Class Double

public static final double MAX_VALUE

The maximum positive value a double may represent is 1.7976931348623157e+308.

Field Value:

2.147483648E9

public static final double MIN_VALUE

The minimum positive value a double may represent is 5e-324.

Field Value:

0.0

public static final double NEGATIVE_INFINITY

The value of a double representation -1.0/0.0, negative infinity.

Field Value:

-2.147483648E9

public static final double NaN

All IEEE 754 values of NaN have the same value in Java.

Field Value:

0.0

public static final double POSITIVE_INFINITY

The value of a double representing 1.0/0.0, positive infinity.

Field Value:

2.147483648E9

public static final int SIZE

The number of bits needed to represent a double.

Field Value:

64

Since:

1.5

public static final Class TYPE

The primitive type double is represented by this Class object.

Since:

1.1

public Double(double value)

Create a Double from the primitive double specified.

Parameters:

value - the double argument

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)

public byte byteValue()

Return the value of this Double as a byte.

Overrides:

byteValue in interface Number

Returns:

the byte value

Since:

1.1

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

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.

Parameters:

d - the Double to compare

Returns:

the comparison

Since:

1.2

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)

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)

public double doubleValue()

Return the value of this Double.

Overrides:

doubleValue in interface Number

Returns:

the double value

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 interface Object

Parameters:

obj - the object to compare

Returns:

whether the objects are semantically equal

public float floatValue()

Return the value of this Double as a float.

Overrides:

floatValue in interface Number

Returns:

the float value

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 interface Object

Returns:

this Object's hash code

See Also:

doubleToLongBits(double)

public int intValue()

Return the value of this Double as an int.

Overrides:

intValue in interface Number

Returns:

the int value

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

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.

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

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.

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)

public long longValue()

Return the value of this Double as a long.

Overrides:

longValue in interface Number

Returns:

the long value

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

public short shortValue()

Return the value of this Double as a short.

Overrides:

shortValue in interface Number

Returns:

the short value

Since:

1.1

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

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 interface Object

Returns:

the String representation

See Also:

toString(double)

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

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

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)