Movatterモバイル変換

java.lang.Object
- java.lang.Number
- - java.lang.Double

All Implemented Interfaces:
Serializable,Comparable<Double>
```
public final classDoubleextendsNumberimplementsComparable<Double>
```
TheDouble class wraps a value of the primitive typedouble in an object. An object of typeDouble contains a single field whose type isdouble.
In addition, this class provides several methods for converting adouble to aString and aString to adouble, as well as other constants and methods useful when dealing with adouble.
Since:
JDK1.0
See Also:
Serialized Form

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`BYTES`	The number of bytes used to represent a`double` value.
`static int`	`MAX_EXPONENT`	Maximum exponent a finite`double` variable may have.
`static double`	`MAX_VALUE`	A constant holding the largest positive finite value of type`double`, (2-2^-52)·2¹⁰²³.
`static int`	`MIN_EXPONENT`	Minimum exponent a normalized`double` variable may have.
`static double`	`MIN_NORMAL`	A constant holding the smallest positive normal value of type`double`, 2^-1022.
`static double`	`MIN_VALUE`	A constant holding the smallest positive nonzero value of type`double`, 2^-1074.
`static double`	`NaN`	A constant holding a Not-a-Number (NaN) value of type`double`.
`static double`	`NEGATIVE_INFINITY`	A constant holding the negative infinity of type`double`.
`static double`	`POSITIVE_INFINITY`	A constant holding the positive infinity of type`double`.
`static int`	`SIZE`	The number of bits used to represent a`double` value.
`staticClass<Double>`	`TYPE`	The`Class` instance representing the primitive type`double`.

Constructor Summary

Constructors
Constructor	Description
`Double(double value)`	Constructs a newly allocated`Double` object that represents the primitive`double` argument.
`Double(String s)`	Constructs a newly allocated`Double` object that represents the floating-point value of type`double` represented by the string.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`byte`	`byteValue()`	Returns the value of this`Double` as a`byte` after a narrowing primitive conversion.
`static int`	`compare(double d1, double d2)`	Compares the two specified`double` values.
`int`	`compareTo(Double anotherDouble)`	Compares two`Double` objects numerically.
`static long`	`doubleToLongBits(double value)`	Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout.
`static long`	`doubleToRawLongBits(double value)`	Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout, preserving Not-a-Number (NaN) values.
`double`	`doubleValue()`	Returns the`double` value of this`Double` object.
`boolean`	`equals(Object obj)`	Compares this object against the specified object.
`float`	`floatValue()`	Returns the value of this`Double` as a`float` after a narrowing primitive conversion.
`int`	`hashCode()`	Returns a hash code for this`Double` object.
`static int`	`hashCode(double value)`	Returns a hash code for a`double` value; compatible with`Double.hashCode()`.
`int`	`intValue()`	Returns the value of this`Double` as an`int` after a narrowing primitive conversion.
`static boolean`	`isFinite(double d)`	Returns`true` if the argument is a finite floating-point value; returns`false` otherwise (for NaN and infinity arguments).
`boolean`	`isInfinite()`	Returns`true` if this`Double` value is infinitely large in magnitude,`false` otherwise.
`static boolean`	`isInfinite(double v)`	Returns`true` if the specified number is infinitely large in magnitude,`false` otherwise.
`boolean`	`isNaN()`	Returns`true` if this`Double` value is a Not-a-Number (NaN),`false` otherwise.
`static boolean`	`isNaN(double v)`	Returns`true` if the specified number is a Not-a-Number (NaN) value,`false` otherwise.
`static double`	`longBitsToDouble(long bits)`	Returns the`double` value corresponding to a given bit representation.
`long`	`longValue()`	Returns the value of this`Double` as a`long` after a narrowing primitive conversion.
`static double`	`max(double a, double b)`	Returns the greater of two`double` values as if by calling`Math.max`.
`static double`	`min(double a, double b)`	Returns the smaller of two`double` values as if by calling`Math.min`.
`static double`	`parseDouble(String s)`	Returns a new`double` initialized to the value represented by the specified`String`, as performed by the`valueOf` method of class`Double`.
`short`	`shortValue()`	Returns the value of this`Double` as a`short` after a narrowing primitive conversion.
`static double`	`sum(double a, double b)`	Adds two`double` values together as per the + operator.
`staticString`	`toHexString(double d)`	Returns a hexadecimal string representation of the`double` argument.
`String`	`toString()`	Returns a string representation of this`Double` object.
`staticString`	`toString(double d)`	Returns a string representation of the`double` argument.
`staticDouble`	`valueOf(double d)`	Returns a`Double` instance representing the specified`double` value.
`staticDouble`	`valueOf(String s)`	Returns a`Double` object holding the`double` value represented by the argument string`s`.

