Class Double

java.lang.Object
java.lang.Number
java.lang.Double
All Implemented Interfaces:
Comparable<Double>
public final class Double extends Number implements Comparable<Double>
The Double class wraps a value of the primitive type double in an object. An object of type Double contains a single field whose type is double. In addition, this class provides several methods for converting a double to a String and a String to a double, as well as other constants and methods useful when dealing with a double. Since: JDK1.0, CLDC 1.1

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final double
    MAX_VALUE
    The largest positive finite value of type double.
    static final double
    MIN_VALUE
    The smallest positive value of type double.
    static final double
    NaN
    A Not-a-Number (NaN) value of type double.
    static final double
    NEGATIVE_INFINITY
    The negative infinity of type double.
    static final double
    POSITIVE_INFINITY
    The positive infinity of type double.
    static final Class<Double>
    TYPE
     

  • Constructor Summary

    Constructors
    Constructor
    Description
    Double(double value)
    Constructs a newly allocated Double object that represents the primitive double argument.

  • Method Summary

    Modifier and Type
    Method
    Description
    byte
    byteValue()
    Returns the value of this Double as a byte (by casting to a byte).
    static int
    compare(double d1, double d2)
     
    int
    compareTo(Double d)
    Compares this object to the specified object to determine their relative order.
    static long
    doubleToLongBits(double value)
    Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout.
    double
    doubleValue()
    Returns the double value of this Double.
    boolean
    equals(Object obj)
    Compares this object against the specified object.
    float
    floatValue()
    Returns the float value of this Double.
    int
    hashCode()
    Returns a hashcode for this Double object.
    int
    intValue()
    Returns the integer value of this Double (by casting to an int).
    boolean
    isInfinite()
    Returns true if this Double value is infinitely large in magnitude.
    static boolean
    isInfinite(double v)
    Returns true if the specified number is infinitely large in magnitude.
    boolean
    isNaN()
    Returns true if this Double value is the special Not-a-Number (NaN) value.
    static boolean
    isNaN(double v)
    Returns true if the specified number is the special Not-a-Number (NaN) value.
    static double
    longBitsToDouble(long bits)
    Returns the double-float corresponding to a given bit representation.
    long
    longValue()
    Returns the long value of this Double (by casting to a long).
    static double
    parseDouble(String s)
    Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double.
    short
    shortValue()
    Returns the value of this Double as a short (by casting to a short).
    String
    toString()
    Returns a String representation of this Double object.
    static String
    toString(double d)
    Creates a string representation of the double argument.
    static Double
    valueOf(double i)
    Returns the object instance of i
    static Double
    valueOf(String s)
    Returns a new Double object initialized to the value represented by the specified string.

    Methods inherited from class Object

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

  • Field Details

    • TYPE

      public static final Class<Double> TYPE

    • MAX_VALUE

      public static final double MAX_VALUE
      The largest positive finite value of type double. It is equal to the value returned by Double.longBitsToDouble(0x7fefffffffffffffL) See Also:Constant Field Values
      See Also:

    • MIN_VALUE

      public static final double MIN_VALUE
      The smallest positive value of type double. It is equal to the value returned by Double.longBitsToDouble(0x1L).
      See Also:

    • NaN

      public static final double NaN
      A Not-a-Number (NaN) value of type double. It is equal to the value returned by Double.longBitsToDouble(0x7ff8000000000000L). See Also:Constant Field Values
      See Also:

    • NEGATIVE_INFINITY

      public static final double NEGATIVE_INFINITY
      The negative infinity of type double. It is equal to the value returned by Double.longBitsToDouble(0xfff0000000000000L). See Also:Constant Field Values
      See Also:

    • POSITIVE_INFINITY

      public static final double POSITIVE_INFINITY
      The positive infinity of type double. It is equal to the value returned by Double.longBitsToDouble(0x7ff0000000000000L). See Also:Constant Field Values
      See Also:

  • Constructor Details

    • Double

      public Double(double value)
      Constructs a newly allocated Double object that represents the primitive double argument. value - the value to be represented by the Double.

  • Method Details

    • byteValue

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

    • doubleToLongBits

      public static long doubleToLongBits(double value)
      Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout. Bit 63 (the bit that is selected by the mask 0x8000000000000000L) represents the sign of the floating-point number. Bits 62-52 (the bits that are selected by the mask 0x7ff0000000000000L) represent the exponent. Bits 51-0 (the bits that are selected by the mask 0x000fffffffffffffL) represent the significand (sometimes called the mantissa) of the floating-point number. If the argument is positive infinity, the result is 0x7ff0000000000000L. If the argument is negative infinity, the result is 0xfff0000000000000L. If the argument is NaN, the result is 0x7ff8000000000000L. In all cases, the result is a long integer that, when given to the longBitsToDouble(long) method, will produce a floating-point value equal to the argument to doubleToLongBits.

