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>
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).
- Since:
- 1.0
- See Also:
- Serialized Form
Field Summary
Modifier and Type | Field | Description |
---|---|---|
static int | BYTES | The number of bytes used to represent an |
static int | MAX_VALUE | A constant holding the maximum value an |
static int | MIN_VALUE | A constant holding the minimum value an |
static int | SIZE | The number of bits used to represent an |
static Class<Integer> | TYPE | The |
Constructor Summary
Constructor | Description |
---|---|
Integer(int value) | Deprecated. It is rarely appropriate to use this constructor. |
Integer(String s) | Deprecated. It is rarely appropriate to use this constructor. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
static int | bitCount(int i) | Returns the number of one-bits in the two's complement binary representation of the specified |
byte | byteValue() | Returns the value of this |
static int | compare(int x,
int y) | Compares two |
int | compareTo(Integer anotherInteger) | Compares two |
static int | compareUnsigned(int x,
int y) | Compares two |
static Integer | decode(String nm) | Decodes a |
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. |
double | doubleValue() | Returns the value of this |
boolean | equals(Object obj) | Compares this object to the specified object. |
float | floatValue() | Returns the value of this |
static Integer | getInteger(String nm) | Determines the integer value of the system property with the specified name. |
static Integer | getInteger(String nm,
int val) | Determines the integer value of the system property with the specified name. |
static Integer | getInteger(String nm,
Integer val) | Returns the integer value of the system property with the specified name. |
int | hashCode() | Returns a hash code for this |
static int | hashCode(int value) | Returns a hash code for an |
static int | highestOneBit(int i) | Returns an |
int | intValue() | Returns the value of this |
long | longValue() | Returns the value of this |
static int | lowestOneBit(int i) | Returns an |
static int | max(int a,
int b) | Returns the greater of two |
static int | min(int a,
int b) | Returns the smaller of two |
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 |
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 |
static int | parseInt(CharSequence s,
int beginIndex,
int endIndex,
int radix) | Parses the |
static int | parseInt(String s) | Parses the string argument as a signed decimal integer. |
static int | parseInt(String s,
int radix) | Parses the string argument as a signed integer in the radix specified by the second argument. |
static int | parseUnsignedInt(CharSequence s,
int beginIndex,
int endIndex,
int radix) | Parses the |
static int | parseUnsignedInt(String s) | Parses the string argument as an unsigned decimal integer. |
static int | parseUnsignedInt(String s,
int radix) | Parses the string argument as an unsigned integer in the radix specified by the second argument. |
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. |
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 |
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 |
static int | rotateLeft(int i,
int distance) | Returns the value obtained by rotating the two's complement binary representation of the specified |
static int | rotateRight(int i,
int distance) | Returns the value obtained by rotating the two's complement binary representation of the specified |
short | shortValue() | Returns the value of this |
static int | signum(int i) | Returns the signum function of the specified |
static int | sum(int a,
int b) | Adds two integers together as per the + operator. |
static String | toBinaryString(int i) | Returns a string representation of the integer argument as an unsigned integer in base 2. |
static String | toHexString(int i) | Returns a string representation of the integer argument as an unsigned integer in base 16. |
static String | toOctalString(int i) | Returns a string representation of the integer argument as an unsigned integer in base 8. |
String | toString() | Returns a |
static String | toString(int i) | Returns a |
static String | toString(int i,
int radix) | Returns a string representation of the first argument in the radix specified by the second argument. |
static long | toUnsignedLong(int x) | Converts the argument to a |
static String | toUnsignedString(int i) | Returns a string representation of the argument as an unsigned decimal value. |
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. |
static Integer | valueOf(int i) | Returns an |
static Integer | valueOf(String s) | Returns an |
static Integer | valueOf(String s,
int radix) | Returns an |
Methods declared in class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
Field Detail
MIN_VALUE
@Native public static final int MIN_VALUE
A constant holding the minimum value an int
can have, -231.