Methods inherited from class java.lang.Object
clone,finalize,getClass,notify,notifyAll,wait,wait,wait

Field Detail
- POSITIVE_INFINITY
```
public static final double POSITIVE_INFINITY
```
  A constant holding the positive infinity of typedouble. It is equal to the value returned byDouble.longBitsToDouble(0x7ff0000000000000L).
  See Also:
  Constant Field Values
- NEGATIVE_INFINITY
```
public static final double NEGATIVE_INFINITY
```
  A constant holding the negative infinity of typedouble. It is equal to the value returned byDouble.longBitsToDouble(0xfff0000000000000L).
  See Also:
  Constant Field Values
- NaN
```
public static final double NaN
```
  A constant holding a Not-a-Number (NaN) value of typedouble. It is equivalent to the value returned byDouble.longBitsToDouble(0x7ff8000000000000L).
  See Also:
  Constant Field Values
- MAX_VALUE
```
public static final double MAX_VALUE
```
  A constant holding the largest positive finite value of typedouble, (2-2^-52)·2¹⁰²³. It is equal to the hexadecimal floating-point literal0x1.fffffffffffffP+1023 and also equal toDouble.longBitsToDouble(0x7fefffffffffffffL).
  See Also:
  Constant Field Values
- MIN_NORMAL
```
public static final double MIN_NORMAL
```
  A constant holding the smallest positive normal value of typedouble, 2^-1022. It is equal to the hexadecimal floating-point literal0x1.0p-1022 and also equal toDouble.longBitsToDouble(0x0010000000000000L).
  Since:
  1.6
  See Also:
  Constant Field Values
- MIN_VALUE
```
public static final double MIN_VALUE
```
  A constant holding the smallest positive nonzero value of typedouble, 2^-1074. It is equal to the hexadecimal floating-point literal0x0.0000000000001P-1022 and also equal toDouble.longBitsToDouble(0x1L).
  See Also:
  Constant Field Values
- MAX_EXPONENT
```
public static final int MAX_EXPONENT
```
  Maximum exponent a finitedouble variable may have. It is equal to the value returned byMath.getExponent(Double.MAX_VALUE).
  Since:
  1.6
  See Also:
  Constant Field Values
- MIN_EXPONENT
```
public static final int MIN_EXPONENT
```
  Minimum exponent a normalizeddouble variable may have. It is equal to the value returned byMath.getExponent(Double.MIN_NORMAL).
  Since:
  1.6
  See Also:
  Constant Field Values
- SIZE
```
public static final int SIZE
```
  The number of bits used to represent adouble value.
  Since:
  1.5
  See Also:
  Constant Field Values
- BYTES
```
public static final int BYTES
```
  The number of bytes used to represent adouble value.
  Since:
  1.8
  See Also:
  Constant Field Values
- TYPE
```
public static final Class<Double> TYPE
```
  TheClass instance representing the primitive typedouble.
  Since:
  JDK1.1

Constructor Detail
- Double
```
public Double(double value)
```
  Constructs a newly allocatedDouble object that represents the primitivedouble argument.
  Parameters:
  value - the value to be represented by theDouble.
- Double
```
public Double(String s)       throwsNumberFormatException
```
  Constructs a newly allocatedDouble object that represents the floating-point value of typedouble represented by the string. The string is converted to adouble value as if by thevalueOf method.
  Parameters:
  s - a string to be converted to aDouble.
  Throws:
  NumberFormatException - if the string does not contain a parsable number.
  See Also:
  valueOf(java.lang.String)

