java.lang
Class Double

java.lang.Object
  java.lang.Double

public final class Double
extends Object

The Double class provides an object wrapper for Double data values and serves as a place for double-oriented operations. A wrapper is useful because most of Java's utility classes require the use of objects. Since doubles are not objects in Java, they need to be "wrapped" in a Double instance.

Version:

1.34, 02 May 1996

Author:

Lee Boynton, Arthur van Hoff

Field Summary

static double	MAX_VALUE The maximum value a double can have.
static double	MIN_VALUE The minimum value a double can have.
static double	NaN Not-a-Number.
static double	NEGATIVE_INFINITY Negative infinity.
static double	POSITIVE_INFINITY Positive infinity.

Constructor Summary

Double(double value)
Constructs a Double wrapper for the specified double value.

Method Summary

byte	byteValue() Returns the value of this Double as a byte (by casting to a byte).
static long	doubleToLongBits(double value) Returns the bit represention of a double-float value
double	doubleValue() Returns the double value of this Double.
boolean	equals(Object obj) Compares this object against the specified object.
float	floatValue() Returns the float value of this Double.
int	hashCode() Returns a hashcode for this Double.
int	intValue() Returns the integer value of this Double (by casting to an int).
boolean	isInfinite() Returns true if this Double value is infinitely large in magnitude.
static boolean	isInfinite(double v) Returns true if the specified number is infinitely large in magnitude.
boolean	isNaN() Returns true if this Double value is the special Not-a-Number (NaN) value.
static boolean	isNaN(double v) Returns true if the specified number is the special Not-a-Number (NaN) value.
static double	longBitsToDouble(long bits) Returns the double-float corresponding to a given bit represention.
long	longValue() Returns the long value of this Double (by casting to a long).
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 (by casting to a short).
String	toString() Returns a String representation of this Double object.
static String	toString(double d) Returns a String representation for the specified double value.
static Double	valueOf(String s) Returns a new Double value initialized to the value represented by the specified String.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

MAX_VALUE

public static final double MAX_VALUE

The maximum value a double can have. The greatest maximum value that a double can have is 1.79769313486231570e+308d.

See Also:

Constant Field Values

MIN_VALUE

public static final double MIN_VALUE

The minimum value a double can have. The lowest minimum value that a double can have is equal to the value of longBitsToDouble(1L)

See Also:

Constant Field Values

NEGATIVE_INFINITY

public static final double NEGATIVE_INFINITY

Negative infinity.

See Also:

Constant Field Values

NaN

public static final double NaN

Not-a-Number. Is not equal to anything, including itself.

See Also:

Constant Field Values

POSITIVE_INFINITY

public static final double POSITIVE_INFINITY

Positive infinity.

See Also:

Constant Field Values

Constructor Detail

Double

public Double(double value)

Constructs a Double wrapper for the specified double value.

Parameters:

value - the initial value of the double

Method Detail

byteValue

public byte byteValue()

Returns the value of this Double as a byte (by casting to a byte).

doubleToLongBits

public static long doubleToLongBits(double value)

Returns the bit represention of a double-float value

doubleValue

public double doubleValue()

Returns the double value of this Double.

equals

public boolean equals(Object obj)

Compares this object against the specified object. To be useful in hashtables this method considers two NaN double values to be equal. This is not according to IEEE specification.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with

Returns:

true if the objects are the same; false otherwise.

See Also:

Boolean.hashCode(), Hashtable

floatValue

public float floatValue()

Returns the float value of this Double.

hashCode

public int hashCode()

Returns a hashcode for this Double.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable

intValue

public int intValue()

Returns the integer value of this Double (by casting to an int).

isInfinite

public boolean isInfinite()

Returns true if this Double value is infinitely large in magnitude.

isInfinite

public static boolean isInfinite(double v)

Returns true if the specified number is infinitely large in magnitude.

Parameters:

v - the value to be tested

isNaN

public boolean isNaN()

Returns true if this Double value is the special Not-a-Number (NaN) value.

isNaN

public static boolean isNaN(double v)

Returns true if the specified number is the special Not-a-Number (NaN) value.

Parameters:

v - the value to be tested

longBitsToDouble

public static double longBitsToDouble(long bits)

Returns the double-float corresponding to a given bit represention.

longValue

public long longValue()

Returns the long value of this Double (by casting to a long).

parseDouble

public static double parseDouble(String s)
                          throws NumberFormatException

Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double.

Parameters:

s - the string to be parsed.

Returns:

the double value represented by the string argument.

Throws:

NumberFormatException - if the string does not contain a parsable double.

Since:

JDK1.2

See Also:

valueOf(String)

shortValue

public short shortValue()

Returns the value of this Double as a short (by casting to a short).

toString

public String toString()

Returns a String representation of this Double object.

Overrides:

toString in class Object

Returns:

a string representation of the object.

toString

public static String toString(double d)

Returns a String representation for the specified double value.

Parameters:

d - the double to be converted

valueOf

public static Double valueOf(String s)
                      throws NumberFormatException

Returns a new Double value initialized to the value represented by the specified String.

Parameters:

s - the String to be parsed

Throws:

NumberFormatException - If the String cannot be parsed.