- See Also:
- Constant Field Values
MAX_VALUE
@Native public static final int MAX_VALUE
A constant holding the maximum value an int
can have, 231-1.
- See Also:
- Constant Field Values
TYPE
public static final Class<Integer> TYPE
The Class
instance representing the primitive type int
.
- Since:
- 1.1
SIZE
@Native public static final int SIZE
The number of bits used to represent an int
value in two's complement binary form.
- Since:
- 1.5
- See Also:
- Constant Field Values
BYTES
public static final int BYTES
The number of bytes used to represent an int
value in two's complement binary form.
- Since:
- 1.8
- See Also:
- Constant Field Values
Constructor Detail
Integer
@Deprecated(since="9") public Integer(int value)
valueOf(int)
is generally a better choice, as it is likely to yield significantly better space and time performance.Constructs a newly allocated Integer
object that represents the specified int
value.
- Parameters:
-
value
- the value to be represented by theInteger
object.
Integer
@Deprecated(since="9") public Integer(String s) throws NumberFormatException
parseInt(String)
to convert a string to a int
primitive, or use valueOf(String)
to convert a string to an Integer
object.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.
- Parameters:
-
s
- theString
to be converted to anInteger
. - Throws:
-
NumberFormatException
- if theString
does not contain a parsable integer.
Method Detail
toString
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()
- Parameters:
-
i
- an integer to be converted to a string. -
radix
- the radix to use in the string representation. - Returns:
- a string representation of the argument in the specified radix.
- See Also:
-
Character.MAX_RADIX
,Character.MIN_RADIX
toUnsignedString
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
.
- Parameters:
-
i
- an integer to be converted to an unsigned string. -
radix
- the radix to use in the string representation. - Returns:
- an unsigned string representation of the argument in the specified radix.
- Since:
- 1.8
- See Also:
toString(int, int)
toHexString
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()
- Parameters:
-
i
- an integer to be converted to a string. - Returns:
- the string representation of the unsigned integer value represented by the argument in hexadecimal (base 16).
- Since:
- 1.0.2
- See Also:
-
parseUnsignedInt(String, int)
,toUnsignedString(int, int)
toOctalString
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'
.- Parameters:
-
i
- an integer to be converted to a string. - Returns:
- the string representation of the unsigned integer value represented by the argument in octal (base 8).
- Since:
- 1.0.2
- See Also:
-
parseUnsignedInt(String, int)
,toUnsignedString(int, int)
toBinaryString
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.
- Parameters:
-
i
- an integer to be converted to a string. - Returns:
- the string representation of the unsigned integer value represented by the argument in binary (base 2).
- Since:
- 1.0.2
- See Also:
-
parseUnsignedInt(String, int)
,toUnsignedString(int, int)
toString
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.
- Parameters:
-
i
- an integer to be converted. - Returns:
- a string representation of the argument in base 10.
toUnsignedString
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.
- Parameters:
-
i
- an integer to be converted to an unsigned string. - Returns:
- an unsigned string representation of the argument.
- Since:
- 1.8
- See Also:
toUnsignedString(int, int)
parseInt
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:
- The first argument is
null
or is a string of length zero. - The radix is either smaller than
Character.MIN_RADIX
or larger thanCharacter.MAX_RADIX
. - Any character of the string is not a digit of the specified radix, except that the first character may be a minus sign
'-'
('\u002D'
) or plus sign'+'
('\u002B'
) provided that the string is longer than length 1. - The value represented by the string is not a value of type
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
- Parameters:
-
s
- theString
containing the integer representation to be parsed -
radix
- the radix to be used while parsings
. - Returns:
- the integer represented by the string argument in the specified radix.
- Throws:
-
NumberFormatException
- if theString
does not contain a parsableint
.
parseInt
public static int parseInt(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException
Parses the CharSequence
argument as a signed int
in the specified radix
, beginning at the specified beginIndex
and extending to endIndex - 1
.
The method does not take steps to guard against the CharSequence
being mutated while parsing.
