Previous
Java API
Index
Next
| Package java.lang |
Previous |
Java API |
Index |
Next |
public final class java.lang.Float
extends java.lang.Number
{
// Fields
public final static float MAX_VALUE;
public final static float MIN_VALUE;
public final static float NaN;
public final static float NEGATIVE_INFINITY;
public final static float POSITIVE_INFINITY;
// Constructors
public Float(double value);
public Float(float value);
public Float(String s);
// Methods
public double doubleValue();
public boolean equals(Object obj);
public static int floatToIntBits(float value);
public float floatValue();
public int hashCode();
public static float intBitsToFloat(int bits);
public int intValue();
public boolean isInfinite();
public static boolean isInfinite(float v);
public boolean isNaN();
public static boolean isNaN(float v);
public long longValue();
public String toString();
public static String toString(float f);
public static Float valueOf(String s);
}
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.
public final static float MAX_VALUE= 3.40282346638528860e+38.The largest positive finite value of type float.
public final static float MIN_VALUE= 1.40129846432481707e-45The smallest positive value of type float.
public final static float NaN = 0.0f/0.0fThe Not-a-Number value of type float.
public final static float NEGATIVE_INFINITY= -1.0f/0.0fThe negative infinity of type float.
public final static float POSITIVE_INFINITY= 1.0f/0.0fThe positive infinity of type float.
public Float(double value)Constructs a newly allocated Float object that represents the argument converted to type float.
Parameter Description value the value to be represented by the Float
public Float(float value)Constructs a newly allocated Float object that represents the primitive float argument.
Parameter Description value the value to be represented by the Float
public Float(String s)throws NumberFormatExceptionConstructs 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 .
Parameter Description s a string to be converted to a Float Throw:
If the string does not contain a parsable number.
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 .
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:
- If f1 and f2 both represent Float.NaN,then the equals method returns true, even though Float.NaN==Float.NaN has the value false.
- If f1 represents +0.0f while f2 represents -0.0f, or vice versa, the equal test has the value false, even though 0.0f==-0.0f has the value true.
Return Value:
Returns true if the objects are the same; false otherwise.
Overrides:
equals in class Object .
See Also: 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.
Return Value:
Returns the bits that represent the floating point number.
Parameter Description value a floating point number
public float floatValue()Return Value:
Returns The float value represented by this object is returned.
Overrides:
floatValue in class Number .
public int hashCode()Return Value:
Returns a hash code value for this object.
Overrides:
hashCode in class Object .
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.
Return Value:
Returns the single format floating-point value with the same bit pattern.
Parameter Description bits an integer
public int intValue()Return Value:
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 .
public boolean isInfinite()Return Value:
Returns true if the value value represented by this object is positive infinity or negative infinity; false otherwise
public static boolean isInfinite(float v)Return Value:
Returns true if the argument is positive infinity or negative infinity; false otherwise
Parameter Description v the value to be tested
public boolean isNaN()Return Value:
Returns true if the value value represented by this object is NaN ; false otherwise
public static boolean isNaN(float v)Return Value:
Returns true if the argument is NaN ; false otherwise
Parameter Description v the value to be tested
public long longValue()Return Value:
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 .
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 .
Return Value:
Returns a String representation of this object.
Overrides:
toString in class Object .
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 10-3 £ |d| £ 107, 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.
Return Value:
Returns a string representation of the argument.
Parameter Description d the float to be converted
public static Float valueOf(String s)throws NumberFormatExceptionParses a string into a Float.
Return Value:
Returns a newly constructed Float initialized to the value represented by the String argument.
Parameter Description s the string to be parsed Throw:
If the string does not contain a parsable number.
© 1996 Sun Microsystems, Inc. All rights reserved.