Long

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java.lang
Class Long

java.lang.Object   
  java.lang.Number   
      java.lang.Long

All Implemented Interfaces:: Serializable , Comparable <Long >

public final class Long
extends Number
implements Comparable <Long >
extends Number
implements Comparable <Long >

The Long class wraps a value of the primitive type long in an object. An object of type Long contains a single field whose type is long.

In addition, this class provides several methods for converting a long to a String and a String to a long, as well as other constants and methods useful when dealing with a long.

Implementation note: The implementations of the "bit twiddling" methods (such as highestOneBit and numberOfTrailingZeros ) are based on material from Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002).

Since:: JDK1.0
See Also:: Serialized Form

Field Summary
`static long`	`MAX_VALUE` A constant holding the maximum value a `long` can have, 2⁶³-1.
`static long`	`MIN_VALUE` A constant holding the minimum value a `long` can have, -2⁶³.
`static int`	`SIZE` The number of bits used to represent a `long` value in two's complement binary form.
`static Class <Long >`	`TYPE` The `Class` instance representing the primitive type `long`.

Constructor Summary
`Long (long value)` Constructs a newly allocated `Long` object that represents the specified `long` argument.
`Long (String s)` Constructs a newly allocated `Long` object that represents the `long` value indicated by the `String` parameter.

Method Summary
`static int`	`bitCount (long i)` Returns the number of one-bits in the two's complement binary representation of the specified `long` value.
`byte`	`byteValue ()` Returns the value of this `Long` as a `byte`.
`int`	`compareTo (Long anotherLong)` Compares two `Long` objects numerically.
`static Long`	`decode (String nm)` Decodes a `String` into a `Long`.
`double`	`doubleValue ()` Returns the value of this `Long` as a `double`.
`boolean`	`equals (Object obj)` Compares this object to the specified object.
`float`	`floatValue ()` Returns the value of this `Long` as a `float`.
`static Long`	`getLong (String nm)` Determines the `long` value of the system property with the specified name.
`static Long`	`getLong (String nm, long val)` Determines the `long` value of the system property with the specified name.
`static Long`	`getLong (String nm, Long val)` Returns the `long` value of the system property with the specified name.
`int`	`hashCode ()` Returns a hash code for this `Long`.
`static long`	`highestOneBit (long i)` Returns an `long` value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specified `long` value.
`int`	`intValue ()` Returns the value of this `Long` as an `int`.
`long`	`longValue ()` Returns the value of this `Long` as a `long` value.
`static long`	`lowestOneBit (long i)` Returns an `long` value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specified `long` value.
`static int`	`numberOfLeadingZeros (long i)` Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified `long` value.
`static int`	`numberOfTrailingZeros (long i)` Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified `long` value.
`static long`	`parseLong (String s)` Parses the string argument as a signed decimal `long`.
`static long`	`parseLong (String s, int radix)` Parses the string argument as a signed `long` in the radix specified by the second argument.
`static long`	`reverse (long i)` Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified `long` value.
`static long`	`reverseBytes (long i)` Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified `long` value.
`static long`	`rotateLeft (long i, int distance)` Returns the value obtained by rotating the two's complement binary representation of the specified `long` value left by the specified number of bits.
`static long`	`rotateRight (long i, int distance)` Returns the value obtained by rotating the two's complement binary representation of the specified `long` value right by the specified number of bits.
`short`	`shortValue ()` Returns the value of this `Long` as a `short`.
`static int`	`signum (long i)` Returns the signum function of the specified `long` value.
`static String`	`toBinaryString (long i)` Returns a string representation of the `long` argument as an unsigned integer in base 2.
`static String`	`toHexString (long i)` Returns a string representation of the `long` argument as an unsigned integer in base 16.
`static String`	`toOctalString (long i)` Returns a string representation of the `long` argument as an unsigned integer in base 8.
`String`	`toString ()` Returns a `String` object representing this `Long`'s value.
`static String`	`toString (long i)` Returns a `String` object representing the specified `long`.
`static String`	`toString (long i, int radix)` Returns a string representation of the first argument in the radix specified by the second argument.
`static Long`	`valueOf (long l)` Returns a `Long` instance representing the specified `long` value.
`static Long`	`valueOf (String s)` Returns a `Long` object holding the value of the specified `String`.
`static Long`	`valueOf (String s, int radix)` Returns a `Long` object holding the value extracted from the specified `String` when parsed with the radix given by the second argument.

Methods inherited from class java.lang.Object
`clone , finalize , getClass , notify , notifyAll , wait , wait , wait`

Field Detail

MIN_VALUE

public static final long MIN_VALUE

A constant holding the minimum value a long can have, -2⁶³.

See Also:: Constant Field Values

MAX_VALUE

public static final long MAX_VALUE

A constant holding the maximum value a long can have, 2⁶³-1.

See Also:: Constant Field Values

TYPE

public static final Class   <Long   > TYPE

The Class instance representing the primitive type long.

Since:: JDK1.1

SIZE

public static final int SIZE

The number of bits used to represent a long value in two's complement binary form.

