public final classIntegerextendsNumberimplementsComparable<Integer>
Integer class wraps a value of the primitive typeint in an object. An object of typeInteger contains a single field whose type isint.In addition, this class provides several methods for converting anint to aString and aString to anint, as well as other constants and methods useful when dealing with anint.
Implementation note: The implementations of the "bit twiddling" methods (such ashighestOneBit andnumberOfTrailingZeros) are based on material from Henry S. Warren, Jr.'sHacker's Delight, (Addison Wesley, 2002).
| Modifier and Type | Field | Description |
|---|---|---|
static int | BYTES | The number of bytes used to represent a int value in two's complement binary form. |
static int | MAX_VALUE | A constant holding the maximum value an int can have, 231-1. |
static int | MIN_VALUE | A constant holding the minimum value an int can have, -231. |
static int | SIZE | The number of bits used to represent an int value in two's complement binary form. |
staticClass<Integer> | TYPE | The Class instance representing the primitive typeint. |
| Constructor | Description |
|---|---|
Integer(int value) | Constructs a newly allocated Integer object that represents the specifiedint value. |
Integer(String s) | Constructs a newly allocated Integer object that represents theint value indicated by theString parameter. |
| 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 int value. |
byte | byteValue() | Returns the value of this Integer as abyte after a narrowing primitive conversion. |
static int | compare(int x, int y) | Compares two int values numerically. |
int | compareTo(Integer anotherInteger) | Compares two Integer objects numerically. |
static int | compareUnsigned(int x, int y) | Compares two int values numerically treating the values as unsigned. |
staticInteger | decode(String nm) | Decodes a String into anInteger. |
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 Integer as adouble after a widening primitive conversion. |
boolean | equals(Object obj) | Compares this object to the specified object. |
float | floatValue() | Returns the value of this Integer as afloat after a widening primitive conversion. |
staticInteger | getInteger(String nm) | Determines the integer value of the system property with the specified name. |
staticInteger | getInteger(String nm, int val) | Determines the integer value of the system property with the specified name. |
staticInteger | 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 Integer. |
static int | hashCode(int value) | Returns a hash code for a int value; compatible withInteger.hashCode(). |
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 specifiedint value. |
int | intValue() | Returns the value of this Integer as anint. |
long | longValue() | Returns the value of this Integer as along after a widening primitive conversion. |
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 specifiedint value. |
static int | max(int a, int b) | Returns the greater of two int values as if by callingMath.max. |
static int | min(int a, int b) | Returns the smaller of two int values as if by callingMath.min. |
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. |
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. |
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(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 int value. |
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. |
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. |
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. |
short | shortValue() | Returns the value of this Integer as ashort after a narrowing primitive conversion. |
static int | signum(int i) | Returns the signum function of the specified int value. |
static int | sum(int a, int b) | Adds two integers together as per the + operator. |
staticString | toBinaryString(int i) | Returns a string representation of the integer argument as an unsigned integer in base 2. |
staticString | toHexString(int i) | Returns a string representation of the integer argument as an unsigned integer in base 16. |
staticString | toOctalString(int i) | Returns a string representation of the integer argument as an unsigned integer in base 8. |
String | toString() | Returns a String object representing thisInteger's value. |
staticString | toString(int i) | Returns a String object representing the specified integer. |
staticString | 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 long by an unsigned conversion. |
staticString | toUnsignedString(int i) | Returns a string representation of the argument as an unsigned decimal value. |
staticString | 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. |
staticInteger | valueOf(int i) | Returns an Integer instance representing the specifiedint value. |
staticInteger | valueOf(String s) | Returns an Integer object holding the value of the specifiedString. |
staticInteger | valueOf(String s, int radix) | Returns an Integer object holding the value extracted from the specifiedString when parsed with the radix given by the second argument. |
@Nativepublic static final int MIN_VALUE
int can have, -231.@Nativepublic static final int MAX_VALUE
int can have, 231-1.public static final Class<Integer> TYPE
Class instance representing the primitive typeint.@Nativepublic static final int SIZE
int value in two's complement binary form.public static final int BYTES
int value in two's complement binary form.public Integer(int value)
Integer object that represents the specifiedint value.value - the value to be represented by theInteger object.public Integer(String s) throwsNumberFormatException
Integer object that represents theint value indicated by theString parameter. The string is converted to anint value in exactly the manner used by theparseInt method for radix 10.s - theString to be converted to anInteger.NumberFormatException - if theString does not contain a parsable integer.parseInt(java.lang.String, int)public static String toString(int i, int radix)
If the radix is smaller thanCharacter.MIN_RADIX or larger thanCharacter.MAX_RADIX, then the radix10 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:
0123456789abcdefghijklmnopqrstuvwxyz'\u0030' through'\u0039' and'\u0061' through'\u007A'. Ifradix isN, then the firstN of these characters are used as radix-N digits in the order shown. Thus, the digits for hexadecimal (radix 16) are0123456789abcdef. If uppercase letters are desired, theString.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_RADIXpublic static String toUnsignedString(int i, int radix)
If the radix is smaller thanCharacter.MIN_RADIX or larger thanCharacter.MAX_RADIX, then the radix10 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 astoString.
