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§1.7 Class Float
public final class java.lang.Float
extends java.lang.Number (I-§1.11)
{
// Fields
public final static float MAX_VALUE; §1.7.1
public final static float MIN_VALUE; §1.7.2
public final static float NaN; §1.7.3
public final static float NEGATIVE_INFINITY; §1.7.4
public final static float POSITIVE_INFINITY; §1.7.5
// Constructors
public Float(double value); §1.7.6
public Float(float value); §1.7.7
public Float(String s); §1.7.8
// Methods
public double doubleValue(); §1.7.9
public boolean equals(Object obj); §1.7.10
public static int floatToIntBits(float value); §1.7.11
public float floatValue(); §1.7.12
public int hashCode(); §1.7.13
public static float intBitsToFloat(int bits); §1.7.14
public int intValue(); §1.7.15
public boolean isInfinite(); §1.7.16
public static boolean isInfinite(float v); §1.7.17
public boolean isNaN(); §1.7.18
public static boolean isNaN(float v); §1.7.19
public long longValue(); §1.7.20
public String toString(); §1.7.21
public static String toString(float f); §1.7.22
public static Float valueOf(String s); §1.7.23
}
This class wraps a value of primitive type float in an object. An object of type Float contains
a single field whose type is float.
In addition, this class provides a number of methods for converting a float to a String and a
String to a float, as well as other constants and methods useful when dealing with a float.
MAX_VALUE
public final static float MAX_VALUE
= 3.40282346638528860e+38.
- The largest positive finite value of type float.
MIN_VALUE
public final static float MIN_VALUE
= 1.40129846432481707e-45
- The smallest positive value of type float.
NaN
public final static float NaN = 0.0f/0.0f
- The Not-a-Number value of type float.
NEGATIVE_INFINITY
public final static float NEGATIVE_INFINITY
= -1.0f/0.0f
- The negative infinity of type float.
POSITIVE_INFINITY
public final static float POSITIVE_INFINITY
= 1.0f/0.0f
- The positive infinity of type float.
Float
public Float(double value)
- Constructs a newly allocated Float object that represents the argument converted to type float.
- Parameters:
value
-
the value to be represented by the Float
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)
throws NumberFormatException
- Constructs a newly allocated Float object that represents the floating-point
value of type float represented by the string. The string is converted to a
float value as if by the valueOf method (I-§1.7.23).
- Parameters:
s
-
a string to be converted to a Float
- Throws
- NumberFormatException (I-§1.41)
- If the string does not contain a parsable number.
doubleValue
public double doubleValue()
- The float value represented by this object is converted to type double
and the result of the conversion is returned.
- Overrides:
- doubleValue in class Number (I-§1.11.1).
equals
public boolean equals(Object obj)
- The result is true if and only if the argument is not null and is a Float object
that represents a float that has the identical bit pattern to the bit pattern of
the float represented by this object.
- Note that in most cases, for two instances of class Float, f1 and f2, the value
of f1.equals(f2) is true if and only if
f1.floatValue() == f2.floatValue()
also has the value true. However, there are two exceptions:
- Returns:
- true if the objects are the same; false otherwise.
- See Also:
- floatToIntBits (I-§1.7.11).
- Overrides:
- equals in class Object (I-§1.12.3).
floatToIntBits
public static int floatToIntBits(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 represents the sign of the floating-point number. Bits 30-23 represent the exponent. Bits 22-0 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 0x7fc00000.
- Parameters:
value
-
a floating point number
- Returns:
- the bits that represent the floating point number.
floatValue
public float floatValue()
- Returns:
- The float value represented by this object is returned.
- Overrides:
- floatValue in class Number (I-§1.11.2).
hashCode
public int hashCode()
- Returns:
- a hash code value for this object.
- Overrides:
- hashCode in class Object (I-§1.12.6).
intBitsToFloat
public static float intBitsToFloat(int bits)
- The argument is considered to be a representation of a floating-point value
according to the IEEE 754 floating-point "single precision" bit layout.
That floating-point value is returned as the result.
- 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 0x7f8fffff or in
the range 0xff800001 through 0xff8fffff, the result is NaN. All IEEE 754 NaN
values are, in effect, lumped together by the Java language into a single
value.
- Parameters:
bits
-
an integer
- Returns:
- the single format floating-point value with the same bit pattern.
intValue
public int intValue()
- Returns:
- The float value represented by this object is converted to type int
and the result of the conversion is returned.
- Overrides:
- intValue in class Number (I-§1.11.3).
isInfinite
public boolean isInfinite()
- Returns:
- true if the value value represented by this object is positive
infinity (I-§1.7.5) or negative infinity(I-§1.7.4); false otherwise
isInfinite
public static boolean isInfinite(float v)
- Parameters:
v
-
the value to be tested
- Returns:
- true if the argument is positive infinity (I-§1.7.5) or negative infinity(I-§1.7.4); false otherwise
isNaN
public boolean isNaN()
- Returns:
- true if the value value represented by this object is NaN (I-§1.7.3); false
otherwise
isNaN
public static boolean isNaN(float v)
- Returns:
- true if the argument is NaN (I-§1.7.3); false otherwise
- Parameters:
v
-
the value to be tested
longValue
public long longValue()
- Returns:
- The float value represented by this object is converted to type
long and the result of the conversion is returned.
- Overrides:
- longValue in class Number (I-§1.11.4).
toString
public String toString()
- The primitive float value represented by this object is converted to a String
exactly as if by the method toString of one argument (I-§1.7.22).
- Returns:
- a String representation of this object.
- Overrides:
- toString in class Object (I-§1.12.9).
toString
public static String toString(float f)
- Creates a string representation of the float argument.
- The values NaN, NEGATIVE_INFINITY, POSITIVE_INFINITY, -0.0, and +0.0
are represented by the strings "NaN", "-Infinity", "Infinity", "-0.0" and "0.0",
respectively.
- If d is in the range , then it is converted to a String in the
style [-]ddd.ddd. Otherwise, it is converted to a string in the style
[-]m.ddddE±±±±xx.
- There is always a minimum of one digit after the decimal point. The number of digits is the minimum needed to uniquely distinguish the argument
value from adjacent values of type float.
- Parameters:
d
-
the float to be converted
- Returns:
- a string representation of the argument.
valueOf
public static Float valueOf(String s)
throws NumberFormatException
- Parses a string into a Float.
- Parameters:
s
-
the string to be parsed
- Returns:
- a newly constructed Float initialized to the value represented by the
String argument.
- Throws
- NumberFormatException (I-§1.41)
- If the string does not contain a parsable number.
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Java API Document (HTML generated by dkramer on April 22, 1996)
Copyright © 1996 Sun Microsystems, Inc.
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