Class Float

java.lang.Object
java.lang.Number
java.lang.Float
All Implemented Interfaces:
Comparable<Float>
public final class Float extends Number implements Comparable<Float>
The Float 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 several 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. Since: JDK1.0, CLDC 1.1

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final float
    MAX_VALUE
    The largest positive value of type float.
    static final float
    MIN_VALUE
    The smallest positive value of type float.
    static final float
    NaN
    The Not-a-Number (NaN) value of type float.
    static final float
    NEGATIVE_INFINITY
    The negative infinity of type float.
    static final float
    POSITIVE_INFINITY
    The positive infinity of type float.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Float(double value)
    Constructs a newly allocated Floatobject that represents the argument converted to type float.
    Float(float value)
    Constructs a newly allocated Float object that represents the primitive float argument.

  • Method Summary

    Modifier and Type
    Method
    Description
    byte
    byteValue()
    Returns the value of this Float as a byte (by casting to a byte).
    static int
    compare(float f1, float f2)
     
    int
    compareTo(Float f)
    Compares this object to the specified object to determine their relative order.
    double
    doubleValue()
    Returns the double value of this Float object.
    boolean
    equals(Object obj)
    Compares this object against some other object.
    static int
    floatToIntBits(float value)
    Returns the bit representation of a single-float value.
    float
    floatValue()
    Returns the float value of this Float object.
    int
    hashCode()
    Returns a hashcode for this Float object.
    static float
    intBitsToFloat(int bits)
    Returns the single-float corresponding to a given bit representation.
    int
    intValue()
    Returns the integer value of this Float (by casting to an int).
    boolean
    isInfinite()
    Returns true if this Float value is infinitely large in magnitude.
    static boolean
    isInfinite(float v)
    Returns true if the specified number is infinitely large in magnitude.
    boolean
    isNaN()
    Returns true if this Float value is Not-a-Number (NaN).
    static boolean
    isNaN(float v)
    Returns true if the specified number is the special Not-a-Number (NaN) value.
    long
    longValue()
    Returns the long value of this Float (by casting to a long).
    static float
    parseFloat(String s)
    Returns a new float initialized to the value represented by the specified String.
    short
    shortValue()
    Returns the value of this Float as a short (by casting to a short).
    String
    toString()
    Returns a String representation of this Float object.
    static String
    toString(float f)
    Returns a String representation for the specified float value.
    static Float
    valueOf(float i)
    Returns the object instance of i
    static Float
    valueOf(String s)
    Returns the floating point value represented by the specified String.

    Methods inherited from class Object

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

  • Field Details

    • MAX_VALUE

      public static final float MAX_VALUE
      The largest positive value of type float. It is equal to the value returned by Float.intBitsToFloat(0x7f7fffff). See Also:Constant Field Values
      See Also:

    • MIN_VALUE

      public static final float MIN_VALUE
      The smallest positive value of type float. It is equal to the value returned by Float.intBitsToFloat(0x1). See Also:Constant Field Values
      See Also:

    • NaN

      public static final float NaN
      The Not-a-Number (NaN) value of type float. It is equal to the value returned by Float.intBitsToFloat(0x7fc00000). See Also:Constant Field Values
      See Also:

    • NEGATIVE_INFINITY

      public static final float NEGATIVE_INFINITY
      The negative infinity of type float. It is equal to the value returned by Float.intBitsToFloat(0xff800000). See Also:Constant Field Values
      See Also:

    • POSITIVE_INFINITY

      public static final float POSITIVE_INFINITY
      The positive infinity of type float. It is equal to the value returned by Float.intBitsToFloat(0x7f800000). See Also:Constant Field Values
      See Also:

  • Constructor Details

    • Float

      public Float(double value)
      Constructs a newly allocated Floatobject that represents the argument converted to type float. 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. value - the value to be represented by the Float.

  • Method Details

    • byteValue

      public byte byteValue()
      Returns the value of this Float as a byte (by casting to a byte).
      Overrides:
      byteValue in class Number

    • doubleValue

      public double doubleValue()
      Returns the double value of this Float object.
      Specified by:
      doubleValue in class Number

    • equals

      public boolean equals(Object obj)
      Compares this object against some other object. 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. For this purpose, two float values are considered to be the same if and only if the method returns the same int value when applied to each. 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. This definition allows hashtables to operate properly.
      Overrides:
      equals in class Object

    • 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. 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 0x7fc00000. In all cases, the result is an integer that, when given to the method, will produce a floating-point value equal to the argument to floatToIntBits.

