java.lang
Class Integer

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

All Implemented Interfaces:

Comparable

public final class Integer
extends Number
implements Comparable

Instances of class Integer represent primitive int values. Additionally, this class provides various helper functions and variables related to ints.

Since:

1.0

Field Summary

static int	MAX_VALUE The maximum value an int can represent is 2147483647 (or 231 - 1).
static int	MIN_VALUE The minimum value an int can represent is -2147483648 (or -231).
static int	SIZE The number of bits needed to represent an int.
static Class	TYPE The primitive type int is represented by this Class object.

Constructor Summary

Integer(int value)
Create an Integer object representing the value of the int argument.

Integer(String s)
Create an Integer object representing the value of the argument after conversion to an int.

Method Summary

byte	byteValue() Return the value of this Integer as a byte.
int	compareTo(Integer i) Compare two Integers numerically by comparing their int values.
int	compareTo(Object o) Behaves like compareTo(Integer) unless the Object is not an Integer.
static Integer	decode(String str) Convert the specified String into an Integer.
double	doubleValue() Return the value of this Integer as a double.
boolean	equals(Object obj) Returns true if obj is an instance of Integer and represents the same int value.
float	floatValue() Return the value of this Integer as a float.
int	hashCode() Return a hashcode representing this Object.
int	intValue() Return the value of this Integer.
long	longValue() Return the value of this Integer as a long.
static int	parseInt(String s) Converts the specified String into an int.
static int	parseInt(String str, int radix) Converts the specified String into an int using the specified radix (base).
short	shortValue() Return the value of this Integer as a short.
static String	toBinaryString(int i) Converts the int to a String assuming it is unsigned in base 2.
static String	toHexString(int i) Converts the int to a String assuming it is unsigned in base 16.
static String	toOctalString(int i) Converts the int to a String assuming it is unsigned in base 8.
String	toString() Converts the Integer value to a String and assumes a radix of 10.
static String	toString(int i) Converts the int to a String and assumes a radix of 10.
static String	toString(int num, int radix) Converts the int to a String using the specified radix (base).
static Integer	valueOf(int val) Returns an Integer object wrapping the value.
static Integer	valueOf(String s) Creates a new Integer object using the String, assuming a radix of 10.
static Integer	valueOf(String s, int radix) Creates a new Integer object using the String and specified radix (base).

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

The minimum value an int can represent is -2147483648 (or -2³¹).

See Also:

Constant Field Values

MAX_VALUE

public static final int MAX_VALUE

The maximum value an int can represent is 2147483647 (or 2³¹ - 1).

See Also:

Constant Field Values

TYPE

public static final Class TYPE

The primitive type int is represented by this Class object.

Since:

1.1

SIZE

public static final int SIZE

The number of bits needed to represent an int.

Since:

1.5

See Also:

Constant Field Values

Constructor Detail

Integer

public Integer(int value)

Create an Integer object representing the value of the int argument.

Parameters:

value - the value to use

Integer

public Integer(String s)

Create an Integer object representing the value of the argument after conversion to an int.

Parameters:

s - the string to convert

Throws:

NumberFormatException - if the String does not contain an int

See Also:

valueOf(String)

Method Detail

toString

public static String toString(int num,
                              int radix)

Converts the int to a String using the specified radix (base). If the radix exceeds Character.MIN_RADIX or Character.MAX_RADIX, 10 is used instead. If the result is negative, the leading character is '-' ('\\u002D'). The remaining characters come from Character.forDigit(digit, radix) ('0'-'9','a'-'z').

Parameters:

num - the int to convert to String

radix - the radix (base) to use in the conversion

Returns:

the String representation of the argument

toHexString

public static String toHexString(int i)

Converts the int to a String assuming it is unsigned in base 16.

Parameters:

i - the int to convert to String

Returns:

the String representation of the argument

toOctalString

public static String toOctalString(int i)

Converts the int to a String assuming it is unsigned in base 8.

Parameters:

i - the int to convert to String

Returns:

the String representation of the argument

toBinaryString

public static String toBinaryString(int i)

Converts the int to a String assuming it is unsigned in base 2.

Parameters:

i - the int to convert to String

Returns:

the String representation of the argument

toString

public static String toString(int i)

Converts the int to a String and assumes a radix of 10.

Parameters:

i - the int to convert to String

Returns:

the String representation of the argument

See Also:

toString(int, int)

parseInt

public static int parseInt(String str,
                           int radix)

Converts the specified String into an int using the specified radix (base). The string must not be null or empty. It may begin with an optional '-', which will negate the answer, provided that there are also valid digits. Each digit is parsed as if by Character.digit(d, radix), and must be in the range 0 to radix - 1. Finally, the result must be within MIN_VALUE to MAX_VALUE, inclusive. Unlike Double.parseDouble, you may not have a leading '+'.

