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) == 0xCABABLStarting from the least significant hexadecimal digit at position 0 from the right, the mask0xFF00FFF0selects 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
trueand 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
0xHexDigits- Signopt
0XHexDigits- Signopt
#HexDigits- Signopt
0OctalDigits- 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) == 0xCA00BAB0LStarting from the least significant hexadecimal digit at position 0 from the right, the mask0xFF00FFF0selects 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
trueand 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 & mThe select operation for determining the position of the one-bit with index
nin alongvalue 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
0xor 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
0followed 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
nullor is a string of length zero. - The
radixis either smaller thanCharacter.MIN_RADIXor 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
nullor is a string of length zero. - The radix is either smaller than
Character.MIN_RADIXor 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
0s.
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 0s.
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
0s.
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. |