java.lang.Object | ||
↳ | java.lang.Number | |
↳ | java.lang.Integer |
The Integer
class wraps a value of the primitive type
int
in an object. An object of type Integer
contains a single field whose type is int
.
In addition, this class provides several methods for converting
an int
to a String
and a String
to an
int
, as well as other constants and methods useful when
dealing with an int
.
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).
Constants | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
int | MAX_VALUE | A constant holding the maximum value an int can
have, 231-1. |
|||||||||
int | MIN_VALUE | A constant holding the minimum value an int can
have, -231. |
|||||||||
int | SIZE | The number of bits used to represent an int value in two's
complement binary form. |
Fields | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
TYPE | The Class instance representing the primitive type
int . |
Public Constructors | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Constructs a newly allocated
Integer object that
represents the specified int value. | |||||||||||
Constructs a newly allocated
Integer object that
represents the int value indicated by the
String parameter. |
Public Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Returns the number of one-bits in the two's complement binary
representation of the specified
int value. | |||||||||||
Returns the value of this
Integer as a
byte . | |||||||||||
Compares two
Integer objects numerically. | |||||||||||
Decodes a
String into an Integer . | |||||||||||
Returns the value of this
Integer as a
double . | |||||||||||
Compares this object to the specified object.
| |||||||||||
Returns the value of this
Integer as a
float . | |||||||||||
Returns the integer value of the system property with the
specified name.
| |||||||||||
Determines the integer value of the system property with the
specified name.
| |||||||||||
Determines the integer value of the system property with the
specified name.
| |||||||||||
Returns a hash code for this
Integer . | |||||||||||
Returns an
int value with at most a single one-bit, in the
position of the highest-order ("leftmost") one-bit in the specified
int value. | |||||||||||
Returns the value of this
Integer as an
int . | |||||||||||
Returns the value of this
Integer as a
long . | |||||||||||
Returns an
int value with at most a single one-bit, in the
position of the lowest-order ("rightmost") one-bit in the specified
int value. | |||||||||||
Returns the number of zero bits preceding the highest-order
("leftmost") one-bit in the two's complement binary representation
of the specified
int value. | |||||||||||
Returns the number of zero bits following the lowest-order ("rightmost")
one-bit in the two's complement binary representation of the specified
int value. | |||||||||||
Parses the string argument as a signed decimal integer.
| |||||||||||
Parses the string argument as a signed integer in the radix
specified by the second argument.
| |||||||||||
Returns the value obtained by reversing the order of the bits in the
two's complement binary representation of the specified
int
value. | |||||||||||
Returns the value obtained by reversing the order of the bytes in the
two's complement representation of the specified
int value. | |||||||||||
Returns the value obtained by rotating the two's complement binary
representation of the specified
int value left by the
specified number of bits. | |||||||||||
Returns the value obtained by rotating the two's complement binary
representation of the specified
int value right by the
specified number of bits. | |||||||||||
Returns the value of this
Integer as a
short . | |||||||||||
Returns the signum function of the specified
int value. | |||||||||||
Returns a string representation of the integer argument as an
unsigned integer in base 2.
| |||||||||||
Returns a string representation of the integer argument as an
unsigned integer in base 16.
| |||||||||||
Returns a string representation of the integer argument as an
unsigned integer in base 8.
| |||||||||||
Returns a
String object representing this
Integer 's value. | |||||||||||
Returns a
String object representing the
specified integer. | |||||||||||
Returns a string representation of the first argument in the
radix specified by the second argument.
| |||||||||||
Returns an
Integer object holding the value
extracted from the specified String when parsed
with the radix given by the second argument. | |||||||||||
Returns an
Integer instance representing the specified
int value. | |||||||||||
Returns an
Integer object holding the
value of the specified String . |
[Expand]
Inherited Methods | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
From class
java.lang.Number
| |||||||||||
From class
java.lang.Object
| |||||||||||
From interface
java.lang.Comparable
|
A constant holding the maximum value an int
can
have, 231-1.
A constant holding the minimum value an int
can
have, -231.
The number of bits used to represent an int
value in two's
complement binary form.
Constructs a newly allocated Integer
object that
represents the specified int
value.
value | the value to be represented by the
Integer object.
|
---|
Constructs a newly allocated Integer
object that
represents the int
value indicated by the
String
parameter. The string is converted to an
int
value in exactly the manner used by the
parseInt
method for radix 10.
s | the String to be converted to an
Integer . |
---|
NumberFormatException | if the String does not
contain a parsable integer. |
---|
Returns the number of one-bits in the two's complement binary
representation of the specified int
value. This function is
sometimes referred to as the population count.
int
value.Returns the value of this Integer
as a
byte
.
byte
.Compares two Integer
objects numerically.
anotherInteger | the Integer to be compared. |
---|
0
if this Integer
is
equal to the argument Integer
; a value less than
0
if this Integer
is numerically less
than the argument Integer
; and a value greater
than 0
if this Integer
is numerically
greater than the argument Integer
(signed
comparison).Decodes a String
into an Integer
.
