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.
 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.
 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

MAX_VALUE

public static final int MAX_VALUE
The largest value of type int. The constant value of this field is 2147483647.

MIN_VALUE

public static final int MIN_VALUE
The smallest value of type int. The constant value of this field is -2147483648.
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

byteValue

public byte byteValue()
Returns the value of this Integer as a byte.
Since:
JDK1.1

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.
Since:
JDE 4.0.0

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.

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.
Since:
JDE 4.0.0

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.

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.

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.

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.

shortValue

public short shortValue()
Returns the value of this Integer as a short.
Since:
JDK1.1

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

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

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.

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.

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

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.

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.



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