Long
public final class Long
extends Number
implements Comparable<Long>
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).
Summary
Constants | |
---|---|
int | BYTES The number of bytes used to represent a |
long | MAX_VALUE A constant holding the maximum value a |
long | MIN_VALUE A constant holding the minimum value a |
int | SIZE The number of bits used to represent a |
Fields | |
---|---|
public static final Class<Long> | TYPE The |
Public constructors | |
---|---|
Long(String s) This constructor is deprecated. It is rarely appropriate to use this constructor. Use | |
Long(long value) This constructor is deprecated. It is rarely appropriate to use this constructor. The static factory |
Public methods | |
---|---|
static int | bitCount(long i) Returns the number of one-bits in the two's complement binary representation of the specified |
byte | byteValue() Returns the value of this |
static int | compare(long x, long y) Compares two |
int | compareTo(Long anotherLong) Compares two |
static int | compareUnsigned(long x, long y) Compares two |
static long | compress(long i, long mask) Returns the value obtained by compressing the bits of the specified |
static Long | decode(String nm) Decodes a |
static long | divideUnsigned(long dividend, long divisor) Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value. |
double | doubleValue() Returns the value of this |
boolean | equals(Object obj) Compares this object to the specified object. |
static long | expand(long i, long mask) Returns the value obtained by expanding the bits of the specified |
float | floatValue() Returns the value of this |
static Long | getLong(String nm, Long val) Returns the |
static Long | getLong(String nm, long val) Determines the |
static Long | getLong(String nm) Determines the |
int | hashCode() Returns a hash code for this |
static int | hashCode(long value) Returns a hash code for a |
static long | highestOneBit(long i) Returns a |
int | intValue() Returns the value of this |
long | longValue() Returns the value of this |
static long | lowestOneBit(long i) Returns a |
static long | max(long a, long b) Returns the greater of two |
static long | min(long a, long b) Returns the smaller of two |
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 |
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 |
static long | parseLong(CharSequence s, int beginIndex, int endIndex, int radix) Parses the |
static long | parseLong(String s, int radix) Parses the string argument as a signed |
static long | parseLong(String s) Parses the string argument as a signed decimal |
static long | parseUnsignedLong(String s, int radix) Parses the string argument as an unsigned |
static long | parseUnsignedLong(String s) Parses the string argument as an unsigned decimal |
static long | parseUnsignedLong(CharSequence s, int beginIndex, int endIndex, int radix) Parses the |
static long | remainderUnsigned(long dividend, long divisor) Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value. |
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 |
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 |
static long | rotateLeft(long i, int distance) Returns the value obtained by rotating the two's complement binary representation of the specified |
static long | rotateRight(long i, int distance) Returns the value obtained by rotating the two's complement binary representation of the specified |
short | shortValue() Returns the value of this |
static int | signum(long i) Returns the signum function of the specified |
static long | sum(long a, long b) Adds two |
static String | toBinaryString(long i) Returns a string representation of the |
static String | toHexString(long i) Returns a string representation of the |
static String | toOctalString(long i) Returns a string representation of the |
static String | toString(long i, int radix) Returns a string representation of the first argument in the radix specified by the second argument. |
String | toString() Returns a |
static String | toString(long i) Returns a |
static String | toUnsignedString(long i) Returns a string representation of the argument as an unsigned decimal value. |
static String | toUnsignedString(long i, int radix) Returns a string representation of the first argument as an unsigned integer value in the radix specified by the second argument. |
static Long | valueOf(String s) Returns a |
static Long | valueOf(String s, int radix) Returns a |
static Long | valueOf(long l) Returns a |
Inherited methods | |
---|---|
Constants
BYTES
public static final int BYTES
The number of bytes used to represent a long
value in two's complement binary form.
Constant Value: 8 (0x00000008)
MAX_VALUE
public static final long MAX_VALUE
A constant holding the maximum value a long
can have, 263-1.
Constant Value: 9223372036854775807 (0x7fffffffffffffff)
MIN_VALUE
public static final long MIN_VALUE
A constant holding the minimum value a long
can have, -263.