- Parameters:
-
s
- theCharSequence
containing theint
representation to be parsed -
beginIndex
- the beginning index, inclusive. -
endIndex
- the ending index, exclusive. -
radix
- the radix to be used while parsings
. - Returns:
- the signed
int
represented by the subsequence in the specified radix. - Throws:
-
NullPointerException
- ifs
is null. -
IndexOutOfBoundsException
- ifbeginIndex
is negative, or ifbeginIndex
is greater thanendIndex
or ifendIndex
is greater thans.length()
. -
NumberFormatException
- if theCharSequence
does not contain a parsableint
in the specifiedradix
, or ifradix
is either smaller thanCharacter.MIN_RADIX
or larger thanCharacter.MAX_RADIX
. - Since:
- 9
parseInt
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.
- Parameters:
-
s
- aString
containing theint
representation to be parsed - Returns:
- the integer value represented by the argument in decimal.
- Throws:
-
NumberFormatException
- if the string does not contain a parsable integer.
parseUnsignedInt
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:
- The first argument is
null
or is a string of length zero. - The radix is either smaller than
Character.MIN_RADIX
or larger thanCharacter.MAX_RADIX
. - Any character of the string is not a digit of the specified radix, except that the first character may be a plus sign
'+'
('\u002B'
) provided that the string is longer than length 1. - The value represented by the string is larger than the largest unsigned
int
, 232-1.
- Parameters:
-
s
- theString
containing the unsigned integer representation to be parsed -
radix
- the radix to be used while parsings
. - Returns:
- the integer represented by the string argument in the specified radix.
- Throws:
-
NumberFormatException
- if theString
does not contain a parsableint
. - Since:
- 1.8
parseUnsignedInt
public static int parseUnsignedInt(CharSequence s, int beginIndex, int endIndex, int radix) throws NumberFormatException
Parses the CharSequence
argument as an unsigned int
in the specified radix
, beginning at the specified beginIndex
and extending to endIndex - 1
.
The method does not take steps to guard against the CharSequence
being mutated while parsing.
- Parameters:
-
s
- theCharSequence
containing the unsignedint
representation to be parsed -
beginIndex
- the beginning index, inclusive. -
endIndex
- the ending index, exclusive. -
radix
- the radix to be used while parsings
. - Returns:
- the unsigned
int
represented by the subsequence in the specified radix. - Throws:
-
NullPointerException
- ifs
is null. -
IndexOutOfBoundsException
- ifbeginIndex
is negative, or ifbeginIndex
is greater thanendIndex
or ifendIndex
is greater thans.length()
. -
NumberFormatException
- if theCharSequence
does not contain a parsable unsignedint
in the specifiedradix
, or ifradix
is either smaller thanCharacter.MIN_RADIX
or larger thanCharacter.MAX_RADIX
. - Since:
- 9
parseUnsignedInt
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 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.
- Parameters:
-
s
- aString
containing the unsignedint
representation to be parsed - Returns:
- the unsigned integer value represented by the argument in decimal.
- Throws:
-
NumberFormatException
- if the string does not contain a parsable unsigned integer. - Since:
- 1.8
valueOf
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))
- Parameters:
-
s
- the string to be parsed. -
radix
- the radix to be used in interpretings
- Returns:
- an
Integer
object holding the value represented by the string argument in the specified radix. - Throws:
-
NumberFormatException
- if theString
does not contain a parsableint
.
valueOf
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))
- Parameters:
-
s
- the string to be parsed. - Returns:
- an
Integer
object holding the value represented by the string argument. - Throws:
-
NumberFormatException
- if the string cannot be parsed as an integer.
valueOf
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.
- Parameters:
-
i
- anint
value. - Returns:
- an
Integer
instance representingi
. - Since:
- 1.5
byteValue
public byte byteValue()
Returns the value of this Integer
as a byte
after a narrowing primitive conversion.
- Overrides:
-
byteValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
byte
.
shortValue
public short shortValue()
Returns the value of this Integer
as a short
after a narrowing primitive conversion.
- Overrides:
-
shortValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
short
.
intValue
public int intValue()
Returns the value of this Integer
as an int
.
