public final class Long extends Number implements Comparable<Long>
Long class wraps a value of the primitive type long in an object. An object
of type Long contains a single field whose type is long.
In addition, this class provides several methods for converting a long to a
String and a String to a long, as well as other constants and methods
useful when dealing with a long.
| Modifier and Type | Field and Description |
|---|---|
static long |
MAX_VALUE
A constant holding the maximum value a
long can have, 263-1. |
static long |
MIN_VALUE
A constant holding the minimum value a
long can have, -263. |
static int |
SIZE
The number of bits used to represent a
long value in two's complement binary form. |
| Constructor and Description |
|---|
Long(long value)
Constructs a newly allocated
Long object that represents the specified long
argument. |
Long(String s)
Constructs a newly allocated
Long object that represents the long value indicated
by the String parameter. |
| Modifier and Type | Method and Description |
|---|---|
byte |
byteValue()
Returns the value of this
Long as a byte. |
static int |
compare(long x,
long y)
Compares two
long values numerically. |
int |
compareTo(Long anotherLong)
Compares two
Long objects numerically. |
static Long |
decode(String nm)
Decodes a
String into a Long. |
double |
doubleValue()
Returns the value of this
Long as a double. |
boolean |
equals(Object obj)
Compares this object to the specified object.
|
float |
floatValue()
Returns the value of this
Long as a float. |
static Long |
getLong(String nm)
Determines the
long value of the system property with the specified name. |
static Long |
getLong(String nm,
long val)
Determines the
long value of the system property with the specified name. |
static Long |
getLong(String nm,
Long val)
Returns the
long value of the system property with the specified name. |
int |
hashCode()
Returns a hash code for this
Long. |
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 |
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 |
rotateLeft(long i,
int distance)
Returns the value obtained by rotating the two's complement binary representation of the
specified
long value left by the specified number of bits. |
static long |
rotateRight(long i,
int distance)
Returns the value obtained by rotating the two's complement binary representation of the
specified
long value right by the specified number of bits. |
short |
shortValue()
Returns the value of this
Long as a short. |
static int |
signum(long i)
Returns the signum function of the specified
long value. |
static String |
toBinaryString(long i)
Returns a string representation of the
long argument as an unsigned integer in
base 2. |
static String |
toHexString(long i)
Returns a string representation of the
long argument as an unsigned integer in
base 16. |
String |
toString()
Returns a
String object representing this Long's value. |
static String |
toString(long i)
Returns a
String object representing the specified long. |
static String |
toString(long i,
int radix)
Returns a string representation of the first argument in the radix specified by the second
argument.
|
static Long |
valueOf(long l)
Returns a
Long instance representing the specified long value. |
static Long |
valueOf(String s)
Returns a
Long object holding the value of the specified String. |
static Long |
valueOf(String s,
int radix)
Returns a
Long object holding the value extracted from the specified String when
parsed with the radix given by the second argument. |
public static final long MAX_VALUE
long can have, 263-1.public static final long MIN_VALUE
long can have, -263.public static final int SIZE
long value in two's complement binary form.public Long(long value)
Long object that represents the specified long
argument.value - the value to be represented by the Long object.public Long(String s) throws NumberFormatException
Long object that represents the long value indicated
by the String parameter. The string is converted to a long value in exactly the
manner used by the parseLong method for radix 10.s - the String to be converted to a Long.NumberFormatException - if the String does not contain a parsable long.parseLong(java.lang.String, int)public byte byteValue()
Long as a byte.public static int compare(long x,
long y)
long values numerically. The value returned is identical to what would be
returned by:
Long.valueOf(x).compareTo(Long.valueOf(y))
x - the first long to comparey - the second long to compare0 if x == y; a value less than 0 if x < y; and
a value greater than 0 if x > ypublic int compareTo(Long anotherLong)
Long objects numerically.compareTo in interface Comparable<Long>anotherLong - the Long to be compared.0 if this Long is equal to the argument Long; a value
less than 0 if this Long is numerically less than the argument
Long; and a value greater than 0 if this Long is numerically
greater than the argument Long (signed comparison).public static Long decode(String nm) throws NumberFormatException
String into a Long. Accepts decimal, hexadecimal, and octal numbers
given by the following grammar:
DecimalNumeral, HexDigits, and OctalDigits are as defined in section 3.10.1 of The Java™ Language Specification, except that underscores are not accepted between digits.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
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.
nm - the String to decode.Long object holding the long value represented by nmNumberFormatException - if the String does not contain a parsable long.parseLong(String, int)public double doubleValue()
Long as a double.doubleValue in class Numberdouble.public boolean equals(@Nullable Object obj)
true if and only if the
argument is not null and is a Long object that contains the same long
value as this object.equals in class Objectobj - the object to compare with.true if the objects are the same; false otherwise.Object.hashCode(),
HashMappublic float floatValue()
Long as a float.floatValue in class Numberfloat.@Nullable public static Long getLong(String nm)
long value of the system property with the specified name.