Constant Value: -9223372036854775808 (0x8000000000000000)
SIZE
public static final int SIZE
The number of bits used to represent a long
value in two's complement binary form.
Constant Value: 64 (0x00000040)
Fields
TYPE
public static final Class<Long> TYPE
The Class
instance representing the primitive type long
.
Public constructors
Long
public Long (String s)
This constructor is deprecated.
It is rarely appropriate to use this constructor. Use parseLong(java.lang.String)
to convert a string to a long
primitive, or use valueOf(java.lang.String)
to convert a string to a 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.
Parameters | |
---|---|
s | String : the String to be converted to a Long . |
Throws | |
---|---|
NumberFormatException | if the String does not contain a parsable long . |
Long
public Long (long value)
This constructor is deprecated.
It is rarely appropriate to use this constructor. The static factory valueOf(long)
is generally a better choice, as it is likely to yield significantly better space and time performance.
Constructs a newly allocated Long
object that represents the specified long
argument.
Parameters | |
---|---|
value | long : the value to be represented by the Long object. |
Public methods
bitCount
public static int bitCount (long i)
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.
Parameters | |
---|---|
i | long : the value whose bits are to be counted |
Returns | |
---|---|
int | the number of one-bits in the two's complement binary representation of the specified long value. |
byteValue
public byte byteValue ()
Returns the value of this Long
as a byte
after a narrowing primitive conversion.
Returns | |
---|---|
byte | the numeric value represented by this object after conversion to type byte . |
compare
public static int compare (long x, long y)
Compares two long
values numerically. The value returned is identical to what would be returned by:
Long.valueOf(x).compareTo(Long.valueOf(y))
Parameters | |
---|---|
x | long : the first long to compare |
y | long : the second long to compare |
Returns | |
---|---|
int | the value 0 if x == y ; a value less than 0 if x < y ; and a value greater than 0 if x > y |
compareTo
public int compareTo (Long anotherLong)
Compares two Long
objects numerically.
Parameters | |
---|---|
anotherLong | Long : the Long to be compared. |
Returns | |
---|---|
int | the value 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). |
compareUnsigned
public static int compareUnsigned (long x, long y)
Compares two long
values numerically treating the values as unsigned.
Parameters | |
---|---|
x | long : the first long to compare |
y | long : the second long to compare |
Returns | |
---|---|
int | the value 0 if x == y ; a value less than 0 if x < y as unsigned values; and a value greater than 0 if x > y as unsigned values |
compress
public static long compress (long i, long mask)
Returns the value obtained by compressing the bits of the specified long
value, i
, in accordance with the specified bit mask.
For each one-bit value mb
of the mask, from least significant to most significant, the bit value of i
at the same bit location as mb
is assigned to the compressed value contiguously starting from the least significant bit location. All the upper remaining bits of the compressed value are set to zero.
API Note:
- Consider the simple case of compressing the digits of a hexadecimal value:
lang="java" : // Compressing drink to food compress(0xCAFEBABEL, 0xFF00FFF0L) == 0xCABABL
Starting from the least significant hexadecimal digit at position 0 from the right, the mask0xFF00FFF0
selects hexadecimal digits at positions 1, 2, 3, 6 and 7 of0xCAFEBABE
. The selected digits occur in the resulting compressed value contiguously from digit position 0 in the same order.The following identities all return
true
and are helpful to understand the behaviour ofcompress
:lang="java" : // Returns 1 if the bit at position n is one compress(x, 1L << n) == (x >> n & 1) // Logical shift right compress(x, -1L << n) == x >>> n // Any bits not covered by the mask are ignored compress(x, m) == compress(x & m, m) // Compressing a value by itself compress(m, m) == (m == -1 || m == 0) ? m : (1L << bitCount(m)) - 1 // Expanding then compressing with the same mask compress(expand(x, m), m) == x & compress(m, m)
The Sheep And Goats (SAG) operation (see Hacker's Delight, section 7.7) can be implemented as follows:
lang="java" : long compressLeft(long i, long mask) { // This implementation follows the description in Hacker's Delight which // is informative. A more optimal implementation is: // Long.compress(i, mask) << -Long.bitCount(mask) return Long.reverse( Long.compress(Long.reverse(i), Long.reverse(mask))); } long sag(long i, long mask) { return compressLeft(i, mask) | Long.compress(i, ~mask); } // Separate the sheep from the goats sag(0x00000000_CAFEBABEL, 0xFFFFFFFF_FF00FFF0L) == 0x00000000_CABABFEEL
Parameters | |
---|---|
i | long : the value whose bits are to be compressed |
mask | long : the bit mask |
Returns | |
---|---|
long | the compressed value |
See also:
decode
public static Long decode (String nm)
Decodes a String
into a Long
. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
DecimalNumeral, HexDigits, and OctalDigits are as defined in section {@jls 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
.