Method Detail

toString
```
public static String toString(double d)
```
Returns a string representation of thedouble argument. All characters mentioned below are ASCII characters.
- If the argument is NaN, the result is the string "NaN".
- Otherwise, the result is a string that represents the sign and magnitude (absolute value) of the argument. If the sign is negative, the first character of the result is '-' ('\u002D'); if the sign is positive, no sign character appears in the result. As for the magnitudem:
  - Ifm is infinity, it is represented by the characters"Infinity"; thus, positive infinity produces the result"Infinity" and negative infinity produces the result"-Infinity".
  - Ifm is zero, it is represented by the characters"0.0"; thus, negative zero produces the result"-0.0" and positive zero produces the result"0.0".
  - Ifm is greater than or equal to 10^-3 but less than 10⁷, then it is represented as the integer part ofm, in decimal form with no leading zeroes, followed by '.' ('\u002E'), followed by one or more decimal digits representing the fractional part ofm.
  - Ifm is less than 10^-3 or greater than or equal to 10⁷, then it is represented in so-called "computerized scientific notation." Letn be the unique integer such that 10ⁿ ≤m < 10ⁿ⁺¹; then leta be the mathematically exact quotient ofm and 10ⁿ so that 1 ≤a < 10. The magnitude is then represented as the integer part ofa, as a single decimal digit, followed by '.' ('\u002E'), followed by decimal digits representing the fractional part ofa, followed by the letter 'E' ('\u0045'), followed by a representation ofn as a decimal integer, as produced by the methodInteger.toString(int).
How many digits must be printed for the fractional part ofm ora? There must be at least one digit to represent the fractional part, and beyond that as many, but only as many, more digits as are needed to uniquely distinguish the argument value from adjacent values of typedouble. That is, suppose thatx is the exact mathematical value represented by the decimal representation produced by this method for a finite nonzero argumentd. Thend must be thedouble value nearest tox; or if twodouble values are equally close tox, thend must be one of them and the least significant bit of the significand ofd must be0.
To create localized string representations of a floating-point value, use subclasses ofNumberFormat.
Parameters:
d - thedouble to be converted.
Returns:
a string representation of the argument.

toHexString

public static String toHexString(double d)

Returns a hexadecimal string representation of thedouble argument. All characters mentioned below are ASCII characters.

If the argument is NaN, the result is the string "NaN".
Otherwise, the result is a string that represents the sign and magnitude of the argument. If the sign is negative, the first character of the result is '-' ('\u002D'); if the sign is positive, no sign character appears in the result. As for the magnitudem:
- Ifm is infinity, it is represented by the string"Infinity"; thus, positive infinity produces the result"Infinity" and negative infinity produces the result"-Infinity".
- Ifm is zero, it is represented by the string"0x0.0p0"; thus, negative zero produces the result"-0x0.0p0" and positive zero produces the result"0x0.0p0".
- Ifm is adouble value with a normalized representation, substrings are used to represent the significand and exponent fields. The significand is represented by the characters"0x1." followed by a lowercase hexadecimal representation of the rest of the significand as a fraction. Trailing zeros in the hexadecimal representation are removed unless all the digits are zero, in which case a single zero is used. Next, the exponent is represented by"p" followed by a decimal string of the unbiased exponent as if produced by a call toInteger.toString on the exponent value.
- Ifm is adouble value with a subnormal representation, the significand is represented by the characters"0x0." followed by a hexadecimal representation of the rest of the significand as a fraction. Trailing zeros in the hexadecimal representation are removed. Next, the exponent is represented by"p-1022". Note that there must be at least one nonzero digit in a subnormal significand.

Examples
Floating-point Value	Hexadecimal String
`1.0`	`0x1.0p0`
`-1.0`	`-0x1.0p0`
`2.0`	`0x1.0p1`
`3.0`	`0x1.8p1`
`0.5`	`0x1.0p-1`
`0.25`	`0x1.0p-2`
`Double.MAX_VALUE`	`0x1.fffffffffffffp1023`
`Minimum Normal Value`	`0x1.0p-1022`
`Maximum Subnormal Value`	`0x0.fffffffffffffp-1022`
`Double.MIN_VALUE`	`0x0.0000000000001p-1022`

