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public final class

Integer

extends Number
implements Comparable<T>
java.lang.Object
   ↳ java.lang.Number
     ↳ java.lang.Integer

Class Overview

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.

See Also

Summary

Constants
int MAX_VALUE

Constant for the maximum int value, 231-1.
int MIN_VALUE

Constant for the minimum int value, -231.
int SIZE

Constant for the number of bits to represent an int in two's compliment form.
Class<Integer> TYPE The java.lang.Class that represents this class.
Public Constructors
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.
Public Methods
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.
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.
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 Integer valueOf(String string, int radix)
Parses the string argument as if it was an int value and returns the result.
static Integer valueOf(String string)
Parses the string argument as if it was an int value and returns the result.
static Integer valueOf(int i)

Returns a Integer instance for the int value passed.

[Expand]
Inherited Methods
From class java.lang.Number
From class java.lang.Object
From interface java.lang.Comparable

Constants

public static final int MAX_VALUE

Constant for the maximum int value, 231-1.

Constant Value: 2147483647 (0x7fffffff)

public static final int MIN_VALUE

Constant for the minimum int value, -231.

Constant Value: -2147483648 (0x80000000)

public static final int SIZE

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

Constant Value: 32 (0x00000020)

public static final Class<Integer> TYPE

The java.lang.Class that represents this class.

Public Constructors

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.

public Integer (String string)

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.

Public Methods

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.

public byte byteValue ()

Returns the byte value which the receiver represents

Returns
  • byte the value of the receiver.

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.

Parameters
object The instance to compare to.
Throws
NullPointerException if object is null.

public static Integer decode (String string)

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.

public double doubleValue ()

Returns the double value which the receiver represents

Returns
  • double the value of the receiver.

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.

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

public float floatValue ()

Returns the float value which the receiver represents

Returns
  • float the value of the receiver.

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.

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.

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.

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.

Returns
  • the receiver's hash
See Also

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.

public int intValue ()

Returns the int value which the receiver represents

Returns
  • int the value of the receiver.

public long longValue ()

Returns the long value which the receiver represents

Returns
  • long the value of the receiver.

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.

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.

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.

public static int parseInt (String string)

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.

public static int parseInt (String string, int radix)

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.

public static int reverse (int i)

Reverses the bytes of a int.

Parameters
i The int to reverse.
Returns
  • The reversed value.

public static int reverseBytes (int i)

Reverses the bytes of a int.

Parameters
i The int to reverse.
Returns
  • The reversed value.

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.

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.

public short shortValue ()

Returns the short value which the receiver represents

Returns
  • short the value of the receiver.

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.

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

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

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

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

public String toString ()

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

Returns
  • a printable representation for the receiver.

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

public static Integer valueOf (String string, int radix)

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.

public static Integer valueOf (String string)

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.

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.