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Java Platform 1.2
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Class java.lang.Integer

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

public final class Integer

extends Number

implements Comparable

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

See Also:

Serialized Form

Field Summary

static int	MAX_VALUE The largest value of type int.
static int	MIN_VALUE The smallest value of type int.
static Class	TYPE The Class object representing the primitive type int.

Constructor Summary

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

Integer(String s)
Constructs a newly allocated Integer object that represents the value represented by the string.

Method Summary

byte	byteValue() Returns the value of this Integer as a byte.
int	compareTo(Integer anotherInteger) Compares two Integers numerically.
int	compareTo(Object o) Compares this Integer to another Object.
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, 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.
static Integer	getInteger(String nm) Determines the integer value of the system property with the specified name.
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, int radix) Parses the string argument as a signed integer in the radix specified by the second argument.
static int	parseInt(String s) Parses the string argument as a signed decimal integer.
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. The unsigned integer value is the argument plus 232if the argument is negative; otherwise it is equal to the argument.
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.
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.
String	toString() Returns a String object representing this Integer's value.
static String	toString(int i, int radix) Creates a string representation of the first argument in the radix specified by the second argument.
static String	toString(int i) Returns a new String object representing the specified integer.
static Integer	valueOf(String s, int radix) Returns a new Integer object initialized to the value of the specified String.
static Integer	valueOf(String s) Returns a new Integer object initialized to the value of the specified String.

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 smallest value of type int.

MAX_VALUE

public static final int MAX_VALUE

The largest value of type int.

TYPE

public static final Class TYPE

The Class object representing the primitive type int.

Since:

JDK1.1

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.

Integer

public Integer(String s)
        throws NumberFormatException

Constructs a newly allocated Integer object that represents the value represented by the string. The string is converted to an int value as if by the valueOf method.

Parameters:

s - the String to be converted to an Integer.

Throws:

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

See Also:

valueOf(java.lang.String, int)

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 '-'. If the first argument is not negative, no sign character appears in the result. The following ASCII characters are used as digits:

   0123456789abcdefghijklmnopqrstuvwxyz
 

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.

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.

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.

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 radix is assumed to be 10.

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 returns a nonnegative value), except that the first character may be an ASCII minus sign '-' to indicate a negative value. The resulting integer value is returned.

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 '-' to indicate a negative value.

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. Throws an exception if the String cannot be parsed as an int.

Parameters:

s - the string to be parsed.

Returns:

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

Throws:

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

valueOf

public static Integer valueOf(String s)
                       throws NumberFormatException

Returns a new Integer object initialized to the value of the specified String. Throws an exception if the String cannot be parsed as an int. The radix is assumed to be 10.

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 does not contain a parsable integer.

byteValue

public byte byteValue()

Returns the value of this Integer as a byte.

Overrides:

byteValue in class Number

Since:

JDK1.1

shortValue

public short shortValue()

Returns the value of this Integer as a short.

Overrides:

shortValue in class Number

Since:

JDK1.1

intValue

public int intValue()

Returns the value of this Integer as an int.

Returns:

the int value represented by this object.

Overrides:

intValue in class Number

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.

Overrides:

longValue in class Number

floatValue

public float floatValue()

Returns the value of this Integer as a float.

Returns:

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

Overrides:

floatValue in class Number

doubleValue

public double doubleValue()

Returns the value of this Integer as a double.

Returns:

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

Overrides:

doubleValue in class Number

toString

public String toString()

Returns a String object representing this Integer's value.

Returns:

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

Overrides:

toString in class Object

hashCode

public int hashCode()

Returns a hashcode for this Integer.

Returns:

a hash code value for this object.

Overrides:

hashCode in class 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.

Parameters:

obj - the object to compare with.

Returns:

true if the objects are the same; false otherwise.

Overrides:

equals in class Object

getInteger

public static Integer getInteger(String nm)

Determines the integer value of the system property with the specified name.

The first argument is treated as the name of a system property. System properties are accessible through getProperty and , a method defined by the System class. 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, or if the property does not have the correct numeric format, then null is returned.

Parameters:

nm - property name.

Returns:

the Integer value of the property.

See Also:

System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)

getInteger

public static Integer getInteger(String nm,
                                 int val)

Determines the integer value of the system property with the specified name.

The first argument is treated as the name of a system property. System properties are accessible through getProperty and , a method defined by the System class. 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, or if the property does not have the correct numeric format, then an Integer object that represents the value of the second argument is returned.

Parameters:

nm - property name.

val - default value.

Returns:

the Integer value of the property.

See Also:

System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)

getInteger

public static Integer getInteger(String nm,
                                 Integer val)

Returns the integer value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through getProperty and a method defined by the System class. 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.

The second argument is the default value. If there is no property of the specified name, or if the property does not have the correct numeric format, then the second argument is returned.

Parameters:

nm - property name.

val - default value.

Returns:

the Integer value of the property.

See Also:

System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String), decode(java.lang.String)

decode

public static Integer decode(String nm)
                      throws NumberFormatException

Decodes a String into an Integer. Accepts decimal, hexadecimal, and octal numbers, in the following formats:

     [-]    
     [-] 0x     
     [-] #      
     [-] 0    
 

The constant following an (optional) negative sign and/or "radix specifier" is parsed as by the Integer.parseInt method with the specified radix (10, 8 or 16). This constant must be positive or a NumberFormatException will result. The result is made negative if first character of the specified String is the negative sign. No whitespace characters are permitted in the String.

Parameters:

nm - the String to decode.

Returns:

the Integer represented by the specified string.

Throws:

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

See Also:

parseInt(String, int)

compareTo

public int compareTo(Integer anotherInteger)

Compares two Integers numerically.

Parameters:

anotherInteger - the Integer to be compared.

Returns:

the value 0 if the argument Integer is equal to this Integer; a value less than 0 if this Integer is numerically less than the Integer argument; and a value greater than 0 if this Integer is numerically greater than the Integer argument (signed comparison).

Since:

JDK1.2

compareTo

public int compareTo(Object o)

Compares this Integer to another Object. If the Object is a Integer, this function behaves like compareTo(Integer). Otherwise, it throws a ClassCastException (as Integers are comparable only to other Integers).

Specified by:

compareTo in interface Comparable

Parameters:

o - the Object to be compared.

Returns:

the value 0 if the argument is a Integer numerically equal to this Integer; a value less than 0 if the argument is a Integer numerically greater than this Integer; and a value greater than 0 if the argument is a Integer numerically less than this Integer.

Throws:

ClassCastException - if the argument is not an Integer.

Since:

JDK1.2

See Also:

Comparable