Since:: 1.5
See Also:: Constant Field Values

Constructor Detail

Long

public Long(long value)

Constructs a newly allocated Long object that represents the specified long argument.

Parameters:: value - the value to be represented by the Long object.

Long

public Long(String    s)
     throws NumberFormatException

Constructs a newly allocated Long object that represents the long value indicated by the String parameter. The string is converted to a long value in exactly the manner used by the parseLong method for radix 10.

Parameters:: s - the String to be converted to a Long.
Throws:: NumberFormatException - if the String does not contain a parsable long.
See Also:: parseLong(java.lang.String, int)

Method Detail

toString

public static String    toString(long i,
                              int radix)

Returns a string representation of the first argument in the radix specified by the second argument.

If the radix is smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX, then the radix 10 is used instead.

If the first argument is negative, the first element of the result is the ASCII minus sign '-' ('\u002d'). If the first argument is not negative, no sign character appears in the result.

The remaining characters of the result represent the magnitude of the first argument. If the magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the magnitude will not be the zero character. The following ASCII characters are used as digits:

   0123456789abcdefghijklmnopqrstuvwxyz

These are '\u0030' through '\u0039' and '\u0061' through '\u007a'. If radix is N, then the first N of these characters are used as radix-N digits in the order shown. Thus, the digits for hexadecimal (radix 16) are 0123456789abcdef. If uppercase letters are desired, the String.toUpperCase()

sample code for java.lang.String.toUpperCase()

definition code for java.lang.String.toUpperCase()

method may be called on the result:

 Long.toString(n, 16).toUpperCase()

Parameters:: i - a longto be converted to a string.; radix - the radix to use in the string representation.
Returns:: a string representation of the argument in the specified radix.
See Also:: Character.MAX_RADIX , Character.MIN_RADIX

toHexString

public static String    toHexString(long i)

Returns a string representation of the long argument as an unsigned integer in base 16.

The unsigned long value is the argument plus 2⁶⁴ if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in hexadecimal (base 16) with no extra leading 0s. If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as hexadecimal digits:

 0123456789abcdef

These are the characters '\u0030' through '\u0039' and '\u0061' through '\u0066'. If uppercase letters are desired, the String.toUpperCase()

method may be called on the result:

 Long.toHexString(n).toUpperCase()

Parameters:: i - a long to be converted to a string.
Returns:: the string representation of the unsigned long value represented by the argument in hexadecimal (base 16).
Since:: JDK 1.0.2

toOctalString

public static String    toOctalString(long i)

Returns a string representation of the long argument as an unsigned integer in base 8.

The unsigned long value is the argument plus 2⁶⁴ if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in octal (base 8) with no extra leading 0s.

If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The following characters are used as octal digits:

01234567

These are the characters '\u0030' through '\u0037'.

Parameters:: i - a long to be converted to a string.
Returns:: the string representation of the unsigned long value represented by the argument in octal (base 8).
Since:: JDK 1.0.2

toBinaryString

public static String    toBinaryString(long i)

Returns a string representation of the long argument as an unsigned integer in base 2.

The unsigned long value is the argument plus 2⁶⁴ if the argument is negative; otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in binary (base 2) with no extra leading 0s. If the unsigned magnitude is zero, it is represented by a single zero character '0' ('\u0030'); otherwise, the first character of the representation of the unsigned magnitude will not be the zero character. The characters '0' ('\u0030') and '1' ('\u0031') are used as binary digits.

Parameters:: i - a long to be converted to a string.
Returns:: the string representation of the unsigned long value represented by the argument in binary (base 2).
Since:: JDK 1.0.2

toString

public static String    toString(long i)

Returns a String object representing the specified long. The argument is converted to signed decimal representation and returned as a string, exactly as if the argument and the radix 10 were given as arguments to the toString(long, int)

sample code for java.lang.Long.toString(long, int)

definition code for java.lang.Long.toString(long, int)

method.

Parameters:: i - a long to be converted.
Returns:: a string representation of the argument in base 10.

parseLong

public static long parseLong(String    s,
                             int radix)
                      throws NumberFormatException

Parses the string argument as a signed long in the radix specified by the second argument. The characters in the string must all be digits of the specified radix (as determined by whether Character.digit(char, int)

sample code for java.lang.Character.digit(char, int)

definition code for java.lang.Character.digit(char, int)

returns a nonnegative value), except that the first character may be an ASCII minus sign '-' ('\u002D') to indicate a negative value. The resulting long value is returned.

Note that neither the character L ('\u004C') nor l ('\u006C') is permitted to appear at the end of the string as a type indicator, as would be permitted in Java programming language source code - except that either L or l may appear as a digit for a radix greater than 22.

An exception of type NumberFormatException is thrown if any of the following situations occurs:

The first argument is null or is a string of length zero.
The radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX .
Any character of the string is not a digit of the specified radix, except that the first character may be a minus sign '-' ('\u002d') provided that the string is longer than length 1.
The value represented by the string is not a value of type long.

