java/6 : java/lang/Integer.java

Integer
https://openjdk.java.net/
GPLv2 + Classpath Exception
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package java.lang;

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).
Author:  Lee Boynton,  Arthur van Hoff,  Josh Bloch,  Joseph D. Darcy
Since: JDK1.0/**
 * The {@code Integer} class wraps a value of the primitive type
 * {@code int} in an object. An object of type {@code Integer}
 * contains a single field whose type is {@code int}.
 *
 * <p>In addition, this class provides several methods for converting
 * an {@code int} to a {@code String} and a {@code String} to an
 * {@code int}, as well as other constants and methods useful when
 * dealing with an {@code int}.
 *
 * <p>Implementation note: The implementations of the "bit twiddling"
 * methods (such as {@link #highestOneBit(int) highestOneBit} and
 * {@link #numberOfTrailingZeros(int) numberOfTrailingZeros}) are
 * based on material from Henry S. Warren, Jr.'s <i>Hacker's
 * Delight</i>, (Addison Wesley, 2002).
 *
 * @author  Lee Boynton
 * @author  Arthur van Hoff
 * @author  Josh Bloch
 * @author  Joseph D. Darcy
 * @since JDK1.0
 */
public final class Integer extends Number implements Comparable<Integer> {
    A constant holding the minimum value an int can have, -2³¹.
/**
     * A constant holding the minimum value an {@code int} can
     * have, -2<sup>31</sup>.
     */
    public static final int   MIN_VALUE = 0x80000000;

    A constant holding the maximum value an int can have, 2³¹-1.
/**
     * A constant holding the maximum value an {@code int} can
     * have, 2<sup>31</sup>-1.
     */
    public static final int   MAX_VALUE = 0x7fffffff;

    The Class instance representing the primitive type int. 
Since:   JDK1.1/**
     * The {@code Class} instance representing the primitive type
     * {@code int}.
     *
     * @since   JDK1.1
     */
    public static final Class<Integer>  TYPE = (Class<Integer>) Class.getPrimitiveClass("int");

    All possible chars for representing a number as a String
/**
     * All possible chars for representing a number as a String
     */
    final static char[] digits = {
        '0' , '1' , '2' , '3' , '4' , '5' ,
        '6' , '7' , '8' , '9' , 'a' , 'b' ,
        'c' , 'd' , 'e' , 'f' , 'g' , 'h' ,
        'i' , 'j' , 'k' , 'l' , 'm' , 'n' ,
        'o' , 'p' , 'q' , 'r' , 's' , 't' ,
        'u' , 'v' , 'w' , 'x' , 'y' , 'z'
    };

    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 String.toUpperCase() method may be called on the result:  Integer.toString(n, 16).toUpperCase() 
Params: i –       an integer to be converted to a string.
radix –   the radix to use in the string representation.
See Also: Character.MAX_RADIX
Character.MIN_RADIX
Returns:  a string representation of the argument in the specified radix./**
     * Returns a string representation of the first argument in the
     * radix specified by the second argument.
     *
     * <p>If the radix is smaller than {@code Character.MIN_RADIX}
     * or larger than {@code Character.MAX_RADIX}, then the radix
     * {@code 10} is used instead.
     *
     * <p>If the first argument is negative, the first element of the
     * result is the ASCII minus character {@code '-'}
     * (<code>'&#92;u002D'</code>). If the first argument is not
     * negative, no sign character appears in the result.
     *
     * <p>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 {@code '0'}
     * (<code>'&#92;u0030'</code>); otherwise, the first character of
     * the representation of the magnitude will not be the zero
     * character.  The following ASCII characters are used as digits:
     *
     * <blockquote>
     *   {@code 0123456789abcdefghijklmnopqrstuvwxyz}
     * </blockquote>
     *
     * These are <code>'&#92;u0030'</code> through
     * <code>'&#92;u0039'</code> and <code>'&#92;u0061'</code> through
     * <code>'&#92;u007A'</code>. If {@code radix} is
     * <var>N</var>, then the first <var>N</var> of these characters
     * are used as radix-<var>N</var> digits in the order shown. Thus,
     * the digits for hexadecimal (radix 16) are
     * {@code 0123456789abcdef}. If uppercase letters are
     * desired, the {@link java.lang.String#toUpperCase()} method may
     * be called on the result:
     *
     * <blockquote>
     *  {@code Integer.toString(n, 16).toUpperCase()}
     * </blockquote>
     *
     * @param   i       an integer to be converted to a string.
     * @param   radix   the radix to use in the string representation.
     * @return  a string representation of the argument in the specified radix.
     * @see     java.lang.Character#MAX_RADIX
     * @see     java.lang.Character#MIN_RADIX
     */
    public static String toString(int i, int radix) {

