java.lang
Class Integer

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

All Implemented Interfaces:

Serializable, Comparable<Integer>

public final class Integer
extends Number
implements Comparable<Integer>

Integer is the wrapper for the primitive type int.

As with the specification, this implementation relied on code laid out in Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002) as well as The Aggregate's Magic Algorithms.

Since:

1.1

See Also:

Number, Serialized Form

Nested Class Summary

(package private) static class

Integer.valueOfCache

Field Summary

static int	MAX_VALUE Constant for the maximum int value, 231-1.
static int	MIN_VALUE Constant for the minimum int value, -231.
static int	SIZE Constant for the number of bits to represent an int in two's compliment form.
static Class<Integer>	TYPE The java.lang.Class that represents this class.

Constructor Summary

Integer(int value)
Constructs a new instance of the receiver which represents the int valued argument.

Integer(String string)
Constructs a new instance of this class given a string.

Method Summary

static int	bitCount(int i) Counts the number of 1 bits in the int value passed; this is sometimes referred to as a population count.
byte	byteValue() Returns the byte value which the receiver represents
int	compareTo(Integer object) Compares this Integer to the Integer passed.
static Integer	decode(String string) Parses the string argument as if it was an int value and returns the result.
double	doubleValue() Returns the double value which the receiver represents
boolean	equals(Object o) Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
float	floatValue() Returns the float value which the receiver represents
static Integer	getInteger(String string) Returns an Integer representing the integer value of the property named by the argument.
static Integer	getInteger(String string, int defaultValue) Returns an Integer representing the integer value of the property named by the argument.
static Integer	getInteger(String string, Integer defaultValue) Returns an Integer representing the integer value of the property named by the argument.
int	hashCode() Returns an integer hash code for the receiver.
static int	highestOneBit(int i) Determines the highest (leftmost) bit that is 1 and returns the value that is the bit mask for that bit.
int	intValue() Returns the int value which the receiver represents
long	longValue() Returns the long value which the receiver represents
static int	lowestOneBit(int i) Determines the lowest (rightmost) bit that is 1 and returns the value that is the bit mask for that bit.
static int	numberOfLeadingZeros(int i) Determines the number of leading zeros in the int passed prior to the highest one bit.
static int	numberOfTrailingZeros(int i) Determines the number of trailing zeros in the int passed after the lowest one bit.
static int	parseInt(String string) Parses the string argument as if it was an int value and returns the result.
static int	parseInt(String string, int radix) Parses the string argument as if it was an int value and returns the result.
static int	reverse(int i) Reverses the bytes of a int.
static int	reverseBytes(int i) Reverses the bytes of a int.
static int	rotateLeft(int i, int distance) Rotates the bits of i to the left by the distance bits.
static int	rotateRight(int i, int distance) Rotates the bits of i to the right by the distance bits.
short	shortValue() Returns the short value which the receiver represents
static int	signum(int i) The signum function for int values.
static String	toBinaryString(int i) Returns a string containing '0' and '1' characters which describe the binary representation of the argument.
static String	toHexString(int i) Returns a string containing characters in the range 0..9, a..f which describe the hexadecimal representation of the argument.
static String	toOctalString(int i) Returns a string containing characters in the range 0..7 which describe the octal representation of the argument.
String	toString() Returns a string containing a concise, human-readable description of the receiver.
static String	toString(int i) Returns a string containing characters in the range 0..9 which describe the decimal representation of the argument.
static String	toString(int i, int radix) Returns a string containing characters in the range 0..9, a..z (depending on the radix) which describe the representation of the argument in that radix.
static Integer	valueOf(int i) Returns a Integer instance for the int value passed.
static Integer	valueOf(String string) Parses the string argument as if it was an int value and returns the result.
static Integer	valueOf(String string, int radix) Parses the string argument as if it was an int value and returns the result.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

MAX_VALUE

public static final int MAX_VALUE

Constant for the maximum int value, 2³¹-1.

See Also:

Constant Field Values

MIN_VALUE

public static final int MIN_VALUE

Constant for the minimum int value, -2³¹.

See Also:

Constant Field Values

SIZE

public static final int SIZE

Constant for the number of bits to represent an int in two's compliment form.

Since:

1.5

See Also:

Constant Field Values

TYPE

public static final Class<Integer> TYPE

The java.lang.Class that represents this class.

Constructor Detail

Integer

public Integer(int value)

Constructs a new instance of the receiver which represents the int valued argument.

Parameters:

value - the int to store in the new instance.

Integer

public Integer(String string)
        throws NumberFormatException

Constructs a new instance of this class given a string.

