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Copyright © 2006 Sun Microsystems, Inc. All rights reserved.

java.lang
Class Integer

java.lang.Object
  |
  +--java.lang.Integer

public final class Integer

extends Object

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.

Since:

JDK1.0

Field Summary

static int	MAX_VALUE The largest value of type int.
static int	MIN_VALUE The smallest value of type int.

Constructor Summary

Integer(int value)
Constructs a newly allocated Integer object that represents the primitive int argument.

Method Summary

byte	byteValue() Returns the value of this Integer as a byte.
boolean	equals(Object obj) Compares this object to the specified object.
int	hashCode() Returns a hashcode 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.
short	shortValue() Returns the value of this Integer as a short.
static String	toBinaryString(int i) Creates a string representation of the integer argument as an unsigned integer in base 2.
static String	toHexString(int i) Creates a string representation of the integer argument as an unsigned integer in base 16.
static String	toOctalString(int i) Creates 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 new String object representing the specified integer.
static String	toString(int i, int radix) Creates a string representation of the first argument in the radix specified by the second argument.
static Integer	valueOf(String s) Returns a new Integer object initialized to the value of the specified String.
static Integer	valueOf(String s, int radix) Returns a new Integer object initialized to the value of the specified String.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

MIN_VALUE

public static final int MIN_VALUE

The smallest value of type int. The constant value of this field is -2147483648.

MAX_VALUE

public static final int MAX_VALUE

The largest value of type int. The constant value of this field is 2147483647.

Constructor Detail

Integer

public Integer(int value)

Constructs a newly allocated Integer object that represents the primitive int argument.

Parameters:

value - the value to be represented by the Integer.

Method Detail

toString

public static String toString(int i,
                              int radix)

Creates 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 the 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.

Parameters:

i - an integer.

radix - the radix.

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)

Creates 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 'u\0039' through '\u0066'.

Parameters:

i - an integer.

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)

Creates 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 octal digits are:

 01234567
 

These are the characters '\u0030' through '\u0037'.

Parameters:

i - an integer

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)

Creates a string representation of the integer argument as an unsigned integer in base 2.

The unsigned integer value is the argument plus 2³²if 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.

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 new 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.

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) 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 integer 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.

radix - the radix to be used.

Returns:

the integer represented by the string argument in the specified radix.

Throws:

NumberFormatException - if the string does not contain a parsable integer.

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) method.

Parameters:

s - a string.

Returns:

the integer 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 a new Integer object initialized to the value of the specified String. 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 of the integer represented by string s

Returns:

a newly constructed Integer initialized to the value represented by the string argument in the specified radix.

Throws:

NumberFormatException - if the String cannot be parsed as an int.

valueOf

public static Integer valueOf(String s)
                       throws NumberFormatException

Returns a new Integer object initialized to 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))
 

Parameters:

s - the string to be parsed.

Returns:

a newly constructed Integer initialized to the value represented by the string argument.

Throws:

NumberFormatException - if the string cannot be parsed as an integer.

byteValue

public byte byteValue()

Returns the value of this Integer as a byte.

Since:

JDK1.1

shortValue

public short shortValue()

Returns the value of this Integer as a short.

Since:

JDK1.1

intValue

public int intValue()

Returns the value of this Integer as an int.

Returns:

the int value represented by this object.

longValue

public long longValue()

Returns the value of this Integer as a long.

Returns:

the int value represented by this object that is converted to type long and the result of the conversion is returned.

toString

public String toString()

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.

Overrides:

toString in class Object

Returns:

a string representation of the value of this object in base 10.

hashCode

public int hashCode()

Returns a hashcode for this Integer.

Overrides:

hashCode in class Object

Returns:

a hash code value for this object, equal to the primitive int value represented by this Integer object.

equals

public boolean equals(Object obj)

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.

Overrides:

equals in class Object

Parameters:

obj - the object to compare with.

Returns:

true if the objects are the same; false otherwise.