        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));
    }

    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 String.toUpperCase() method may be called on the result:  Integer.toHexString(n).toUpperCase() 
Params: 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:   JDK1.0.2/**
     * Returns a string representation of the integer argument as an
     * unsigned integer in base&nbsp;16.
     *
     * <p>The unsigned integer value is the argument plus 2<sup>32</sup>
     * 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&nbsp;16) with no extra leading
     * {@code 0}s. If the unsigned magnitude is zero, it is
     * represented by a single zero character {@code '0'}
     * (<code>'&#92;u0030'</code>); 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:
     *
     * <blockquote>
     *  {@code 0123456789abcdef}
     * </blockquote>
     *
     * These are the characters <code>'&#92;u0030'</code> through
     * <code>'&#92;u0039'</code> and <code>'&#92;u0061'</code> through
     * <code>'&#92;u0066'</code>. If uppercase letters are
     * desired, the {@link java.lang.String#toUpperCase()} method may
     * be called on the result:
     *
     * <blockquote>
     *  {@code Integer.toHexString(n).toUpperCase()}
     * </blockquote>
     *
     * @param   i   an integer to be converted to a string.
     * @return  the string representation of the unsigned integer value
     *          represented by the argument in hexadecimal (base&nbsp;16).
     * @since   JDK1.0.2
     */
    public static String toHexString(int i) {
        return toUnsignedString(i, 4);
    }

    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'.
Params: 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:   JDK1.0.2/**
     * Returns a string representation of the integer argument as an
     * unsigned integer in base&nbsp;8.
     *
     * <p>The unsigned integer value is the argument plus 2<sup>32</sup>
     * 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&nbsp;8) with no extra leading {@code 0}s.
     *
     * <p>If the unsigned magnitude is zero, it is represented by a
     * single zero character {@code '0'}
     * (<code>'&#92;u0030'</code>); 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:
     *
     * <blockquote>
     * {@code 01234567}
     * </blockquote>
     *
     * These are the characters <code>'&#92;u0030'</code> through
     * <code>'&#92;u0037'</code>.
     *
     * @param   i   an integer to be converted to a string.
     * @return  the string representation of the unsigned integer value
     *          represented by the argument in octal (base&nbsp;8).
     * @since   JDK1.0.2
     */
    public static String toOctalString(int i) {
        return toUnsignedString(i, 3);
    }

    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.
Params: 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:   JDK1.0.2/**
     * Returns a string representation of the integer argument as an
     * unsigned integer in base&nbsp;2.
     *
     * <p>The unsigned integer value is the argument plus 2<sup>32</sup>
     * 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&nbsp;2) with no extra leading {@code 0}s.
     * If the unsigned magnitude is zero, it is represented by a
     * single zero character {@code '0'}
     * (<code>'&#92;u0030'</code>); otherwise, the first character of
     * the representation of the unsigned magnitude will not be the
     * zero character. The characters {@code '0'}
     * (<code>'&#92;u0030'</code>) and {@code '1'}
     * (<code>'&#92;u0031'</code>) are used as binary digits.
     *
     * @param   i   an integer to be converted to a string.
     * @return  the string representation of the unsigned integer value
     *          represented by the argument in binary (base&nbsp;2).
     * @since   JDK1.0.2
     */
    public static String toBinaryString(int i) {
        return toUnsignedString(i, 1);
    }