Parameters:: d - thedouble to be converted.
Returns:: a hex string representation of the argument.
Since:: 1.5

valueOf
```
public static Double valueOf(String s)                      throwsNumberFormatException
```
Returns aDouble object holding thedouble value represented by the argument strings.
Ifs isnull, then aNullPointerException is thrown.
Leading and trailing whitespace characters ins are ignored. Whitespace is removed as if by theString.trim() method; that is, both ASCII space and control characters are removed. The rest ofs should constitute aFloatValue as described by the lexical syntax rules:
FloatValue:
Sign_optNaN
Sign_optInfinity
Sign_opt FloatingPointLiteral
Sign_opt HexFloatingPointLiteral
SignedInteger
HexFloatingPointLiteral:
HexSignificand BinaryExponent FloatTypeSuffix_opt
HexSignificand:
HexNumeral
HexNumeral.
0xHexDigits_opt. HexDigits
0X HexDigits_opt.HexDigits
BinaryExponent:
BinaryExponentIndicator SignedInteger
BinaryExponentIndicator:
p
P
whereSign,FloatingPointLiteral,HexNumeral,HexDigits,SignedInteger andFloatTypeSuffix are as defined in the lexical structure sections ofThe Java™ Language Specification, except that underscores are not accepted between digits. Ifs does not have the form of aFloatValue, then aNumberFormatException is thrown. Otherwise,s is regarded as representing an exact decimal value in the usual "computerized scientific notation" or as an exact hexadecimal value; this exact numerical value is then conceptually converted to an "infinitely precise" binary value that is then rounded to typedouble by the usual round-to-nearest rule of IEEE 754 floating-point arithmetic, which includes preserving the sign of a zero value. Note that the round-to-nearest rule also implies overflow and underflow behaviour; if the exact value ofs is large enough in magnitude (greater than or equal to (MAX_VALUE +ulp(MAX_VALUE)/2), rounding todouble will result in an infinity and if the exact value ofs is small enough in magnitude (less than or equal toMIN_VALUE/2), rounding to float will result in a zero. Finally, after rounding aDouble object representing thisdouble value is returned.
To interpret localized string representations of a floating-point value, use subclasses ofNumberFormat.
Note that trailing format specifiers, specifiers that determine the type of a floating-point literal (1.0f is afloat value;1.0d is adouble value), donot influence the results of this method. In other words, the numerical value of the input string is converted directly to the target floating-point type. The two-step sequence of conversions, string tofloat followed byfloat todouble, isnot equivalent to converting a string directly todouble. For example, thefloat literal0.1f is equal to thedouble value0.10000000149011612; thefloat literal0.1f represents a different numerical value than thedouble literal0.1. (The numerical value 0.1 cannot be exactly represented in a binary floating-point number.)
To avoid calling this method on an invalid string and having aNumberFormatException be thrown, the regular expression below can be used to screen the input string:
```
  final String Digits     = "(\\p{Digit}+)";  final String HexDigits  = "(\\p{XDigit}+)";  // an exponent is 'e' or 'E' followed by an optionally  // signed decimal integer.  final String Exp        = "[eE][+-]?"+Digits;  final String fpRegex    =      ("[\\x00-\\x20]*"+  // Optional leading "whitespace"       "[+-]?(" + // Optional sign character       "NaN|" +           // "NaN" string       "Infinity|" +      // "Infinity" string       // A decimal floating-point string representing a finite positive       // number without a leading sign has at most five basic pieces:       // Digits . Digits ExponentPart FloatTypeSuffix       //       // Since this method allows integer-only strings as input       // in addition to strings of floating-point literals, the       // two sub-patterns below are simplifications of the grammar       // productions from section 3.10.2 of       // The Java Language Specification.       // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt       "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+       // . Digits ExponentPart_opt FloatTypeSuffix_opt       "(\\.("+Digits+")("+Exp+")?)|"+       // Hexadecimal strings       "((" +        // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt        "(0[xX]" + HexDigits + "(\\.)?)|" +        // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt        "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +        ")[pP][+-]?" + Digits + "))" +       "[fFdD]?))" +       "[\\x00-\\x20]*");// Optional trailing "whitespace"  if (Pattern.matches(fpRegex, myString))      Double.valueOf(myString); // Will not throw NumberFormatException  else {      // Perform suitable alternative action  }
```
Parameters:
s - the string to be parsed.
Returns:
aDouble object holding the value represented by theString argument.
Throws:
NumberFormatException - if the string does not contain a parsable number.

