| Methods Summary |
|---|
| 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.
// HD, Figure 5-2
i = i - ((i >>> 1) & 0x55555555);
i = (i & 0x33333333) + ((i >>> 2) & 0x33333333);
i = (i + (i >>> 4)) & 0x0f0f0f0f;
i = i + (i >>> 8);
i = i + (i >>> 16);
return i & 0x3f;
|
| public byte | byteValue()Returns the value of this Integer as a
byte.
return (byte)value;
|
| public int | compareTo(java.lang.Integer anotherInteger)Compares two Integer objects numerically.
int thisVal = this.value;
int anotherVal = anotherInteger.value;
return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1));
|
| public static java.lang.Integer | decode(java.lang.String nm)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
- Sign:
-
DecimalNumeral, HexDigits, and OctalDigits
are defined in §3.10.1
of the Java
Language Specification.
The sequence of characters following an (optional) negative
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 {@link
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.
int radix = 10;
int index = 0;
boolean negative = false;
Integer result;
// Handle minus sign, if present
if (nm.startsWith("-")) {
negative = true;
index++;
}
// Handle radix specifier, if present
if (nm.startsWith("0x", index) || nm.startsWith("0X", index)) {
index += 2;
radix = 16;
}
else if (nm.startsWith("#", index)) {
index ++;
radix = 16;
}
else if (nm.startsWith("0", index) && nm.length() > 1 + index) {
index ++;
radix = 8;
}
if (nm.startsWith("-", index))
throw new NumberFormatException("Negative sign in wrong position");
try {
result = Integer.valueOf(nm.substring(index), radix);
result = negative ? new Integer(-result.intValue()) : result;
} catch (NumberFormatException e) {
// If number is Integer.MIN_VALUE, we'll end up here. The next line
// handles this case, and causes any genuine format error to be
// rethrown.
String constant = negative ? new String("-" + nm.substring(index))
: nm.substring(index);
result = Integer.valueOf(constant, radix);
}
return result;
|
| public double | doubleValue()Returns the value of this Integer as a
double.
return (double)value;
|
| public boolean | equals(java.lang.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.
if (obj instanceof Integer) {
return value == ((Integer)obj).intValue();
}
return false;
|
| public float | floatValue()Returns the value of this Integer as a
float.
return (float)value;
|
| static void | getChars(int i, int index, char[] buf)Places characters representing the integer i into the
character array buf. The characters are placed into
the buffer backwards starting with the least significant
digit at the specified index (exclusive), and working
backwards from there.
Will fail if i == Integer.MIN_VALUE
int q, r;
int charPos = index;
char sign = 0;
if (i < 0) {
sign = '-";
i = -i;
}
// Generate two digits per iteration
while (i >= 65536) {
q = i / 100;
// really: r = i - (q * 100);
r = i - ((q << 6) + (q << 5) + (q << 2));
i = q;
buf [--charPos] = DigitOnes[r];
buf [--charPos] = DigitTens[r];
}
// Fall thru to fast mode for smaller numbers
// assert(i <= 65536, i);
for (;;) {
q = (i * 52429) >>> (16+3);
r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
buf [--charPos] = digits [r];
i = q;
if (i == 0) break;
}
if (sign != 0) {
buf [--charPos] = sign;
}
|
| public static java.lang.Integer | getInteger(java.lang.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
{@link java.lang.System#getProperty(java.lang.String)} method. The
string value of this property is then interpreted as an integer
value and an Integer object representing this value is
returned. Details of possible numeric formats can be found with
the definition of getProperty.
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)
return getInteger(nm, null);
|
| public static java.lang.Integer | getInteger(java.lang.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 {@link
java.lang.System#getProperty(java.lang.String)} method. The
string value of this property is then interpreted as an integer
value and an Integer object representing this value is
returned. Details of possible numeric formats can be found with
the definition of getProperty.
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.
Integer result = getInteger(nm, null);
return (result == null) ? new Integer(val) : result;
|
| public static java.lang.Integer | getInteger(java.lang.String nm, java.lang.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
{@link java.lang.System#getProperty(java.lang.String)} method.
