Integer

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java.lang
Class Integer

java.lang.Object   
  java.lang.Number   
      java.lang.Integer

All Implemented Interfaces:: Serializable , Comparable <Integer >

public final class Integer
extends Number
implements Comparable <Integer >
extends Number
implements Comparable <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).

Since:: JDK1.0
See Also:: Serialized Form

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

MIN_VALUE

public static final int MIN_VALUE

A constant holding the minimum value an int can have, -2³¹.

See Also:: Constant Field Values

MAX_VALUE

public static final int MAX_VALUE

A constant holding the maximum value an int can have, 2³¹-1.

See Also:: Constant Field Values

TYPE

public static final Class   <Integer   > TYPE

The Class instance representing the primitive type int.

Since:: JDK1.1

SIZE

public static final int SIZE

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

Since:: 1.5
See Also:: Constant Field Values

Constructor Detail

Integer

public Integer(int value)

Constructs a newly allocated Integer object that represents the specified int value.

Parameters:: value - the value to be represented by the Integer object.

Integer

public Integer(String    s)
        throws NumberFormatException

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.

Parameters:: s - the String to be converted to an Integer.
Throws:: NumberFormatException - if the String does not contain a parsable integer.
See Also:: parseInt(java.lang.String, int)

Method Detail

toString

public static String    toString(int 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 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()

sample code for java.lang.String.toUpperCase()

definition code for java.lang.String.toUpperCase()

method may be called on the result:

 Integer.toString(n, 16).toUpperCase()

Parameters:: i - an integer to be converted to a string.; radix - the radix to use in the string representation.
Returns:: a string representation of the argument in the specified radix.
See Also:: Character.MAX_RADIX , Character.MIN_RADIX

toHexString

public static String    toHexString(int i)

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 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()

Parameters:: i - an integer to be converted to a string.
Returns:: the string representation of the unsigned integer value represented by the argument in hexadecimal (base 16).
Since:: JDK1.0.2

toOctalString

public static String    toOctalString(int i)

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 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 - an integer to be converted to a string.
Returns:: the string representation of the unsigned integer value represented by the argument in octal (base 8).
Since:: JDK1.0.2

toBinaryString

public static String    toBinaryString(int i)

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 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 - an integer to be converted to a string.
Returns:: the string representation of the unsigned integer value represented by the argument in binary (base 2).
Since:: JDK1.0.2

toString

public static String    toString(int i)

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)

sample code for java.lang.Integer.toString(int, int)

definition code for java.lang.Integer.toString(int, int)

method.

Parameters:: i - an integer to be converted.
Returns:: a string representation of the argument in base 10.

parseInt

public static int parseInt(String    s,
                           int radix)
                    throws NumberFormatException

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 Character.digit(char, int)

sample code for java.lang.Character.digit(char, int)

definition code for java.lang.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:

The first argument is null or is a string of length zero.
The radix is either smaller than Character.MIN_RADIX or larger than Character.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') provided that the string is longer than length 1.
The value represented by the string is not a value of type 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

Parameters:: s - the String containing the integer representation to be parsed; radix - the radix to be used while parsing s.
Returns:: the integer represented by the string argument in the specified radix.
Throws:: NumberFormatException - if the String does not contain a parsable int.

parseInt

public static int parseInt(String    s)
                    throws NumberFormatException

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)

sample code for java.lang.Integer.parseInt(java.lang.String, int)

definition code for java.lang.Integer.parseInt(java.lang.String, int)

method.

Parameters:: s - a String containing the int representation to be parsed
Returns:: the integer value represented by the argument in decimal.
Throws:: NumberFormatException - if the string does not contain a parsable integer.

valueOf

public static Integer    valueOf(String    s,
                              int radix)
                       throws NumberFormatException

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))

Parameters:: s - the string to be parsed.; radix - the radix to be used in interpreting s
Returns:: an Integer object holding the value represented by the string argument in the specified radix.
Throws:: NumberFormatException - if the String does not contain a parsable int.

valueOf

public static Integer    valueOf(String    s)
                       throws NumberFormatException

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)

sample code for java.lang.Integer.parseInt(java.lang.String)

definition code for java.lang.Integer.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))

Parameters:: s - the string to be parsed.
Returns:: an Integer object holding the value represented by the string argument.
Throws:: NumberFormatException - if the string cannot be parsed as an integer.

valueOf

public static Integer    valueOf(int i)

Returns a 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)

sample code for java.lang.Integer.Integer(int)

definition code for java.lang.Integer.Integer(int)

, as this method is likely to yield significantly better space and time performance by caching frequently requested values.

Parameters:: i - an int value.
Returns:: a Integer instance representing i.
Since:: 1.5

byteValue

public byte byteValue()

Returns the value of this Integer as a byte.

Overrides:: byteValue in class Number

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

shortValue

public short shortValue()

Returns the value of this Integer as a short.

Overrides:: shortValue in class Number

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

intValue

public int intValue()

Returns the value of this Integer as an int.

Specified by:: intValue in class Number

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

longValue

public long longValue()

Returns the value of this Integer as a long.

Specified by:: longValue in class Number

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

floatValue

public float floatValue()

Returns the value of this Integer as a float.

Specified by:: floatValue in class Number

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

doubleValue

public double doubleValue()

Returns the value of this Integer as a double.

Specified by:: doubleValue in class Number

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

toString

public String    toString()

Returns a <

java.lang Class Integer

MIN_VALUE

MAX_VALUE

TYPE

SIZE

Integer

Integer

toString

toHexString

toOctalString

toBinaryString

toString

parseInt

parseInt

valueOf

valueOf

valueOf

byteValue

shortValue

intValue

longValue

floatValue

doubleValue

toString

java.lang
Class Integer