java.lang.Object | ||
↳ | java.lang.Number | |
↳ | java.lang.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).
Constants | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
long | MAX_VALUE | A constant holding the maximum value a long can
have, 263-1. |
|||||||||
long | MIN_VALUE | A constant holding the minimum value a long can
have, -263. |
|||||||||
int | SIZE | The number of bits used to represent a long value in two's
complement binary form. |
Fields | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
TYPE | The Class instance representing the primitive type
long . |
Public Constructors | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Constructs a newly allocated
Long object that
represents the specified long argument. | |||||||||||
Constructs a newly allocated
Long object that
represents the long value indicated by the
String parameter. |
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Returns the number of one-bits in the two's complement binary
representation of the specified
long value. | |||||||||||
Returns the value of this
Long as a
byte . | |||||||||||
Compares two
Long objects numerically. | |||||||||||
Decodes a
String into a Long . | |||||||||||
Returns the value of this
Long as a
double . | |||||||||||
Compares this object to the specified object.
| |||||||||||
Returns the value of this
Long as a
float . | |||||||||||
Determines the
long value of the system property
with the specified name. | |||||||||||
Returns the
long value of the system property with
the specified name. | |||||||||||
Determines the
long value of the system property
with the specified name. | |||||||||||
Returns a hash code for this
Long . | |||||||||||
Returns a
long value with at most a single one-bit, in the
position of the highest-order ("leftmost") one-bit in the specified
long value. | |||||||||||
Returns the value of this
Long as an
int . | |||||||||||
Returns the value of this
Long as a
long value. | |||||||||||
Returns a
long value with at most a single one-bit, in the
position of the lowest-order ("rightmost") one-bit in the specified
long value. | |||||||||||
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. | |||||||||||
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. | |||||||||||
Parses the string argument as a signed
long in the
radix specified by the second argument. | |||||||||||
Parses the string argument as a signed decimal
long . | |||||||||||
Returns the value obtained by reversing the order of the bits in the
two's complement binary representation of the specified
long
value. | |||||||||||
Returns the value obtained by reversing the order of the bytes in the
two's complement representation of the specified
long value. | |||||||||||
Returns the value obtained by rotating the two's complement binary
representation of the specified
long value left by the
specified number of bits. | |||||||||||
Returns the value obtained by rotating the two's complement binary
representation of the specified
long value right by the
specified number of bits. | |||||||||||
Returns the value of this
Long as a
short . | |||||||||||
Returns the signum function of the specified
long value. | |||||||||||
Returns a string representation of the
long
argument as an unsigned integer in base 2. | |||||||||||
Returns a string representation of the
long
argument as an unsigned integer in base 16. | |||||||||||
Returns a string representation of the
long
argument as an unsigned integer in base 8. | |||||||||||
Returns a
String object representing this
Long 's value. | |||||||||||
Returns a
String object representing the specified
long . | |||||||||||
Returns a string representation of the first argument in the
radix specified by the second argument.
| |||||||||||
Returns a
Long object holding the value
extracted from the specified String when parsed
with the radix given by the second argument. | |||||||||||
Returns a
Long instance representing the specified
long value. | |||||||||||
Returns a
Long object holding the value
of the specified String . |
[Expand]
Inherited Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
From class
java.lang.Number
| |||||||||||
From class
java.lang.Object
| |||||||||||
From interface
java.lang.Comparable
|
A constant holding the maximum value a long
can
have, 263-1.
A constant holding the minimum value a long
can
have, -263.
The number of bits used to represent a long
value in two's
complement binary form.
Constructs a newly allocated Long
object that
represents the specified long
argument.
value | the value to be represented by the
Long object.
|
---|
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.
s | the String to be converted to a
Long . |
---|
NumberFormatException | if the String does not
contain a parsable long . |
---|
Returns the number of one-bits in the two's complement binary
representation of the specified long
value. This function is
sometimes referred to as the population count.
long
value.Returns the value of this Long
as a
byte
.
byte
.Compares two Long
objects numerically.
anotherLong | the Long to be compared. |
---|
0
if this Long
is
equal to the argument Long
; a value less than
0
if this Long
is numerically less
than the argument Long
; and a value greater
than 0
if this Long
is numerically
greater than the argument Long
(signed
comparison).Decodes a String
into a Long
.
