java.lang

Class Integer

Implemented Interfaces:
Comparable<T>, Serializable

public final class Integer
extends Number
implements Comparable<T>

Instances of class Integer represent primitive int values. Additionally, this class provides various helper functions and variables related to ints.
Since:
1.0
See Also:
Serialized Form

Field Summary

static int
MAX_VALUE
The maximum value an int can represent is 2147483647 (or 231 - 1).
static int
MIN_VALUE
The minimum value an int can represent is -2147483648 (or -231).
static int
SIZE
The number of bits needed to represent an int.
static Class
TYPE
The primitive type int is represented by this Class object.

Constructor Summary

Integer(int value)
Create an Integer object representing the value of the int argument.
Integer(String s)
Create an Integer object representing the value of the argument after conversion to an int.

Method Summary

static int
bitCount(int x)
Return the number of bits set in x.
byte
byteValue()
Return the value of this Integer as a byte.
int
compareTo(Integer i)
Compare two Integers numerically by comparing their int values.
static Integer
decode(String str)
Convert the specified String into an Integer.
double
doubleValue()
Return the value of this Integer as a double.
boolean
equals(Object obj)
Returns true if obj is an instance of Integer and represents the same int value.
float
floatValue()
Return the value of this Integer as a float.
static Integer
getInteger(String nm)
Get the specified system property as an Integer.
static Integer
getInteger(String nm, int val)
Get the specified system property as an Integer, or use a default int value if the property is not found or is not decodable.
static Integer
getInteger(String nm, Integer def)
Get the specified system property as an Integer, or use a default Integer value if the property is not found or is not decodable.
int
hashCode()
Return a hashcode representing this Object.
static int
highestOneBit(int value)
Find the highest set bit in value, and return a new value with only that bit set.
int
intValue()
Return the value of this Integer.
long
longValue()
Return the value of this Integer as a long.
static int
lowestOneBit(int value)
Find the lowest set bit in value, and return a new value with only that bit set.
static int
numberOfLeadingZeros(int value)
Return the number of leading zeros in value.
static int
numberOfTrailingZeros(int value)
Find the number of trailing zeros in value.
static int
parseInt(String s)
Converts the specified String into an int.
static int
parseInt(String str, int radix)
Converts the specified String into an int using the specified radix (base).
static int
reverse(int val)
Reverse the bits in val.
static int
reverseBytes(int val)
Reverse the bytes in val.
static int
rotateLeft(int x, int distance)
Rotate x to the left by distance bits.
static int
rotateRight(int x, int distance)
Rotate x to the right by distance bits.
short
shortValue()
Return the value of this Integer as a short.
static int
signum(int x)
Return 1 if x is positive, -1 if it is negative, and 0 if it is zero.
static String
toBinaryString(int i)
Converts the int to a String assuming it is unsigned in base 2.
static String
toHexString(int i)
Converts the int to a String assuming it is unsigned in base 16.
static String
toOctalString(int i)
Converts the int to a String assuming it is unsigned in base 8.
String
toString()
Converts the Integer value to a String and assumes a radix of 10.
static String
toString(int i)
Converts the int to a String and assumes a radix of 10.
static String
toString(int num, int radix)
Converts the int to a String using the specified radix (base).
static Integer
valueOf(int val)
Returns an Integer object wrapping the value.
static Integer
valueOf(String s)
Creates a new Integer object using the String, assuming a radix of 10.
static Integer
valueOf(String s, int radix)
Creates a new Integer object using the String and specified radix (base).

Methods inherited from class java.lang.Number

byteValue, doubleValue, floatValue, intValue, longValue, shortValue

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

MAX_VALUE

public static final int MAX_VALUE
The maximum value an int can represent is 2147483647 (or 231 - 1).
Field Value:
2147483647

MIN_VALUE

public static final int MIN_VALUE
The minimum value an int can represent is -2147483648 (or -231).
Field Value:
-2147483648

SIZE

public static final int SIZE
The number of bits needed to represent an int.
Field Value:
32
Since:
1.5

TYPE

public static final Class TYPE
The primitive type int is represented by this Class object.
Since:
1.1

