Double (GNU libgcj 4.8.0 Documentation)

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

All Implemented Interfaces:

Serializable, Comparable<Double>
```
public final class Double
extends Number
implements Comparable<Double>
```
Instances of class Double represent primitive double values. Additionally, this class provides various helper functions and variables related to doubles.

Since:

1.0

See Also:
Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`MAX_VALUE` The maximum positive value a `double` may represent is 1.7976931348623157e+308.
`static double`	`MIN_VALUE` The minimum positive value a `double` may represent is 5e-324.
`static double`	`NaN` All IEEE 754 values of NaN have the same value in Java.
`static double`	`NEGATIVE_INFINITY` The value of a double representation -1.0/0.0, negative infinity.
`static double`	`POSITIVE_INFINITY` The value of a double representing 1.0/0.0, positive infinity.
`static int`	`SIZE` The number of bits needed to represent a `double`.
`static Class<Double>`	`TYPE` The primitive type `double` is represented by this `Class` object.

Constructor Summary

Constructors
Constructor and Description

Double(double value)
Create a Double from the primitive double specified.

Double(String s)
Create a Double from the specified String.

Constructors
Constructor and Description
`Double(double value)` Create a `Double` from the primitive `double` specified.
`Double(String s)` Create a `Double` from the specified `String`.

Method Summary

Methods
Modifier and Type	Method and Description
`byte`	`byteValue()` Return the value of this `Double` as a `byte`.
`static int`	`compare(double x, double y)` Behaves like `new Double(x).compareTo(new Double(y))`; in other words this compares two doubles, special casing NaN and zero, without the overhead of objects.
`int`	`compareTo(Double d)` Compare two Doubles numerically by comparing their `double` values.
`static long`	`doubleToLongBits(double value)` Convert the double to the IEEE 754 floating-point "double format" bit layout.
`static long`	`doubleToRawLongBits(double value)` Convert the double to the IEEE 754 floating-point "double format" bit layout.
`double`	`doubleValue()` Return the value of this `Double`.
`boolean`	`equals(Object obj)` Returns `true` if `obj` is an instance of `Double` and represents the same double value.
`float`	`floatValue()` Return the value of this `Double` as a `float`.
`int`	`hashCode()` Return a hashcode representing this Object.
`int`	`intValue()` Return the value of this `Double` as an `int`.
`boolean`	`isInfinite()` Return `true` if the value of this `Double` is the same as `NEGATIVE_INFINITY` or `POSITIVE_INFINITY`, otherwise return `false`.
`static boolean`	`isInfinite(double v)` Return `true` if the `double` has a value equal to either `NEGATIVE_INFINITY` or `POSITIVE_INFINITY`, otherwise return `false`.
`boolean`	`isNaN()` Return `true` if the value of this `Double` is the same as `NaN`, otherwise return `false`.
`static boolean`	`isNaN(double v)` Return `true` if the `double` has the same value as `NaN`, otherwise return `false`.
`static double`	`longBitsToDouble(long bits)` Convert the argument in IEEE 754 floating-point "double format" bit layout to the corresponding float.
`long`	`longValue()` Return the value of this `Double` as a `long`.
`static double`	`parseDouble(String str)` Parse the specified `String` as a `double`.
`short`	`shortValue()` Return the value of this `Double` as a `short`.
`static String`	`toHexString(double d)` Convert a double value to a hexadecimal string.
`String`	`toString()` Convert the `double` value of this `Double` to a `String`.
`static String`	`toString(double d)` Convert the `double` to a `String`.
`static Double`	`valueOf(double val)` Returns a `Double` object wrapping the value.
`static Double`	`valueOf(String s)` Create a new `Double` object using the `String`.

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

Field Detail
- MAX_VALUE
```
public static final double MAX_VALUE
```
  The maximum positive value a double may represent is 1.7976931348623157e+308.
  
  See Also:
  Constant Field Values
- MIN_VALUE
```
public static final double MIN_VALUE
```
  The minimum positive value a double may represent is 5e-324.
  
  See Also:
  Constant Field Values
- NEGATIVE_INFINITY
```
public static final double NEGATIVE_INFINITY
```
  The value of a double representation -1.0/0.0, negative infinity.
  
  See Also:
  Constant Field Values
- POSITIVE_INFINITY
```
public static final double POSITIVE_INFINITY
```
  The value of a double representing 1.0/0.0, positive infinity.
  
  See Also:
  Constant Field Values
- NaN
```
public static final double NaN
```
  All IEEE 754 values of NaN have the same value in Java.
  
  See Also:
  Constant Field Values
- SIZE
```
public static final int SIZE
```
  The number of bits needed to represent a double.
  
  Since:
  
  1.5
  
  See Also:
  Constant Field Values
- TYPE
```
public static final Class<Double> TYPE
```
  The primitive type double is represented by this Class object.
  
