public final class Integer extends Number implements Comparable<Integer>
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.
| Modifier and Type | Field and Description |
|---|---|
static int |
MAX_VALUE
A constant holding the maximum value an
int can have, 231-1. |
static int |
MIN_VALUE
A constant holding the minimum value an
int can have, -231. |
static int |
SIZE
The number of bits used to represent an
int value in two's complement binary form. |
| Constructor and Description |
|---|
Integer(int value)
Constructs a newly allocated
Integer object that represents the specified int
value. |
Integer(String s)
Constructs a newly allocated
Integer object that represents the int value
indicated by the String parameter. |
| Modifier and Type | Method and Description |
|---|---|
byte |
byteValue()
Returns the value of this
Integer as a byte. |
static int |
compare(int x,
int y)
Compares two
int values numerically. |
int |
compareTo(Integer anotherInteger)
Compares two
Integer objects numerically. |
static Integer |
decode(String nm)
Decodes a
String into an Integer. |
double |
doubleValue()
Returns the value of this
Integer as a double. |
boolean |
equals(Object obj)
Compares this object to the specified object.
|
float |
floatValue()
Returns the value of this
Integer as a float. |
static Integer |
getInteger(String nm)
Determines the integer value of the system property with the specified name.
|
static Integer |
getInteger(String nm,
int val)
Determines the integer value of the system property with the specified name.
|
static Integer |
getInteger(String nm,
Integer val)
Returns the integer value of the system property with the specified name.
|
int |
hashCode()
Returns a hash code for this
Integer. |
int |
intValue()
Returns the value of this
Integer as an int. |
long |
longValue()
Returns the value of this
Integer as a long. |
static int |
parseInt(String s)
Parses the string argument as a signed decimal integer.
|
static int |
parseInt(String s,
int radix)
Parses the string argument as a signed integer in the radix specified by the second argument.
|
static int |
rotateLeft(int i,
int distance)
Returns the value obtained by rotating the two's complement binary representation of the
specified
int value left by the specified number of bits. |
static int |
rotateRight(int i,
int distance)
Returns the value obtained by rotating the two's complement binary representation of the
specified
int value right by the specified number of bits. |
short |
shortValue()
Returns the value of this
Integer as a short. |
static int |
signum(int i)
Returns the signum function of the specified
int value. |
static String |
toBinaryString(int i)
Returns a string representation of the integer argument as an unsigned integer in
base 2.
|
static String |
toHexString(int i)
Returns a string representation of the integer argument as an unsigned integer in
base 16.
|
static String |
toOctalString(int i)
Returns a string representation of the integer argument as an unsigned integer in
base 8.
|
String |
toString()
Returns a
String object representing this Integer's value. |
static String |
toString(int i)
Returns a
String object representing the specified integer. |
static String |
toString(int i,
int radix)
Returns a string representation of the first argument in the radix specified by the second
argument.
|
static Integer |
valueOf(int i)
Returns an
Integer instance representing the specified int value. |
static Integer |
valueOf(String s)
Returns an
Integer object holding the value of the specified String. |
static Integer |
valueOf(String s,
int radix)
Returns an
Integer object holding the value extracted from the specified
String when parsed with the radix given by the second argument. |
public static final int MAX_VALUE
int can have, 231-1.public static final int MIN_VALUE
int can have, -231.public static final int SIZE
int value in two's complement binary form.public Integer(int value)
Integer object that represents the specified int
value.value - the value to be represented by the Integer object.public Integer(String s) throws NumberFormatException
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.parseInt(java.lang.String, int)public static int compare(int x,
int y)
int values numerically. The value returned is identical to what would be
returned by:
Integer.valueOf(x).compareTo(Integer.valueOf(y))
x - the first int to comparey - the second int to compare0 if x == y; a value less than 0 if x < y;
and a value greater than 0 if x > ypublic static Integer decode(String nm) throws NumberFormatException
String into an Integer. 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 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 nmNumberFormatException - if the String does not contain a parsable integer.parseInt(java.lang.String, int)public static Integer getInteger(String nm)
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 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.System.getProperty(java.lang.String),
System.getProperty(java.lang.String, java.lang.String)public static Integer getInteger(String nm, int val)
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 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.System.getProperty(java.lang.String),
System.getProperty(java.lang.String, java.lang.String)public static Integer getInteger(String nm, Integer val)
System.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.System.getProperty(java.lang.String),
System.getProperty(java.lang.String, java.lang.String),
decode(java.lang.String)public static int parseInt(String s) throws NumberFormatException
'-' (
'\u002D') to indicate a negative value or an ASCII plus sign '+' (
'\u002B') to indicate a positive 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 parsedNumberFormatException - if the string does not contain a parsable integer.public static int parseInt(String s, int radix) throws NumberFormatException
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 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.
Character.MIN_RADIX or larger than
Character.MAX_RADIX.
'-' ('\u002D') or plus sign
'+' ('\u002B') provided that the string is longer than length 1.
int.
Examples:
parseInt("0", 10) returns 0
parseInt("473", 10) returns 473
parseInt("+42", 10) returns 42
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 parsedradix - the radix to be used while parsing s.NumberFormatException - if the String does not contain a parsable int.public static int rotateLeft(int i,
int distance)
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.public static int rotateRight(int i,
int distance)
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.public static int signum(int i)
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.public static String toBinaryString(int i)
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 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 - an integer to be converted to a string.public static String toHexString(int i)
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 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:
Integer.toHexString(n).toUpperCase() i - an integer to be converted to a string.public static String toOctalString(int i)
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 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'.i - an integer to be converted to a string.public static String toString(int i)
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.public static String toString(int 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
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
String.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.Character.MAX_RADIX,
Character.MIN_RADIXpublic static Integer valueOf(int i)
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.
This method will always cache values in the range -128 to 127, inclusive, and may cache other
values outside of this range.i - an int value.Integer instance representing i.public static Integer valueOf(String s) throws NumberFormatException
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.public static Integer valueOf(String s, int radix) throws NumberFormatException
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 sInteger object holding the value represented by the string argument in the
specified radix.NumberFormatException - if the String does not contain a parsable int.public byte byteValue()
Integer as a byte.public int compareTo(Integer anotherInteger)
Integer objects numerically.compareTo in interface Comparable<Integer>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).public double doubleValue()
Integer as a double.doubleValue in class Numberdouble.public boolean equals(Object obj)
true if and only if the
argument is not null and is an Integer object that contains the same
int 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()
Integer as a float.floatValue in class Numberfloat.public int hashCode()
Integer.hashCode in class Objectint value
represented by this Integer object.Object.equals(java.lang.Object),
System.identityHashCode(java.lang.Object)public int intValue()
Integer as an int.public long longValue()
Integer as a long.public short shortValue()
Integer as a short.shortValue in class Numbershort.public String toString()
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.