java::lang::Double Class Reference

Inheritance diagram for java::lang::Double:

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java::lang::Numberjava::lang::Objectjava::lang::Interfacejava::lang::Comparable
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Collaboration diagram for java::lang::Double:

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java::lang::Numberjava::lang::Objectjava::lang::Interfacejava::lang::Comparable
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List of all members.


Detailed Description

The Double class is the standard wrapper for byte values.

Author:
Yuh-Jye Chang
Version:
1.20, 02/02/00
Since:
JDK1.1

Public Member Functions

 Double (jdouble _value=0)
 Constructs a newly allocated Double object that represents the primitive double argument.
 operator jdouble & ()
virtual jboolean isNaN () const
 Returns true if this Double value is Not-a-Number (NaN).
virtual jboolean isInfinite () const
 Returns true if this Double value is infinitely large in magnitude.
virtual String toString () const
 Returns a String representation of this Double object.
virtual jbyte byteValue () const
 Returns the value of this Double as a byte.
virtual jshort shortValue () const
 Returns the value of this Double as a short.
virtual jint intValue () const
 Returns the value of this Double as an int.
virtual jlong longValue () const
 Returns the value of this Double as a long.
virtual jfloat floatValue () const
 Returns the value of this Double as a float.
virtual jdouble doubleValue () const
 Returns the value of this Float as a double.
virtual jboolean equals (const Object &src) const
 Compares this object against the specified object.
virtual jint hashCode () const
 Returns a hashcode for this Double object.
virtual jint compareTo (const Object &src) const
 Compares two Doubles numerically.

Static Public Member Functions

static jlong doubleToLongBits (jdouble value)
 Returns a representation of the specified floating-point value according to the IEEE 754 floating-point "double format" bit layout.
static jdouble longBitsToDouble (jlong bits)
 Returns the double-float corresponding to a given bit represention.
static jboolean isNaN (jdouble v)
 Returns true if the specified number is the special Not-a-Number (NaN) value.
static jboolean isInfinite (jdouble v)
 Returns true if the specified number is infinitely large in magnitude.
static String toString (jdouble f)
 Creates a string representation of the double argument.
static Double valueOf (const String &s)
 Returns a new Double object initialized to the value represented by the specified string.
static jdouble parseDouble (const String &s)
 Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double.

Static Public Attributes

static const jdouble POSITIVE_INFINITY
 The positive infinity of type double.
static const jdouble NEGATIVE_INFINITY
 The negative infinity of type double.
static const jdouble NaN
 The Not-a-Number (NaN) value of type double.
static const jdouble MIN_VALUE
 The smallest positive value of type double.
static const jdouble MAX_VALUE
 The largest positive value of type double.

Constructor & Destructor Documentation

java::lang::Double::Double ( jdouble  _value = 0  ) 

Constructs a newly allocated Double object that represents the primitive double argument.

Parameters:
value the value to be represented by the Double.


Member Function Documentation

static jlong java::lang::Double::doubleToLongBits ( jdouble  value  )  [static]

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.

Parameters:
value a double precision floating-point number.
Returns:
the bits that represent the floating-point number.

static jdouble java::lang::Double::longBitsToDouble ( jlong  bits  )  [static]

Returns the double-float corresponding to a given bit represention.

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. Distinct values of NaN are only accessible by use of the Double.doubleToRawLongBits method.

In all other cases, let s, e, and m be three values that can be computed from the argument: <blockquote>

 int s = ((bits >> 63) == 0) ? 1 : -1;
 int e = (int)((bits >> 52) & 0x7ffL);
 long m = (e == 0) ?
                 (bits & 0xfffffffffffffL) << 1 :
                 (bits & 0xfffffffffffffL) | 0x10000000000000L;
 
</blockquote> Then the floating-point result equals the value of the mathematical expression s&#183;m&#183;2e-1075.

Parameters:
bits any long integer.
Returns:
the double floating-point value with the same bit pattern.

static jboolean java::lang::Double::isNaN ( jdouble  v  )  [static]

Returns true if the specified number is the special Not-a-Number (NaN) value.

Parameters:
v the value to be tested.
Returns:
true if the argument is NaN; false otherwise.

static jboolean java::lang::Double::isInfinite ( jdouble  v  )  [static]

Returns true if the specified number is infinitely large in magnitude.

Parameters:
v the value to be tested.
Returns:
true if the argument is positive infinity or negative infinity; false otherwise.

static String java::lang::Double::toString ( jdouble  f  )  [static]

Creates a string representation of the double argument.

All characters mentioned below are ASCII characters.

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.

Parameters:
d the double to be converted.
Returns:
a string representation of the argument.

static Double java::lang::Double::valueOf ( const String s  )  [static]

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: <blockquote>


 FloatValue:

        Signopt FloatingPointLiteral
 
</blockquote> where Sign and FloatingPointLiteral are as defined in ?.10.2 of the Java Language Specification. If it does not have the form of a FloatValue, 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.