valueOf
```
public static Double valueOf(double d)
```
Returns aDouble instance representing the specifieddouble value. If a newDouble instance is not required, this method should generally be used in preference to the constructorDouble(double), as this method is likely to yield significantly better space and time performance by caching frequently requested values.
Parameters:
d - a double value.
Returns:
aDouble instance representingd.
Since:
1.5

parseDouble
```
public static double parseDouble(String s)                          throwsNumberFormatException
```
Returns a newdouble initialized to the value represented by the specifiedString, as performed by thevalueOf method of classDouble.
Parameters:
s - the string to be parsed.
Returns:
thedouble value represented by the string argument.
Throws:
NullPointerException - if the string is null
NumberFormatException - if the string does not contain a parsabledouble.
Since:
1.2
See Also:
valueOf(String)

isNaN
```
public static boolean isNaN(double v)
```
Returnstrue if the specified number is a Not-a-Number (NaN) value,false otherwise.
Parameters:
v - the value to be tested.
Returns:
true if the value of the argument is NaN;false otherwise.

isInfinite
```
public static boolean isInfinite(double v)
```
Returnstrue if the specified number is infinitely large in magnitude,false otherwise.
Parameters:
v - the value to be tested.
Returns:
true if the value of the argument is positive infinity or negative infinity;false otherwise.

isFinite
```
public static boolean isFinite(double d)
```
Returnstrue if the argument is a finite floating-point value; returnsfalse otherwise (for NaN and infinity arguments).
Parameters:
d - thedouble value to be tested
Returns:
true if the argument is a finite floating-point value,false otherwise.
Since:
1.8

isNaN
```
public boolean isNaN()
```
Returnstrue if thisDouble value is a Not-a-Number (NaN),false otherwise.
Returns:
true if the value represented by this object is NaN;false otherwise.

isInfinite
```
public boolean isInfinite()
```
Returnstrue if thisDouble value is infinitely large in magnitude,false otherwise.
Returns:
true if the value represented by this object is positive infinity or negative infinity;false otherwise.

toString
```
public String toString()
```
Returns a string representation of thisDouble object. The primitivedouble value represented by this object is converted to a string exactly as if by the methodtoString of one argument.
Overrides:
toString in class Object
Returns:
aString representation of this object.
See Also:
toString(double)

byteValue
```
public byte byteValue()
```
Returns the value of thisDouble as abyte after a narrowing primitive conversion.
Overrides:
byteValue in class Number
Returns:
thedouble value represented by this object converted to typebyte
Since:
JDK1.1
See The Java™ Language Specification:
5.1.3 Narrowing Primitive Conversions

shortValue
```
public short shortValue()
```
Returns the value of thisDouble as ashort after a narrowing primitive conversion.
Overrides:
shortValue in class Number
Returns:
thedouble value represented by this object converted to typeshort
Since:
JDK1.1
See The Java™ Language Specification:
5.1.3 Narrowing Primitive Conversions

intValue
```
public int intValue()
```
Returns the value of thisDouble as anint after a narrowing primitive conversion.
Specified by:
intValue in class Number
Returns:
thedouble value represented by this object converted to typeint
See The Java™ Language Specification:
5.1.3 Narrowing Primitive Conversions

longValue
```
public long longValue()
```
Returns the value of thisDouble as along after a narrowing primitive conversion.
Specified by:
longValue in class Number
Returns:
thedouble value represented by this object converted to typelong
See The Java™ Language Specification:
5.1.3 Narrowing Primitive Conversions

floatValue
```
public float floatValue()
```
Returns the value of thisDouble as afloat after a narrowing primitive conversion.
Specified by:
floatValue in class Number
Returns:
thedouble value represented by this object converted to typefloat
Since:
JDK1.0
See The Java™ Language Specification:
5.1.3 Narrowing Primitive Conversions

doubleValue
```
public double doubleValue()
```
Returns thedouble value of thisDouble object.
Specified by:
doubleValue in class Number
Returns:
thedouble value represented by this object

hashCode
```
public int hashCode()
```
Returns a hash code for thisDouble object. The result is the exclusive OR of the two halves of thelong integer bit representation, exactly as produced by the methoddoubleToLongBits(double), of the primitivedouble value represented by thisDouble object. That is, the hash code is the value of the expression:
(int)(v^(v>>>32))
wherev is defined by:
long v = Double.doubleToLongBits(this.doubleValue());
Overrides:
hashCode in class Object
Returns:
ahash code value for this object.
See Also:
Object.equals(java.lang.Object),System.identityHashCode(java.lang.Object)