Parameters | |
---|---|
nm | String : the String to decode. |
Returns | |
---|---|
Long | a Long object holding the long value represented by nm |
Throws | |
---|---|
NumberFormatException | if the String does not contain a parsable long . |
See also:
divideUnsigned
public static long divideUnsigned (long dividend, long divisor)
Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
Note that in two's complement arithmetic, the three other basic arithmetic operations of add, subtract, and multiply are bit-wise identical if the two operands are regarded as both being signed or both being unsigned. Therefore separate addUnsigned
, etc. methods are not provided.
Parameters | |
---|---|
dividend | long : the value to be divided |
divisor | long : the value doing the dividing |
Returns | |
---|---|
long | the unsigned quotient of the first argument divided by the second argument |
See also:
doubleValue
public double doubleValue ()
Returns the value of this Long
as a double
after a widening primitive conversion.
Returns | |
---|---|
double | the numeric value represented by this object after conversion to type double . |
equals
public boolean equals (Object obj)
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.
Parameters | |
---|---|
obj | Object : the object to compare with. |
Returns | |
---|---|
boolean | true if the objects are the same; false otherwise. |
expand
public static long expand (long i, long mask)
Returns the value obtained by expanding the bits of the specified long
value, i
, in accordance with the specified bit mask.
For each one-bit value mb
of the mask, from least significant to most significant, the next contiguous bit value of i
starting at the least significant bit is assigned to the expanded value at the same bit location as mb
. All other remaining bits of the expanded value are set to zero.
API Note:
- Consider the simple case of expanding the digits of a hexadecimal value:
lang="java" : expand(0x0000CABABL, 0xFF00FFF0L) == 0xCA00BAB0L
Starting from the least significant hexadecimal digit at position 0 from the right, the mask0xFF00FFF0
selects the first five hexadecimal digits of0x0000CABAB
. The selected digits occur in the resulting expanded value in order at positions 1, 2, 3, 6, and 7.The following identities all return
true
and are helpful to understand the behaviour ofexpand
:lang="java" : // Logically shift right the bit at position 0 expand(x, 1L << n) == (x & 1) << n // Logically shift right expand(x, -1L << n) == x << n // Expanding all bits returns the mask expand(-1L, m) == m // Any bits not covered by the mask are ignored expand(x, m) == expand(x, m) & m // Compressing then expanding with the same mask expand(compress(x, m), m) == x & m
The select operation for determining the position of the one-bit with index
n
in along
value can be implemented as follows:lang="java" : long select(long i, long n) { // the one-bit in i (the mask) with index n long nthBit = Long.expand(1L << n, i); // the bit position of the one-bit with index n return Long.numberOfTrailingZeros(nthBit); } // The one-bit with index 0 is at bit position 1 select(0b10101010_10101010, 0) == 1 // The one-bit with index 3 is at bit position 7 select(0b10101010_10101010, 3) == 7
Parameters | |
---|---|
i | long : the value whose bits are to be expanded |
mask | long : the bit mask |
Returns | |
---|---|
long | the expanded value |
See also:
floatValue
public float floatValue ()
Returns the value of this Long
as a float
after a widening primitive conversion.