    • doubleValue

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

    • equals

      public boolean equals(Object obj)
      Compares this object against the specified object. The result is true if and only if the argument is not null and is a Double object that represents a double that has the identical bit pattern to the bit pattern of the double represented by this object. For this purpose, two double values are considered to be the same if and only if the method returns the same long value when applied to each. Note that in most cases, for two instances of class Double, d1 and d2, the value of d1.equals(d2) is true if and only if d1.doubleValue() == d2.doubleValue() also has the value true. However, there are two exceptions: If d1 and d2 both represent Double.NaN, then the equals method returns true, even though Double.NaN==Double.NaN has the value false. If d1 represents +0.0 while d2 represents -0.0, or vice versa, the equals test has the value false, even though +0.0==-0.0 has the value true. This allows hashtables to operate properly.
      Overrides:
      equals in class Object

    • floatValue

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

    • hashCode

      public int hashCode()
      Returns a hashcode for this Double object. The result is the exclusive OR of the two halves of the long integer bit representation, exactly as produced by the method , of the primitive double value represented by this Double object. That is, the hashcode is the value of the expression: (int)(v^(v>>>32)) where v is defined by: long v = Double.doubleToLongBits(this.doubleValue());
      Overrides:
      hashCode in class Object

    • intValue

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

    • isInfinite

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

    • isInfinite

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

    • isNaN

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

    • isNaN

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

    • longBitsToDouble

      public static double longBitsToDouble(long bits)
      Returns the double-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 "double precision" bit layout. That floating-point value is returned as the result. If the argument is 0x7ff0000000000000L, the result is positive infinity. If the argument is 0xfff0000000000000L, the result is negative infinity. If the argument is any value in the range 0x7ff0000000000001L through 0x7fffffffffffffffL or in the range 0xfff0000000000001L through 0xffffffffffffffffL, the result is NaN. All IEEE 754 NaN values of type double are, in effect, lumped together by the Java programming language into a single 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 >> 63) == 0) ? 1 : -1; int e = (int)((bits >> 52) & 0x7ffL); long m = (e == 0) ? (bits & 0xfffffffffffffL) invalid input: '<'invalid input: '<' 1 : (bits & 0xfffffffffffffL) | 0x10000000000000L; Then the floating-point result equals the value of the mathematical expression 2e-1075.

    • longValue

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

    • parseDouble

      public static double parseDouble(String s) throws NumberFormatException
      Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double.
      Throws:
      NumberFormatException

    • shortValue

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

    • toString

      public String toString()
      Returns a String representation of this Double object. The primitive double 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(double d)
      Creates a string representation of the double argument. All characters 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 : If is infinity, it is represented by the characters "Infinity"; thus, positive infinity produces the result "Infinity" and negative infinity produces the result "-Infinity". If 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 is greater than or equal to 10-3 but less than 107, then it is represented as the integer part of , in decimal form with no leading zeroes, followed by '.' (.), followed by one or more decimal digits representing the fractional part of . If is less than 10-3 or not less than 107, then it is represented in so-called "computerized scientific notation." Let be the unique integer such that 10n = 10n+1; then let be the mathematically exact quotient of and 10n so that 1 = 10. The magnitude is then represented as the integer part of , as a single decimal digit, followed by '.' (.), followed by decimal digits representing the fractional part of , followed by the letter 'E' (E), followed by a representation of as a decimal integer, as produced by the method . 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 double. That is, suppose that x is the exact mathematical value represented by the decimal representation produced by this method for a finite nonzero argument d. Then d must be the double value nearest to x; or if two double values are equally close to x, then d must be one of them and the least significant bit of the significand of d must be 0.

    • valueOf

      public static Double valueOf(String s) throws NumberFormatException
      Returns a new Double object initialized to the value represented by the specified string. The string s is interpreted as the representation of a floating-point value and a Double 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 rule: where and 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 double by the usual round-to-nearest rule of IEEE 754 floating-point arithmetic. Finally, a new object of class Double is created to represent the double value.
      Throws:
      NumberFormatException

    • valueOf

      public static Double valueOf(double i)
      Returns the object instance of i
      Parameters:
      i - the primitive
      Returns:
      object instance

    • compare

      public static int compare(double d1, double d2)

    • compareTo

      public int compareTo(Double d)
      Description copied from interface: Comparable
      Compares this object to the specified object to determine their relative order.
      Specified by:
      compareTo in interface Comparable<Double>
      Parameters:
      d - 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.