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)
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 leading0s.
The value of the argument can be recovered from the returned strings by callingInteger.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:
0123456789abcdef'\u0030' through'\u0039' and'\u0061' through'\u0066'. If uppercase letters are desired, theString.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)
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 leading0s.
The value of the argument can be recovered from the returned strings by callingInteger.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:
01234567'\u0030' through'\u0037'.i - an integer to be converted to a string.parseUnsignedInt(String, int),toUnsignedString(int, int)public static String toBinaryString(int i)
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 leading0s.
The value of the argument can be recovered from the returned strings by callingInteger.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)
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 thetoString(int, int) method.i - an integer to be converted.public static String toUnsignedString(int i)
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) throwsNumberFormatException
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 typeNumberFormatException is thrown if any of the following situations occurs:
null or is a string of length zero.Character.MIN_RADIX or larger thanCharacter.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 411787s - theString containing the integer representation to be parsedradix - the radix to be used while parsings.NumberFormatException - if theString does not contain a parsableint.public static int parseInt(String s) throwsNumberFormatException
'-' ('\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 theparseInt(java.lang.String, int) method.s - aString containing theint representation to be parsedNumberFormatException - if the string does not contain a parsable integer.public static int parseUnsignedInt(String s, int radix) throwsNumberFormatException
MAX_VALUE. The characters in the string must all be digits of the specified radix (as determined by whetherCharacter.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 typeNumberFormatException is thrown if any of the following situations occurs:
null or is a string of length zero.Character.MIN_RADIX or larger thanCharacter.MAX_RADIX.'+' ('\u002B') provided that the string is longer than length 1.int, 232-1.s - theString containing the unsigned integer representation to be parsedradix - the radix to be used while parsings.NumberFormatException - if theString does not contain a parsableint.public static int parseUnsignedInt(String s) throwsNumberFormatException
'+' ('\u002B'). The resulting integer value is returned, exactly as if the argument and the radix 10 were given as arguments to theparseUnsignedInt(java.lang.String, int) method.s - aString containing the unsignedint representation to be parsedNumberFormatException - if the string does not contain a parsable unsigned integer.public static Integer valueOf(String s, int radix) throwsNumberFormatException
Integer object holding the value extracted from the specifiedString 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 theparseInt(java.lang.String, int) method. The result is anInteger object that represents the integer value specified by the string.In other words, this method returns anInteger 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 interpretingsInteger object holding the value represented by the string argument in the specified radix.NumberFormatException - if theString does not contain a parsableint.public static Integer valueOf(String s) throwsNumberFormatException
Integer object holding the value of the specifiedString. The argument is interpreted as representing a signed decimal integer, exactly as if the argument were given to theparseInt(java.lang.String) method. The result is anInteger object that represents the integer value specified by the string.In other words, this method returns anInteger 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)
Integer instance representing the specifiedint value. If a newInteger instance is not required, this method should generally be used in preference to the constructorInteger(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 - anint value.Integer instance representingi.public byte byteValue()
Integer as abyte after a narrowing primitive conversion.public short shortValue()
Integer as ashort after a narrowing primitive conversion.shortValue in class Numbershort.public int intValue()
Integer as anint.public long longValue()
Integer as along after a widening primitive conversion.longValue in class Numberlong.toUnsignedLong(int)public float floatValue()
Integer as afloat after a widening primitive conversion.floatValue in class Numberfloat.public double doubleValue()
Integer as adouble after a widening primitive conversion.doubleValue in class Numberdouble.public String toString()
String object representing thisInteger'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 thetoString(int) method.public int hashCode()
Integer.hashCode in class Objectint value represented by thisInteger object.Object.equals(java.lang.Object),System.identityHashCode(java.lang.Object)public static int hashCode(int value)
int value; compatible withInteger.hashCode().value - the value to hashint value.public boolean equals(Object obj)
true if and only if the argument is notnull and is anInteger object that contains the sameint value as this object.equals in class Objectobj - the object to compare with.true if the objects are the same;false otherwise.Object.hashCode(),HashMappublic static Integer getInteger(String nm)
The first argument is treated as the name of a system property. System properties are accessible through theSystem.getProperty(java.lang.String) method. The string value of this property is then interpreted as an integer value using the grammar supported bydecode and anInteger object representing this value is returned.