  Since:
  
  1.1

Constructor Detail
- Double
```
public Double(double value)
```
  Create a Double from the primitive double specified.
  
  Parameters:
  value - the double argument
- Double
```
public Double(String s)
```
  Create a Double from the specified String. This method calls Double.parseDouble().
  
  Parameters:
  s - the String to convert
  
  Throws:
  
  NumberFormatException - if s cannot be parsed as a double
  
  NullPointerException - if s is null
  See Also:
  parseDouble(String)

Method Detail

toString

public static String toString(double d)

Convert the double to a String. Floating-point string representation is fairly complex: here is a rundown of the possible values. "[-]" indicates that a negative sign will be printed if the value (or exponent) is negative. "<number>" means a string of digits ('0' to '9'). "<digit>" means a single digit ('0' to '9').

Value of Double	String Representation
[+-] 0	`[-]0.0`
Between [+-] 10^-3 and 10⁷, exclusive	`[-]number.number`
Other numeric value	`[-]<digit>.<number> E[-]<number>`
[+-] infinity	`[-]Infinity`
NaN	`NaN`

Yes, negative zero is a possible value. Note that there is always a . and at least one digit printed after it: even if the number is 3, it will be printed as 3.0. After the ".", all digits will be printed except trailing zeros. The result is rounded to the shortest decimal number which will parse back to the same double.

To create other output formats, use NumberFormat.

Parameters:: d - the double to convert
Returns:: the String representing the double

toHexString
```
public static String toHexString(double d)
```
Convert a double value to a hexadecimal string. This converts as follows:
- A NaN value is converted to the string "NaN".
- Positive infinity is converted to the string "Infinity".
- Negative infinity is converted to the string "-Infinity".
- For all other values, the first character of the result is '-' if the value is negative. This is followed by '0x1.' if the value is normal, and '0x0.' if the value is denormal. This is then followed by a (lower-case) hexadecimal representation of the mantissa, with leading zeros as required for denormal values. The next character is a 'p', and this is followed by a decimal representation of the unbiased exponent.
Parameters:
d - the double value

Returns:
the hexadecimal string representation
Since:

1.5

valueOf
```
public static Double valueOf(double val)
```
Returns a Double object wrapping the value. In contrast to the Double constructor, this method may cache some values. It is used by boxing conversion.

Parameters:
val - the value to wrap

Returns:
the Double
Since:

1.5

valueOf
```
public static Double valueOf(String s)
```
Create a new Double object using the String.

Parameters:
s - the String to convert

Returns:
the new Double

Throws:

NumberFormatException - if s cannot be parsed as a double

NullPointerException - if s is null.
See Also:
parseDouble(String)

parseDouble
```
public static double parseDouble(String str)
```
Parse the specified String as a double. The extended BNF grammar is as follows:
```
 DecodableString:
      ( [ - | + ] NaN )
    | ( [ - | + ] Infinity )
    | ( [ - | + ] FloatingPoint
              [ f | F | d
                | D] )
 FloatingPoint:
      ( { Digit }+ [ . { Digit } ]
              [ Exponent ] )
    | ( . { Digit }+ [ Exponent ] )
 Exponent:
      ( ( e | E )
              [ - | + ] { Digit }+ )
 Digit: '0' through '9'
 
```
NaN and infinity are special cases, to allow parsing of the output of toString. Otherwise, the result is determined by calculating n * 10^exponent to infinite precision, then rounding to the nearest double. Remember that many numbers cannot be precisely represented in floating point. In case of overflow, infinity is used, and in case of underflow, signed zero is used. Unlike Integer.parseInt, this does not accept Unicode digits outside the ASCII range.
If an unexpected character is found in the String, a NumberFormatException will be thrown. Leading and trailing 'whitespace' is ignored via String.trim(), but spaces internal to the actual number are not allowed.
To parse numbers according to another format, consider using NumberFormat.
Parameters:
str - the String to convert

Returns:
the double value of s

Throws:

NumberFormatException - if s cannot be parsed as a double

NullPointerException - if s is null
Since:

1.2

See Also:
MIN_VALUE, MAX_VALUE, POSITIVE_INFINITY, NEGATIVE_INFINITY

isNaN
```
public static boolean isNaN(double v)
```
Return true if the double has the same value as NaN, otherwise return false.

Parameters:
v - the double to compare

Returns:
whether the argument is NaN.

isInfinite
```
public static boolean isInfinite(double v)
```
Return true if the double has a value equal to either NEGATIVE_INFINITY or POSITIVE_INFINITY, otherwise return false.

Parameters:
v - the double to compare

Returns:
whether the argument is (-/+) infinity.

isNaN
```
public boolean isNaN()
```
Return true if the value of this Double is the same as NaN, otherwise return false.

Returns:
whether this Double is NaN

isInfinite
```
public boolean isInfinite()
```
Return true if the value of this Double is the same as NEGATIVE_INFINITY or POSITIVE_INFINITY, otherwise return false.