    • floatValue

      public float floatValue()
      Returns the float value of this Float object.
      Specified by:
      floatValue in class Number

    • hashCode

      public int hashCode()
      Returns a hashcode for this Float object. The result is the integer bit representation, exactly as produced by the method , of the primitive float value represented by this Float object.
      Overrides:
      hashCode in class Object

    • intBitsToFloat

      public static float intBitsToFloat(int bits)
      Returns the single-float corresponding to a given bit representation. 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. 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) invalid input: '<'invalid input: '<' 1 : (bits & 0x7fffff) | 0x800000; Then the floating-point result equals the value of the mathematical expression .

    • intValue

      public int intValue()
      Returns the integer value of this Float (by casting to an int).
      Specified by:
      intValue in class Number

    • isInfinite

      public boolean isInfinite()
      Returns true if this Float value is infinitely large in magnitude.

    • isInfinite

      public static boolean isInfinite(float v)
      Returns true if the specified number is infinitely large in magnitude.

    • isNaN

      public boolean isNaN()
      Returns true if this Float value is Not-a-Number (NaN).

    • isNaN

      public static boolean isNaN(float v)
      Returns true if the specified number is the special Not-a-Number (NaN) value.

    • longValue

      public long longValue()
      Returns the long value of this Float (by casting to a long).
      Specified by:
      longValue in class Number

    • parseFloat

      public static float parseFloat(String s) throws NumberFormatException
      Returns a new float initialized to the value represented by the specified String.
      Throws:
      NumberFormatException

    • shortValue

      public short shortValue()
      Returns the value of this Float as a short (by casting to a short).
      Overrides:
      shortValue in class Number

    • toString

      public String toString()
      Returns a String representation of this Float object. The primitive float value represented by this object is converted to a String exactly as if by the method toString of one argument.
      Overrides:
      toString in class Object

    • toString

      public static String toString(float f)
      Returns a String representation for the specified float value. The argument is converted to a readable string format as follows. All characters and characters in strings mentioned below are ASCII characters. If the argument is NaN, the result is the string "NaN". Otherwise, the result is a string that represents the sign and magnitude (absolute value) of the argument. If the sign is negative, the first character of the result is '-' ('-'); if the sign is positive, no sign character appears in the result. As for the magnitude m: If m is infinity, it is represented by the characters "Infinity"; thus, positive infinity produces the result "Infinity" and negative infinity produces the result "-Infinity". If m is zero, it is represented by the characters "0.0"; thus, negative zero produces the result "-0.0" and positive zero produces the result "0.0". If m is greater than or equal to 10-3 but less than 107, then it is represented as the integer part of m, in decimal form with no leading zeroes, followed by '.' (.), followed by one or more decimal digits representing the fractional part of m. If m is less than 10-3 or not less than 107, then it is represented in so-called "computerized scientific notation." Let n be the unique integer such that 10n =m 1; then let a be the mathematically exact quotient of m and 10n so that 1 a < 10. The magnitude is then represented as the integer part of a, as a single decimal digit, followed by '.' (.), followed by decimal digits representing the fractional part of a, followed by the letter 'E' (E), followed by a representation of n as a decimal integer, as produced by the method of one argument. How many digits must be printed for the fractional part of m or a? There must be at least one digit to represent the fractional part, and beyond that as many, but only as many, more digits as are needed to uniquely distinguish the argument value from adjacent values of type float. That is, suppose that x is the exact mathematical value represented by the decimal representation produced by this method for a finite nonzero argument f. Then f must be the float value nearest to x; or, if two float values are equally close to xthen f must be one of them and the least significant bit of the significand of f must be 0.

    • valueOf

      public static Float valueOf(String s) throws NumberFormatException
      Returns the floating point value represented by the specified String. The string s is interpreted as the representation of a floating-point value and a Float object representing that value is created and returned. If s is null, then a NullPointerException is thrown. Leading and trailing whitespace characters in s are ignored. The rest of s should constitute a FloatValue as described by the lexical syntax rules: where , are as defined in Section 3.10.2 of the . If it does not have the form of a , then a NumberFormatException is thrown. Otherwise, it is regarded as representing an exact decimal value in the usual "computerized scientific notation"; this exact decimal value is then conceptually converted to an "infinitely precise" binary value that is then rounded to type float by the usual round-to-nearest rule of IEEE 754 floating-point arithmetic.
      Throws:
      NumberFormatException

    • valueOf

      public static Float valueOf(float i)
      Returns the object instance of i
      Parameters:
      i - the primitive
      Returns:
      object instance

    • compare

      public static int compare(float f1, float f2)

    • compareTo

      public int compareTo(Float f)
      Description copied from interface: Comparable
      Compares this object to the specified object to determine their relative order.
      Specified by:
      compareTo in interface Comparable<Float>
      Parameters:
      f - the object to compare to this instance.
      Returns:
      a negative integer if this instance is less than another; a positive integer if this instance is greater than another; 0 if this instance has the same order as another.