Accepts decimal, hexadecimal, and octal numbers given by the
following grammar:
DecimalNumeral, HexDigits, and OctalDigits are defined in §3.10.1 of the Java Language Specification.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0x
HexDigits- Signopt
0X
HexDigits- Signopt
#
HexDigits- Signopt
0
OctalDigits
- Sign:
-
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
.
nm | the String to decode. |
---|
Long
object holding the long
value represented by nm
NumberFormatException | if the String does not
contain a parsable long . |
---|
Returns the value of this Long
as a
double
.
double
.
Compares this object to the specified object. The result is
true
if and only if the argument is not
null
and is a Long
object that
contains the same long
value as this object.
obj | the object to compare with. |
---|
true
if the objects are the same;
false
otherwise.
Returns the value of this Long
as a
float
.
float
.
Determines the long
value of the system property
with the specified name.
The first argument is treated as the name of a system property.
System properties are accessible through the getProperty(java.lang.String)
method. The
string value of this property is then interpreted as a
long
value and a Long
object
representing this value is returned. Details of possible
numeric formats can be found with the definition of
getProperty
.
The second argument is the default value. A Long
object
that represents the value of the second argument is returned if there
is no property of the specified name, if the property does not have
the correct numeric format, or if the specified name is empty or null.
In other words, this method returns a Long
object equal
to the value of:
getLong(nm, new Long(val))
but in practice it may be implemented in a manner such as:
to avoid the unnecessary allocation of aLong result = getLong(nm, null); return (result == null) ? new Long(val) : result;
Long
object when
the default value is not needed.nm | property name. |
---|---|
val | default value. |
Long
value of the property.Returns the long
value of the system property with
the specified name. The first argument is treated as the name
of a system property. System properties are accessible through
the getProperty(java.lang.String)
method. The string value of this property is then interpreted
as a long
value, as per the
Long.decode
method, and a Long
object
representing this value is returned.
0x
or the ASCII character #
, not followed by
a minus sign, then the rest of it is parsed as a hexadecimal integer
exactly as for the method valueOf(java.lang.String, int)
with radix 16.
0
followed by another character, it is parsed as
an octal integer exactly as by the method valueOf(java.lang.String, int)
with radix 8.
valueOf(java.lang.String, int)
with radix 10.
Note that, in every case, neither L
('\u004C'
) nor l
('\u006C'
) is permitted to appear at the end
of the property value as a type indicator, as would be
permitted in Java programming language source code.
The second argument is the default value. The default value is
returned if there is no property of the specified name, if the
property does not have the correct numeric format, or if the
specified name is empty or null
.
nm | property name. |
---|---|
val | default value. |
Long
value of the property.Determines the long
value of the system property
with the specified name.
The first argument is treated as the name of a system property.
System properties are accessible through the getProperty(java.lang.String)
method. The
string value of this property is then interpreted as a
long
value and a Long
object
representing this value is returned. Details of possible
numeric formats can be found with the definition of
getProperty
.
If there is no property with the specified name, if the
specified name is empty or null
, or if the
property does not have the correct numeric format, then
null
is returned.
In other words, this method returns a Long
object equal to
the value of:
getLong(nm, null)
nm | property name. |
---|
Long
value of the property.Returns a hash code for this Long
. The result is
the exclusive OR of the two halves of the primitive
long
value held by this Long
object. That is, the hashcode is the value of the expression:
(int)(this.longValue()^(this.longValue()>>>32))
Returns a long
value with at most a single one-bit, in the
position of the highest-order ("leftmost") one-bit in the specified
long
value. Returns zero if the specified value has no
one-bits in its two's complement binary representation, that is, if it
is equal to zero.
long
value with a single one-bit, in the position
of the highest-order one-bit in the specified value, or zero if
the specified value is itself equal to zero.Returns the value of this Long
as an
int
.
int
.
Returns the value of this Long
as a
long
value.
long
.
