public final class Long extends Number implements Comparable<Long>
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).
Modifier and Type | Field and Description |
---|---|
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 and Description |
---|
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.
|
Modifier and Type | Method and Description |
---|---|
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 .
|
static int |
compare(long x, long y)
Compares two long values numerically.
|
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 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.
|
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 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.
|
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.
|
public static final long MIN_VALUE
long
can have, -263.
public static final long MAX_VALUE
long
can have, 263-1.
public static final Class<Long> TYPE
Class
instance representing the primitive type long
.
public static final int SIZE
long
value in two's complement binary form.
public Long(long value)
Long
object that represents the specified long
argument.
value
- the value to be represented by the Long
object.
public Long(String s) throws NumberFormatException
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
.
parseLong(java.lang.String, int)
public static String toString(long i, int radix)
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()
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.
Character.MAX_RADIX
, Character.MIN_RADIX
public static String toHexString(long i)
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 String.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).
public static String toOctalString(long i)
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).
public static String toBinaryString(long i)
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).
public static String toString(long i)
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.
public static long parseLong(String s, int radix) throws NumberFormatException
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)
returns a nonnegative value), except that the first character may be an ASCII minus sign '-'
('\u002D'
) to indicate a negative value or an ASCII plus sign '+'
('\u002B'
) to indicate a positive 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 Character.MIN_RADIX
or larger than Character.MAX_RADIX
.'-'
('\u002d'
) or plus sign '+'
('\u002B'
) provided that the string is longer than length 1.long
.Examples:
parseLong("0", 10) returns 0L parseLong("473", 10) returns 473L parseLong("+42", 10) returns 42L 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
.
public static long parseLong(String s) throws NumberFormatException
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 or an ASCII plus sign '+'
('\u002B'
) to indicate a positive 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
.
public static Long valueOf(String s, int radix) throws NumberFormatException
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
.
public static Long valueOf(String s) throws NumberFormatException
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
.
public static Long valueOf(long l)
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. Note that unlike the corresponding method in the Integer
class, this method is not required to cache values within a particular range.
l
- a long value.
Long
instance representing l
.
public static Long decode(String nm) throws NumberFormatException
String
into a Long
. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
DecimalNumeral, HexDigits, and OctalDigits are as defined in section 3.10.1 of The Java™ Language Specification, except that underscores are not accepted between digits.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0x
HexDigits- Signopt
0X
HexDigits- Signopt
#
HexDigits- Signopt
0
OctalDigits- Sign:
-
+
The sequence of characters following an optional 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
.
parseLong(String, int)
public byte byteValue()
Long
as a byte
.
public short shortValue()
Long
as a short
.
shortValue
in class Number
short
.
public int intValue()
Long
as an int
.
public long longValue()
Long
as a long
value.
public float floatValue()
Long
as a float
.
floatValue
in class Number
float
.
public double doubleValue()
Long
as a double
.
doubleValue
in class Number
double
.
public String toString()
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.
public int hashCode()
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))
hashCode
in class Object
Object.equals(java.lang.Object)
, System.identityHashCode(java.lang.Object)
public boolean equals(Object obj)
true
if and only if the argument is not null
and is a Long
object that contains the same long
value as this object.
equals
in class Object
obj
- the object to compare with.
true
if the objects are the same; false
otherwise.
Object.hashCode()
, HashMap
public static Long getLong(String nm)
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 System.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.
System.getProperty(java.lang.String)
, System.getProperty(java.lang.String, java.lang.String)
public static Long getLong(String nm, long val)
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 System.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.
System.getProperty(java.lang.String)
, System.getProperty(java.lang.String, java.lang.String)
public static Long getLong(String nm, Long val)
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 System.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.
System.getProperty(java.lang.String)
, System.getProperty(java.lang.String, java.lang.String)
, decode(java.lang.String)
public int compareTo(Long anotherLong)
Long
objects numerically.
compareTo
in interface Comparable<Long>
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).
public static int compare(long x, long y)
long
values numerically. The value returned is identical to what would be returned by:
Long.valueOf(x).compareTo(Long.valueOf(y))
x
- the first long
to compare
y
- the second long
to compare
0
if x == y
; a value less than 0
if x < y
; and a value greater than 0
if x > y
public static long highestOneBit(long i)
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.
public static long lowestOneBit(long i)
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.
public static int numberOfLeadingZeros(long i)
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.
public static int numberOfTrailingZeros(long i)
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.
public static int bitCount(long i)
long
value. This function is sometimes referred to as the population count.
long
value.
public static long rotateLeft(long i, int distance)
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.
public static long rotateRight(long i, int distance)
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.
public static long reverse(long i)
long
value.
long
value.
public static int signum(long i)
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.
public static long reverseBytes(long i)
long
value.
long
value.
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