    Convert the integer to an unsigned number.
/**
     * Convert the integer to an unsigned number.
     */
    private static String toUnsignedString(int i, int shift) {
        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));
    }


    final static char [] DigitTens = {
        '0', '0', '0', '0', '0', '0', '0', '0', '0', '0',
        '1', '1', '1', '1', '1', '1', '1', '1', '1', '1',
        '2', '2', '2', '2', '2', '2', '2', '2', '2', '2',
        '3', '3', '3', '3', '3', '3', '3', '3', '3', '3',
        '4', '4', '4', '4', '4', '4', '4', '4', '4', '4',
        '5', '5', '5', '5', '5', '5', '5', '5', '5', '5',
        '6', '6', '6', '6', '6', '6', '6', '6', '6', '6',
        '7', '7', '7', '7', '7', '7', '7', '7', '7', '7',
        '8', '8', '8', '8', '8', '8', '8', '8', '8', '8',
        '9', '9', '9', '9', '9', '9', '9', '9', '9', '9',
        } ;

    final static char [] DigitOnes = {
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
        } ;

        // 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
        //

    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. 
Params: i –   an integer to be converted.
Returns:  a string representation of the argument in base 10./**
     * Returns a {@code 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.
     *
     * @param   i   an integer to be converted.
     * @return  a string representation of the argument in base&nbsp;10.
     */
    public static String toString(int i) {
        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);
    }

    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
/**
     * 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
     */
    static void getChars(int i, int index, char[] buf) {
        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;
        }
    }

    final static int [] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999,
                                      99999999, 999999999, Integer.MAX_VALUE };

    // Requires positive x
    static int stringSize(int x) {
        for (int i=0; ; i++)
            if (x <= sizeTable[i])
                return i+1;
    }

    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. 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 than 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

Params: s –  the String containing the integer representation to be parsed
radix –  the radix to be used while parsing s.
Throws: NumberFormatException – if the String does not contain a parsable int.
Returns:     the integer represented by the string argument in the
            specified 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 {@code '-'} (<code>'&#92;u002D'</code>) to
     * indicate a negative value. The resulting integer value is
     * returned.
     *
     * <p>An exception of type {@code NumberFormatException} is
     * thrown if any of the following situations occurs:
     * <ul>
     * <li>The first argument is {@code null} or is a string of
     * length zero.
     *
     * <li>The radix is either smaller than
     * {@link java.lang.Character#MIN_RADIX} or
     * larger than {@link java.lang.Character#MAX_RADIX}.
     *
     * <li>Any character of the string is not a digit of the specified
     * radix, except that the first character may be a minus sign
     * {@code '-'} (<code>'&#92;u002D'</code>) provided that the
     * string is longer than length 1.
     *
     * <li>The value represented by the string is not a value of type
     * {@code int}.
     * </ul>
     *
     * <p>Examples:
     * <blockquote><pre>
     * 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
     * </pre></blockquote>
     *
     * @param      s   the {@code String} containing the integer
     *                  representation to be parsed
     * @param      radix   the radix to be used while parsing {@code s}.
     * @return     the integer represented by the string argument in the
     *             specified radix.
     * @exception  NumberFormatException if the {@code String}
     *             does not contain a parsable {@code int}.
     */
    public static int parseInt(String s, int radix)
                throws NumberFormatException
    {
        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, len = s.length();
        int limit = -Integer.MAX_VALUE;
        int multmin;
        int digit;

        if (len > 0) {
            char firstChar = s.charAt(0);
            if (firstChar < '0') { // Possible leading "-"
                if (firstChar == '-') {
                    negative = true;
                    limit = Integer.MIN_VALUE;
                } else
                    throw NumberFormatException.forInputString(s);

                if (len == 1) // Cannot have lone "-"
                    throw NumberFormatException.forInputString(s);
                i++;
            }
            multmin = limit / radix;
            while (i < len) {
                // 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);
        }
        return negative ? result : -result;
    }

    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 parseInt(String, int) method. 
Params: s –  a String containing the int representation to be parsed
Throws: NumberFormatException –  if the string does not contain a
              parsable integer.
Returns:     the integer value represented by the argument in decimal./**
     * 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 {@code '-'}
     * (<code>'&#92;u002D'</code>) 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.
     *
     * @param s    a {@code String} containing the {@code int}
     *             representation to be parsed
     * @return     the integer value represented by the argument in decimal.
     * @exception  NumberFormatException  if the string does not contain a
     *               parsable integer.
     */
    public static int parseInt(String s) throws NumberFormatException {
        return parseInt(s,10);
    }

