public final class Integer extends Number implements Comparable<Integer>
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
.
Implementation note: The implementations of the "bit twiddling" methods (such as highestOneBit
and numberOfTrailingZeros
) are based on material from Henry S. Warren, Jr.'s Hacker's Delight, (Addison Wesley, 2002).
@Native public static final int MIN_VALUE
A constant holding the minimum value an int
can have, -231.
@Native public static final int MAX_VALUE
A constant holding the maximum value an int
can have, 231-1.
public static final Class<Integer> TYPE
The Class
instance representing the primitive type int
.
@Native public static final int SIZE
The number of bits used to represent an int
value in two's complement binary form.
public static final int BYTES
The number of bytes used to represent a int
value in two's complement binary form.
public Integer(int value)
Constructs a newly allocated Integer
object that represents the specified int
value.
value
- the value to be represented by the Integer
object.public Integer(String s) throws NumberFormatException
Constructs a newly allocated Integer
object that represents the int
value indicated by the String
parameter. The string is converted to an int
value in exactly the manner used by the parseInt
method for radix 10.
s
- the String
to be converted to an Integer
.NumberFormatException
- if the String
does not contain a parsable integer.parseInt(java.lang.String, int)
public static String toString(int i, int radix)
Returns 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:
0123456789abcdefghijklmnopqrstuvwxyzThese are
'\u0030'
through '\u0039'
and '\u0061'
through '\u007A'
. If 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
. If uppercase letters are desired, the String.toUpperCase()
method may be called on the result: Integer.toString(n, 16).toUpperCase()
i
- an integer to be converted to a string.radix
- the radix to use in the string representation.Character.MAX_RADIX
, Character.MIN_RADIX
public static String toUnsignedString(int i, int radix)
Returns a string representation of the first argument as an unsigned integer value 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.
Note that since the first argument is treated as an unsigned value, no leading sign character is printed.
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 behavior of radixes and the characters used as digits are the same as toString
.
i
- an integer to be converted to an unsigned string.radix
- the radix to use in the string representation.toString(int, int)
public static String toHexString(int i)
Returns 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 0
s.
The value of the argument can be recovered from the returned string s
by calling Integer.parseUnsignedInt(s, 16)
.
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:
0123456789abcdefThese are the characters
'\u0030'
through '\u0039'
and '\u0061'
through '\u0066'
. If uppercase letters are desired, the String.toUpperCase()
method may be called on the result: Integer.toHexString(n).toUpperCase()
i
- an integer to be converted to a string.parseUnsignedInt(String, int)
, toUnsignedString(int, int)
public static String toOctalString(int i)
Returns 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 0
s.
The value of the argument can be recovered from the returned string s
by calling Integer.parseUnsignedInt(s, 8)
.
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 octal digits:
01234567These are the characters
'\u0030'
through '\u0037'
.i
- an integer to be converted to a string.parseUnsignedInt(String, int)
, toUnsignedString(int, int)
public static String toBinaryString(int i)
Returns a string representation of the integer argument as an unsigned integer in base 2.
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 binary (base 2) with no extra leading 0
s.
The value of the argument can be recovered from the returned string s
by calling Integer.parseUnsignedInt(s, 2)
.
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.
i
- an integer to be converted to a string.parseUnsignedInt(String, int)
, toUnsignedString(int, int)
public static String toString(int i)
Returns a 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.
i
- an integer to be converted.public static String toUnsignedString(int i)
Returns a string representation of the argument as an unsigned decimal value. The argument is converted to unsigned decimal representation and returned as a string exactly as if the argument and radix 10 were given as arguments to the toUnsignedString(int,
int)
method.
i
- an integer to be converted to an unsigned string.toUnsignedString(int, int)
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 or an ASCII plus sign '+'
('\u002B'
) to indicate a positive value. The resulting integer value is returned.
