java.lang
Class Float

java.lang.Object
  java.lang.Number
      java.lang.Float

public final class Float
extends Number

Minimal Float implementation.

Author:

Lawrie Griffiths, Sven Köhler

Field Summary

static float	NaN
static float	NEGATIVE_INFINITY
static float	POSITIVE_INFINITY
static int	SIZE

Constructor Summary

Float(double value)

Float(float value)
Constructs a newly allocated Float object that represents the primitive float argument.

Float(String s)

Method Summary

byte	byteValue() Return the byte value of this Number.
double	doubleValue() Return the double value of this Number.
boolean	equals(Object o)
static int	floatToIntBits(float value) Returns the bit representation of a single-float value.
static int	floatToRawIntBits(float value) Returns the bit representation of a single-float value.
float	floatValue() Returns the float value of this Float object.
int	hashCode()
static float	intBitsToFloat(int value) Returns the single-float corresponding to a given bit represention.
int	intValue() Return the int value of this Number.
boolean	isInfinite()
static boolean	isInfinite(float v)
boolean	isNaN()
static boolean	isNaN(float val)
long	longValue() Return the long value of this Number.
static float	parseFloat(String s) Converts a String value into a float
short	shortValue() Return the short value of this Number.
String	toString()
static String	toString(float f) Convert a float to a String
static Float	valueOf(float f)
static Float	valueOf(String s)

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

POSITIVE_INFINITY

public static final float POSITIVE_INFINITY

See Also:

Constant Field Values

NEGATIVE_INFINITY

public static final float NEGATIVE_INFINITY

See Also:

Constant Field Values

NaN

public static final float NaN

See Also:

Constant Field Values

SIZE

public static final int SIZE

See Also:

Constant Field Values

Constructor Detail

Float

public Float(double value)

Float

public Float(float value)

Constructs a newly allocated Float object that represents the primitive float argument.

Parameters:

value - - the value to be represented by the Float.

Float

public Float(String s)

Method Detail

byteValue

public byte byteValue()

Description copied from class: Number

Return the byte value of this Number.

Overrides:

byteValue in class Number

Returns:

the byte value

doubleValue

public double doubleValue()

Description copied from class: Number

Return the double value of this Number.

Specified by:

doubleValue in class Number

Returns:

the double value

equals

public boolean equals(Object o)

Overrides:

equals in class Object

floatToRawIntBits

public static int floatToRawIntBits(float value)

Returns the bit representation of a single-float value. The result is a representation of the floating-point argument according to the IEEE 754 floating-point "single precision" bit layout.

• Bit 31 (the bit that is selected by the mask 0x80000000) represents the sign of the floating-point number.
• Bits 30-23 (the bits that are selected by the mask 0x7f800000) represent the exponent.
• Bits 22-0 (the bits that are selected by the mask 0x007fffff) represent the significand (sometimes called the mantissa) of the floating-point number.
• If the argument is positive infinity, the result is 0x7f800000.
• If the argument is negative infinity, the result is 0xff800000.

  If the argument is NaN, the result is the integer representing the actual NaN value.

In all cases, the result is an integer that, when given to the intBitsToFloat(int) method, will produce a floating-point value equal to the argument to floatToRawIntBits.

Parameters:

value - a floating-point number.

Returns:

the bits that represent the floating-point number.

floatToIntBits

public static int floatToIntBits(float value)

Returns the bit representation of a single-float value. The result is a representation of the floating-point argument according to the IEEE 754 floating-point "single precision" bit layout. Unlike floatToRawIntBits this method does collapse all NaN values into a standard single value. This value is 0x7fc00000.

Parameters:

value - a floating-point number.

Returns:

the bits that represent the floating-point number.

floatValue

public float floatValue()

Returns the float value of this Float object.

Specified by:

floatValue in class Number

Returns:

the float value represented by this object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

intBitsToFloat

public static float intBitsToFloat(int value)

Returns the single-float corresponding to a given bit represention. The argument is considered to be a representation of a floating-point value according to the IEEE 754 floating-point "single precision" bit layout.

If the argument is 0x7f800000, the result is positive infinity.

If the argument is 0xff800000, the result is negative infinity.

If the argument is any value in the range 0x7f800001 through 0x7fffffff or in the range 0xff800001 through 0xffffffff, the result is NaN. All IEEE 754 NaN values of type float are, in effect, lumped together by the Java programming language into a single float value called NaN. Distinct values of NaN are only accessible by use of the Float.floatToRawIntBits method.

In all other cases, let s, e, and m be three values that can be computed from the argument:

 int s = ((bits >> 31) == 0) ? 1 : -1;
 int e = ((bits >> 23) & 0xff);
 int m = (e == 0) ?
                                 (bits & 0x7fffff) << 1 :
                                 (bits & 0x7fffff) | 0x800000;
 

Then the floating-point result equals the value of the mathematical expression s·m·2^e-150.

Parameters:

value - an integer.

Returns:

the single-format floating-point value with the same bit pattern.

intValue

public int intValue()

Description copied from class: Number

Return the int value of this Number.

Specified by:

intValue in class Number

Returns:

the int value

isInfinite

public boolean isInfinite()

isInfinite

public static boolean isInfinite(float v)

isNaN

public boolean isNaN()

isNaN

public static boolean isNaN(float val)

longValue

public long longValue()

Description copied from class: Number

Return the long value of this Number.

Specified by:

longValue in class Number

Returns:

the long value

parseFloat

public static float parseFloat(String s)
                        throws NumberFormatException

Converts a String value into a float

Parameters:

s - String representation of float. Must only contain numbers and an optional decimal, and optional - sign at front.

Returns:

float number

Throws:

NumberFormatException

shortValue

public short shortValue()

Description copied from class: Number

Return the short value of this Number.

Overrides:

shortValue in class Number

Returns:

the short value

toString

public String toString()

Overrides:

toString in class Object

toString

public static String toString(float f)

Convert a float to a String

Parameters:

f - the float to be converted

Returns:

the String representation of the float

valueOf

public static Float valueOf(float f)

valueOf

public static Float valueOf(String s)