntegralValue(java.math.BigDecimal, java.math.MathContext) see #remainder(java.math.BigDecimal, java.math.MathContext) since 1.5 // we use the identity x = i * y + r to determine r BigDecimal[] result = new BigDecimal[2]; result[0] = this.divideToIntegralValue(divisor); result[1] = this.subtract(result[0].multiply(divisor)); return result;
public java.math.BigDecimal[]	divideAndRemainder(java.math.BigDecimal divisor, java.math.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. param divisor value by which this BigDecimal is to be divided, and the remainder computed. param mc the context to use. return a two element BigDecimal array: the quotient (the result of divideToIntegralValue) is the initial element and the remainder is the final element. throws ArithmeticException if divisor==0 throws 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. see #divideToIntegralValue(java.math.BigDecimal, java.math.MathContext) see #remainder(java.math.BigDecimal, java.math.MathContext) since 1.5 if (mc.precision == 0) return divideAndRemainder(divisor); BigDecimal[] result = new BigDecimal[2]; BigDecimal lhs = this; result[0] = lhs.divideToIntegralValue(divisor, mc); result[1] = lhs.subtract(result[0].multiply(divisor)); return result;
public java.math.BigDecimal	divideToIntegralValue(java.math.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()). param divisor value by which this BigDecimal is to be divided. return The integer part of this / divisor. throws ArithmeticException if divisor==0 since 1.5 // Calculate preferred scale int preferredScale = (int)Math.max(Math.min((long)this.scale() - divisor.scale(), Integer.MAX_VALUE), Integer.MIN_VALUE); this.inflate(); divisor.inflate(); if (this.abs().compareTo(divisor.abs()) < 0) { // much faster when this << divisor return BigDecimal.valueOf(0, preferredScale); } if(this.signum() == 0 && divisor.signum() != 0) return this.setScale(preferredScale); // Perform a divide with enough digits to round to a correct // integer value; then remove any fractional digits int maxDigits = (int)Math.min(this.precision() + (long)Math.ceil(10.0*divisor.precision()/3.0) + Math.abs((long)this.scale() - divisor.scale()) + 2, Integer.MAX_VALUE); BigDecimal quotient = this.divide(divisor, new MathContext(maxDigits, RoundingMode.DOWN)); if (quotient.scale > 0) { quotient = quotient.setScale(0, RoundingMode.DOWN). stripZerosToMatchScale(preferredScale); } if (quotient.scale < preferredScale) { // pad with zeros if necessary quotient = quotient.setScale(preferredScale); } return quotient;
public java.math.BigDecimal	divideToIntegralValue(java.math.BigDecimal divisor, java.math.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. param divisor value by which this BigDecimal is to be divided. param mc the context to use. return The integer part of this / divisor. throws ArithmeticException if divisor==0 throws ArithmeticException if mc.precision > 0 and the result requires a precision of more than mc.precision digits. since 1.5 author Joseph D. Darcy if (mc.precision == 0 || // exact result (this.abs().compareTo(divisor.abs()) < 0) ) // zero result return divideToIntegralValue(divisor); // Calculate preferred scale int preferredScale = (int)Math.max(Math.min((long)this.scale() - divisor.scale(), Integer.MAX_VALUE), Integer.MIN_VALUE); /* * Perform a normal divide to mc.precision digits. If the * remainder has absolute value less than the divisor, the * integer portion of the quotient fits into mc.precision * digits. Next, remove any fractional digits from the * quotient and adjust the scale to the preferred value. */ BigDecimal result = this.divide(divisor, new MathContext(mc.precision, RoundingMode.DOWN)); int resultScale = result.scale(); if (result.scale() < 0) { /* * Result is an integer. See if quotient represents the * full integer portion of the exact quotient; if it does, * the computed remainder will be less than the divisor. */ BigDecimal product = result.multiply(divisor); // If the quotient is the full integer value, // |dividend-product| < |divisor|. if (this.subtract(product).abs().compareTo(divisor.abs()) >= 0) { throw new ArithmeticException("Division impossible"); } } else if (result.scale() > 0) { /* * Integer portion of quotient will fit into precision * digits; recompute quotient to scale 0 to avoid double * rounding and then try to adjust, if necessary. */ result = result.setScale(0, RoundingMode.DOWN); } // else result.scale() == 0; int precisionDiff; if ((preferredScale > result.scale()) && (precisionDiff = mc.precision - result.precision()) > 0 ) { return result.setScale(result.scale() + Math.min(precisionDiff, preferredScale - result.scale) ); } else return result.stripZerosToMatchScale(preferredScale);