    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(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)) 
Params: s –   the string to be parsed.
radix – the radix to be used in interpreting s
Throws: NumberFormatException – if the String does not contain a parsable int.
Returns:  an Integer object holding the value represented by the string argument in the specified radix./**
     * Returns an {@code Integer} object holding the value
     * extracted from the specified {@code 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 {@code Integer} object that
     * represents the integer value specified by the string.
     *
     * <p>In other words, this method returns an {@code Integer}
     * object equal to the value of:
     *
     * <blockquote>
     *  {@code new Integer(Integer.parseInt(s, radix))}
     * </blockquote>
     *
     * @param      s   the string to be parsed.
     * @param      radix the radix to be used in interpreting {@code s}
     * @return     an {@code Integer} object holding the value
     *             represented by the string argument in the specified
     *             radix.
     * @exception NumberFormatException if the {@code String}
     *            does not contain a parsable {@code int}.
     */
    public static Integer valueOf(String s, int radix) throws NumberFormatException {
        return new Integer(parseInt(s,radix));
    }

    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(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)) 
Params: s –   the string to be parsed.
Throws: NumberFormatException –  if the string cannot be parsed
            as an integer.
Returns:  an Integer object holding the value represented by the string argument./**
     * Returns an {@code Integer} object holding the
     * value of the specified {@code 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
     * {@code Integer} object that represents the integer value
     * specified by the string.
     *
     * <p>In other words, this method returns an {@code Integer}
     * object equal to the value of:
     *
     * <blockquote>
     *  {@code new Integer(Integer.parseInt(s))}
     * </blockquote>
     *
     * @param      s   the string to be parsed.
     * @return     an {@code Integer} object holding the value
     *             represented by the string argument.
     * @exception  NumberFormatException  if the string cannot be parsed
     *             as an integer.
     */
    public static Integer valueOf(String s) throws NumberFormatException
    {
        return new Integer(parseInt(s, 10));
    }

    private static class IntegerCache {
        private IntegerCache(){}

        static final Integer cache[] = new Integer[-(-128) + 127 + 1];

        static {
            for(int i = 0; i < cache.length; i++)
                cache[i] = new Integer(i - 128);
        }
    }

    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. 
Params: i – an int value.
Returns: an Integer instance representing i.
Since:  1.5/**
     * Returns an {@code Integer} instance representing the specified
     * {@code int} value.  If a new {@code 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.
     *
     * @param  i an {@code int} value.
     * @return an {@code Integer} instance representing {@code i}.
     * @since  1.5
     */
    public static Integer valueOf(int i) {
        final int offset = 128;
        if (i >= -128 && i <= 127) { // must cache
            return IntegerCache.cache[i + offset];
        }
        return new Integer(i);
    }

    The value of the Integer. 
@serial /**
     * The value of the {@code Integer}.
     *
     * @serial
     */
    private final int value;

    Constructs a newly allocated Integer object that represents the specified int value. 
Params: value –  the value to be represented by the Integer object./**
     * Constructs a newly allocated {@code Integer} object that
     * represents the specified {@code int} value.
     *
     * @param   value   the value to be represented by the
     *                  {@code Integer} object.
     */
    public Integer(int value) {
        this.value = value;
    }

    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. 
Params: s –  the String to be converted to an Integer.
Throws: NumberFormatException –  if the String does not contain a parsable integer.
See Also: parseInt(String, int)/**
     * Constructs a newly allocated {@code Integer} object that
     * represents the {@code int} value indicated by the
     * {@code String} parameter. The string is converted to an
     * {@code int} value in exactly the manner used by the
     * {@code parseInt} method for radix 10.
     *
     * @param      s   the {@code String} to be converted to an
     *                 {@code Integer}.
     * @exception  NumberFormatException  if the {@code String} does not
     *               contain a parsable integer.
     * @see        java.lang.Integer#parseInt(java.lang.String, int)
     */
    public Integer(String s) throws NumberFormatException {
        this.value = parseInt(s, 10);
    }

    Returns the value of this Integer as a byte. /**
     * Returns the value of this {@code Integer} as a
     * {@code byte}.
     */
    public byte byteValue() {
        return (byte)value;
    }

    Returns the value of this Integer as a short. /**
     * Returns the value of this {@code Integer} as a
     * {@code short}.
     */
    public short shortValue() {
        return (short)value;
    }