hashCode
```
public static int hashCode(double value)
```
Returns a hash code for adouble value; compatible withDouble.hashCode().
Parameters:
value - the value to hash
Returns:
a hash code value for adouble value.
Since:
1.8

equals
```
public boolean equals(Object obj)
```
Compares this object against the specified object. The result istrue if and only if the argument is notnull and is aDouble object that represents adouble that has the same value as thedouble represented by this object. For this purpose, twodouble values are considered to be the same if and only if the methoddoubleToLongBits(double) returns the identicallong value when applied to each.
Note that in most cases, for two instances of classDouble,d1 andd2, the value ofd1.equals(d2) istrue if and only if
d1.doubleValue() == d2.doubleValue()
also has the valuetrue. However, there are two exceptions:
- Ifd1 andd2 both representDouble.NaN, then theequals method returnstrue, even thoughDouble.NaN==Double.NaN has the valuefalse.
- Ifd1 represents+0.0 whiled2 represents-0.0, or vice versa, theequal test has the valuefalse, even though+0.0==-0.0 has the valuetrue.
This definition allows hash tables to operate properly.
Overrides:
equals in class Object
Parameters:
obj - the object to compare with.
Returns:
true if the objects are the same;false otherwise.
See Also:
doubleToLongBits(double)

doubleToLongBits
```
public static long doubleToLongBits(double value)
```
Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout.
Bit 63 (the bit that is selected by the mask0x8000000000000000L) represents the sign of the floating-point number. Bits 62-52 (the bits that are selected by the mask0x7ff0000000000000L) represent the exponent. Bits 51-0 (the bits that are selected by the mask0x000fffffffffffffL) represent the significand (sometimes called the mantissa) of the floating-point number.
If the argument is positive infinity, the result is0x7ff0000000000000L.
If the argument is negative infinity, the result is0xfff0000000000000L.
If the argument is NaN, the result is0x7ff8000000000000L.
In all cases, the result is along integer that, when given to thelongBitsToDouble(long) method, will produce a floating-point value the same as the argument todoubleToLongBits (except all NaN values are collapsed to a single "canonical" NaN value).
Parameters:
value - adouble precision floating-point number.
Returns:
the bits that represent the floating-point number.

doubleToRawLongBits
```
public static long doubleToRawLongBits(double value)
```
Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout, preserving Not-a-Number (NaN) values.
Bit 63 (the bit that is selected by the mask0x8000000000000000L) represents the sign of the floating-point number. Bits 62-52 (the bits that are selected by the mask0x7ff0000000000000L) represent the exponent. Bits 51-0 (the bits that are selected by the mask0x000fffffffffffffL) represent the significand (sometimes called the mantissa) of the floating-point number.
If the argument is positive infinity, the result is0x7ff0000000000000L.
If the argument is negative infinity, the result is0xfff0000000000000L.
If the argument is NaN, the result is thelong integer representing the actual NaN value. Unlike thedoubleToLongBits method,doubleToRawLongBits does not collapse all the bit patterns encoding a NaN to a single "canonical" NaN value.
In all cases, the result is along integer that, when given to thelongBitsToDouble(long) method, will produce a floating-point value the same as the argument todoubleToRawLongBits.
Parameters:
value - adouble precision floating-point number.
Returns:
the bits that represent the floating-point number.
Since:
1.3