private java.math.BigDecimal	doRound(java.math.MathContext mc) Returns a BigDecimal rounded according to the MathContext settings; used only if mc.precision>0. Does not change this; if rounding is needed a new BigDecimal is created and returned. param mc the context to use. return a BigDecimal rounded according to the MathContext settings. May return this, if no rounding needed. throws ArithmeticException if the rounding mode is RoundingMode.UNNECESSARY and the result is inexact. this.inflate(); if (precision == 0) { if (mc.roundingMax != null && intVal.compareTo(mc.roundingMax) < 0 && intVal.compareTo(mc.roundingMin) > 0) return this; // no rounding needed precision(); // find it } int drop = precision - mc.precision; // digits to discard if (drop <= 0) // we fit return this; BigDecimal rounded = dropDigits(mc, drop); // we need to double-check, in case of the 999=>1000 case return rounded.doRound(mc);
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 the Java Language Specification: if this BigDecimal has too great a magnitude represent as a double, it will be converted to {@link Double#NEGATIVE_INFINITY} or {@link 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. return this BigDecimal converted to a double. if (scale == 0 && intCompact != INFLATED) return (double)intCompact; // Somewhat inefficient, but guaranteed to work. return Double.parseDouble(this.toString());
private java.math.BigDecimal	dropDigits(java.math.MathContext mc, int drop) Removes digits from the significand of a BigDecimal, rounding according to the MathContext settings. Does not change this; a new BigDecimal is always created and returned. Actual rounding is carried out, as before, by the divide method, as this minimized code changes. It might be more efficient in most cases to move rounding to here, so we can do a round-to-length rather than round-to-scale. param mc the context to use. param drop the number of digits to drop, must be > 0 return a BigDecimal rounded according to the MathContext settings. May return this, if no rounding needed. throws ArithmeticException if the rounding mode is RoundingMode.UNNECESSARY and the result is inexact. // here if we need to round; make the divisor = 10**drop) // [calculating the BigInteger here saves setScale later] BigDecimal divisor = new BigDecimal(tenToThe(drop), 0); // divide to same scale to force round to length BigDecimal rounded = this.divide(divisor, scale, mc.roundingMode.oldMode); rounded.scale = checkScale((long)rounded.scale - drop ); // adjust the scale return rounded;
public boolean	equals(java.lang.Object x) Compares this BigDecimal with the specified Object for equality. Unlike {@link #compareTo(BigDecimal) 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). param x Object to which this BigDecimal is to be compared. return true if and only if the specified Object is a BigDecimal whose value and scale are equal to this BigDecimal's. see #compareTo(java.math.BigDecimal) see #hashCode if (!(x instanceof BigDecimal)) return false; BigDecimal xDec = (BigDecimal) x; if (scale != xDec.scale) return false; if (this.intCompact != INFLATED && xDec.intCompact != INFLATED) return this.intCompact == xDec.intCompact; return this.inflate().intVal.equals(xDec.inflate().intVal);
public float	floatValue() Converts this BigDecimal to a float. This conversion is similar to the narrowing primitive conversion from double to float defined in the Java Language Specification: if this BigDecimal has too great a magnitude to represent as a float, it will be converted to {@link Float#NEGATIVE_INFINITY} or {@link 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. return this BigDecimal converted to a float. if (scale == 0 && intCompact != INFLATED) return (float)intCompact; // Somewhat inefficient, but guaranteed to work. return Float.parseFloat(this.toString());
private java.lang.String	getValueString(int signum, java.lang.String intString, int scale) /* Insert decimal point */ StringBuilder buf; int insertionPoint = intString.length() - scale; if (insertionPoint == 0) { /* Point goes right before intVal */ return (signum<0 ? "-0." : "0.") + intString; } else if (insertionPoint > 0) { /* Point goes inside intVal */ buf = new StringBuilder(intString); buf.insert(insertionPoint, '."); if (signum < 0) buf.insert(0, '-"); } else { /* We must insert zeros between point and intVal */ buf = new StringBuilder(3-insertionPoint + intString.length()); buf.append(signum<0 ? "-0." : "0."); for (int i=0; i<-insertionPoint; i++) buf.append('0"); buf.append(intString); } return buf.toString();
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. return hash code for this BigDecimal. see #equals(Object) if (intCompact != INFLATED) { long val2 = (intCompact < 0)?-intCompact:intCompact; int temp = (int)( ((int)(val2 >>> 32)) * 31 + (val2 & 0xffffffffL)); return 31*((intCompact < 0) ?-temp:temp) + scale; } else return 31*intVal.hashCode() + scale;
private java.math.BigDecimal	inflate() Assign appropriate BigInteger to intVal field if intVal is null, i.e. the compact representation is in use. if (intVal == null) intVal = BigInteger.valueOf(intCompact); return this;
private int	intLength(int x) Returns the length of an unsigned int, in decimal digits. param i the int (treated as unsigned) return the length of the unscaled value, in decimal digits int digits; if (x < 0) { // 'negative' is 10 digits unsigned return 10; } else { // positive integer if (x <= 9) return 1; // "Hacker's Delight" section 11-4 for(int i = -1; ; i++) { if (x <= ilogTable[i+1]) return i +1; } }