Parameters:

string - a string representation of an int quantity.

Throws:

NumberFormatException - if the argument could not be parsed as an int quantity.

Method Detail

byteValue

public byte byteValue()

Returns the byte value which the receiver represents

Overrides:

byteValue in class Number

Returns:

byte the value of the receiver.

compareTo

public int compareTo(Integer object)

Compares this Integer to the Integer passed. If this instance's value is equal to the value of the instance passed, then 0 is returned. If this instance's value is less than the value of the instance passed, then a negative value is returned. If this instance's value is greater than the value of the instance passed, then a positive value is returned.

Specified by:

compareTo in interface Comparable<Integer>

Parameters:

object - The instance to compare to.

Returns:

int which should be <0 if the receiver should sort before the argument, 0 if the receiver should sort in the same position as the argument, and >0 if the receiver should sort after the argument.

Throws:

NullPointerException - if object is null.

Since:

1.2

decode

public static Integer decode(String string)
                      throws NumberFormatException

Parses the string argument as if it was an int value and returns the result. Throws NumberFormatException if the string does not represent an int quantity. The string may be a hexadecimal ("0x..."), octal ("0..."), or decimal ("...") representation of an integer

Parameters:

string - a string representation of an int quantity.

Returns:

Integer the value represented by the argument

Throws:

NumberFormatException - if the argument could not be parsed as an int quantity.

doubleValue

public double doubleValue()

Returns the double value which the receiver represents

Specified by:

doubleValue in class Number

Returns:

double the value of the receiver.

equals

public boolean equals(Object o)

Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.

In this case, the argument must also be an Integer, and the receiver and argument must represent the same int value.

Overrides:

equals in class Object

Parameters:

o - the object to compare with this object

Returns:

true if the object is the same as this object false if it is different from this object

See Also:

hashCode()

floatValue

public float floatValue()

Returns the float value which the receiver represents

Specified by:

floatValue in class Number

Returns:

float the value of the receiver.

getInteger

public static Integer getInteger(String string)

Returns an Integer representing the integer value of the property named by the argument. If the property could not be found, or its value could not be parsed as an integer, answer null.

Parameters:

string - The name of the desired integer property.

Returns:

Integer An Integer representing the value of the property.

getInteger

public static Integer getInteger(String string,
                                 int defaultValue)

Returns an Integer representing the integer value of the property named by the argument. If the property could not be found, or its value could not be parsed as an integer, answer an Integer representing the second argument.

Parameters:

string - The name of the desired integer property.

Returns:

Integer An Integer representing the value of the property.

getInteger

public static Integer getInteger(String string,
                                 Integer defaultValue)

Returns an Integer representing the integer value of the property named by the argument. If the property could not be found, or its value could not be parsed as an integer, answer the second argument.

Parameters:

string - The name of the desired integer property.

Returns:

Integer An Integer representing the value of the property.

hashCode

public int hashCode()

Returns an integer hash code for the receiver. Any two objects which answer true when passed to equals must answer the same value for this method.

Overrides:

hashCode in class Object

Returns:

the receiver's hash

See Also:

equals(java.lang.Object)

intValue

public int intValue()

Returns the int value which the receiver represents

Specified by:

intValue in class Number

Returns:

int the value of the receiver.

longValue

public long longValue()

Returns the long value which the receiver represents

Specified by:

longValue in class Number

Returns:

long the value of the receiver.

parseInt

public static int parseInt(String string)
                    throws NumberFormatException

Parses the string argument as if it was an int value and returns the result. Throws NumberFormatException if the string does not represent an int quantity.

Parameters:

string - a string representation of an int quantity.

Returns:

int the value represented by the argument

Throws:

NumberFormatException - if the argument could not be parsed as an int quantity.

parseInt

public static int parseInt(String string,
                           int radix)
                    throws NumberFormatException

Parses the string argument as if it was an int value and returns the result. Throws NumberFormatException if the string does not represent an int quantity. The second argument specifies the radix to use when parsing the value.

Parameters:

string - a string representation of an int quantity.

radix - the base to use for conversion.

Returns:

int the value represented by the argument

Throws:

NumberFormatException - if the argument could not be parsed as an int quantity.

shortValue

public short shortValue()

Returns the short value which the receiver represents

Overrides:

shortValue in class Number

Returns:

short the value of the receiver.

toBinaryString

public static String toBinaryString(int i)

Returns a string containing '0' and '1' characters which describe the binary representation of the argument.