An exception of type NumberFormatException
is thrown if any of the following situations occurs:
null
or is a string of length zero. Character.MIN_RADIX
or larger than Character.MAX_RADIX
. '-'
('\u002D'
) or plus sign '+'
('\u002B'
) provided that the string is longer than length 1. int
. Examples:
parseInt("0", 10) returns 0 parseInt("473", 10) returns 473 parseInt("+42", 10) returns 42 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
s
- the String
containing the integer representation to be parsedradix
- the radix to be used while parsing s
.NumberFormatException
- if the String
does not contain a parsable int
.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 or an ASCII plus sign '+'
('\u002B'
) to indicate a positive 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.
s
- a String
containing the int
representation to be parsedNumberFormatException
- if the string does not contain a parsable integer.public static int parseUnsignedInt(String s, int radix) throws NumberFormatException
Parses the string argument as an unsigned integer in the radix specified by the second argument. An unsigned integer maps the values usually associated with negative numbers to positive numbers larger than MAX_VALUE
. 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 plus sign '+'
('\u002B'
). The resulting integer value is returned.
An exception of type NumberFormatException
is thrown if any of the following situations occurs:
null
or is a string of length zero. Character.MIN_RADIX
or larger than Character.MAX_RADIX
. '+'
('\u002B'
) provided that the string is longer than length 1. int
, 232-1. s
- the String
containing the unsigned integer representation to be parsedradix
- the radix to be used while parsing s
.NumberFormatException
- if the String
does not contain a parsable int
.public static int parseUnsignedInt(String s) throws NumberFormatException
Parses the string argument as an unsigned decimal integer. The characters in the string must all be decimal digits, except that the first character may be an an ASCII plus sign '+'
('\u002B'
). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to the parseUnsignedInt(java.lang.String, int)
method.
s
- a String
containing the unsigned int
representation to be parsedNumberFormatException
- if the string does not contain a parsable unsigned integer.public static Integer valueOf(String s, int radix) throws NumberFormatException
Returns an Integer
object holding the value extracted from the specified String
when parsed with the radix given by the second argument. 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))
s
- the string to be parsed.radix
- the radix to be used in interpreting s
Integer
object holding the value represented by the string argument in the specified radix.NumberFormatException
- if the String
does not contain a parsable int
.public static Integer valueOf(String s) throws NumberFormatException
Returns an Integer
object holding 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))
s
- the string to be parsed.Integer
object holding the value represented by the string argument.NumberFormatException
- if the string cannot be parsed as an integer.public static Integer valueOf(int i)
Returns an Integer
instance representing the specified int
value. If a new Integer
instance is not required, this method should generally be used in preference to the constructor Integer(int)
, as this method is likely to yield significantly better space and time performance by caching frequently requested values. This method will always cache values in the range -128 to 127, inclusive, and may cache other values outside of this range.
i
- an int
value.Integer
instance representing i
.public byte byteValue()
Returns the value of this Integer
as a byte
after a narrowing primitive conversion.
byteValue
in class Number
byte
.public short shortValue()
Returns the value of this Integer
as a short
after a narrowing primitive conversion.
shortValue
in class Number
short
.public int intValue()
Returns the value of this Integer
as an int
.
intValue
in class Number
int
.public long longValue()
Returns the value of this Integer
as a long
after a widening primitive conversion.
longValue
in class Number
long
.toUnsignedLong(int)
public float floatValue()
Returns the value of this Integer
as a float
after a widening primitive conversion.
floatValue
in class Number
float
.public double doubleValue()
Returns the value of this Integer
as a double
after a widening primitive conversion.
doubleValue
in class Number
double
.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.
toString
in class Object
public int hashCode()
Returns a hash code for this Integer
.
hashCode
in class Object
int
value represented by this Integer
object.Object.equals(java.lang.Object)
, System.identityHashCode(java.lang.Object)
public static int hashCode(int value)
Returns a hash code for a int
value; compatible with Integer.hashCode()
.
value
- the value to hashint
value.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.
equals
in class Object
obj
- the object to compare with.true
if the objects are the same; false
otherwise.Object.hashCode()
, HashMap
public static Integer getInteger(String nm)
Determines the integer value of the system property with the specified name.
The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String)
method. The string value of this property is then interpreted as an integer value using the grammar supported by decode
and an Integer
object representing this value is returned.
If there is no property with the specified name, if the specified name is empty or null
, or if the property does not have the correct numeric format, then null
is returned.