public int	intValue() Converts this BigDecimal to an int. This conversion is analogous to a narrowing primitive conversion from double to short as defined in 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. return this BigDecimal converted to an int. return (intCompact != INFLATED && scale == 0) ? (int)intCompact : toBigInteger().intValue();
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. return this BigDecimal converted to an int. throws ArithmeticException if this has a nonzero fractional part, or will not fit in an int. since 1.5 long num; num = this.longValueExact(); // will check decimal part if ((int)num != num) throw new java.lang.ArithmeticException("Overflow"); return (int)num;
private java.lang.String	layoutChars(boolean sci) Lay out this BigDecimal into a char[] array. The Java 1.2 equivalent to this was called getValueString. param sci true for Scientific exponential notation; false for Engineering return string with canonical string representation of this BigDecimal if (scale == 0) // zero scale is trivial return (intCompact != INFLATED) ? Long.toString(intCompact): intVal.toString(); // Get the significand as an absolute value char coeff[]; if (intCompact != INFLATED) coeff = Long.toString(Math.abs(intCompact)).toCharArray(); else coeff = intVal.abs().toString().toCharArray(); // Construct a buffer, with sufficient capacity for all cases. // If E-notation is needed, length will be: +1 if negative, +1 // if '.' needed, +2 for "E+", + up to 10 for adjusted exponent. // Otherwise it could have +1 if negative, plus leading "0.00000" StringBuilder buf=new StringBuilder(coeff.length+14); if (signum() < 0) // prefix '-' if negative buf.append('-"); long adjusted = -(long)scale + (coeff.length-1); if ((scale >= 0) && (adjusted >= -6)) { // plain number int pad = scale - coeff.length; // count of padding zeros if (pad >= 0) { // 0.xxx form buf.append('0"); buf.append('."); for (; pad>0; pad--) { buf.append('0"); } buf.append(coeff); } else { // xx.xx form buf.append(coeff, 0, -pad); buf.append('."); buf.append(coeff, -pad, scale); } } else { // E-notation is needed if (sci) { // Scientific notation buf.append(coeff[0]); // first character if (coeff.length > 1) { // more to come buf.append('."); buf.append(coeff, 1, coeff.length-1); } } else { // Engineering notation int sig = (int)(adjusted % 3); if (sig < 0) sig += 3; // [adjusted was negative] adjusted -= sig; // now a multiple of 3 sig++; if (signum() == 0) { switch (sig) { case 1: buf.append('0"); // exponent is a multiple of three break; case 2: buf.append("0.00"); adjusted += 3; break; case 3: buf.append("0.0"); adjusted += 3; break; default: throw new AssertionError("Unexpected sig value " + sig); } } else if (sig >= coeff.length) { // significand all in integer buf.append(coeff, 0, coeff.length); // may need some zeros, too for (int i = sig - coeff.length; i > 0; i--) buf.append('0"); } else { // xx.xxE form buf.append(coeff, 0, sig); buf.append('."); buf.append(coeff, sig, coeff.length-sig); } } if (adjusted != 0) { // [!sci could have made 0] buf.append('E"); if (adjusted > 0) // force sign for positive buf.append('+"); buf.append(adjusted); } } return buf.toString();
private static int	longCompareTo(long x, long y) return (x < y) ? -1 : (x == y) ? 0 : 1;
private static long	longTenToThe(long val, int n) Compute val * 10 ^ n; return this product if it is representable as a long, INFLATED otherwise. // System.err.print("\tval " + val + "\t power " + n + "\tresult "); if (n >= 0 && n < thresholds.length) { if (Math.abs(val) <= thresholds[n][0] ) { // System.err.println(val * thresholds[n][1]); return val * thresholds[n][1]; } } // System.err.println(INFLATED); return INFLATED;
public long	longValue() Converts this BigDecimal to a long. This conversion is analogous to a narrowing primitive conversion from double to short as defined in 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. return this BigDecimal converted to a long. return (intCompact != INFLATED && scale == 0) ? intCompact: toBigInteger().longValue();
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. return this BigDecimal converted to a long. throws ArithmeticException if this has a nonzero fractional part, or will not fit in a long. since 1.5 if (intCompact != INFLATED && scale == 0) return intCompact; // If more than 19 digits in integer part it cannot possibly fit if ((precision() - scale) > 19) // [OK for negative scale too] throw new java.lang.ArithmeticException("Overflow"); // Fastpath zero and < 1.0 numbers (the latter can be very slow // to round if very small) if (this.signum() == 0) return 0; if ((this.precision() - this.scale) <= 0) throw new ArithmeticException("Rounding necessary"); // round to an integer, with Exception if decimal part non-0 BigDecimal num = this.setScale(0, ROUND_UNNECESSARY).inflate(); if (num.precision() >= 19) { // need to check carefully if (LONGMIN == null) { // initialize constants LONGMIN = BigInteger.valueOf(Long.MIN_VALUE); LONGMAX = BigInteger.valueOf(Long.MAX_VALUE); } if ((num.intVal.compareTo(LONGMIN) < 0) || (num.intVal.compareTo(LONGMAX) > 0)) throw new java.lang.ArithmeticException("Overflow"); } return num.intVal.longValue();