    Returns the value of this Integer as an int. /**
     * Returns the value of this {@code Integer} as an
     * {@code int}.
     */
    public int intValue() {
        return value;
    }

    Returns the value of this Integer as a long. /**
     * Returns the value of this {@code Integer} as a
     * {@code long}.
     */
    public long longValue() {
        return (long)value;
    }

    Returns the value of this Integer as a float. /**
     * Returns the value of this {@code Integer} as a
     * {@code float}.
     */
    public float floatValue() {
        return (float)value;
    }

    Returns the value of this Integer as a double. /**
     * Returns the value of this {@code Integer} as a
     * {@code double}.
     */
    public double doubleValue() {
        return (double)value;
    }

    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. 
Returns:  a string representation of the value of this object in
         base 10./**
     * Returns a {@code String} object representing this
     * {@code 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  a string representation of the value of this object in
     *          base&nbsp;10.
     */
    public String toString() {
        return String.valueOf(value);
    }

    Returns a hash code for this Integer. 
Returns:  a hash code value for this object, equal to the primitive int value represented by this Integer object./**
     * Returns a hash code for this {@code Integer}.
     *
     * @return  a hash code value for this object, equal to the
     *          primitive {@code int} value represented by this
     *          {@code Integer} object.
     */
    public int hashCode() {
        return value;
    }

    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. 
Params: obj –   the object to compare with.
Returns:  true if the objects are the same; false otherwise./**
     * Compares this object to the specified object.  The result is
     * {@code true} if and only if the argument is not
     * {@code null} and is an {@code Integer} object that
     * contains the same {@code int} value as this object.
     *
     * @param   obj   the object to compare with.
     * @return  {@code true} if the objects are the same;
     *          {@code false} otherwise.
     */
    public boolean equals(Object obj) {
        if (obj instanceof Integer) {
            return value == ((Integer)obj).intValue();
        }
        return false;
    }

    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(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) 
Params: nm –   property name.
See Also: System.getProperty(String)
System.getProperty(String, String)
Returns:  the Integer value of the property./**
     * Determines the integer value of the system property with the
     * specified name.
     *
     * <p>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 {@code Integer} object representing this value is
     * returned. Details of possible numeric formats can be found with
     * the definition of {@code getProperty}.
     *
     * <p>If there is no property with the specified name, if the specified name
     * is empty or {@code null}, or if the property does not have
     * the correct numeric format, then {@code null} is returned.
     *
     * <p>In other words, this method returns an {@code Integer}
     * object equal to the value of:
     *
     * <blockquote>
     *  {@code getInteger(nm, null)}
     * </blockquote>
     *
     * @param   nm   property name.
     * @return  the {@code Integer} value of the property.
     * @see     java.lang.System#getProperty(java.lang.String)
     * @see     java.lang.System#getProperty(java.lang.String, java.lang.String)
     */
    public static Integer getInteger(String nm) {
        return getInteger(nm, null);
    }

    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(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. 
Params: nm –   property name.
val –   default value.
See Also: System.getProperty(String)
System.getProperty(String, String)
Returns:  the Integer value of the property./**
     * Determines the integer value of the system property with the
     * specified name.
     *
     * <p>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 {@code Integer} object representing this value is
     * returned. Details of possible numeric formats can be found with
     * the definition of {@code getProperty}.
     *
     * <p>The second argument is the default value. An {@code 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
     * {@code null}.
     *
     * <p>In other words, this method returns an {@code Integer} object
     * equal to the value of:
     *
     * <blockquote>
     *  {@code getInteger(nm, new Integer(val))}
     * </blockquote>
     *
     * but in practice it may be implemented in a manner such as:
     *
     * <blockquote><pre>
     * Integer result = getInteger(nm, null);
     * return (result == null) ? new Integer(val) : result;
     * </pre></blockquote>
     *
     * to avoid the unnecessary allocation of an {@code Integer}
     * object when the default value is not needed.
     *
     * @param   nm   property name.
     * @param   val   default value.
     * @return  the {@code Integer} value of the property.
     * @see     java.lang.System#getProperty(java.lang.String)
     * @see     java.lang.System#getProperty(java.lang.String, java.lang.String)
     */
    public static Integer getInteger(String nm, int val) {
        Integer result = getInteger(nm, null);
        return (result == null) ? new Integer(val) : result;
    }