Accepts decimal, hexadecimal, and octal numbers given
by the following grammar:
DecimalNumeral, HexDigits, and OctalDigits are defined in §3.10.1 of the Java Language Specification.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0x
HexDigits- Signopt
0X
HexDigits- Signopt
#
HexDigits- Signopt
0
OctalDigits
- Sign:
-
The sequence of characters following an (optional) negative
sign and/or radix specifier ("0x
", "0X
",
"#
", or leading zero) is parsed as by the Integer.parseInt
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. |
---|
Integer
object holding the int
value represented by nm
NumberFormatException | if the String does not
contain a parsable integer. |
---|
Returns the value of this Integer
as a
double
.
double
.
Compares this object to the specified object. The result is
true
if and only if the argument is not
null
and is an Integer
object that
contains the same int
value as this object.
obj | the object to compare with. |
---|
true
if the objects are the same;
false
otherwise.
Returns the value of this Integer
as a
float
.
float
.
Returns the integer 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 an
integer value, as per the Integer.decode
method,
and an Integer
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 by 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.
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. |
Integer
value of the property.Determines the integer 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 an integer
value and an Integer
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 an Integer
object equal to the value of:
getInteger(nm, null)
nm | property name. |
---|
Integer
value of the property.Determines the integer 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 an integer
value and an Integer
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. An Integer
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 an Integer
object
equal to the value of:
getInteger(nm, new Integer(val))
but in practice it may be implemented in a manner such as:
to avoid the unnecessary allocation of anInteger result = getInteger(nm, null); return (result == null) ? new Integer(val) : result;
Integer
object when the default value is not needed.nm | property name. |
---|---|
val | default value. |
Integer
value of the property.Returns a hash code for this Integer
.
int
value represented by this
Integer
object.
Returns an int
value with at most a single one-bit, in the
position of the highest-order ("leftmost") one-bit in the specified
int
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.
int
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.Returns the value of this Integer
as an
int
.
int
.
Returns the value of this Integer
as a
long
.
long
.
Returns an int
value with at most a single one-bit, in the
position of the lowest-order ("rightmost") one-bit in the specified
int
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.
int
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.Returns the number of zero bits preceding the highest-order
("leftmost") one-bit in the two's complement binary representation
of the specified int
value. Returns 32 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 int
values x:
31 - numberOfLeadingZeros(x)
32 - numberOfLeadingZeros(x - 1)
int
value, or 32 if the value
is equal to zero.Returns the number of zero bits following the lowest-order ("rightmost")
one-bit in the two's complement binary representation of the specified
int
value. Returns 32 if the specified value has no
one-bits in its two's complement representation, in other words if it is
equal to zero.
int
value, or 32 if the value is equal
to zero.Parses the string argument as a signed decimal integer. 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. The
resulting integer value is returned, exactly as if the argument
and the radix 10 were given as arguments to the parseInt(java.lang.String, int)
method.
s | a String containing the int
representation to be parsed |
---|
NumberFormatException | if the string does not contain a parsable integer. |
---|
Parses the string argument as a signed integer 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. The resulting integer value is
returned.
An exception of type NumberFormatException
is
thrown if any of the following situations occurs:
null
or is a string of
length zero.
MIN_RADIX
or
larger than MAX_RADIX
.
'-'
('\u002D'
) provided that the
string is longer than length 1.
int
.
Examples:
parseInt("0", 10) returns 0 parseInt("473", 10) returns 473 parseInt("-0", 10) returns 0 parseInt("-FF", 16) returns -255 parseInt("1100110", 2) returns 102 parseInt("2147483647", 10) returns 2147483647 parseInt("-2147483648", 10) returns -2147483648 parseInt("2147483648", 10) throws a NumberFormatException parseInt("99", 8) throws a NumberFormatException parseInt("Kona", 10) throws a NumberFormatException parseInt("Kona", 27) returns 411787
s | the String containing the integer
representation to be parsed |
---|---|
radix | the radix to be used while parsing s . |
NumberFormatException | if the String
does not contain a parsable int .
|
---|
Returns the value obtained by reversing the order of the bits in the
two's complement binary representation of the specified int
value.