The first argument is treated as the name of a system property. System properties are accessible
through the System.getProperty(java.lang.String) method. The string value of
this property is then interpreted as a long value and a Long object representing
this value is returned. Details of possible numeric formats can be found with the definition of
getProperty.
If there is no property with the specified name, if the specified name is empty or null,
or if the property does not have the correct numeric format, then null is returned.
In other words, this method returns a Long object equal to the value of:
getLong(nm, null) nm - property name.Long value of the property.System.getProperty(java.lang.String),
System.getProperty(java.lang.String, java.lang.String)public static Long getLong(String nm, long val)
long value of the system property with the specified name.
The first argument is treated as the name of a system property. System properties are accessible
through the System.getProperty(java.lang.String) method. The string value of
this property is then interpreted as a long value and a Long object representing
this value is returned. Details of possible numeric formats can be found with the definition of
getProperty.
The second argument is the default value. A Long object that represents the value of the
second argument is returned if there is no property of the specified name, if the property does
not have the correct numeric format, or if the specified name is empty or null.
In other words, this method returns a Long object equal to the value of:
getLong(nm, new Long(val))
but in practice it may be implemented in a manner such as:
to avoid the unnecessary allocation of aLong result = getLong(nm, null); return (result == null) ? new Long(val) : result;
Long object when the default value is not
needed.nm - property name.val - default value.Long value of the property.System.getProperty(java.lang.String),
System.getProperty(java.lang.String, java.lang.String)public static Long getLong(String nm, Long val)
long value of the system property with the specified name. The first argument
is treated as the name of a system property. System properties are accessible through the
System.getProperty(java.lang.String) method. The string value of this property
is then interpreted as a long value, as per the Long.decode method, and a
Long object representing this value is returned.
0x or the ASCII character
#, not followed by a minus sign, then the rest of it is parsed as a hexadecimal integer
exactly as for the method valueOf(java.lang.String, int) with radix 16.
0 followed by another
character, it is parsed as an octal integer exactly as by the method
valueOf(java.lang.String, int) with radix 8.
valueOf(java.lang.String, int) with radix 10.
Note that, in every case, neither L ('\u004C') nor l (
'\u006C') is permitted to appear at the end of the property value as a type
indicator, as would be permitted in Java programming language source code.
The second argument is the default value. The default value is returned if there is no property
of the specified name, if the property does not have the correct numeric format, or if the
specified name is empty or null.
nm - property name.val - default value.Long value of the property.System.getProperty(java.lang.String),
System.getProperty(java.lang.String, java.lang.String),
decode(java.lang.String)public int hashCode()
Long. The result is the exclusive OR of the two halves of
the primitive long value held by this Long object. That is, the hashcode is the
value of the expression:
(int)(this.longValue()^(this.longValue()>>>32)) hashCode in class ObjectObject.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public int intValue()
Long as an int.public long longValue()
Long as a long value.public static long parseLong(@Nullable String s) throws NumberFormatException
long. The characters in the string must
all be decimal digits, except that the first character may be an ASCII minus sign '-'
(\u002D') to indicate a negative value or an ASCII plus sign '+'
('\u002B') to indicate a positive value. The resulting long value is
returned, exactly as if the argument and the radix 10 were given as arguments to the
parseLong(java.lang.String, int) method.
Note that neither the character L ('\u004C') nor l (
'\u006C') is permitted to appear at the end of the string as a type indicator,
as would be permitted in Java programming language source code.
s - a String containing the long representation to be parsedlong represented by the argument in decimal.NumberFormatException - if the string does not contain a parsable long.public static long parseLong(@Nullable String s, int radix) throws NumberFormatException
long in the radix specified by the second
argument. The characters in the string must all be digits of the specified radix (as determined
by whether Character.digit(char, int) returns a nonnegative value), except that
the first character may be an ASCII minus sign '-' ( '\u002D') to
indicate a negative value or an ASCII plus sign '+' ( '\u002B') to
indicate a positive value. The resulting long value is returned.
Note that neither the character L ('\u004C') nor l (
'\u006C') is permitted to appear at the end of the string as a type indicator,
as would be permitted in Java programming language source code - except that either L or
l may appear as a digit for a radix greater than 22.
An exception of type NumberFormatException is thrown if any of the following situations
occurs:
null or is a string of length zero.
radix is either smaller than Character.MIN_RADIX or larger than
Character.MAX_RADIX.
'-' ('\u002d') or plus sign '+'
('\u002B') provided that the string is longer than length 1.
long.
Examples:
parseLong("0", 10) returns 0L
parseLong("473", 10) returns 473L
parseLong("+42", 10) returns 42L
parseLong("-0", 10) returns 0L
parseLong("-FF", 16) returns -255L
parseLong("1100110", 2) returns 102L
parseLong("99", 8) throws a NumberFormatException
parseLong("Hazelnut", 10) throws a NumberFormatException
parseLong("Hazelnut", 36) returns 1356099454469L
s - the String containing the long representation to be parsed.radix - the radix to be used while parsing s.long represented by the string argument in the specified radix.NumberFormatException - if the string does not contain a parsable long.public static long rotateLeft(long i,
int distance)
long value left by the specified number of bits. (Bits shifted out of the left
hand, or high-order, side reenter on the right, or low-order.)