- Specified by:
-
intValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
int
.
longValue
public long longValue()
Returns the value of this Integer
as a long
after a widening primitive conversion.
- Specified by:
-
longValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
long
. - See Also:
toUnsignedLong(int)
floatValue
public float floatValue()
Returns the value of this Integer
as a float
after a widening primitive conversion.
- Specified by:
-
floatValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
float
.
doubleValue
public double doubleValue()
Returns the value of this Integer
as a double
after a widening primitive conversion.
- Specified by:
-
doubleValue
in classNumber
- Returns:
- the numeric value represented by this object after conversion to type
double
.
toString
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.
- Overrides:
-
toString
in classObject
- Returns:
- a string representation of the value of this object in base 10.
hashCode
public int hashCode()
Returns a hash code for this Integer
.
- Overrides:
-
hashCode
in classObject
- Returns:
- a hash code value for this object, equal to the primitive
int
value represented by thisInteger
object. - See Also:
-
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
hashCode
public static int hashCode(int value)
Returns a hash code for an int
value; compatible with Integer.hashCode()
.
- Parameters:
-
value
- the value to hash - Returns:
- a hash code value for an
int
value. - Since:
- 1.8
equals
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.
- Overrides:
-
equals
in classObject
- Parameters:
-
obj
- the object to compare with. - Returns:
-
true
if the objects are the same;false
otherwise. - See Also:
-
Object.hashCode()
,HashMap
getInteger
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)
- Parameters:
-
nm
- property name. - Returns:
- the
Integer
value of the property. - Throws:
-
SecurityException
- for the same reasons asSystem.getProperty
- See Also:
-
System.getProperty(java.lang.String)
,System.getProperty(java.lang.String, java.lang.String)
getInteger
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.- Parameters:
-
nm
- property name. -
val
- default value. - Returns:
- the
Integer
value of the property. - Throws:
-
SecurityException
- for the same reasons asSystem.getProperty
- See Also:
-
System.getProperty(java.lang.String)
,System.getProperty(java.lang.String, java.lang.String)
getInteger
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:
- If the property value begins with the two ASCII characters
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 methodvalueOf(java.lang.String, int)
with radix 16. - If the property value begins with the ASCII character
0
followed by another character, it is parsed as an octal integer exactly as by the methodvalueOf(java.lang.String, int)
with radix 8. - Otherwise, the property value is parsed as a decimal integer exactly as by the method
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
.
- Parameters:
-
nm
- property name. -
val
- default value. - Returns:
- the
Integer
value of the property. - Throws:
-
SecurityException
- for the same reasons asSystem.getProperty
- See Also:
-
System.getProperty(java.lang.String)
,System.getProperty(java.lang.String, java.lang.String)
decode
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:
- DecodableString:
-
Signopt DecimalNumeral
- Signopt
0x
HexDigits- Signopt
0X
HexDigits- Signopt
#
HexDigits- Signopt
0
OctalDigits - Signopt
- Sign:
-
-
+
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
.
- Parameters:
-
nm
- theString
to decode. - Returns:
- an
Integer
object holding theint
value represented bynm
- Throws:
-
NumberFormatException
- if theString
does not contain a parsable integer. - See Also:
parseInt(java.lang.String, int)
compareTo
public int compareTo(Integer anotherInteger)
Compares two Integer
objects numerically.
- Specified by:
-
compareTo
in interfaceComparable<Integer>
- Parameters:
-
anotherInteger
- theInteger
to be compared. - Returns:
- the value
0
if thisInteger
is equal to the argumentInteger
; a value less than0
if thisInteger
is numerically less than the argumentInteger
; and a value greater than0
if thisInteger
is numerically greater than the argumentInteger
(signed comparison). - Since:
- 1.2
compare
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))
- Parameters:
-
x
- the firstint
to compare -
y
- the secondint
to compare - Returns:
- the value
0
ifx == y
; a value less than0
ifx < y
; and a value greater than0
ifx > y
- Since:
- 1.7
compareUnsigned
public static int compareUnsigned(int x, int y)
Compares two int
values numerically treating the values as unsigned.