The string value of this property is then interpreted as an
integer value, as per the Integer.decode method,
and an Integer object representing this value is
returned.
- 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 method
{@link #valueOf(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 method
{@link #valueOf(java.lang.String, int)} with radix 8.
- Otherwise, the property value is parsed as a decimal integer
exactly as by the method {@link #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.
String v = null;
try {
v = System.getProperty(nm);
} catch (IllegalArgumentException e) {
} catch (NullPointerException e) {
}
if (v != null) {
try {
return Integer.decode(v);
} catch (NumberFormatException e) {
}
}
return val;
|
| public int | hashCode()Returns a hash code for this Integer.
return value;
|
| 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.
// HD, Figure 3-1
i |= (i >> 1);
i |= (i >> 2);
i |= (i >> 4);
i |= (i >> 8);
i |= (i >> 16);
return i - (i >>> 1);
|
| public int | intValue()Returns the value of this Integer as an
int.
return value;
|
| public long | longValue()Returns the value of this Integer as a
long.
return (long)value;
|
| 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.
// HD, Section 2-1
return i & -i;
|
| 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)
// HD, Figure 5-6
if (i == 0)
return 32;
int n = 1;
if (i >>> 16 == 0) { n += 16; i <<= 16; }
if (i >>> 24 == 0) { n += 8; i <<= 8; }
if (i >>> 28 == 0) { n += 4; i <<= 4; }
if (i >>> 30 == 0) { n += 2; i <<= 2; }
n -= i >>> 31;
return n;
|
| 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.
// HD, Figure 5-14
int y;
if (i == 0) return 32;
int n = 31;
y = i <<16; if (y != 0) { n = n -16; i = y; }
y = i << 8; if (y != 0) { n = n - 8; i = y; }
y = i << 4; if (y != 0) { n = n - 4; i = y; }
y = i << 2; if (y != 0) { n = n - 2; i = y; }
return n - ((i << 1) >>> 31);
|
| public static int | parseInt(java.lang.String s)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. The resulting
integer value is returned, exactly as if the argument and the radix
10 were given as arguments to the
{@link #parseInt(java.lang.String, int)} method.
return parseInt(s,10);
|
| public static int | parseInt(java.lang.String s, int radix)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 {@link java.lang.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. 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
{@link java.lang.Character#MIN_RADIX} or
larger than {@link java.lang.Character#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') 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("-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
if (s == null) {
throw new NumberFormatException("null");
}
if (radix < Character.MIN_RADIX) {
throw new NumberFormatException("radix " + radix +
" less than Character.MIN_RADIX");
}
if (radix > Character.MAX_RADIX) {
throw new NumberFormatException("radix " + radix +
" greater than Character.MAX_RADIX");
}
int result = 0;
boolean negative = false;
int i = 0, max = s.length();
int limit;
int multmin;
int digit;
if (max > 0) {
if (s.charAt(0) == '-") {
negative = true;
limit = Integer.MIN_VALUE;
i++;
} else {
limit = -Integer.MAX_VALUE;
}
multmin = limit / radix;
if (i < max) {
digit = Character.digit(s.charAt(i++),radix);
if (digit < 0) {
throw NumberFormatException.forInputString(s);
} else {
result = -digit;
}
}
while (i < max) {
// Accumulating negatively avoids surprises near MAX_VALUE
digit = Character.digit(s.charAt(i++),radix);
if (digit < 0) {
throw NumberFormatException.forInputString(s);
}
if (result < multmin) {
throw NumberFormatException.forInputString(s);
}
result *= radix;
if (result < limit + digit) {
throw NumberFormatException.forInputString(s);
}
result -= digit;
}
} else {
throw NumberFormatException.forInputString(s);
}
if (negative) {
if (i > 1) {
return result;
} else { /* Only got "-" */
throw NumberFormatException.forInputString(s);
}
} else {
return -result;
}
|
| 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.