In other words, this method returns an Integer
object equal to the value of:
getInteger(nm, null)
nm
- property name.Integer
value of the property.SecurityException
- for the same reasons as System.getProperty
System.getProperty(java.lang.String)
, System.getProperty(java.lang.String, java.lang.String)
public static Integer getInteger(String nm, int val)
Determines the integer value of the system property with the specified name.
The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String)
method. The string value of this property is then interpreted as an integer value using the grammar supported by decode
and an Integer
object representing this value is returned.
The second argument is the default value. An Integer
object that represents the value of the second argument is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or null
.
In other words, this method returns an Integer
object equal to the value of:
getInteger(nm, new Integer(val))but in practice it may be implemented in a manner such as:
Integer result = getInteger(nm, null); return (result == null) ? new Integer(val) : result;to avoid the unnecessary allocation of an
Integer
object when the default value is not needed.nm
- property name.val
- default value.Integer
value of the property.SecurityException
- for the same reasons as System.getProperty
System.getProperty(java.lang.String)
, System.getProperty(java.lang.String, java.lang.String)
public static Integer getInteger(String nm, Integer val)
Returns the integer value of the system property with the specified name. The first argument is treated as the name of a system property. System properties are accessible through the System.getProperty(java.lang.String)
method. The string value of this property is then interpreted as an integer value, as per the decode
method, and an Integer
object representing this value is returned; in summary:
0x
or the ASCII character #
, not followed by a minus sign, then the rest of it is parsed as a hexadecimal integer exactly as by the method valueOf(java.lang.String, int)
with radix 16. 0
followed by another character, it is parsed as an octal integer exactly as by the method valueOf(java.lang.String, int)
with radix 8. valueOf(java.lang.String, int)
with radix 10. The second argument is the default value. The default value is returned if there is no property of the specified name, if the property does not have the correct numeric format, or if the specified name is empty or null
.
nm
- property name.val
- default value.Integer
value of the property.SecurityException
- for the same reasons as System.getProperty
System.getProperty(java.lang.String)
, System.getProperty(java.lang.String, java.lang.String)
public static Integer decode(String nm) throws NumberFormatException
Decodes a String
into an Integer
. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:
0x
HexDigits 0X
HexDigits #
HexDigits 0
OctalDigits -
+
The sequence of characters following an optional sign and/or radix specifier ("0x
", "0X
", "#
", or leading zero) is parsed as by the Integer.parseInt
method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or a NumberFormatException
will be thrown. The result is negated if first character of the specified String
is the minus sign. No whitespace characters are permitted in the String
.
nm
- the String
to decode.Integer
object holding the int
value represented by nm
NumberFormatException
- if the String
does not contain a parsable integer.parseInt(java.lang.String, int)
public int compareTo(Integer anotherInteger)
Compares two Integer
objects numerically.
compareTo
in interface Comparable<Integer>
anotherInteger
- the Integer
to be compared.0
if this Integer
is equal to the argument Integer
; a value less than 0
if this Integer
is numerically less than the argument Integer
; and a value greater than 0
if this Integer
is numerically greater than the argument Integer
(signed comparison).public static int compare(int x, int y)
Compares two int
values numerically. The value returned is identical to what would be returned by:
Integer.valueOf(x).compareTo(Integer.valueOf(y))
x
- the first int
to comparey
- the second int
to compare0
if x == y
; a value less than 0
if x < y
; and a value greater than 0
if x > y
public static int compareUnsigned(int x, int y)
Compares two int
values numerically treating the values as unsigned.
x
- the first int
to comparey
- the second int
to compare0
if x == y
; a value less than 0
if x < y
as unsigned values; and a value greater than 0
if x > y
as unsigned valuespublic static long toUnsignedLong(int x)
Converts the argument to a long
by an unsigned conversion. In an unsigned conversion to a long
, the high-order 32 bits of the long
are zero and the low-order 32 bits are equal to the bits of the integer argument. Consequently, zero and positive int
values are mapped to a numerically equal long
value and negative int
values are mapped to a long
value equal to the input plus 232.
x
- the value to convert to an unsigned long
long
by an unsigned conversionpublic static int divideUnsigned(int dividend, int divisor)
Returns the unsigned quotient of dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
Note that in two's complement arithmetic, the three other basic arithmetic operations of add, subtract, and multiply are bit-wise identical if the two operands are regarded as both being signed or both being unsigned. Therefore separate addUnsigned
, etc. methods are not provided.