Returns | |
---|---|
float | the numeric value represented by this object after conversion to type float . |
getLong
public static Long getLong (String nm, Long val)
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 System.getProperty(java.lang.String)
method. The string value of this property is then interpreted as a long
value, as per the decode
method, and a Long
object representing this value is returned; in summary:
- If the property value begins with the two ASCII characters
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 methodvalueOf(java.lang.String, int)
with radix 16. - If the property value begins with the ASCII character
0
followed by another character, it is parsed as an octal integer exactly as by the methodvalueOf(java.lang.String, int)
with radix 8. - Otherwise the property value is parsed as a decimal integer exactly as by the method
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
.
Parameters | |
---|---|
nm | String : property name. |
val | Long : default value. |
Returns | |
---|---|
Long | the Long value of the property. |
Throws | |
---|---|
SecurityException | for the same reasons as System.getProperty |
getLong
public static Long getLong (String nm, long val)
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 System.getProperty(java.lang.String)
method. The string value of this property is then interpreted as a long
value using the grammar supported by decode
and a Long
object representing this value is returned.
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, Long.valueOf(val))
but in practice it may be implemented in a manner such as: to avoid the unnecessary allocation of a Long result = getLong(nm, null); return (result == null) ? Long.valueOf(val) : result;
Long
object when the default value is not needed. Parameters | |
---|---|
nm | String : property name. |
val | long : default value. |
Returns | |
---|---|
Long | the Long value of the property. |
Throws | |
---|---|
SecurityException | for the same reasons as System.getProperty |
getLong
public static Long getLong (String nm)
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 System.getProperty(java.lang.String)
method. The string value of this property is then interpreted as a long
value using the grammar supported by decode
and a Long
object representing this value is returned.
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)
Parameters | |
---|---|
nm | String : property name. |
Returns | |
---|---|
Long | the Long value of the property. |
Throws | |
---|---|
SecurityException | for the same reasons as System.getProperty |
hashCode
public int hashCode ()
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 | |
---|---|
int | a hash code value for this object. |
hashCode
public static int hashCode (long value)
Returns a hash code for a long
value; compatible with Long.hashCode()
.
Parameters | |
---|---|
value | long : the value to hash |
Returns | |
---|---|
int | a hash code value for a long value. |
highestOneBit
public 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. 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.
Parameters | |
---|---|
i | long : the value whose highest one bit is to be computed |
Returns | |
---|---|
long | a 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. |
intValue
public int intValue ()
Returns the value of this Long
as an int
after a narrowing primitive conversion.
Returns | |
---|---|
int | 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.
Returns | |
---|---|
long | the numeric value represented by this object after conversion to type long . |
lowestOneBit
public 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. 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.
Parameters | |
---|---|
i | long : the value whose lowest one bit is to be computed |
Returns | |
---|---|
long | a 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. |
max
public static long max (long a, long b)
Returns the greater of two long
values as if by calling Math.max
.
Parameters | |
---|---|
a | long : the first operand |
b | long : the second operand |
Returns | |
---|---|
long | the greater of a and b |
See also:
min
public static long min (long a, long b)
Returns the smaller of two long
values as if by calling Math.min
.
Parameters | |
---|---|
a | long : the first operand |
b | long : the second operand |
Returns | |
---|---|
long | the smaller of a and b |
See also:
numberOfLeadingZeros
public 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. 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:
- floor(log2(x)) =
63 - numberOfLeadingZeros(x)
- ceil(log2(x)) =
64 - numberOfLeadingZeros(x - 1)
Parameters | |
---|---|
i | long : the value whose number of leading zeros is to be computed |
Returns | |
---|---|
int | the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified long value, or 64 if the value is equal to zero. |
numberOfTrailingZeros
public 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. 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.
Parameters | |
---|---|
i | long : the value whose number of trailing zeros is to be computed |
Returns | |
---|---|
int | the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified long value, or 64 if the value is equal to zero. |
parseLong
public static long parseLong (CharSequence s, int beginIndex, int endIndex, int radix)
Parses the CharSequence
argument as a signed long
in the specified radix
, beginning at the specified beginIndex
and extending to endIndex - 1
.
The method does not take steps to guard against the CharSequence
being mutated while parsing.