int
value.Returns the value obtained by reversing the order of the bytes in the
two's complement representation of the specified int
value.
int
value.Returns the value obtained by rotating the two's complement binary
representation of the specified int
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 32 is a
no-op, so all but the last five bits of the rotation distance can be
ignored, even if the distance is negative: rotateLeft(val,
distance) == rotateLeft(val, distance & 0x1F)
.
int
value left by the
specified number of bits.Returns the value obtained by rotating the two's complement binary
representation of the specified int
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 32 is a
no-op, so all but the last five bits of the rotation distance can be
ignored, even if the distance is negative: rotateRight(val,
distance) == rotateRight(val, distance & 0x1F)
.
int
value right by the
specified number of bits.Returns the value of this Integer
as a
short
.
short
.Returns the signum function of the specified int
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.)
int
value.Returns a string representation of the integer argument as an unsigned integer in base 2.
The unsigned integer value is the argument plus 232
if the argument is negative; otherwise it is equal to the
argument. This value is converted to a string of ASCII digits
in binary (base 2) with no extra leading 0
s.
If the unsigned magnitude is zero, it is represented by a
single zero character '0'
('\u0030'
); otherwise, the first character of
the representation of the unsigned magnitude will not be the
zero character. The characters '0'
('\u0030'
) and '1'
('\u0031'
) are used as binary digits.
i | an integer to be converted to a string. |
---|
Returns a string representation of the integer argument as an unsigned integer in base 16.
The unsigned integer value is the argument plus 232
if the argument is negative; otherwise, it is equal to the
argument. This value is converted to a string of ASCII digits
in hexadecimal (base 16) with no extra leading
0
s. If the unsigned magnitude is zero, it is
represented by a single zero character '0'
('\u0030'
); otherwise, the first character of
the representation of the unsigned magnitude will not be the
zero character. The following characters are used as
hexadecimal digits:
0123456789abcdef
These are the characters '\u0030'
through
'\u0039'
and '\u0061'
through
'\u0066'
. If uppercase letters are
desired, the toUpperCase()
method may
be called on the result:
Integer.toHexString(n).toUpperCase()
i | an integer to be converted to a string. |
---|
Returns a string representation of the integer argument as an unsigned integer in base 8.
The unsigned integer value is the argument plus 232
if the argument is negative; otherwise, it is equal to the
argument. This value is converted to a string of ASCII digits
in octal (base 8) with no extra leading 0
s.
If the unsigned magnitude is zero, it is represented by a
single zero character '0'
('\u0030'
); otherwise, the first character of
the representation of the unsigned magnitude will not be the
zero character. The following characters are used as octal
digits:
01234567
These are the characters '\u0030'
through
'\u0037'
.i | an integer to be converted to a string. |
---|
Returns a String
object representing this
Integer
's value. The value is converted to signed
decimal representation and returned as a string, exactly as if
the integer value were given as an argument to the toString(int)
method.
Returns a String
object representing the
specified integer. The argument is converted to signed decimal
representation and returned as a string, exactly as if the
argument and radix 10 were given as arguments to the toString(int, int)
method.
i | an integer to be converted. |
---|
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 character '-'
('\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:
Integer.toString(n, 16).toUpperCase()
i | an integer to be converted to a string. |
---|---|
radix | the radix to use in the string representation. |
Returns an Integer
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 integer in the radix
specified by the second argument, exactly as if the arguments
were given to the parseInt(java.lang.String, int)
method. The result is an Integer
object that
represents the integer value specified by the string.
In other words, this method returns an Integer
object equal to the value of:
new Integer(Integer.parseInt(s, radix))
s | the string to be parsed. |
---|---|
radix | the radix to be used in interpreting s |
Integer
object holding the value
represented by the string argument in the specified
radix.NumberFormatException | if the String
does not contain a parsable int .
|
---|
Returns an Integer
instance representing the specified
int
value. If a new Integer
instance is not
required, this method should generally be used in preference to
the constructor Integer(int)
, as this method is likely
to yield significantly better space and time performance by
caching frequently requested values.
i | an int value. |
---|
Integer
instance representing i
.Returns an Integer
object holding the
value of the specified String
. The argument is
interpreted as representing a signed decimal integer, exactly
as if the argument were given to the parseInt(java.lang.String)
method. The result is an
Integer
object that represents the integer value
specified by the string.
In other words, this method returns an Integer
object equal to the value of:
new Integer(Integer.parseInt(s))
s | the string to be parsed. |
---|
Integer
object holding the value
represented by the string argument.NumberFormatException | if the string cannot be parsed as an integer. |
---|