Returns a long
value with at most a single one-bit, in the
position of the lowest-order ("rightmost") one-bit in the specified
long
value. Returns zero if the specified value has no
one-bits in its two's complement binary representation, that is, if it
is equal to zero.
long
value with a single one-bit, in the position
of the lowest-order one-bit in the specified value, or zero if
the specified value is itself equal to zero.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. Returns 64 if the
specified value has no one-bits in its two's complement representation,
in other words if it is equal to zero.
Note that this method is closely related to the logarithm base 2.
For all positive long
values x:
63 - numberOfLeadingZeros(x)
64 - numberOfLeadingZeros(x - 1)
long
value, or 64 if the value
is equal to zero.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. Returns 64 if the specified value has no
one-bits in its two's complement representation, in other words if it is
equal to zero.
long
value, or 64 if the value is equal
to zero.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 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:
null
or is a string of
length zero.
radix
is either smaller than MIN_RADIX
or larger than MAX_RADIX
.
'-'
('\u002d'
) provided that the
string is longer than length 1.
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
s | the String containing the
long representation to be parsed. |
---|---|
radix | the radix to be used while parsing s . |
long
represented by the string argument in
the specified radix.NumberFormatException | if the string does not contain a
parsable long .
|
---|
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)
method.
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.
s | a String containing the long
representation to be parsed |
---|
long
represented by the argument in
decimal.NumberFormatException | if the string does not contain a
parsable long .
|
---|
Returns the value obtained by reversing the order of the bits in the
two's complement binary representation of the specified long
value.
long
value.Returns the value obtained by reversing the order of the bytes in the
two's complement representation of the specified long
value.
long
value.Returns the value obtained by rotating the two's complement binary
representation of the specified long
value left by the
specified number of bits. (Bits shifted out of the left hand, or
high-order, side reenter on the right, or low-order.)
Note that left rotation with a negative distance is equivalent to
right rotation: rotateLeft(val, -distance) == rotateRight(val,
distance)
. Note also that rotation by any multiple of 64 is a
no-op, so all but the last six bits of the rotation distance can be
ignored, even if the distance is negative: rotateLeft(val,
distance) == rotateLeft(val, distance & 0x3F)
.
long
value left by the
specified number of bits.Returns the value obtained by rotating the two's complement binary
representation of the specified long
value right by the
specified number of bits. (Bits shifted out of the right hand, or
low-order, side reenter on the left, or high-order.)
Note that right rotation with a negative distance is equivalent to
left rotation: rotateRight(val, -distance) == rotateLeft(val,
distance)
. Note also that rotation by any multiple of 64 is a
no-op, so all but the last six bits of the rotation distance can be
ignored, even if the distance is negative: rotateRight(val,
distance) == rotateRight(val, distance & 0x3F)
.
long
value right by the
specified number of bits.Returns the value of this Long
as a
short
.
short
.Returns the signum function of the specified long
value. (The
return value is -1 if the specified value is negative; 0 if the
specified value is zero; and 1 if the specified value is positive.)
long
value.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
0
s. 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.
i | a long to be converted to a string. |
---|
long
value represented by the argument in binary (base 2).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 0
s. 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 toUpperCase()
method may be called
on the result:
Long.toHexString(n).toUpperCase()
i | a long to be converted to a string. |
---|
long
value represented by the argument in hexadecimal
(base 16).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
0
s.
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'
.i | a long to be converted to a string. |
---|
long
value represented by the argument in octal (base 8).Returns a String
object representing this
Long
's value. The value is converted to signed
decimal representation and returned as a string, exactly as if
the long
value were given as an argument to the
toString(long)
method.
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)
method.
i | a long to be converted. |
---|
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 toUpperCase()
method may
be called on the result:
Long.toString(n, 16).toUpperCase()
i | a long to be converted to a string. |
---|---|
radix | the radix to use in the string representation. |
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))
s | the string to be parsed |
---|---|
radix | the radix to be used in interpreting s |
Long
object holding the value
represented by the string argument in the specified
radix.NumberFormatException | If the String does not
contain a parsable long .
|
---|
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)
, as this method is likely to yield
significantly better space and time performance by caching
frequently requested values.
l | a long value. |
---|
Long
instance representing l
.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)
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))
s | the string to be parsed. |
---|
Long
object holding the value
represented by the string argument.NumberFormatException | If the string cannot be parsed
as a long .
|
---|