- Parameters:
-
x
- the firstint
to compare -
y
- the secondint
to compare - Returns:
- the value
0
ifx == y
; a value less than0
ifx < y
as unsigned values; and a value greater than0
ifx > y
as unsigned values - Since:
- 1.8
toUnsignedLong
public 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.
- Parameters:
-
x
- the value to convert to an unsignedlong
- Returns:
- the argument converted to
long
by an unsigned conversion - Since:
- 1.8
divideUnsigned
public 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.
- Parameters:
-
dividend
- the value to be divided -
divisor
- the value doing the dividing - Returns:
- the unsigned quotient of the first argument divided by the second argument
- Since:
- 1.8
- See Also:
remainderUnsigned(int, int)
remainderUnsigned
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.
- Parameters:
-
dividend
- the value to be divided -
divisor
- the value doing the dividing - Returns:
- the unsigned remainder of the first argument divided by the second argument
- Since:
- 1.8
- See Also:
divideUnsigned(int, int)
highestOneBit
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.
- Parameters:
-
i
- the value whose highest one bit is to be computed - Returns:
- an
int
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. - Since:
- 1.5
lowestOneBit
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.
- Parameters:
-
i
- the value whose lowest one bit is to be computed - Returns:
- an
int
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. - Since:
- 1.5
numberOfLeadingZeros
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:
- floor(log2(x)) =
31 - numberOfLeadingZeros(x)
- ceil(log2(x)) =
32 - numberOfLeadingZeros(x - 1)
- Parameters:
-
i
- the value whose number of leading zeros is to be computed - 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, or 32 if the value is equal to zero. - Since:
- 1.5
numberOfTrailingZeros
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.
- Parameters:
-
i
- the value whose number of trailing zeros is to be computed - 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, or 32 if the value is equal to zero. - Since:
- 1.5
bitCount
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.
- Parameters:
-
i
- the value whose bits are to be counted - Returns:
- the number of one-bits in the two's complement binary representation of the specified
int
value. - Since:
- 1.5
rotateLeft
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)
.
- Parameters:
-
i
- the value whose bits are to be rotated left -
distance
- the number of bit positions to rotate left - Returns:
- the value obtained by rotating the two's complement binary representation of the specified
int
value left by the specified number of bits. - Since:
- 1.5
rotateRight
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)
.
- Parameters:
-
i
- the value whose bits are to be rotated right -
distance
- the number of bit positions to rotate right - Returns:
- the value obtained by rotating the two's complement binary representation of the specified
int
value right by the specified number of bits. - Since:
- 1.5
reverse
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.
- Parameters:
-
i
- the value to be reversed - Returns:
- the value obtained by reversing order of the bits in the specified
int
value. - Since:
- 1.5
signum
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.)
- Parameters:
-
i
- the value whose signum is to be computed - Returns:
- the signum function of the specified
int
value. - Since:
- 1.5
reverseBytes
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.
- Parameters:
-
i
- the value whose bytes are to be reversed - Returns:
- the value obtained by reversing the bytes in the specified
int
value. - Since:
- 1.5
sum
public static int sum(int a, int b)
Adds two integers together as per the + operator.
- Parameters:
-
a
- the first operand -
b
- the second operand - Returns:
- the sum of
a
andb
- Since:
- 1.8
- See Also:
BinaryOperator
max
public static int max(int a, int b)
Returns the greater of two int
values as if by calling Math.max
.
- Parameters:
-
a
- the first operand -
b
- the second operand - Returns:
- the greater of
a
andb
- Since:
- 1.8
- See Also:
BinaryOperator
min
public static int min(int a, int b)
Returns the smaller of two int
values as if by calling Math.min
.
- Parameters:
-
a
- the first operand -
b
- the second operand - Returns:
- the smaller of
a
andb
- Since:
- 1.8
- See Also:
BinaryOperator