Parameters:

i - an int to get the binary representation of

Returns:

String the binary representation of the argument

toHexString

public static String toHexString(int i)

Returns a string containing characters in the range 0..9, a..f which describe the hexadecimal representation of the argument.

Parameters:

i - an int to get the hex representation of

Returns:

String the hex representation of the argument

toOctalString

public static String toOctalString(int i)

Returns a string containing characters in the range 0..7 which describe the octal representation of the argument.

Parameters:

i - an int to get the octal representation of

Returns:

String the hex representation of the argument

toString

public String toString()

Returns a string containing a concise, human-readable description of the receiver.

Overrides:

toString in class Object

Returns:

a printable representation for the receiver.

toString

public static String toString(int i)

Returns a string containing characters in the range 0..9 which describe the decimal representation of the argument.

Parameters:

i - an int to get the representation of

Returns:

String the representation of the argument

toString

public static String toString(int i,
                              int radix)

Returns a string containing characters in the range 0..9, a..z (depending on the radix) which describe the representation of the argument in that radix.

Parameters:

i - an int to get the representation of

radix - the base to use for conversion.

Returns:

String the representation of the argument

valueOf

public static Integer valueOf(String string)
                       throws NumberFormatException

Parses the string argument as if it was an int value and returns the result. Throws NumberFormatException if the string does not represent an int quantity.

Parameters:

string - a string representation of an int quantity.

Returns:

Integer the value represented by the argument

Throws:

NumberFormatException - if the argument could not be parsed as an int quantity.

valueOf

public static Integer valueOf(String string,
                              int radix)
                       throws NumberFormatException

Parses the string argument as if it was an int value and returns the result. Throws NumberFormatException if the string does not represent an int quantity. The second argument specifies the radix to use when parsing the value.

Parameters:

string - a string representation of an int quantity.

radix - the base to use for conversion.

Returns:

Integer the value represented by the argument

Throws:

NumberFormatException - if the argument could not be parsed as an int quantity.

highestOneBit

public static int highestOneBit(int i)

Determines the highest (leftmost) bit that is 1 and returns the value that is the bit mask for that bit. This is sometimes referred to as the Most Significant 1 Bit.

Parameters:

i - The int to interrogate.

Returns:

The bit mask indicating the highest 1 bit.

Since:

1.5

lowestOneBit

public static int lowestOneBit(int i)

Determines the lowest (rightmost) bit that is 1 and returns the value that is the bit mask for that bit. This is sometimes referred to as the Least Significant 1 Bit.

Parameters:

i - The int to interrogate.

Returns:

The bit mask indicating the lowest 1 bit.

Since:

1.5

numberOfLeadingZeros

public static int numberOfLeadingZeros(int i)

Determines the number of leading zeros in the int passed prior to the highest one bit.

Parameters:

i - The int to process.

Returns:

The number of leading zeros.

Since:

1.5

numberOfTrailingZeros

public static int numberOfTrailingZeros(int i)

Determines the number of trailing zeros in the int passed after the lowest one bit.

Parameters:

i - The int to process.

Returns:

The number of trailing zeros.

Since:

1.5

bitCount

public static int bitCount(int i)

Counts the number of 1 bits in the int value passed; this is sometimes referred to as a population count.

Parameters:

i - The int value to process.

Returns:

The number of 1 bits.

Since:

1.5

rotateLeft

public static int rotateLeft(int i,
                             int distance)

Rotates the bits of i to the left by the distance bits.

Parameters:

i - The int value to rotate left.

distance - The number of bits to rotate.

Returns:

The rotated value.

Since:

1.5

rotateRight

public static int rotateRight(int i,
                              int distance)

Rotates the bits of i to the right by the distance bits.

Parameters:

i - The int value to rotate right.

distance - The number of bits to rotate.

Returns:

The rotated value.

Since:

1.5

reverseBytes

public static int reverseBytes(int i)

Reverses the bytes of a int.

Parameters:

i - The int to reverse.

Returns:

The reversed value.

Since:

1.5

reverse

public static int reverse(int i)

Reverses the bytes of a int.

Parameters:

i - The int to reverse.

Returns:

The reversed value.

Since:

1.5

signum

public static int signum(int i)

The signum function for int values. This method returns -1 for negative values, 1 for positive values and 0 for the value 0.

Parameters:

i - The int value.

Returns:

-1 if negative, 1 if positive otherwise 0.

Since:

1.5

valueOf

public static Integer valueOf(int i)

Returns a Integer instance for the int value passed. This method is preferred over the constructor, as this method may maintain a cache of instances.

Parameters:

i - The int value.

Returns:

A Integer instance.

Since:

1.5