private static void	matchScale(java.math.BigDecimal[] val) Match the scales of two BigDecimals to align their least significant digits. If the scales of val[0] and val[1] differ, rescale (non-destructively) the lower-scaled BigDecimal so they match. That is, the lower-scaled reference will be replaced by a reference to a new object with the same scale as the other BigDecimal. param val array of two elements referring to the two BigDecimals to be aligned. if (val[0].scale < val[1].scale) val[0] = val[0].setScale(val[1].scale); else if (val[1].scale < val[0].scale) val[1] = val[1].setScale(val[0].scale);
public java.math.BigDecimal	max(java.math.BigDecimal val) Returns the maximum of this BigDecimal and val. param val value with which the maximum is to be computed. return the BigDecimal whose value is the greater of this BigDecimal and val. If they are equal, as defined by the {@link #compareTo(BigDecimal) compareTo} method, this is returned. see #compareTo(java.math.BigDecimal) return (compareTo(val) >= 0 ? this : val);
public java.math.BigDecimal	min(java.math.BigDecimal val) Returns the minimum of this BigDecimal and val. param val value with which the minimum is to be computed. return the BigDecimal whose value is the lesser of this BigDecimal and val. If they are equal, as defined by the {@link #compareTo(BigDecimal) compareTo} method, this is returned. see #compareTo(java.math.BigDecimal) return (compareTo(val) <= 0 ? this : val);
public java.math.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). param n number of places to move the decimal point to the left. return a BigDecimal which is equivalent to this one with the decimal point moved n places to the left. throws ArithmeticException if scale overflows. // Cannot use movePointRight(-n) in case of n==Integer.MIN_VALUE int newScale = checkScale((long)scale + n); BigDecimal num; if (intCompact != INFLATED) num = BigDecimal.valueOf(intCompact, newScale); else num = new BigDecimal(intVal, newScale); return (num.scale<0 ? num.setScale(0) : num);
public java.math.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). param n number of places to move the decimal point to the right. return a BigDecimal which is equivalent to this one with the decimal point moved n places to the right. throws ArithmeticException if scale overflows. // Cannot use movePointLeft(-n) in case of n==Integer.MIN_VALUE int newScale = checkScale((long)scale - n); BigDecimal num; if (intCompact != INFLATED) num = BigDecimal.valueOf(intCompact, newScale); else num = new BigDecimal(intVal, newScale); return (num.scale<0 ? num.setScale(0) : num);
public java.math.BigDecimal	multiply(java.math.BigDecimal multiplicand) Returns a BigDecimal whose value is (this × multiplicand), and whose scale is (this.scale() + multiplicand.scale()). param multiplicand value to be multiplied by this BigDecimal. return this * multiplicand long x = this.intCompact; long y = multiplicand.intCompact; int productScale = checkScale((long)scale+multiplicand.scale); // Might be able to do a more clever check incorporating the // inflated check into the overflow computation. if (x != INFLATED && y != INFLATED) { /* * If the product is not an overflowed value, continue * to use the compact representation. if either of x or y * is INFLATED, the product should also be regarded as * an overflow. See "Hacker's Delight" section 2-12 for * explanation of the overflow test. */ long product = x * y; if ( !(y != 0L && product/y != x) ) // not overflowed return BigDecimal.valueOf(product, productScale); } BigDecimal result = new BigDecimal(this.inflate().intVal.multiply(multiplicand.inflate().intVal), productScale); return result;
public java.math.BigDecimal	multiply(java.math.BigDecimal multiplicand, java.math.MathContext mc) Returns a BigDecimal whose value is (this × multiplicand), with rounding according to the context settings. param multiplicand value to be multiplied by this BigDecimal. param mc the context to use. return this * multiplicand, rounded as necessary. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 if (mc.precision == 0) return multiply(multiplicand); BigDecimal lhs = this; return lhs.inflate().multiply(multiplicand.inflate()).doRound(mc);
public java.math.BigDecimal	negate() Returns a BigDecimal whose value is (-this), and whose scale is this.scale(). return -this. BigDecimal result; if (intCompact != INFLATED) result = BigDecimal.valueOf(-intCompact, scale); else { result = new BigDecimal(intVal.negate(), scale); result.precision = precision; } return result;
public java.math.BigDecimal	negate(java.math.MathContext mc) Returns a BigDecimal whose value is (-this), with rounding according to the context settings. param mc the context to use. return -this, rounded as necessary. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 return negate().plus(mc);