    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(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 valueOf(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 valueOf(String, int) with radix 8. 
Otherwise, the property value is parsed as a decimal integer exactly as by the method valueOf(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. 
Params: nm –   property name.
val –   default value.
See Also: System.getProperty(String)
System.getProperty(String, String)
decode
Returns:  the Integer value of the property./**
     * 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 {@code Integer.decode} method,
     * and an {@code Integer} object representing this value is
     * returned.
     *
     * <ul><li>If the property value begins with the two ASCII characters
     *         {@code 0x} or the ASCII character {@code #}, 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.
     * <li>If the property value begins with the ASCII character
     *     {@code 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.
     * <li>Otherwise, the property value is parsed as a decimal integer
     * exactly as by the method {@link #valueOf(java.lang.String, int)}
     * with radix 10.
     * </ul>
     *
     * <p>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 {@code null}.
     *
     * @param   nm   property name.
     * @param   val   default value.
     * @return  the {@code Integer} value of the property.
     * @see     java.lang.System#getProperty(java.lang.String)
     * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
     * @see java.lang.Integer#decode
     */
    public static Integer getInteger(String nm, Integer val) {
        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;
    }

    Decodes a String into an Integer. Accepts decimal, hexadecimal, and octal numbers given by the following grammar: 

DecodableString:
Sign_opt DecimalNumeral
Sign_opt 0x HexDigits
Sign_opt 0X HexDigits
Sign_opt # HexDigits
Sign_opt 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 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. 
Params: nm – the String to decode.
Throws: NumberFormatException –  if the String does not contain a parsable integer.
See Also: parseInt(String, int)
Returns:  an Integer object holding the int value represented by nm/**
     * Decodes a {@code String} into an {@code Integer}.
     * Accepts decimal, hexadecimal, and octal numbers given
     * by the following grammar:
     *
     * <blockquote>
     * <dl>
     * <dt><i>DecodableString:</i>
     * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
     * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
     * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
     * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
     * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
     * <p>
     * <dt><i>Sign:</i>
     * <dd>{@code -}
     * </dl>
     * </blockquote>
     *
     * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
     * are defined in <a href="http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html#48282">&sect;3.10.1</a>
     * of the <a href="http://java.sun.com/docs/books/jls/html/">Java
     * Language Specification</a>.
     *
     * <p>The sequence of characters following an (optional) negative
     * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
     * "{@code #}", or leading zero) is parsed as by the {@code
     * 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 {@code
     * String} is the minus sign.  No whitespace characters are
     * permitted in the {@code String}.
     *
     * @param     nm the {@code String} to decode.
     * @return    an {@code Integer} object holding the {@code int}
     *             value represented by {@code nm}
     * @exception NumberFormatException  if the {@code String} does not
     *            contain a parsable integer.
     * @see java.lang.Integer#parseInt(java.lang.String, int)
     */
    public static Integer decode(String nm) throws NumberFormatException {
        int radix = 10;
        int index = 0;
        boolean negative = false;
        Integer result;

        if (nm.length() == 0)
            throw new NumberFormatException("Zero length string");
        char firstChar = nm.charAt(0);
        // Handle sign, if present
        if (firstChar == '-') {
            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("Sign character 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 ? ("-" + nm.substring(index))
                                       : nm.substring(index);
            result = Integer.valueOf(constant, radix);
        }
        return result;
    }

    Compares two Integer objects numerically. 
Params: anotherInteger –  the Integer to be compared.
Returns:  the value 0 if this Integer is equal to the argument Integer; a value less than 0 if this Integer is numerically less than the argument Integer; and a value greater than 0 if this Integer is numerically greater than the argument Integer (signed comparison).
Since:   1.2/**
     * Compares two {@code Integer} objects numerically.
     *
     * @param   anotherInteger   the {@code Integer} to be compared.
     * @return  the value {@code 0} if this {@code Integer} is
     *          equal to the argument {@code Integer}; a value less than
     *          {@code 0} if this {@code Integer} is numerically less
     *          than the argument {@code Integer}; and a value greater
     *          than {@code 0} if this {@code Integer} is numerically
     *           greater than the argument {@code Integer} (signed
     *           comparison).
     * @since   1.2
     */
    public int compareTo(Integer anotherInteger) {
        int thisVal = this.value;
        int anotherVal = anotherInteger.value;
        return (thisVal<anotherVal ? -1 : (thisVal==anotherVal ? 0 : 1));
    }