Parameters:

str - the String to convert

radix - the radix (base) to use in the conversion

Returns:

the String argument converted to int

Throws:

NumberFormatException - if s cannot be parsed as an int

parseInt

public static int parseInt(String s)

Converts the specified String into an int. This function assumes a radix of 10.

Parameters:

s - the String to convert

Returns:

the int value of s

Throws:

NumberFormatException - if s cannot be parsed as an int

See Also:

parseInt(String, int)

valueOf

public static Integer valueOf(String s,
                              int radix)

Creates a new Integer object using the String and specified radix (base).

Parameters:

s - the String to convert

radix - the radix (base) to convert with

Returns:

the new Integer

Throws:

NumberFormatException - if s cannot be parsed as an int

See Also:

parseInt(String, int)

valueOf

public static Integer valueOf(String s)

Creates a new Integer object using the String, assuming a radix of 10.

Parameters:

s - the String to convert

Returns:

the new Integer

Throws:

NumberFormatException - if s cannot be parsed as an int

See Also:

Integer(String), parseInt(String)

valueOf

public static Integer valueOf(int val)

Returns an Integer object wrapping the value. In contrast to the Integer constructor, this method will cache some values. It is used by boxing conversion.

Parameters:

val - the value to wrap

Returns:

the Integer

byteValue

public byte byteValue()

Return the value of this Integer as a byte.

Overrides:

byteValue in class Number

Returns:

the byte value

shortValue

public short shortValue()

Return the value of this Integer as a short.

Overrides:

shortValue in class Number

Returns:

the short value

intValue

public int intValue()

Return the value of this Integer.

Specified by:

intValue in class Number

Returns:

the int value

longValue

public long longValue()

Return the value of this Integer as a long.

Specified by:

longValue in class Number

Returns:

the long value

floatValue

public float floatValue()

Return the value of this Integer as a float.

Specified by:

floatValue in class Number

Returns:

the float value

doubleValue

public double doubleValue()

Return the value of this Integer as a double.

Specified by:

doubleValue in class Number

Returns:

the double value

toString

public String toString()

Converts the Integer value to a String and assumes a radix of 10.

Overrides:

toString in class Object

Returns:

the String representation

See Also:

Object.getClass(), Object.hashCode(), Class.getName(), toHexString(int)

hashCode

public int hashCode()

Return a hashcode representing this Object. Integer's hash code is simply its value.

Overrides:

hashCode in class Object

Returns:

this Object's hash code

See Also:

Object.equals(Object), System.identityHashCode(Object)

equals

public boolean equals(Object obj)

Returns true if obj is an instance of Integer and represents the same int value.

Overrides:

equals in class Object

Parameters:

obj - the object to compare

Returns:

whether these Objects are semantically equal

See Also:

Object.hashCode()

decode

public static Integer decode(String str)

Convert the specified String into an Integer. The String may represent decimal, hexadecimal, or octal numbers.

The extended BNF grammar is as follows:

 DecodableString:
      ( [ - ] DecimalNumber )
    | ( [ - ] ( 0x | 0X
              | # ) HexDigit { HexDigit } )
    | ( [ - ] 0 { OctalDigit } )
 DecimalNumber:
        DecimalDigit except '0' { DecimalDigit }
 DecimalDigit:
        Character.digit(d, 10) has value 0 to 9
 OctalDigit:
        Character.digit(d, 8) has value 0 to 7
 DecimalDigit:
        Character.digit(d, 16) has value 0 to 15
 

Finally, the value must be in the range MIN_VALUE to MAX_VALUE, or an exception is thrown.

Parameters:

str - the String to interpret

Returns:

the value of the String as an Integer

Throws:

NumberFormatException - if s cannot be parsed as a int

NullPointerException - if s is null

Since:

1.2

compareTo

public int compareTo(Integer i)

Compare two Integers numerically by comparing their int values. The result is positive if the first is greater, negative if the second is greater, and 0 if the two are equal.

Parameters:

i - the Integer to compare

Returns:

the comparison

Since:

1.2

compareTo

public int compareTo(Object o)

Behaves like compareTo(Integer) unless the Object is not an Integer.

Specified by:

compareTo in interface Comparable

Parameters:

o - the object to compare

Returns:

the comparison

Throws:

ClassCastException - if the argument is not an Integer

Since:

1.2

See Also:

compareTo(Integer), Comparable