public java.math.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 {@link #negate()}. return this. see #negate() since 1.5 return this;
public java.math.BigDecimal	plus(java.math.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 {@link #round(MathContext)} method. param mc the context to use. return this, rounded as necessary. A zero result will have a scale of 0. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. see #round(MathContext) since 1.5 if (mc.precision == 0) // no rounding please return this; return this.doRound(mc);
public java.math.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 {@link #ONE}. Note that future releases may expand the allowable exponent range of this method. param n power to raise this BigDecimal to. return thisn throws ArithmeticException if n is out of range. since 1.5 if (n < 0 || n > 999999999) throw new ArithmeticException("Invalid operation"); // No need to calculate pow(n) if result will over/underflow. // Don't attempt to support "supernormal" numbers. int newScale = checkScale((long)scale * n); this.inflate(); return new BigDecimal(intVal.pow(n), newScale);
public java.math.BigDecimal	pow(int n, java.math.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: An 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 if n is zero, {@link #ONE} is returned even if this is zero, otherwise if 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. if 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. The final value from either the positive or negative case is then rounded to the destination precision. param n power to raise this BigDecimal to. param mc the context to use. return thisn using the ANSI standard X3.274-1996 algorithm throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY, or n is out of range. since 1.5 if (mc.precision == 0) return pow(n); if (n < -999999999 || n > 999999999) throw new ArithmeticException("Invalid operation"); if (n == 0) return ONE; // x**0 == 1 in X3.274 this.inflate(); BigDecimal lhs = this; MathContext workmc = mc; // working settings int mag = Math.abs(n); // magnitude of n if (mc.precision > 0) { int elength = intLength(mag); // length of n in digits if (elength > mc.precision) // X3.274 rule throw new ArithmeticException("Invalid operation"); workmc = new MathContext(mc.precision + elength + 1, mc.roundingMode); } // ready to carry out power calculation... BigDecimal acc = ONE; // accumulator boolean seenbit = false; // set once we've seen a 1-bit for (int i=1;;i++) { // for each bit [top bit ignored] mag += mag; // shift left 1 bit if (mag < 0) { // top bit is set seenbit = true; // OK, we're off acc = acc.multiply(lhs, workmc); // acc=acc*x } if (i == 31) break; // that was the last bit if (seenbit) acc=acc.multiply(acc, workmc); // acc=acc*acc [square] // else (!seenbit) no point in squaring ONE } // if negative n, calculate the reciprocal using working precision if (n<0) // [hence mc.precision>0] acc=ONE.divide(acc, workmc); // round to final precision and strip zeros return acc.doRound(mc);
private java.math.BigDecimal[]	preAlign(java.math.BigDecimal lhs, java.math.BigDecimal augend, long padding, java.math.MathContext mc) Returns an array of length two, the sum of whose entries is equal to the rounded sum of the {@code BigDecimal} arguments. If the digit positions of the arguments have a sufficient gap between them, the value smaller in magnitude can be condensed into a "sticky bit" and the end result will round the same way if the precision of the final result does not include the high order digit of the small magnitude operand. Note that while strictly speaking this is an optimization, it makes a much wider range of additions practical. This corresponds to a pre-shift operation in a fixed precision floating-point adder; this method is complicated by variable precision of the result as determined by the MathContext. A more nuanced operation could implement a "right shift" on the smaller magnitude operand so that the number of digits of the smaller operand could be reduced even though the significands partially overlapped. assert padding != 0; BigDecimal big; BigDecimal small; if (padding < 0) { // lhs is big; augend is small big = lhs; small = augend; } else { // lhs is small; augend is big big = augend; small = lhs; } /* * This is the estimated scale of an ulp of the result; it * assumes that the result doesn't have a carry-out on a true * add (e.g. 999 + 1 => 1000) or any subtractive cancellation * on borrowing (e.g. 100 - 1.2 => 98.8) */ long estResultUlpScale = (long)big.scale - big.precision() + mc.precision; /* * The low-order digit position of big is big.scale(). This * is true regardless of whether big has a positive or * negative scale. The high-order digit position of small is * small.scale - (small.precision() - 1). To do the full * condensation, the digit positions of big and small must be * disjoint *and* the digit positions of small should not be * directly visible in the result. */ long smallHighDigitPos = (long)small.scale - small.precision() + 1; if (smallHighDigitPos > big.scale + 2 && // big and small disjoint smallHighDigitPos > estResultUlpScale + 2) { // small digits not visible small = BigDecimal.valueOf(small.signum(), this.checkScale(Math.max(big.scale, estResultUlpScale) + 3)); } // Since addition is symmetric, preserving input order in // returned operands doesn't matter BigDecimal[] result = {big, small}; return result;