// HD, Figure 7-1
i = (i & 0x55555555) << 1 | (i >>> 1) & 0x55555555;
i = (i & 0x33333333) << 2 | (i >>> 2) & 0x33333333;
i = (i & 0x0f0f0f0f) << 4 | (i >>> 4) & 0x0f0f0f0f;
i = (i << 24) | ((i & 0xff00) << 8) |
((i >>> 8) & 0xff00) | (i >>> 24);
return i;
|
| 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.
return ((i >>> 24) ) |
((i >> 8) & 0xFF00) |
((i << 8) & 0xFF0000) |
((i << 24));
|
| 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).
return (i << distance) | (i >>> -distance);
|
| 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).
return (i >>> distance) | (i << -distance);
|
| public short | shortValue()Returns the value of this Integer as a
short.
return (short)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.)
// HD, Section 2-7
return (i >> 31) | (-i >>> 31);
|
| static int | stringSize(int x)
// Requires positive x
for (int i=0; ; i++)
if (x <= sizeTable[i])
return i+1;
|
| public static java.lang.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 0s.
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.
return toUnsignedString(i, 1);
|
| public static java.lang.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
0s. 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
These are the characters '\u0030' through
'\u0039' and '\u0061' through
'\u0066'. If uppercase letters are
desired, the {@link java.lang.String#toUpperCase()} method may
be called on the result:
Integer.toHexString(n).toUpperCase()
return toUnsignedString(i, 4);
|
| public static java.lang.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 0s.
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
These are the characters '\u0030' through
'\u0037'.
return toUnsignedString(i, 3);
|
| public static java.lang.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:
0123456789abcdefghijklmnopqrstuvwxyz
These 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 {@link java.lang.String#toUpperCase()} method may
be called on the result:
Integer.toString(n, 16).toUpperCase()
if (radix < Character.MIN_RADIX || radix > Character.MAX_RADIX)
radix = 10;
/* Use the faster version */
if (radix == 10) {
return toString(i);
}
char buf[] = new char[33];
boolean negative = (i < 0);
int charPos = 32;
if (!negative) {
i = -i;
}
while (i <= -radix) {
buf[charPos--] = digits[-(i % radix)];
i = i / radix;
}
buf[charPos] = digits[-i];
if (negative) {
buf[--charPos] = '-";
}
return new String(buf, charPos, (33 - charPos));
|
| public java.lang.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 {@link
java.lang.Integer#toString(int)} method.
return String.valueOf(value);
|
| public static java.lang.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 {@link
#toString(int, int)} method.
// I use the "invariant division by multiplication" trick to
// accelerate Integer.toString. In particular we want to
// avoid division by 10.
//
// The "trick" has roughly the same performance characteristics
// as the "classic" Integer.toString code on a non-JIT VM.
// The trick avoids .rem and .div calls but has a longer code
// path and is thus dominated by dispatch overhead. In the
// JIT case the dispatch overhead doesn't exist and the
// "trick" is considerably faster than the classic code.
//
// TODO-FIXME: convert (x * 52429) into the equiv shift-add
// sequence.
//
// RE: Division by Invariant Integers using Multiplication
// T Gralund, P Montgomery
// ACM PLDI 1994
//
if (i == Integer.MIN_VALUE)
return "-2147483648";
int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
char[] buf = new char[size];
getChars(i, size, buf);
return new String(0, size, buf);
|
| private static java.lang.String | toUnsignedString(int i, int shift)Convert the integer to an unsigned number.
char[] buf = new char[32];
int charPos = 32;
int radix = 1 << shift;
int mask = radix - 1;
do {
buf[--charPos] = digits[i & mask];
i >>>= shift;
} while (i != 0);
return new String(buf, charPos, (32 - charPos));
|
| public static java.lang.Integer | valueOf(java.lang.String s, int radix)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 {@link #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))
return new Integer(parseInt(s,radix));
|
| public static java.lang.Integer | valueOf(java.lang.String s)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 {@link
#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))
return new Integer(parseInt(s, 10));
|
| public static java.lang.Integer | valueOf(int i)Returns a 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
{@link #Integer(int)}, as this method is likely to yield
significantly better space and time performance by caching
frequently requested values.
for(int i = 0; i < cache.length; i++)
cache[i] = new Integer(i - 128);
final int offset = 128;
if (i >= -128 && i <= 127) { // must cache
return IntegerCache.cache[i + offset];
}
return new Integer(i);
|