Constructor Details

Integer

public Integer(int value)
Create an Integer object representing the value of the int argument.
Parameters:
value - the value to use

Integer

public Integer(String s)
Create an Integer object representing the value of the argument after conversion to an int.
Parameters:
s - the string to convert
Throws:
NumberFormatException - if the String does not contain an int

Method Details

bitCount

public static int bitCount(int x)
Return the number of bits set in x.
Parameters:
x - value to examine
Since:
1.5

byteValue

public byte byteValue()
Return the value of this Integer as a byte.
Overrides:
byteValue in interface Number
Returns:
the byte value

compareTo

public int compareTo(Integer i)
Compare two Integers numerically by comparing their int values. The result is positive if the first is greater, negative if the second is greater, and 0 if the two are equal.
Parameters:
i - the Integer to compare
Returns:
the comparison
Since:
1.2

decode

public static Integer decode(String str)
Convert the specified String into an Integer. The String may represent decimal, hexadecimal, or octal numbers.

The extended BNF grammar is as follows:

 DecodableString:
      ( [ - ] DecimalNumber )
    | ( [ - ] ( 0x | 0X
              | # ) HexDigit { HexDigit } )
    | ( [ - ] 0 { OctalDigit } )
 DecimalNumber:
        DecimalDigit except '0' { DecimalDigit }
 DecimalDigit:
        Character.digit(d, 10) has value 0 to 9
 OctalDigit:
        Character.digit(d, 8) has value 0 to 7
 DecimalDigit:
        Character.digit(d, 16) has value 0 to 15
 
Finally, the value must be in the range MIN_VALUE to MAX_VALUE, or an exception is thrown.
Parameters:
str - the String to interpret
Returns:
the value of the String as an Integer
Throws:
NumberFormatException - if s cannot be parsed as a int
NullPointerException - if s is null
Since:
1.2

doubleValue

public double doubleValue()
Return the value of this Integer as a double.
Overrides:
doubleValue in interface Number
Returns:
the double value

equals

public boolean equals(Object obj)
Returns true if obj is an instance of Integer and represents the same int value.
Overrides:
equals in interface Object
Parameters:
obj - the object to compare
Returns:
whether these Objects are semantically equal

floatValue

public float floatValue()
Return the value of this Integer as a float.
Overrides:
floatValue in interface Number
Returns:
the float value

getInteger

public static Integer getInteger(String nm)
Get the specified system property as an Integer. The decode() method will be used to interpret the value of the property.
Parameters:
nm - the name of the system property
Returns:
the system property as an Integer, or null if the property is not found or cannot be decoded
Throws:
SecurityException - if accessing the system property is forbidden

getInteger

public static Integer getInteger(String nm,
                                 int val)
Get the specified system property as an Integer, or use a default int value if the property is not found or is not decodable. The decode() method will be used to interpret the value of the property.
Parameters:
nm - the name of the system property
val - the default value
Returns:
the value of the system property, or the default
Throws:
SecurityException - if accessing the system property is forbidden

getInteger

public static Integer getInteger(String nm,
                                 Integer def)
Get the specified system property as an Integer, or use a default Integer value if the property is not found or is not decodable. The decode() method will be used to interpret the value of the property.
Parameters:
nm - the name of the system property
def - the default value
Returns:
the value of the system property, or the default
Throws:
SecurityException - if accessing the system property is forbidden

hashCode

public int hashCode()
Return a hashcode representing this Object. Integer's hash code is simply its value.
Overrides:
hashCode in interface Object
Returns:
this Object's hash code

highestOneBit

public static int highestOneBit(int value)
Find the highest set bit in value, and return a new value with only that bit set.
Parameters:
value - the value to examine
Since:
1.5

intValue

public int intValue()
Return the value of this Integer.
Overrides:
intValue in interface Number
Returns:
the int value

longValue

public long longValue()
Return the value of this Integer as a long.
Overrides:
longValue in interface Number
Returns:
the long value

lowestOneBit

public static int lowestOneBit(int value)
Find the lowest set bit in value, and return a new value with only that bit set.
Parameters:
value - the value to examine
Since:
1.5

numberOfLeadingZeros

public static int numberOfLeadingZeros(int value)
Return the number of leading zeros in value.
Parameters:
value - the value to examine
Since:
1.5