Parameters | |
---|---|
s | CharSequence : the CharSequence containing the long representation to be parsed |
beginIndex | int : the beginning index, inclusive. |
endIndex | int : the ending index, exclusive. |
radix | int : the radix to be used while parsing s . |
Returns | |
---|---|
long | the signed long represented by the subsequence in the specified radix. |
Throws | |
---|---|
NullPointerException | if s is null. |
IndexOutOfBoundsException | if beginIndex is negative, or if beginIndex is greater than endIndex or if endIndex is greater than s.length() . |
NumberFormatException | if the CharSequence does not contain a parsable long in the specified radix , or if radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX . |
parseLong
public static long parseLong (String s, int radix)
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)
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 or equal to 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 thanCharacter.MIN_RADIX
or larger thanCharacter.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'
) or plus sign'+'
('\u002B'
) 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("+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
Parameters | |
---|---|
s | String : the String containing the long representation to be parsed. |
radix | int : the radix to be used while parsing s . |
Returns | |
---|---|
long | 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)
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 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.
Parameters | |
---|---|
s | String : a String containing the long representation to be parsed |
Returns | |
---|---|
long | the long represented by the argument in decimal. |
Throws | |
---|---|
NumberFormatException | if the string does not contain a parsable long . |
parseUnsignedLong
public static long parseUnsignedLong (String s, int radix)
Parses the string argument as an unsigned long
in the radix specified by the second argument. An unsigned integer maps the values usually associated with negative numbers to positive numbers larger than MAX_VALUE
. 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 plus sign '+'
('\u002B'
). The resulting integer value is returned.
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 thanCharacter.MAX_RADIX
. - Any character of the string is not a digit of the specified radix, except that the first character may be a plus sign
'+'
('\u002B'
) provided that the string is longer than length 1. - The value represented by the string is larger than the largest unsigned
long
, 264-1.
Parameters | |
---|---|
s | String : the String containing the unsigned integer representation to be parsed |
radix | int : the radix to be used while parsing s . |
Returns | |
---|---|
long | the unsigned long represented by the string argument in the specified radix. |
Throws | |
---|---|
NumberFormatException | if the String does not contain a parsable long . |
parseUnsignedLong
public static long parseUnsignedLong (String s)
Parses the string argument as an unsigned decimal long
. The characters in the string must all be decimal digits, except that the first character may be an ASCII plus sign '+'
('\u002B'
). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseUnsignedLong(java.lang.String, int)
method.
Parameters | |
---|---|
s | String : a String containing the unsigned long representation to be parsed |
Returns | |
---|---|
long | the unsigned long value represented by the decimal string argument |
Throws | |
---|---|
NumberFormatException | if the string does not contain a parsable unsigned integer. |
parseUnsignedLong
public static long parseUnsignedLong (CharSequence s, int beginIndex, int endIndex, int radix)
Parses the CharSequence
argument as an unsigned long
in the specified radix
, beginning at the specified beginIndex
and extending to endIndex - 1
.
The method does not take steps to guard against the CharSequence
being mutated while parsing.
Parameters | |
---|---|
s | CharSequence : the CharSequence containing the unsigned long representation to be parsed |
beginIndex | int : the beginning index, inclusive. |
endIndex | int : the ending index, exclusive. |
radix | int : the radix to be used while parsing s . |
Returns | |
---|---|
long | the unsigned long represented by the subsequence in the specified radix. |
Throws | |
---|---|
NullPointerException | if s is null. |
IndexOutOfBoundsException | if beginIndex is negative, or if beginIndex is greater than endIndex or if endIndex is greater than s.length() . |
NumberFormatException | if the CharSequence does not contain a parsable unsigned long in the specified radix , or if radix is either smaller than Character.MIN_RADIX or larger than Character.MAX_RADIX . |
remainderUnsigned
public static long remainderUnsigned (long dividend, long divisor)
Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
Parameters | |
---|---|
dividend | long : the value to be divided |
divisor | long : the value doing the dividing |
Returns | |
---|---|
long | the unsigned remainder of the first argument divided by the second argument |
See also:
reverse
public 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.
Parameters | |
---|---|
i | long : the value to be reversed |
Returns | |
---|---|
long | the value obtained by reversing order of the bits in the specified long value. |
reverseBytes
public 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.