Examples:

 parseLong("0", 10) returns 0L
 parseLong("473", 10) returns 473L
 parseLong("-0", 10) returns 0L
 parseLong("-FF", 16) returns -255L
 parseLong("1100110", 2) returns 102L
 parseLong("99", 8) throws a NumberFormatException
 parseLong("Hazelnut", 10) throws a NumberFormatException
 parseLong("Hazelnut", 36) returns 1356099454469L

Parameters:: s - the String containing the long representation to be parsed.; radix - the radix to be used while parsing s.
Returns:: the long represented by the string argument in the specified radix.
Throws:: NumberFormatException - if the string does not contain a parsable long.

parseLong

public static long parseLong(String    s)
                      throws NumberFormatException

Parses the string argument as a signed decimal long. The characters in the string must all be decimal digits, except that the first character may be an ASCII minus sign '-' (\u002D') to indicate a negative value. The resulting long value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseLong(java.lang.String, int)

sample code for java.lang.Long.parseLong(java.lang.String, int)

definition code for java.lang.Long.parseLong(java.lang.String, int)

method.

Parameters:: s - a String containing the long representation to be parsed
Returns:: the long represented by the argument in decimal.
Throws:: NumberFormatException - if the string does not contain a parsable long.

valueOf

public static Long    valueOf(String    s,
                           int radix)
                    throws NumberFormatException

Returns a Long object holding the value extracted from the specified String when parsed with the radix given by the second argument. The first argument is interpreted as representing a signed long in the radix specified by the second argument, exactly as if the arguments were given to the parseLong(java.lang.String, int)

method. The result is a Long object that represents the long value specified by the string.

In other words, this method returns a Long object equal to the value of:

new Long(Long.parseLong(s, radix))

Parameters:: s - the string to be parsed; radix - the radix to be used in interpreting s
Returns:: a Long object holding the value represented by the string argument in the specified radix.
Throws:: NumberFormatException - If the String does not contain a parsable long.

valueOf

public static Long    valueOf(String    s)
                    throws NumberFormatException

Returns a Long object holding the value of the specified String. The argument is interpreted as representing a signed decimal long, exactly as if the argument were given to the parseLong(java.lang.String)

sample code for java.lang.Long.parseLong(java.lang.String)

definition code for java.lang.Long.parseLong(java.lang.String)

method. The result is a Long object that represents the integer value specified by the string.

In other words, this method returns a Long object equal to the value of:

 new Long(Long.parseLong(s))

Parameters:: s - the string to be parsed.
Returns:: a Long object holding the value represented by the string argument.
Throws:: NumberFormatException - If the string cannot be parsed as a long.

valueOf

public static Long    valueOf(long l)

Returns a Long instance representing the specified long value. If a new Long instance is not required, this method should generally be used in preference to the constructor Long(long)

sample code for java.lang.Long.Long(long)

definition code for java.lang.Long.Long(long)

, as this method is likely to yield significantly better space and time performance by caching frequently requested values.

Parameters:: l - a long value.
Returns:: a Long instance representing l.
Since:: 1.5

decode

public static Long    decode(String    nm)
                   throws NumberFormatException

Decodes a String into a Long. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:

DecodableString:
Sign_opt DecimalNumeral
Sign_opt 0x HexDigits
Sign_opt 0X HexDigits
Sign_opt # HexDigits
Sign_opt 0 OctalDigits

Sign:
-

DecimalNumeral, HexDigits, and OctalDigits are defined in §3.10.1 of the Java Language Specification.

The sequence of characters following an (optional) negative sign and/or radix specifier ("0x", "0X", "#", or leading zero) is parsed as by the Long.parseLong method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or a NumberFormatException will be thrown. The result is negated if first character of the specified String is the minus sign. No whitespace characters are permitted in the String.

Parameters:: nm - the String to decode.
Returns:: a Long object holding the long value represented by nm
Throws:: NumberFormatException - if the String does not contain a parsable long.
Since:: 1.2
See Also:: parseLong(String, int)

byteValue

public byte byteValue()

Returns the value of this Long as a byte.

Overrides:: byteValue in class Number

Returns:: the numeric value represented by this object after conversion to type byte.

shortValue

public short shortValue()

Returns the value of this Long as a short.

Overrides:: shortValue in class Number

Returns:: the numeric value represented by this object after conversion to type short.

intValue

public int intValue()

Returns the value of this Long as an int.

Specified by:: intValue in class Number

Returns:: the numeric value represented by this object after conversion to type int.

longValue

public long longValue()

Returns the value of this Long as a long value.

Specified by:: longValue in class Number

Returns:: the numeric value represented by this object after conversion to type long.

java.lang Class Long

MIN_VALUE

MAX_VALUE

TYPE

SIZE

Long

Long

toString

toHexString

toOctalString

toBinaryString

toString

parseLong

parseLong

valueOf

valueOf

valueOf

decode

byteValue

shortValue

intValue

longValue

floatValue

java.lang
Class Long