    // Bit twiddling

    The number of bits used to represent an int value in two's complement binary form. 
Since: 1.5/**
     * The number of bits used to represent an {@code int} value in two's
     * complement binary form.
     *
     * @since 1.5
     */
    public static final int SIZE = 32;

    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. 
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/**
     * Returns an {@code int} value with at most a single one-bit, in the
     * position of the highest-order ("leftmost") one-bit in the specified
     * {@code 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.
     *
     * @return an {@code 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
     */
    public static int highestOneBit(int i) {
        // HD, Figure 3-1
        i |= (i >>  1);
        i |= (i >>  2);
        i |= (i >>  4);
        i |= (i >>  8);
        i |= (i >> 16);
        return i - (i >>> 1);
    }

    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. 
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/**
     * Returns an {@code int} value with at most a single one-bit, in the
     * position of the lowest-order ("rightmost") one-bit in the specified
     * {@code 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.
     *
     * @return an {@code 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
     */
    public static int lowestOneBit(int i) {
        // HD, Section 2-1
        return i & -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) 
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/**
     * Returns the number of zero bits preceding the highest-order
     * ("leftmost") one-bit in the two's complement binary representation
     * of the specified {@code 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.
     *
     * <p>Note that this method is closely related to the logarithm base 2.
     * For all positive {@code int} values x:
     * <ul>
     * <li>floor(log<sub>2</sub>(x)) = {@code 31 - numberOfLeadingZeros(x)}
     * <li>ceil(log<sub>2</sub>(x)) = {@code 32 - numberOfLeadingZeros(x - 1)}
     * </ul>
     *
     * @return the number of zero bits preceding the highest-order
     *     ("leftmost") one-bit in the two's complement binary representation
     *     of the specified {@code int} value, or 32 if the value
     *     is equal to zero.
     * @since 1.5
     */
    public static int numberOfLeadingZeros(int i) {
        // 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;
    }

    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. 
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/**
     * Returns the number of zero bits following the lowest-order ("rightmost")
     * one-bit in the two's complement binary representation of the specified
     * {@code 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.
     *
     * @return the number of zero bits following the lowest-order ("rightmost")
     *     one-bit in the two's complement binary representation of the
     *     specified {@code int} value, or 32 if the value is equal
     *     to zero.
     * @since 1.5
     */
    public static int numberOfTrailingZeros(int i) {
        // 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);
    }

    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.
Returns: the number of one-bits in the two's complement binary representation of the specified int value.
Since: 1.5/**
     * Returns the number of one-bits in the two's complement binary
     * representation of the specified {@code int} value.  This function is
     * sometimes referred to as the <i>population count</i>.
     *
     * @return the number of one-bits in the two's complement binary
     *     representation of the specified {@code int} value.
     * @since 1.5
     */
    public static int bitCount(int i) {
        // 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;
    }

    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). 
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/**
     * Returns the value obtained by rotating the two's complement binary
     * representation of the specified {@code 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.)
     *
     * <p>Note that left rotation with a negative distance is equivalent to
     * right rotation: {@code 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: {@code rotateLeft(val,
     * distance) == rotateLeft(val, distance & 0x1F)}.
     *
     * @return the value obtained by rotating the two's complement binary
     *     representation of the specified {@code int} value left by the
     *     specified number of bits.
     * @since 1.5
     */
    public static int rotateLeft(int i, int distance) {
        return (i << distance) | (i >>> -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). 
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/**
     * Returns the value obtained by rotating the two's complement binary
     * representation of the specified {@code 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.)
     *
     * <p>Note that right rotation with a negative distance is equivalent to
     * left rotation: {@code 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: {@code rotateRight(val,
     * distance) == rotateRight(val, distance & 0x1F)}.
     *
     * @return the value obtained by rotating the two's complement binary
     *     representation of the specified {@code int} value right by the
     *     specified number of bits.
     * @since 1.5
     */
    public static int rotateRight(int i, int distance) {
        return (i >>> distance) | (i << -distance);
    }

