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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 value in two's complement binary form.

long MAX_VALUE

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

long MIN_VALUE

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

int SIZE

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

Fields

public static final Class<Long> TYPE

The Class instance representing the primitive type long.

Public constructors

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.

Public methods

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, Long val)

Returns the long value of the system property with the specified name.

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.

int hashCode()

Returns a hash code for this Long.

static int hashCode(long value)

Returns a hash code for a long value; compatible with Long.hashCode().

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 long max(long a, long b)

Returns the greater of two long values as if by calling Math.max.

static long min(long a, long b)

Returns the smaller of two long values as if by calling Math.min.

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 long sum(long a, long b)

Adds two long values together as per the + operator.

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.

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 String object representing this Long's value.

static String toString(long i)

Returns a String object representing the specified long.

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.

static Long valueOf(long l)

Returns a Long instance representing the specified long value.

Inherited methods

From class java.lang.Number
From class java.lang.Object
From interface java.lang.Comparable

Constants

BYTES

Added in API level 24
int BYTES

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

Constant Value: 8 (0x00000008)

MAX_VALUE

Added in API level 1
long MAX_VALUE

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

Constant Value: 9223372036854775807 (0x7fffffffffffffff)

MIN_VALUE

Added in API level 1
long MIN_VALUE

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

Constant Value: -9223372036854775808 (0x8000000000000000)

SIZE

Added in API level 1
int SIZE

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

Constant Value: 64 (0x00000040)

Fields

TYPE

Added in API level 1
Class<Long> TYPE

The Class instance representing the primitive type long.

Public constructors

Long

Added in API level 1
Long (long value)

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

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

Long

Added in API level 1
Long (String s)

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.

See also:

Public methods

bitCount

Added in API level 1
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
Returns
int the number of one-bits in the two's complement binary representation of the specified long value.

byteValue

Added in API level 1
byte byteValue ()

Returns the value of this Long as a byte.

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

compare

Added in API level 19
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

Added in API level 1
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).

decode

Added in API level 1
Long decode (String nm)

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

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

Sign:
-
+
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.

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:

doubleValue

Added in API level 1
double doubleValue ()

Returns the value of this Long as a double.

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

equals

Added in API level 1
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.

floatValue

Added in API level 1
float floatValue ()

Returns the value of this Long as a float.

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

getLong

Added in API level 1
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 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.

  • 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 method valueOf(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 method valueOf(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.

See also:

getLong

Added in API level 1
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 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)

Parameters
nm String: property name.
Returns
Long the Long value of the property.

See also:

getLong

Added in API level 1
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 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:
 Long result = getLong(nm, null);
 return (result == null) ? new Long(val) : result;
 
to avoid the unnecessary allocation of a 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.

See also:

hashCode

Added in API level 1
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

Added in API level 24
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

Added in API level 1
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
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

Added in API level 1
int intValue ()

Returns the value of this Long as an int.

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

longValue

Added in API level 1
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

Added in API level 1
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
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

Added in API level 24
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

Added in API level 24
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

Added in API level 1
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
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

Added in API level 1
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
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

Added in API level 1
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.

parseLong

Added in API level 1
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 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:

  • The first argument is null or is a string of length zero.
  • The radix is either smaller than MIN_RADIX or larger than 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.

reverse

Added in API level 1
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
Returns
long the value obtained by reversing order of the bits in the specified long value.

reverseBytes

Added in API level 1
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
Returns
long the value obtained by reversing the bytes in the specified long value.

rotateLeft

Added in API level 1
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
distance int
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

Added in API level 1
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
distance int
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

Added in API level 1
short shortValue ()

Returns the value of this Long as a short.

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

signum

Added in API level 1
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
Returns
int the signum function of the specified long value.

sum

Added in API level 24
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

Added in API level 1
String toBinaryString (long i)

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

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

Parameters
i 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

Added in API level 1
String toHexString (long i)

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

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

0123456789abcdef
These are the characters '\u0030' through '\u0039' and '\u0061' through '\u0066'. If uppercase letters are desired, the 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

Added in API level 1
String toOctalString (long i)

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

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

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

01234567
These are the characters '\u0030' through '\u0037'.

Parameters
i 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

Added in API level 1
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 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

Added in API level 1
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

Added in API level 1
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.

valueOf

Added in API level 1
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:

new Long(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

Added in API level 1
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:

new Long(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

Added in API level 1
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. Note that unlike the corresponding method in the Integer class, this method is not required to cache values within a particular range.

Parameters
l long: a long value.
Returns
Long a Long instance representing l.
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