java.lang.Number
java.lang.Integer
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JavaTM 2 Platform Standard Ed. 5.0 |
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java.lang.Object
public final class 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).
| Field Summary | |
|---|---|
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. |
static Class<Integer> |
TYPE
The Class instance representing the primitive type
int. |
| Constructor Summary | |
|---|---|
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. |
|
| Method Summary | |
|---|---|
static int |
bitCount(int i)
Returns the number of one-bits in the two's complement binary representation of the specified int value. |
byte |
byteValue()
Returns the value of this Integer as a
byte. |
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. |
static int |
highestOneBit(int i)
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. |
int |
intValue()
Returns the value of this Integer as an
int. |
long |
longValue()
Returns the value of this Integer as a
long. |
static int |
lowestOneBit(int i)
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. |
static int |
numberOfLeadingZeros(int i)
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. |
static int |
numberOfTrailingZeros(int i)
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. |
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 |
reverse(int i)
Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified int value. |
static int |
reverseBytes(int i)
Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified int value. |
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 a 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. |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Field Detail |
|---|
public static final int MIN_VALUE
int can
have, -231.
public static final int MAX_VALUE
int can
have, 231-1.
public static final Class<Integer> TYPE
Class instance representing the primitive type
int.
public static final int SIZE
| Constructor Detail |
|---|
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)| Method Detail |
|---|
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:
These are0123456789abcdefghijklmnopqrstuvwxyz
'\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 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:
These are the characters0123456789abcdef
'\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:
These are the characters01234567
'\u0030' through
'\u0037'.
i - an integer to be converted to a string.
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 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 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. 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') 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 parsedradix - the radix to be used while parsing s.
NumberFormatException - if the String
does not contain a parsable int.
public static int parseInt(String s)
throws NumberFormatException
'-'
('\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.
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 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.
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(int i)
Integer(int), as this method is likely to yield
significantly better space and time performance by caching
frequently requested values.
i - an int value.
public byte byteValue()
Integer as a
byte.
byteValue in class Numberbyte.public short shortValue()
Integer as a
short.
shortValue in class Numbershort.public int intValue()
Integer as an
int.
intValue in class Numberint.public long longValue()
Integer as a
long.
longValue in class Numberlong.public float floatValue()
Integer as a
float.
floatValue in class Numberfloat.public double doubleValue()
Integer as a
double.
doubleValue in class Numberdouble.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.
toString in class Objectpublic int hashCode()
Integer.
hashCode in class Objectint value represented by this
Integer object.Object.equals(java.lang.Object),
Hashtablepublic 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(),
Hashtablepublic 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))
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 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 defined in §3.10.1 of the Java Language Specification.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0xHexDigits- Signopt
0XHexDigits- Signopt
#HexDigits- Signopt
0OctalDigits
- 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.parseInt(java.lang.String, int)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 static int highestOneBit(int i)
public static int lowestOneBit(int i)
public static int numberOfLeadingZeros(int i)
Note that this method is closely related to the logarithm base 2. For all positive int values x:
public static int numberOfTrailingZeros(int i)
public static int bitCount(int i)
public static int rotateLeft(int i,
int distance)
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).
public static int rotateRight(int i,
int distance)
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).
public static int reverse(int i)
public static int signum(int i)
public static int reverseBytes(int i)
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JavaTM 2 Platform Standard Ed. 5.0 |
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Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.