Parameters:
s the string to be parsed.
Returns:
a newly constructed Double initialized to the value represented by the string argument.
Exceptions:
NumberFormatException if the string does not contain a parsable number.

static jdouble java::lang::Double::parseDouble ( const String s  )  [static]

Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double.

Parameters:
s the string to be parsed.
Returns:
the double value represented by the string argument.
Exceptions:
NumberFormatException if the string does not contain a parsable double.
See also:
java.lang.Double::valueOf(String)
Since:
1.2

java::lang::Double::operator jdouble & (  ) 

virtual jboolean java::lang::Double::isNaN (  )  const [virtual]

Returns true if this Double value is Not-a-Number (NaN).

Returns:
true if the value represented by this object is NaN; false otherwise.

virtual jboolean java::lang::Double::isInfinite (  )  const [virtual]

Returns true if this Double value is infinitely large in magnitude.

Returns:
true if the value represented by this object is positive infinity or negative infinity; false otherwise.

virtual String java::lang::Double::toString (  )  const [virtual]

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.

Returns:
a String representation of this object.
See also:
java.lang.Float::toString(float)

Reimplemented from java::lang::Object.

virtual jbyte java::lang::Double::byteValue (  )  const [virtual]

Returns the value of this Double as a byte.

Since:
JDK1.1

Reimplemented from java::lang::Number.

virtual jshort java::lang::Double::shortValue (  )  const [virtual]

Returns the value of this Double as a short.

Since:
JDK1.1

Reimplemented from java::lang::Number.

virtual jint java::lang::Double::intValue (  )  const [virtual]

Returns the value of this Double as an int.

Returns:
the int value represented by this object.

Implements java::lang::Number.

virtual jlong java::lang::Double::longValue (  )  const [virtual]

Returns the value of this Double as a long.

Returns:
the byte value represented by this object that is converted to type long and the result of the conversion is returned.

Implements java::lang::Number.

virtual jfloat java::lang::Double::floatValue (  )  const [virtual]

Returns the value of this Double as a float.

Returns:
the byte value represented by this object is converted to type float and the result of the conversion is returned.

Implements java::lang::Number.

virtual jdouble java::lang::Double::doubleValue (  )  const [virtual]

Returns the value of this Float as a double.

Returns:
the byte value represented by this object is converted to type double and the result of the conversion is returned.

Implements java::lang::Number.

virtual jboolean java::lang::Double::equals ( const Object src  )  const [virtual]

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 doubleToLongBits(double) 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 <blockquote>

   d1.doubleValue() == d2.doubleValue()
 
</blockquote>

also has the value true. However, there are two exceptions:

Parameters:
obj the object to compare with.
Returns:
true if the objects are the same; false otherwise.

Reimplemented from java::lang::Object.

virtual jint java::lang::Double::hashCode (  )  const [virtual]

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 doubleToLongBits(double), of the primitive double value represented by this Double object. That is, the hashcode is the value of the expression: <blockquote>

 (int)(v^(v>>>32))
 
</blockquote> where v is defined by: <blockquote>
 long v = Double.doubleToLongBits(this.doubleValue());
 
</blockquote>

Returns:
a hash code value for this object.

Reimplemented from java::lang::Object.

virtual jint java::lang::Double::compareTo ( const Object src  )  const [virtual]

Compares two Doubles numerically.

There are two ways in which comparisons performed by this method differ from those performed by the Java language numerical comparison operators (<, <=, ==, >= >) when applied to primitive doubles:

This ensures that Double.compareTo(Object) (which inherits its behavior from this method) obeys the general contract for Comparable.compareTo, and that the natural order on Doubles is total.

Parameters:
anotherDouble the Double to be compared.
Returns:
the value 0 if anotherDouble is numerically equal to this Double; a value less than 0 if this Double is numerically less than anotherDouble; and a value greater than 0 if this Double is numerically greater than anotherDouble.
Since:
1.2
See also:
Comparable::compareTo(Object)

Reimplemented from java::lang::Comparable.


Member Data Documentation

const jdouble java::lang::Double::POSITIVE_INFINITY [static]

The positive infinity of type double.

It is equal to the value returned by Double.longBitsToDouble(0x7f80000000000000).

const jdouble java::lang::Double::NEGATIVE_INFINITY [static]

The negative infinity of type double.

It is equal to the value returned by Double.longBitsToDouble(0xff80000000000000).

const jdouble java::lang::Double::NaN [static]

The Not-a-Number (NaN) value of type double.

It is equal to the value returned by Double.longBitsToDouble(0x7fc0000000000000).

const jdouble java::lang::Double::MIN_VALUE [static]

The smallest positive value of type double.

It is equal to the value returned by Double.longBitsToDouble(0x1).

const jdouble java::lang::Double::MAX_VALUE [static]

The largest positive value of type double.

It is equal to the value returned by Double.longBitsToDouble(0x7f7fffffffffffff).


The documentation for this class was generated from the following file:
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