Float (GNU libgcj 4.8.0 Documentation)

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

All Implemented Interfaces:

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

Since:

1.0

See Also:
Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static float`	`MAX_VALUE` The maximum positive value a `double` may represent is 3.4028235e+38f.
`static float`	`MIN_VALUE` The minimum positive value a `float` may represent is 1.4e-45.
`static float`	`NaN` All IEEE 754 values of NaN have the same value in Java.
`static float`	`NEGATIVE_INFINITY` The value of a float representation -1.0/0.0, negative infinity.
`static float`	`POSITIVE_INFINITY` The value of a float representation 1.0/0.0, positive infinity.
`static int`	`SIZE` The number of bits needed to represent a `float`.
`static Class<Float>`	`TYPE` The primitive type `float` is represented by this `Class` object.

Constructor Summary

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

Method Summary

Methods
Modifier and Type	Method and Description
`byte`	`byteValue()` Return the value of this `Float` as a `byte`.
`static int`	`compare(float x, float y)` Behaves like `new Float(x).compareTo(new Float(y))`; in other words this compares two floats, special casing NaN and zero, without the overhead of objects.
`int`	`compareTo(Float f)` Compare two Floats numerically by comparing their `float` values.
`double`	`doubleValue()` Return the value of this `Float` as a `double`
`boolean`	`equals(Object obj)` Returns `true` if `obj` is an instance of `Float` and represents the same float value.
`static int`	`floatToIntBits(float value)` Convert the float to the IEEE 754 floating-point "single format" bit layout.
`static int`	`floatToRawIntBits(float value)` Convert the float to the IEEE 754 floating-point "single format" bit layout.
`float`	`floatValue()` Return the value of this `Float`.
`int`	`hashCode()` Return a hashcode representing this Object.
`static float`	`intBitsToFloat(int bits)` Convert the argument in IEEE 754 floating-point "single format" bit layout to the corresponding float.
`int`	`intValue()` Return the value of this `Integer` as an `int`.
`boolean`	`isInfinite()` Return `true` if the value of this `Float` is the same as `NEGATIVE_INFINITY` or `POSITIVE_INFINITY`, otherwise return `false`.
`static boolean`	`isInfinite(float v)` Return `true` if the `float` has a value equal to either `NEGATIVE_INFINITY` or `POSITIVE_INFINITY`, otherwise return `false`.
`boolean`	`isNaN()` Return `true` if the value of this `Float` is the same as `NaN`, otherwise return `false`.
`static boolean`	`isNaN(float v)` Return `true` if the `float` has the same value as `NaN`, otherwise return `false`.
`long`	`longValue()` Return the value of this `Integer` as a `long`.
`static float`	`parseFloat(String str)` Parse the specified `String` as a `float`.
`short`	`shortValue()` Return the value of this `Float` as a `short`.
`static String`	`toHexString(float f)` Convert a float value to a hexadecimal string.
`String`	`toString()` Convert the `float` value of this `Float` to a `String`.
`static String`	`toString(float f)` Convert the `float` to a `String`.
`static Float`	`valueOf(float val)` Returns a `Float` object wrapping the value.
`static Float`	`valueOf(String s)` Creates a new `Float` 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 float MAX_VALUE
```
  The maximum positive value a double may represent is 3.4028235e+38f.
  
  See Also:
  Constant Field Values
- MIN_VALUE
```
public static final float MIN_VALUE
```
  The minimum positive value a float may represent is 1.4e-45.
  
  See Also:
  Constant Field Values
- NEGATIVE_INFINITY
```
public static final float NEGATIVE_INFINITY
```
  The value of a float representation -1.0/0.0, negative infinity.
  
  See Also:
  Constant Field Values
- POSITIVE_INFINITY
```
public static final float POSITIVE_INFINITY
```
  The value of a float representation 1.0/0.0, positive infinity.
  
  See Also:
  Constant Field Values
- NaN
```
public static final float NaN
```
  All IEEE 754 values of NaN have the same value in Java.
  
  See Also:
  Constant Field Values
- TYPE
```
public static final Class<Float> TYPE
```
  The primitive type float is represented by this Class object.
  
  Since:
  
  1.1
- SIZE
```
public static final int SIZE
```
  The number of bits needed to represent a float.
  
  Since:
  
  1.5
  
  See Also:
  Constant Field Values

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

Method Detail

toString

public static String toString(float f)

Convert the float 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 Float	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 float.

To create other output formats, use NumberFormat.

Parameters:: f - the float to convert
Returns:: the String representing the float

toHexString
```
public static String toHexString(float f)
```
Convert a float 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:
f - the float value

Returns:
the hexadecimal string representation
Since:

1.5

valueOf
```
public static Float valueOf(String s)
```
Creates a new Float object using the String.

Parameters:
s - the String to convert

Returns:
the new Float

Throws:

NumberFormatException - if s cannot be parsed as a float

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

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