If there is no property with the specified name, if the specified name is empty ornull, or if the property does not have the correct numeric format, thennull is returned.
In other words, this method returns anInteger object equal to the value of:
getInteger(nm, null)nm - property name.Integer value of the property.SecurityException - for the same reasons asSystem.getPropertySystem.getProperty(java.lang.String),System.getProperty(java.lang.String, java.lang.String)public static Integer getInteger(String nm, int val)
The first argument is treated as the name of a system property. System properties are accessible through theSystem.getProperty(java.lang.String) method. The string value of this property is then interpreted as an integer value using the grammar supported bydecode and anInteger object representing this value is returned.
The second argument is the default value. AnInteger 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 ornull.
In other words, this method returns anInteger object equal to the value of:
getInteger(nm, new Integer(val))to avoid the unnecessary allocation of anInteger result = getInteger(nm, null); return (result == null) ? new Integer(val) : result;
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 asSystem.getPropertySystem.getProperty(java.lang.String),System.getProperty(java.lang.String, java.lang.String)public static Integer getInteger(String nm,Integer val)
System.getProperty(java.lang.String) method. The string value of this property is then interpreted as an integer value, as per thedecode method, and anInteger 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 methodvalueOf(java.lang.String, int) with radix 16.0 followed by another character, it is parsed as an octal integer exactly as by the methodvalueOf(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 ornull.
nm - property name.val - default value.Integer value of the property.SecurityException - for the same reasons asSystem.getPropertySystem.getProperty(java.lang.String),System.getProperty(java.lang.String, java.lang.String)public static Integer decode(String nm) throwsNumberFormatException
String into anInteger. Accepts decimal, hexadecimal, and octal numbers given by the following grammar:DecimalNumeral,HexDigits, andOctalDigits are as defined in section 3.10.1 ofThe Java™ Language Specification, except that underscores are not accepted between digits.
- DecodableString:
- Signopt DecimalNumeral
- Signopt
0xHexDigits- Signopt
0XHexDigits- Signopt
#HexDigits- Signopt
0OctalDigits- Sign:
-+
The sequence of characters following an optional sign and/or radix specifier ("0x", "0X", "#", or leading zero) is parsed as by theInteger.parseInt method with the indicated radix (10, 16, or 8). This sequence of characters must represent a positive value or aNumberFormatException will be thrown. The result is negated if first character of the specifiedString is the minus sign. No whitespace characters are permitted in theString.
nm - theString to decode.Integer object holding theint value represented bynmNumberFormatException - if theString does not contain a parsable integer.parseInt(java.lang.String, int)public int compareTo(Integer anotherInteger)
Integer objects numerically.compareTo in interface Comparable<Integer>anotherInteger - theInteger to be compared.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).public static int compare(int x, int y)
int values numerically. The value returned is identical to what would be returned by:Integer.valueOf(x).compareTo(Integer.valueOf(y))
x - the firstint to comparey - the secondint to compare0 ifx == y; a value less than0 ifx < y; and a value greater than0 ifx > ypublic static int compareUnsigned(int x, int y)
int values numerically treating the values as unsigned.x - the firstint to comparey - the secondint to compare0 ifx == y; a value less than0 ifx < y as unsigned values; and a value greater than0 ifx > y as unsigned valuespublic static long toUnsignedLong(int x)
long by an unsigned conversion. In an unsigned conversion to along, the high-order 32 bits of thelong are zero and the low-order 32 bits are equal to the bits of the integer argument. Consequently, zero and positiveint values are mapped to a numerically equallong value and negativeint values are mapped to along value equal to the input plus 232.x - the value to convert to an unsignedlonglong by an unsigned conversionpublic static int divideUnsigned(int dividend, int divisor)
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 separateaddUnsigned, 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)
dividend - the value to be divideddivisor - the value doing the dividingdivideUnsigned(int, int)public static int highestOneBit(int i)
int value with at most a single one-bit, in the position of the highest-order ("leftmost") one-bit in the specifiedint 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)
int value with at most a single one-bit, in the position of the lowest-order ("rightmost") one-bit in the specifiedint 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)
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 positiveint 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)
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)
int value. This function is sometimes referred to as thepopulation count.i - the value whose bits are to be countedint value.public static int rotateLeft(int i, int distance)
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)
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)
int value.i - the value to be reversedint value.public static int signum(int i)
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)
int value.i - the value whose bytes are to be reversedint value.public static int sum(int a, int b)
a - the first operandb - the second operanda andbBinaryOperatorpublic static int max(int a, int b)
int values as if by callingMath.max.a - the first operandb - the second operanda andbBinaryOperatorpublic static int min(int a, int b)
int values as if by callingMath.min.a - the first operandb - the second operanda andbBinaryOperator