Note that left rotation with a negative distance is equivalent to right rotation:
rotateLeft(val, -distance) == rotateRight(val,
distance). Note also that rotation by any multiple of 64 is a no-op, so all but the last six
bits of the rotation distance can be ignored, even if the distance is negative:
rotateLeft(val,
distance) == rotateLeft(val, distance & 0x3F).
i - the value whose bits are to be rotated leftdistance - the number of bit positions to rotate leftlong value left by the specified number of bits.public static long rotateRight(long i,
int distance)
long value right by the specified number of bits. (Bits shifted out of the
right hand, or low-order, side reenter on the left, or high-order.)
Note that right rotation with a negative distance is equivalent to left rotation:
rotateRight(val, -distance) == rotateLeft(val,
distance). Note also that rotation by any multiple of 64 is a no-op, so all but the last six
bits of the rotation distance can be ignored, even if the distance is negative:
rotateRight(val,
distance) == rotateRight(val, distance & 0x3F).
i - the value whose bits are to be rotated rightdistance - the number of bit positions to rotate rightlong value right by the specified number of bits.public short shortValue()
Long as a short.shortValue in class Numbershort.public static int signum(long i)
long value. (The return value is -1 if the
specified value is negative; 0 if the specified value is zero; and 1 if the specified value is
positive.)i - the value whose signum is to be computedlong value.public static String toBinaryString(long i)
long argument as an unsigned integer in
base 2.
The unsigned long value is the argument plus 264 if the argument is negative;
otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in
binary (base 2) with no extra leading 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.
i - a long to be converted to a string.long value represented by the argument
in binary (base 2).public static String toHexString(long i)
long argument as an unsigned integer in
base 16.
The unsigned long value is the argument plus 264 if the argument is negative;
otherwise, it is equal to the argument. This value is converted to a string of ASCII digits in
hexadecimal (base 16) with no extra leading 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 String.toUpperCase() method may be called on the result:
Long.toHexString(n).toUpperCase() i - a long to be converted to a string.long value represented by the argument
in hexadecimal (base 16).public String toString()
String object representing this Long's value. The value is converted to
signed decimal representation and returned as a string, exactly as if the long value were
given as an argument to the toString(long) method.public static String toString(long i)
String object representing the specified long. The argument is
converted to signed decimal representation and returned as a string, exactly as if the argument
and the radix 10 were given as arguments to the toString(long, int) method.i - a long to be converted.public static String toString(long i, int radix)
If the radix is smaller than Character.MIN_RADIX or larger than
Character.MAX_RADIX, then the radix 10 is used instead.
If the first argument is negative, the first element of the result is the ASCII minus sign
'-' ('\u002d'). If the first argument is not negative, no sign character
appears in the result.
The remaining characters of the result represent the magnitude of the first argument. If the
magnitude is zero, it is represented by a single zero character '0' (
'\u0030'); otherwise, the first character of the representation of the magnitude
will not be the zero character. The following ASCII characters are used as digits:
0123456789abcdefghijklmnopqrstuvwxyz
These are '\u0030' through '\u0039' and
'\u0061' through '\u007a'. If radix is N,
then the first N of these characters are used as radix-N digits in the
order shown. Thus, the digits for hexadecimal (radix 16) are 0123456789abcdef. If
uppercase letters are desired, the String.toUpperCase() method may be called on
the result:
Long.toString(n, 16).toUpperCase() i - a long to be converted to a string.radix - the radix to use in the string representation.Character.MAX_RADIX,
Character.MIN_RADIXpublic static Long valueOf(long l)
Long instance representing the specified long value. If a new
Long instance is not required, this method should generally be used in preference to the
constructor Long(long), as this method is likely to yield significantly better space and
time performance by caching frequently requested values.
Note that unlike the corresponding method in the
Integer class, this method is not required to cache values within a particular
range.l - a long value.Long instance representing l.public static Long valueOf(String s) throws NumberFormatException
Long object holding the value of the specified String. The argument is
interpreted as representing a signed decimal long, exactly as if the argument were given
to the parseLong(java.lang.String) method. The result is a Long object that
represents the integer value specified by the string.
In other words, this method returns a Long object equal to the value of:
new Long(Long.parseLong(s)) s - the string to be parsed.Long object holding the value represented by the string argument.NumberFormatException - If the string cannot be parsed as a long.public static Long valueOf(String s, int radix) throws NumberFormatException
Long object holding the value extracted from the specified String when
parsed with the radix given by the second argument. The first argument is interpreted as
representing a signed long in the radix specified by the second argument, exactly as if
the arguments were given to the parseLong(java.lang.String, int) method. The result is a
Long object that represents the long value specified by the string.
In other words, this method returns a Long object equal to the value of:
new Long(Long.parseLong(s, radix)) s - the string to be parsedradix - the radix to be used in interpreting sLong object holding the value represented by the string argument in the
specified radix.NumberFormatException - If the String does not contain a parsable long.