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. return the precision of this BigDecimal. since 1.5 int result = precision; if (result == 0) { result = digitLength(); precision = result; } return result;
private static void	print(java.lang.String name, java.math.BigDecimal bd) System.err.format("%s:\tintCompact %d\tintVal %d\tscale %d\tprecision %d%n", name, bd.intCompact, bd.intVal, bd.scale, bd.precision);
private synchronized void	readObject(java.io.ObjectInputStream s) Reconstitute the BigDecimal instance from a stream (that is, deserialize it). param s the stream being read. // Read in all fields s.defaultReadObject(); // validate possibly bad fields if (intVal == null) { String message = "BigDecimal: null intVal in stream"; throw new java.io.StreamCorruptedException(message); // [all values of scale are now allowed] } // Set intCompact to uninitialized value; could also see if the // intVal was small enough to fit as a compact value. intCompact = INFLATED;
public java.math.BigDecimal	remainder(java.math.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). param divisor value by which this BigDecimal is to be divided. return this % divisor. throws ArithmeticException if divisor==0 since 1.5 BigDecimal divrem[] = this.divideAndRemainder(divisor); return divrem[1];
public java.math.BigDecimal	remainder(java.math.BigDecimal divisor, java.math.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). param divisor value by which this BigDecimal is to be divided. param mc the context to use. return this % divisor, rounded as necessary. throws ArithmeticException if divisor==0 throws 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. see #divideToIntegralValue(java.math.BigDecimal, java.math.MathContext) since 1.5 BigDecimal divrem[] = this.divideAndRemainder(divisor, mc); return divrem[1];
public java.math.BigDecimal	round(java.math.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 {@link #plus(MathContext)} method. param mc the context to use. return a BigDecimal rounded according to the MathContext settings. throws ArithmeticException if the rounding mode is UNNECESSARY and the BigDecimal operation would require rounding. see #plus(MathContext) since 1.5 // Scaling/Rounding Operations return plus(mc);
private java.math.BigDecimal	roundOp(java.math.MathContext mc) Round an operand; used only if digits > 0. Does not change this; if rounding is needed a new BigDecimal is created and returned. param mc the context to use. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. BigDecimal rounded = doRound(mc); return rounded;
private void	roundThis(java.math.MathContext mc) Round this BigDecimal according to the MathContext settings; used only if precision > 0. WARNING: This method should only be called on new objects as it mutates the value fields. param mc the context to use. throws ArithmeticException if the rounding mode is RoundingMode.UNNECESSARY and the BigDecimal operation would require rounding. BigDecimal rounded = doRound(mc); if (rounded == this) // wasn't rounded return; this.intVal = rounded.intVal; this.intCompact = rounded.intCompact; this.scale = rounded.scale; this.precision = rounded.precision;
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. return the scale of this BigDecimal. return scale;
public java.math.BigDecimal	scaleByPowerOfTen(int n) Returns a BigDecimal whose numerical value is equal to (this * 10n). The scale of the result is (this.scale() - n). throws ArithmeticException if the scale would be outside the range of a 32-bit integer. since 1.5 this.inflate(); BigDecimal num = new BigDecimal(intVal, checkScale((long)scale - n)); num.precision = precision; return num;
public java.math.BigDecimal	setScale(int newScale, java.math.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. param newScale scale of the BigDecimal value to be returned. param roundingMode The rounding mode to apply. return 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. throws ArithmeticException if roundingMode==UNNECESSARY and the specified scaling operation would require rounding. see RoundingMode since 1.5 return setScale(newScale, roundingMode.oldMode);
