This class provides an immutable object
wrapper around the int
primitive data type. This class also contains useful minimum and
maximum constants and useful
conversion methods.
parseInt( ) and
valueOf( ) convert a string to an
int or to an Integer,
respectively. Each can take a radix argument to specify the base the
value is represented in. decode(
) also converts a
String to an Integer. It
assumes a hexadecimal number if the string
begins with "0X" or
"0x", or an octal number if the
string begins with "0". Otherwise,
a decimal number is assumed. toString(
) converts
in the other direction, and the static version
takes a radix argument. toBinaryString(
)
,
toOctalString( ), and toHexString(
) convert an int to a string using base
2, base 8, and base 16. These methods treat the integer as an
unsigned value. Other routines return the value of an
Integer as various primitive types, and, finally,
the getInteger( ) methods return the integer value of a
named property from the system property list, or the specified
default value.
Java 5.0 adds a number of static methods
that operate on the bits of an int value.
rotateLeft( ) and rotateRight( )
shift the bits the specified distance in the specified direction,
with bits shifted off one end being shifted in on the other end.
signum( ) returns
the sign of the integer as -1, 0, or 1. highestOneBit(
)
, numberOfTrailingZeros(
), bitCount( ) and related methods can
be useful if you use an int value as a set of bits
and want to iterate through the ones bits in the set.
Figure 10-35. java.lang.Integer
public final class
Integer extends Number implements Comparable<Integer> {
// Public Constructors
public
Integer (int
value );
public
Integer (String
s ) throws NumberFormatException;
// Public Constants
public static final int
MAX_VALUE ; =2147483647
public static final int
MIN_VALUE ; =-2147483648
5.0 public static final int
SIZE ; =32
1.1 public static final Class<Integer>
TYPE ;
// Public Class Methods
5.0 public static int
bitCount (int
i );
1.1 public static Integer
decode (String
nm ) throws NumberFormatException;
public static Integer
getInteger (String
nm );
public static Integer
getInteger (String
nm , int
val );
public static Integer
getInteger (String
nm , Integer
val );
5.0 public static int
highestOneBit (int
i );
5.0 public static int
lowestOneBit (int
i );
5.0 public static int
numberOfLeadingZeros (int
i );
5.0 public static int
numberOfTrailingZeros (int
i );
public static int
parseInt (String
s ) throws NumberFormatException;
public static int
parseInt (String
s , int
radix ) throws NumberFormatException;
5.0 public static int
reverse (int
i );
5.0 public static int
reverseBytes (int
i );
5.0 public static int
rotateLeft (int
i , int
distance );
5.0 public static int
rotateRight (int
i , int
distance );
5.0 public static int
signum (int
i );
public static String
toBinaryString (int
i );
public static String
toHexString (int
i );
public static String
toOctalString (int
i );
public static String
toString (int
i );
public static String
toString (int
i , int
radix );
5.0 public static Integer
valueOf (int
i );
public static Integer
valueOf (String
s ) throws NumberFormatException;
public static Integer
valueOf (String
s , int
radix ) throws NumberFormatException;
// Methods Implementing Comparable
1.2 public int
compareTo (Integer
anotherInteger );
// Public Methods Overriding Number
1.1 public byte
byteValue ( );
public double
doubleValue ( );
public float
floatValue ( );
public int
intValue ( );
public long
longValue ( );
1.1 public short
shortValue ( );
// Public Methods Overriding Object
public boolean
equals (Object
obj );
public int
hashCode ( );
public String
toString ( );
}