dividend
- the value to be divideddivisor
- the value doing the dividingremainderUnsigned(int, int)
public static int remainderUnsigned(int dividend, int divisor)
Returns the unsigned remainder from dividing the first argument by the second where each argument and the result is interpreted as an unsigned value.
dividend
- the value to be divideddivisor
- the value doing the dividingdivideUnsigned(int, int)
public static int highestOneBit(int i)
Returns an int
value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specified int
value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.
i
- the value whose highest one bit is to be computedint
value with a single one-bit, in the position of the highest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.public static int lowestOneBit(int i)
Returns an int
value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specified int
value. Returns zero if the specified value has no one-bits in its two's complement binary representation, that is, if it is equal to zero.
i
- the value whose lowest one bit is to be computedint
value with a single one-bit, in the position of the lowest-order one-bit in the specified value, or zero if the specified value is itself equal to zero.public static int numberOfLeadingZeros(int i)
Returns the number of zero bits preceding the highest-order ("leftmost") one-bit in the two's complement binary representation of the specified int
value. Returns 32 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.
Note that this method is closely related to the logarithm base 2. For all positive int
values x:
31 - numberOfLeadingZeros(x)
32 - numberOfLeadingZeros(x - 1)
i
- the value whose number of leading zeros is to be computedint
value, or 32 if the value is equal to zero.public static int numberOfTrailingZeros(int i)
Returns the number of zero bits following the lowest-order ("rightmost") one-bit in the two's complement binary representation of the specified int
value. Returns 32 if the specified value has no one-bits in its two's complement representation, in other words if it is equal to zero.
i
- the value whose number of trailing zeros is to be computedint
value, or 32 if the value is equal to zero.public static int bitCount(int i)
Returns the number of one-bits in the two's complement binary representation of the specified int
value. This function is sometimes referred to as the population count.
i
- the value whose bits are to be countedint
value.public static int rotateLeft(int i, int distance)
Returns the value obtained by rotating the two's complement binary representation of the specified int
value left by the specified number of bits. (Bits shifted out of the left hand, or high-order, side reenter on the right, or low-order.)
Note that left rotation with a negative distance is equivalent to right rotation: rotateLeft(val, -distance) == rotateRight(val,
distance)
. Note also that rotation by any multiple of 32 is a no-op, so all but the last five bits of the rotation distance can be ignored, even if the distance is negative: rotateLeft(val,
distance) == rotateLeft(val, distance & 0x1F)
.
i
- the value whose bits are to be rotated leftdistance
- the number of bit positions to rotate leftint
value left by the specified number of bits.public static int rotateRight(int i, int distance)
Returns the value obtained by rotating the two's complement binary representation of the specified int
value right by the specified number of bits. (Bits shifted out of the right hand, or low-order, side reenter on the left, or high-order.)
Note that right rotation with a negative distance is equivalent to left rotation: rotateRight(val, -distance) == rotateLeft(val,
distance)
. Note also that rotation by any multiple of 32 is a no-op, so all but the last five bits of the rotation distance can be ignored, even if the distance is negative: rotateRight(val,
distance) == rotateRight(val, distance & 0x1F)
.
i
- the value whose bits are to be rotated rightdistance
- the number of bit positions to rotate rightint
value right by the specified number of bits.public static int reverse(int i)
Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified int
value.
i
- the value to be reversedint
value.public static int signum(int i)
Returns the signum function of the specified int
value. (The return value is -1 if the specified value is negative; 0 if the specified value is zero; and 1 if the specified value is positive.)
i
- the value whose signum is to be computedint
value.public static int reverseBytes(int i)
Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified int
value.
i
- the value whose bytes are to be reversedint
value.public static int sum(int a, int b)
Adds two integers together as per the + operator.
a
- the first operandb
- the second operanda
and b
BinaryOperator
public static int max(int a, int b)
Returns the greater of two int
values as if by calling Math.max
.
a
- the first operandb
- the second operanda
and b
BinaryOperator
public static int min(int a, int b)
Returns the smaller of two int
values as if by calling Math.min
.
a
- the first operandb
- the second operanda
and b
BinaryOperator
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Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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