public java.math.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 {@link #setScale(int, RoundingMode)} method should be used in preference to this legacy method. param newScale scale of the BigDecimal value to be returned. param roundingMode The rounding mode to apply. return 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. throws ArithmeticException if roundingMode==ROUND_UNNECESSARY and the specified scaling operation would require rounding. throws IllegalArgumentException if roundingMode does not represent a valid rounding mode. see #ROUND_UP see #ROUND_DOWN see #ROUND_CEILING see #ROUND_FLOOR see #ROUND_HALF_UP see #ROUND_HALF_DOWN see #ROUND_HALF_EVEN see #ROUND_UNNECESSARY if (roundingMode < ROUND_UP || roundingMode > ROUND_UNNECESSARY) throw new IllegalArgumentException("Invalid rounding mode"); if (newScale == this.scale) // easy case return this; if (this.signum() == 0) // zero can have any scale return BigDecimal.valueOf(0, newScale); if (newScale > this.scale) { // [we can use checkScale to assure multiplier is valid] int raise = checkScale((long)newScale - this.scale); if (intCompact != INFLATED) { long scaledResult = longTenToThe(intCompact, raise); if (scaledResult != INFLATED) return BigDecimal.valueOf(scaledResult, newScale); this.inflate(); } BigDecimal result = new BigDecimal(intVal.multiply(tenToThe(raise)), newScale); if (this.precision > 0) result.precision = this.precision + newScale - this.scale; return result; } // scale < this.scale // we cannot perfectly predict the precision after rounding return divide(ONE, newScale, roundingMode);
public java.math.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. param newScale scale of the BigDecimal value to be returned. return 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. throws ArithmeticException if the specified scaling operation would require rounding. see #setScale(int, int) see #setScale(int, RoundingMode) return setScale(newScale, ROUND_UNNECESSARY);
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. return this BigDecimal converted to a short. throws ArithmeticException if this has a nonzero fractional part, or will not fit in a short. since 1.5 long num; num = this.longValueExact(); // will check decimal part if ((short)num != num) throw new java.lang.ArithmeticException("Overflow"); return (short)num;
public int	signum() Returns the signum function of this BigDecimal. return -1, 0, or 1 as the value of this BigDecimal is negative, zero, or positive. return (intCompact != INFLATED)? Long.signum(intCompact): intVal.signum();
public java.math.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] return a numerically equal BigDecimal with any trailing zeros removed. since 1.5 this.inflate(); return (new BigDecimal(intVal, scale)).stripZerosToMatchScale(Long.MIN_VALUE);
private java.math.BigDecimal	stripZerosToMatchScale(long preferredScale) Remove insignificant trailing zeros from this BigDecimal until the preferred scale is reached or no more zeros can be removed. If the preferred scale is less than Integer.MIN_VALUE, all the trailing zeros will be removed. BigInteger assistance could help, here? WARNING: This method should only be called on new objects as it mutates the value fields. return this BigDecimal with a scale possibly reduced to be closed to the preferred scale. boolean compact = (intCompact != INFLATED); this.inflate(); BigInteger qr[]; // quotient-remainder pair while ( intVal.abs().compareTo(BigInteger.TEN) >= 0 && scale > preferredScale) { if (intVal.testBit(0)) break; // odd number cannot end in 0 qr = intVal.divideAndRemainder(BigInteger.TEN); if (qr[1].signum() != 0) break; // non-0 remainder intVal=qr[0]; scale = checkScale((long)scale-1); // could Overflow if (precision > 0) // adjust precision if known precision--; } if (compact) intCompact = intVal.longValue(); return this;
public java.math.BigDecimal	subtract(java.math.BigDecimal subtrahend) Returns a BigDecimal whose value is (this - subtrahend), and whose scale is max(this.scale(), subtrahend.scale()). param subtrahend value to be subtracted from this BigDecimal. return this - subtrahend BigDecimal arg[] = {this, subtrahend}; matchScale(arg); long x = arg[0].intCompact; long y = arg[1].intCompact; // Might be able to do a more clever check incorporating the // inflated check into the overflow computation. if (x != INFLATED && y != INFLATED) { long difference = x - y; /* * If the difference is not an overflowed value, continue * to use the compact representation. if either of x or y * is INFLATED, the difference should also be regarded as * an overflow. See "Hacker's Delight" section 2-12 for * explanation of the overflow test. */ if ( ((x ^ y) & (difference ^ x) ) >> 63 == 0L ) // not overflowed return BigDecimal.valueOf(difference, arg[0].scale); } return new BigDecimal(arg[0].inflate().intVal.subtract(arg[1].inflate().intVal), arg[0].scale);
public java.math.BigDecimal	subtract(java.math.BigDecimal subtrahend, java.math.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). param subtrahend value to be subtracted from this BigDecimal. param mc the context to use. return this - subtrahend, rounded as necessary. throws ArithmeticException if the result is inexact but the rounding mode is UNNECESSARY. since 1.5 if (mc.precision == 0) return subtract(subtrahend); // share the special rounding code in add() this.inflate(); subtrahend.inflate(); BigDecimal rhs = new BigDecimal(subtrahend.intVal.negate(), subtrahend.scale); rhs.precision = subtrahend.precision; return add(rhs, mc);