Parameters | |
---|---|
i | long : the value whose bytes are to be reversed |
Returns | |
---|---|
long | the value obtained by reversing the bytes in the specified long value. |
rotateLeft
public 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. (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)
.
Parameters | |
---|---|
i | long : the value whose bits are to be rotated left |
distance | int : the number of bit positions to rotate left |
Returns | |
---|---|
long | the value obtained by rotating the two's complement binary representation of the specified long value left by the specified number of bits. |
rotateRight
public 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. (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)
.
Parameters | |
---|---|
i | long : the value whose bits are to be rotated right |
distance | int : the number of bit positions to rotate right |
Returns | |
---|---|
long | the value obtained by rotating the two's complement binary representation of the specified long value right by the specified number of bits. |
shortValue
public short shortValue ()
Returns the value of this Long
as a short
after a narrowing primitive conversion.
Returns | |
---|---|
short | the numeric value represented by this object after conversion to type short . |
signum
public static int signum (long i)
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.)
Parameters | |
---|---|
i | long : the value whose signum is to be computed |
Returns | |
---|---|
int | the signum function of the specified long value. |
sum
public static long sum (long a, long b)
Adds two long
values together as per the + operator.
Parameters | |
---|---|
a | long : the first operand |
b | long : the second operand |
Returns | |
---|---|
long | the sum of a and b |
See also:
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 0
s.
The value of the argument can be recovered from the returned string s
by calling 2)
.
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 | long : a long to be converted to a string. |
Returns | |
---|---|
String | the string representation of the unsigned long value represented by the argument in binary (base 2). |
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 0
s.
The value of the argument can be recovered from the returned string s
by calling 16)
.
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 | long : a long to be converted to a string. |
Returns | |
---|---|
String | the string representation of the unsigned long value represented by the argument in hexadecimal (base 16). |
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 0
s.
The value of the argument can be recovered from the returned string s
by calling 8)
.
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 | long : a long to be converted to a string. |
Returns | |
---|---|
String | the string representation of the unsigned long value represented by the argument in octal (base 8). |
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()
method may be called on the result: Long.toString(n, 16).toUpperCase()
Parameters | |
---|---|
i | long : a long to be converted to a string. |
radix | int : the radix to use in the string representation. |
Returns | |
---|---|
String | a string representation of the argument in the specified radix. |
See also:
toString
public String toString ()
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 | |
---|---|
String | a string representation of the value of this object in base 10. |
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)
method.
Parameters | |
---|---|
i | long : a long to be converted. |
Returns | |
---|---|
String | a string representation of the argument in base 10. |
toUnsignedString
public static String toUnsignedString (long i)
Returns a string representation of the argument as an unsigned decimal value. The argument is converted to unsigned decimal representation and returned as a string exactly as if the argument and radix 10 were given as arguments to the toUnsignedString(long, int)
method.
Parameters | |
---|---|
i | long : an integer to be converted to an unsigned string. |
Returns | |
---|---|
String | an unsigned string representation of the argument. |
See also:
toUnsignedString
public static String toUnsignedString (long i, int radix)
Returns a string representation of the first argument as an unsigned integer value 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.
Note that since the first argument is treated as an unsigned value, no leading sign character is printed.
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 behavior of radixes and the characters used as digits are the same as toString
.
Parameters | |
---|---|
i | long : an integer to be converted to an unsigned string. |
radix | int : the radix to use in the string representation. |
Returns | |
---|---|
String | an unsigned string representation of the argument in the specified radix. |
See also:
valueOf
public static Long valueOf (String s)
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:
Long.valueOf(Long.parseLong(s))
Parameters | |
---|---|
s | String : the string to be parsed. |
Returns | |
---|---|
Long | 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 (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. 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:
Long.valueOf(Long.parseLong(s, radix))
Parameters | |
---|---|
s | String : the string to be parsed |
radix | int : the radix to be used in interpreting s |
Returns | |
---|---|
Long | 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 (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)
, as this method is likely to yield significantly better space and time performance by caching frequently requested values. This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range.
Parameters | |
---|---|
l | long : a long value. |
Returns | |
---|---|
Long | a Long instance representing l . |