    Returns the value obtained by reversing the order of the bits in the two's complement binary representation of the specified int value. 
Returns: the value obtained by reversing order of the bits in the specified int value.
Since: 1.5/**
     * Returns the value obtained by reversing the order of the bits in the
     * two's complement binary representation of the specified {@code int}
     * value.
     *
     * @return the value obtained by reversing order of the bits in the
     *     specified {@code int} value.
     * @since 1.5
     */
    public static int reverse(int i) {
        // 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;
    }

    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.) 
Returns: the signum function of the specified int value.
Since: 1.5/**
     * Returns the signum function of the specified {@code 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.)
     *
     * @return the signum function of the specified {@code int} value.
     * @since 1.5
     */
    public static int signum(int i) {
        // HD, Section 2-7
        return (i >> 31) | (-i >>> 31);
    }

    Returns the value obtained by reversing the order of the bytes in the two's complement representation of the specified int value. 
Returns: the value obtained by reversing the bytes in the specified int value.
Since: 1.5/**
     * Returns the value obtained by reversing the order of the bytes in the
     * two's complement representation of the specified {@code int} value.
     *
     * @return the value obtained by reversing the bytes in the specified
     *     {@code int} value.
     * @since 1.5
     */
    public static int reverseBytes(int i) {
        return ((i >>> 24)           ) |
               ((i >>   8) &   0xFF00) |
               ((i <<   8) & 0xFF0000) |
               ((i << 24));
    }

    use serialVersionUID from JDK 1.0.2 for interoperability /** use serialVersionUID from JDK 1.0.2 for interoperability */
    private static final long serialVersionUID = 1360826667806852920L;
}
Author:	Lee Boynton, Arthur van Hoff, Josh Bloch, Joseph D. Darcy
Since:	JDK1.0
Params:	i – an integer to be converted to a string. radix – the radix to use in the string representation.
See Also:	Character.MAX_RADIX Character.MIN_RADIX
Returns:	a string representation of the argument in the specified radix.
Params:	i – an integer to be converted.
Returns:	a string representation of the argument in base 10.
Params:	s – the `String` containing the integer representation to be parsed radix – the radix to be used while parsing `s`.
Throws:	NumberFormatException – if the `String` does not contain a parsable `int`.
Returns:	the integer represented by the string argument in the specified radix.
Params:	s – a `String` containing the `int` representation to be parsed
Throws:	NumberFormatException – if the string does not contain a parsable integer.
Returns:	the integer value represented by the argument in decimal.
Params:	s – the string to be parsed. radix – the radix to be used in interpreting `s`
Throws:	NumberFormatException – if the `String` does not contain a parsable `int`.
Returns:	an `Integer` object holding the value represented by the string argument in the specified radix.
Params:	s – the string to be parsed.
Throws:	NumberFormatException – if the string cannot be parsed as an integer.
Returns:	an `Integer` object holding the value represented by the string argument.
Params:	i – an `int` value.
Returns:	an `Integer` instance representing `i`.
Since:	1.5
Params:	s – the `String` to be converted to an `Integer`.
Throws:	NumberFormatException – if the `String` does not contain a parsable integer.
See Also:	parseInt(String, int)
Params:	obj – the object to compare with.
Returns:	`true` if the objects are the same; `false` otherwise.
Params:	nm – property name.
See Also:	System.getProperty(String) System.getProperty(String, String)
Returns:	the `Integer` value of the property.
Params:	nm – property name. val – default value.
See Also:	System.getProperty(String) System.getProperty(String, String)
Returns:	the `Integer` value of the property.
Params:	nm – the `String` to decode.
Throws:	NumberFormatException – if the `String` does not contain a parsable integer.
See Also:	parseInt(String, int)
Returns:	an `Integer` object holding the `int` value represented by `nm`
Params:	anotherInteger – the `Integer` to be compared.
Returns:	the value `0` if this `Integer` is equal to the argument `Integer`; a value less than `0` if this `Integer` is numerically less than the argument `Integer`; and a value greater than `0` if this `Integer` is numerically greater than the argument `Integer` (signed comparison).
Since:	1.2
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
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
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
Returns:	the number of one-bits in the two's complement binary representation of the specified `int` value.
Since:	1.5
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
Returns:	the value obtained by reversing order of the bits in the specified `int` value.
Since:	1.5
/

java/ 6/ java/lang/Integer.java