private static java.math.BigInteger	tenToThe(int n) Return 10 to the power n, as a BigInteger. param n the power of ten to be returned (>=0) return a BigInteger with the value (10n) if (n < TENPOWERS.length) // use value from constant array return TENPOWERS[n]; // BigInteger.pow is slow, so make 10**n by constructing a // BigInteger from a character string (still not very fast) char tenpow[] = new char[n + 1]; tenpow[0] = '1"; for (int i = 1; i <= n; i++) tenpow[i] = '0"; return new BigInteger(tenpow);
public java.math.BigInteger	toBigInteger() Converts this BigDecimal to a BigInteger. This conversion is analogous to a narrowing primitive conversion from double to long as defined in 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 {@link #toBigIntegerExact()} method. return this BigDecimal converted to a BigInteger. // force to an integer, quietly return this.setScale(0, ROUND_DOWN).inflate().intVal;
public java.math.BigInteger	toBigIntegerExact() Converts this BigDecimal to a BigInteger, checking for lost information. An exception is thrown if this BigDecimal has a nonzero fractional part. return this BigDecimal converted to a BigInteger. throws ArithmeticException if this has a nonzero fractional part. since 1.5 // round to an integer, with Exception if decimal part non-0 return this.setScale(0, ROUND_UNNECESSARY).inflate().intVal;
public java.lang.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 {@link #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 {@link #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 {@linkplain #BigDecimal(String) 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. return string representation of this BigDecimal, using engineering notation if an exponent is needed. since 1.5 return layoutChars(false);
public java.lang.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 {@linkplain #BigDecimal(String) 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.) return a string representation of this BigDecimal without an exponent field. since 1.5 see #toString() see #toEngineeringString() BigDecimal bd = this; if (bd.scale < 0) bd = bd.setScale(0); bd.inflate(); if (bd.scale == 0) // No decimal point return bd.intVal.toString(); return bd.getValueString(bd.signum(), bd.intVal.abs().toString(), bd.scale);
public java.lang.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: There is a one-to-one mapping between the distinguishable 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 {@link #BigDecimal(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 {@link java.text.NumberFormat} class and its subclasses. The {@link #toEngineeringString} method may be used for presenting numbers with exponents in engineering notation, and the {@link #setScale(int,RoundingMode) setScale} method may be used for rounding a BigDecimal so it has a known number of digits after the decimal point. The digit-to-character mapping provided by Character.forDigit is used. return string representation of this BigDecimal. see Character#forDigit see #BigDecimal(java.lang.String) if (stringCache == null) stringCache = layoutChars(true); return stringCache;
public java.math.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()]. return the size of an ulp of this since 1.5 return BigDecimal.valueOf(1, this.scale());
public java.math.BigInteger	unscaledValue() Returns a BigInteger whose value is the unscaled value of this BigDecimal. (Computes (this * 10this.scale()).) return the unscaled value of this BigDecimal. since 1.2 return this.inflate().intVal;
public static java.math.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.. param unscaledVal unscaled value of the BigDecimal. param scale scale of the BigDecimal. return a BigDecimal whose value is (unscaledVal × 10-scale). if (scale == 0 && unscaledVal >= 0 && unscaledVal <= 10) { return zeroThroughTen[(int)unscaledVal]; } if (compactLong(unscaledVal)) return new BigDecimal(unscaledVal, scale); return new BigDecimal(BigInteger.valueOf(unscaledVal), scale);
public static java.math.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. param val value of the BigDecimal. return a BigDecimal whose value is val. return valueOf(val, 0);
public static java.math.BigDecimal	valueOf(double val) Translates a double into a BigDecimal, using the double's canonical string representation provided by the {@link 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 {@link Double#toString(double)}. param val double to convert to a BigDecimal. return a BigDecimal whose value is equal to or approximately equal to the value of val. throws NumberFormatException if val is infinite or NaN. since 1.5 // Reminder: a zero double returns '0.0', so we cannot fastpath // to use the constant ZERO. This might be important enough to // justify a factory approach, a cache, or a few private // constants, later. return new BigDecimal(Double.toString(val));
private void	writeObject(java.io.ObjectOutputStream s) Serialize this BigDecimal to the stream in question param s the stream to serialize to. // Must inflate to maintain compatible serial form. this.inflate(); // Write proper fields s.defaultWriteObject();