Parameters:
val - the value to wrap

Returns:
the Float
Since:

1.5

parseFloat
```
public static float parseFloat(String str)
```
Parse the specified String as a float. 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 float. 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 float value of s

Throws:

NumberFormatException - if str cannot be parsed as a float

NullPointerException - if str is null
Since:

1.2

See Also:
MIN_VALUE, MAX_VALUE, POSITIVE_INFINITY, NEGATIVE_INFINITY

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

Parameters:
v - the float to compare

Returns:
whether the argument is NaN

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

Parameters:
v - the float to compare

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

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

Returns:
whether this Float is NaN

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

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

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

Overrides:

toString in class Object

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

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

Overrides:

byteValue in class Number

Returns:
the byte value
Since:

1.1

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

Overrides:

shortValue in class Number

Returns:
the short value
Since:

1.1

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

Specified by:

intValue in class Number

Returns:
the int value

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

Specified by:

longValue in class Number

Returns:
the long value

floatValue
```
public float floatValue()
```
Return the value of this Float.

Specified by:

floatValue in class Number

Returns:
the float value

doubleValue
```
public double doubleValue()
```
Return the value of this Float as a double

Specified by:

doubleValue in class Number

Returns:
the double value

hashCode
```
public int hashCode()
```
Return a hashcode representing this Object. Float's hash code is calculated by calling floatToIntBits(floatValue()).

Overrides:

hashCode in class Object

Returns:
this Object's hash code
See Also:
floatToIntBits(float)

equals
```
public boolean equals(Object obj)
```
Returns true if obj is an instance of Float and represents the same float value. Unlike comparing two floats with ==, this treats two instances of Float.NaN as equal, but treats 0.0 and -0.0 as unequal.
Note that f1.equals(f2) is identical to floatToIntBits(f1.floatValue()) == floatToIntBits(f2.floatValue()).

Overrides:

equals in class Object

Parameters:
obj - the object to compare

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

floatToIntBits
```
public static int floatToIntBits(float value)
```
Convert the float to the IEEE 754 floating-point "single format" bit layout. Bit 31 (the most significant) is the sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and bits 22-0 (masked by 0x007fffff) are the mantissa. This function collapses all versions of NaN to 0x7fc00000. The result of this function can be used as the argument to Float.intBitsToFloat(int) to obtain the original float value.

Parameters:
value - the float to convert

Returns:
the bits of the float
See Also:
intBitsToFloat(int)

floatToRawIntBits
```
public static int floatToRawIntBits(float value)
```
Convert the float to the IEEE 754 floating-point "single format" bit layout. Bit 31 (the most significant) is the sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and bits 22-0 (masked by 0x007fffff) 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 Float.intBitsToFloat(int) to obtain the original float value.

Parameters:
value - the float to convert

Returns:
the bits of the float
See Also:
intBitsToFloat(int)

intBitsToFloat
```
public static float intBitsToFloat(int bits)
```
Convert the argument in IEEE 754 floating-point "single format" bit layout to the corresponding float. Bit 31 (the most significant) is the sign bit, bits 30-23 (masked by 0x7f800000) represent the exponent, and bits 22-0 (masked by 0x007fffff) are the mantissa. This function leaves NaN alone, so that you can recover the bit pattern with Float.floatToRawIntBits(float).

Parameters:
bits - the bits to convert

Returns:
the float represented by the bits
See Also:
floatToIntBits(float), floatToRawIntBits(float)

compareTo
```
public int compareTo(Float f)
```
Compare two Floats numerically by comparing their float 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 floats, including POSITIVE_INFINITY, and positive zero is considered greater than negative zero.

Specified by:

compareTo in interface Comparable<Float>

Parameters:
f - the Float to compare

Returns:
the comparison
Since:

1.2

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

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

Returns:
the comparison
Since:

1.4

Class Float

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MAX_VALUE

MIN_VALUE

NEGATIVE_INFINITY

POSITIVE_INFINITY

NaN

TYPE

SIZE

Constructor Detail

Float

Float

Float

Method Detail

toString

toHexString

valueOf

valueOf

parseFloat

isNaN

isInfinite

isNaN

isInfinite

toString

byteValue

shortValue

intValue

longValue

floatValue

doubleValue

hashCode

equals

floatToIntBits

floatToRawIntBits

intBitsToFloat

compareTo

compare