longBitsToDouble
```
public static double longBitsToDouble(long bits)
```
Returns thedouble value corresponding to a given bit representation. The argument is considered to be a representation of a floating-point value according to the IEEE 754 floating-point "double format" bit layout.
If the argument is0x7ff0000000000000L, the result is positive infinity.
If the argument is0xfff0000000000000L, the result is negative infinity.
If the argument is any value in the range0x7ff0000000000001L through0x7fffffffffffffffL or in the range0xfff0000000000001L through0xffffffffffffffffL, the result is a NaN. No IEEE 754 floating-point operation provided by Java can distinguish between two NaN values of the same type with different bit patterns. Distinct values of NaN are only distinguishable by use of theDouble.doubleToRawLongBits method.
In all other cases, lets,e, andm be three values that can be computed from the argument:
```
 int s = ((bits >> 63) == 0) ? 1 : -1; int e = (int)((bits >> 52) & 0x7ffL); long m = (e == 0) ?                 (bits & 0xfffffffffffffL) << 1 :                 (bits & 0xfffffffffffffL) | 0x10000000000000L;
```
Then the floating-point result equals the value of the mathematical expressions·m·2^e-1075.
Note that this method may not be able to return adouble NaN with exactly same bit pattern as thelong argument. IEEE 754 distinguishes between two kinds of NaNs, quiet NaNs andsignaling NaNs. The differences between the two kinds of NaN are generally not visible in Java. Arithmetic operations on signaling NaNs turn them into quiet NaNs with a different, but often similar, bit pattern. However, on some processors merely copying a signaling NaN also performs that conversion. In particular, copying a signaling NaN to return it to the calling method may perform this conversion. SolongBitsToDouble may not be able to return adouble with a signaling NaN bit pattern. Consequently, for somelong values,doubleToRawLongBits(longBitsToDouble(start)) maynot equalstart. Moreover, which particular bit patterns represent signaling NaNs is platform dependent; although all NaN bit patterns, quiet or signaling, must be in the NaN range identified above.
Parameters:
bits - anylong integer.
Returns:
thedouble floating-point value with the same bit pattern.

compareTo
```
public int compareTo(Double anotherDouble)
```
Compares twoDouble objects numerically. There are two ways in which comparisons performed by this method differ from those performed by the Java language numerical comparison operators (<, <=, ==, >=, >) when applied to primitivedouble values:
- Double.NaN is considered by this method to be equal to itself and greater than all otherdouble values (includingDouble.POSITIVE_INFINITY).
- 0.0d is considered by this method to be greater than-0.0d.
This ensures that thenatural ordering ofDouble objects imposed by this method isconsistent with equals.
Specified by:
compareTo in interface Comparable<Double>
Parameters:
anotherDouble - theDouble to be compared.
Returns:
the value0 ifanotherDouble is numerically equal to thisDouble; a value less than0 if thisDouble is numerically less thananotherDouble; and a value greater than0 if thisDouble is numerically greater thananotherDouble.
Since:
1.2

compare
```
public static int compare(double d1,                          double d2)
```
Compares the two specifieddouble values. The sign of the integer value returned is the same as that of the integer that would be returned by the call:
```
    new Double(d1).compareTo(new Double(d2))
```
Parameters:
d1 - the firstdouble to compare
d2 - the seconddouble to compare
Returns:
the value0 ifd1 is numerically equal tod2; a value less than0 ifd1 is numerically less thand2; and a value greater than0 ifd1 is numerically greater thand2.
Since:
1.4

sum
```
public static double sum(double a,                         double b)
```
Adds twodouble values together as per the + operator.
Parameters:
a - the first operand
b - the second operand
Returns:
the sum ofa andb
Since:
1.8
See Also:
BinaryOperator
See The Java™ Language Specification:
4.2.4 Floating-Point Operations

max
```
public static double max(double a,                         double b)
```
Returns the greater of twodouble values as if by callingMath.max.
Parameters:
a - the first operand
b - the second operand
Returns:
the greater ofa andb
Since:
1.8
See Also:
BinaryOperator

min
```
public static double min(double a,                         double b)
```
Returns the smaller of twodouble values as if by callingMath.min.
Parameters:
a - the first operand
b - the second operand
Returns:
the smaller ofa andb.
Since:
1.8
See Also:
BinaryOperator

Movatterモバイル変換

Class Double

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

POSITIVE_INFINITY

NEGATIVE_INFINITY

NaN

MAX_VALUE

MIN_NORMAL

MIN_VALUE

MAX_EXPONENT

MIN_EXPONENT

SIZE

BYTES

TYPE

Constructor Detail

Double

Double

Method Detail

toString

toHexString

valueOf

valueOf

parseDouble

isNaN

isInfinite

isFinite

isNaN

isInfinite

toString

byteValue

shortValue

intValue

longValue

floatValue

doubleValue

hashCode

hashCode

equals

doubleToLongBits

doubleToRawLongBits

longBitsToDouble

compareTo

compare

sum

max

min