Returns:
whether this Double is (-/+) infinity

toString
```
public String toString()
```
Convert the double value of this Double to a String. This method calls Double.toString(double) to do its dirty work.

Overrides:

toString in class Object

Returns:
the String representation
See Also:
toString(double)

byteValue
```
public byte byteValue()
```
Return the value of this Double as a byte.

Overrides:

byteValue in class Number

Returns:
the byte value
Since:

1.1

shortValue
```
public short shortValue()
```
Return the value of this Double as a short.

Overrides:

shortValue in class Number

Returns:
the short value
Since:

1.1

intValue
```
public int intValue()
```
Return the value of this Double as an int.

Specified by:

intValue in class Number

Returns:
the int value

longValue
```
public long longValue()
```
Return the value of this Double as a long.

Specified by:

longValue in class Number

Returns:
the long value

floatValue
```
public float floatValue()
```
Return the value of this Double as a float.

Specified by:

floatValue in class Number

Returns:
the float value

doubleValue
```
public double doubleValue()
```
Return the value of this Double.

Specified by:

doubleValue in class Number

Returns:
the double value

hashCode
```
public int hashCode()
```
Return a hashcode representing this Object. Double's hash code is calculated by:
long v = Double.doubleToLongBits(doubleValue()); int hash = (int)(v^(v>>32)).

Overrides:

hashCode in class Object

Returns:
this Object's hash code
See Also:
doubleToLongBits(double)

equals
```
public boolean equals(Object obj)
```
Returns true if obj is an instance of Double and represents the same double value. Unlike comparing two doubles with ==, this treats two instances of Double.NaN as equal, but treats 0.0 and -0.0 as unequal.
Note that d1.equals(d2) is identical to doubleToLongBits(d1.doubleValue()) == doubleToLongBits(d2.doubleValue()).

Overrides:

equals in class Object

Parameters:
obj - the object to compare

Returns:
whether the objects are semantically equal
See Also:
Object.hashCode()

doubleToLongBits
```
public static long doubleToLongBits(double value)
```
Convert the double to the IEEE 754 floating-point "double format" bit layout. Bit 63 (the most significant) is the sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. This function collapses all versions of NaN to 0x7ff8000000000000L. The result of this function can be used as the argument to Double.longBitsToDouble(long) to obtain the original double value.

Parameters:
value - the double to convert

Returns:
the bits of the double
See Also:
longBitsToDouble(long)

doubleToRawLongBits
```
public static long doubleToRawLongBits(double value)
```
Convert the double to the IEEE 754 floating-point "double format" bit layout. Bit 63 (the most significant) is the sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. This function leaves NaN alone, rather than collapsing to a canonical value. The result of this function can be used as the argument to Double.longBitsToDouble(long) to obtain the original double value.

Parameters:
value - the double to convert

Returns:
the bits of the double
See Also:
longBitsToDouble(long)

longBitsToDouble
```
public static double longBitsToDouble(long bits)
```
Convert the argument in IEEE 754 floating-point "double format" bit layout to the corresponding float. Bit 63 (the most significant) is the sign bit, bits 62-52 (masked by 0x7ff0000000000000L) represent the exponent, and bits 51-0 (masked by 0x000fffffffffffffL) are the mantissa. This function leaves NaN alone, so that you can recover the bit pattern with Double.doubleToRawLongBits(double).

Parameters:
bits - the bits to convert

Returns:
the double represented by the bits
See Also:
doubleToLongBits(double), doubleToRawLongBits(double)

compareTo
```
public int compareTo(Double d)
```
Compare two Doubles numerically by comparing their double values. The result is positive if the first is greater, negative if the second is greater, and 0 if the two are equal. However, this special cases NaN and signed zero as follows: NaN is considered greater than all other doubles, including POSITIVE_INFINITY, and positive zero is considered greater than negative zero.

Specified by:

compareTo in interface Comparable<Double>

Parameters:
d - the Double to compare

Returns:
the comparison
Since:

1.2

compare
```
public static int compare(double x,
          double y)
```
Behaves like new Double(x).compareTo(new Double(y)); in other words this compares two doubles, special casing NaN and zero, without the overhead of objects.

Parameters:
x - the first double to compare
y - the second double to compare

Returns:
the comparison
Since:

1.4

Class Double

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MAX_VALUE

MIN_VALUE

NEGATIVE_INFINITY

POSITIVE_INFINITY

NaN

SIZE

TYPE

Constructor Detail

Double

Double

Method Detail

toString

toHexString

valueOf

valueOf

parseDouble

isNaN

isInfinite

isNaN

isInfinite

toString

byteValue

shortValue

intValue

longValue

floatValue

doubleValue

hashCode

equals

doubleToLongBits

doubleToRawLongBits

longBitsToDouble

compareTo

compare