numberOfTrailingZeros

public static int numberOfTrailingZeros(int value)
Find the number of trailing zeros in value.
Parameters:
value - the value to examine
Since:
1.5

parseInt

public static int parseInt(String s)
Converts the specified String into an int. This function assumes a radix of 10.
Parameters:
s - the String to convert
Returns:
the int value of s
Throws:
NumberFormatException - if s cannot be parsed as an int

parseInt

public static int parseInt(String str,
                           int radix)
Converts the specified String into an int using the specified radix (base). The string must not be null or empty. It may begin with an optional '-', which will negate the answer, provided that there are also valid digits. Each digit is parsed as if by Character.digit(d, radix), and must be in the range 0 to radix - 1. Finally, the result must be within MIN_VALUE to MAX_VALUE, inclusive. Unlike Double.parseDouble, you may not have a leading '+'.
Parameters:
str - the String to convert
radix - the radix (base) to use in the conversion
Returns:
the String argument converted to int
Throws:
NumberFormatException - if s cannot be parsed as an int

reverse

public static int reverse(int val)
Reverse the bits in val.
Since:
1.5

reverseBytes

public static int reverseBytes(int val)
Reverse the bytes in val.
Since:
1.5

rotateLeft

public static int rotateLeft(int x,
                             int distance)
Rotate x to the left by distance bits.
Parameters:
x - the value to rotate
distance - the number of bits by which to rotate
Since:
1.5

rotateRight

public static int rotateRight(int x,
                              int distance)
Rotate x to the right by distance bits.
Parameters:
x - the value to rotate
distance - the number of bits by which to rotate
Since:
1.5

shortValue

public short shortValue()
Return the value of this Integer as a short.
Overrides:
shortValue in interface Number
Returns:
the short value

signum

public static int signum(int x)
Return 1 if x is positive, -1 if it is negative, and 0 if it is zero.
Parameters:
x - the value to examine
Since:
1.5

toBinaryString

public static String toBinaryString(int i)
Converts the int to a String assuming it is unsigned in base 2.
Parameters:
i - the int to convert to String
Returns:
the String representation of the argument

toHexString

public static String toHexString(int i)
Converts the int to a String assuming it is unsigned in base 16.
Parameters:
i - the int to convert to String
Returns:
the String representation of the argument

toOctalString

public static String toOctalString(int i)
Converts the int to a String assuming it is unsigned in base 8.
Parameters:
i - the int to convert to String
Returns:
the String representation of the argument

toString

public String toString()
Converts the Integer value to a String and assumes a radix of 10.
Overrides:
toString in interface Object
Returns:
the String representation

toString

public static String toString(int i)
Converts the int to a String and assumes a radix of 10.
Parameters:
i - the int to convert to String
Returns:
the String representation of the argument

toString

public static String toString(int num,
                              int radix)
Converts the int to a String using the specified radix (base). If the radix exceeds Character.MIN_RADIX or Character.MAX_RADIX, 10 is used instead. If the result is negative, the leading character is '-' ('\\u002D'). The remaining characters come from Character.forDigit(digit, radix) ('0'-'9','a'-'z').
Parameters:
num - the int to convert to String
radix - the radix (base) to use in the conversion
Returns:
the String representation of the argument

valueOf

public static Integer valueOf(int val)
Returns an Integer object wrapping the value. In contrast to the Integer constructor, this method will cache some values. It is used by boxing conversion.
Parameters:
val - the value to wrap
Returns:
the Integer

valueOf

public static Integer valueOf(String s)
Creates a new Integer object using the String, assuming a radix of 10.
Parameters:
s - the String to convert
Returns:
the new Integer
Throws:
NumberFormatException - if s cannot be parsed as an int

valueOf

public static Integer valueOf(String s,
                              int radix)
Creates a new Integer object using the String and specified radix (base).
Parameters:
s - the String to convert
radix - the radix (base) to convert with
Returns:
the new Integer
Throws:
NumberFormatException - if s cannot be parsed as an int

Integer.java -- object wrapper for int Copyright (C) 1998, 1999, 2001, 2002, 2004, 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.