/*
 * @(#)Integer.java	1.64 01/02/09
 *
 * Copyright 1994-2001 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */

package java.lang;

/**
 * The Integer class wraps a value of the primitive type <code>int</code>
 * in an object. An object of type <code>Integer</code> contains a
 * single field whose type is <code>int</code>.
 * <p>
 * In addition, this class provides several methods for converting
 * an <code>int</code> to a <code>String</code> and a
 * <code>String</code> to an <code>int</code>, as well as other
 * constants and methods useful when dealing with an
 * <code>int</code>.
 *
 * @author  Lee Boynton
 * @author  Arthur van Hoff
 * @version 1.64, 02/09/01
 * @since   JDK1.0
 */
public final class Integer extends Number implements Comparable {
    /**
     * The smallest value of type <code>int</code>. The constant 
     * value of this field is <tt>-2147483648</tt>.
     */
    public static final int   MIN_VALUE = 0x80000000;

    /**
     * The largest value of type <code>int</code>. The constant 
     * value of this field is <tt>2147483647</tt>.
     */
    public static final int   MAX_VALUE = 0x7fffffff;

    /**
     * The Class object representing the primitive type int.
     *
     * @since   JDK1.1
     */
    public static final Class	TYPE = Class.getPrimitiveClass("int");

    /**
     * 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'
    };

    /**
     * Creates 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</code> or
     * larger than <code>Character.MAX_RADIX</code>, then the radix
     * <code>10</code> is used instead.
     * <p>
     * If the first argument is negative, the first element of the 
     * result is the ASCII minus character <code>'-'</code> 
     * (<tt>'\u002d'</tt>). 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 <tt>'0'</tt> (<tt>'\u0030'</tt>); 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><pre>
     *   0123456789abcdefghijklmnopqrstuvwxyz
     * </pre></blockquote>
     * These are <tt>'\u0030'</tt> through <tt>'\u0039'</tt> and 
     * <tt>'\u0061'</tt> through <tt>'\u007a'</tt>. If the 
     * <tt>radix</tt> is <var>N</var>, then the first <var>N</var> of these 
     * characters are used as radix-<var>N</var> digets in the order shown. 
     * Thus, the digits for hexadecimal (radix 16) are 
     * <tt>0123456789abcdef</tt>. If uppercase letters are desired, the 
     * {@link java.lang.String#toUpperCase()} method 
     * may be called on the result:
     * <blockquote><pre>
     * Integer.toString(n, 16).toUpperCase()
     * </pre></blockquote>
     *
     * @param   i       an integer.
     * @param   radix   the radix.
     * @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));
    }


    /**
     * Creates a string representation of the integer argument as an
     * unsigned integer in base 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 16) with no extra leading <code>0</code>s. If the 
     * unsigned magnitude is zero, it is represented by a single zero 
     * character <tt>'0'</tt> (<tt>'\u0030'</tt>); 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><pre>
     * 0123456789abcdef
     * </pre></blockquote>
     * These are the characters <tt>'\u0030'</tt> through <tt>'\u0039'</tt> 
     * and <tt>'u\0039'</tt> through <tt>'\u0066'</tt>. If the uppercase 
     * letters are desired, the {@link java.lang.String#toUpperCase()} 
     * method may be called on the result:
     * <blockquote><pre>
     * Long.toHexString(n).toUpperCase()
     * </pre></blockquote>
     *
     * @param   i   an integer.
     * @return  the string representation of the unsigned integer value
     *          represented by the argument in hexadecimal (base 16).
     * @since   JDK1.0.2
     */
    public static String toHexString(int i) {
	return toUnsignedString(i, 4);
    }

    /**
     * Creates a string representation of the integer argument as an
     * unsigned integer in base 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 8) with no extra leading <code>0</code>s. 
     * <p>
     * If the unsigned magnitude is zero, it is represented by a single 
     * zero character <tt>'0'</tt> (<tt>'\u0030'</tt>); otherwise, the 
     * first character of the representation of the unsigned magnitude will 
     * not be the zero character. The octal digits are:
     * <blockquote><pre>
     * 01234567
     * </pre></blockquote>
     * These are the characters <tt>'\u0030'</tt> through <tt>'\u0037'</tt>. 
     *
     * @param   i   an integer
     * @return  the string representation of the unsigned integer value
     *          represented by the argument in octal (base 8).
     * @since   JDK1.0.2
     */
    public static String toOctalString(int i) {
	return toUnsignedString(i, 3);
    }

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

    /**
     * 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 characterists 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 new 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 <tt>10</tt> 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 10.
     */
    public static String toString(int i) {
	int q, r, charPos  ; 
	charPos = 12 ; 
	char buf [] = new char [charPos] ; 
	char sign = 0 ; 

  	if (i == Integer.MIN_VALUE) {
            return "-2147483648";
        }

	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 ... 
	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 ; 
	}

	// Use the back-door private constructor -- we abandon the char [].  
	// This requires that we drop the "private" from the
	// java.lang.String: String (int Offset,int Count,char[] Value) constructor.

	return new String ( charPos, 12 - charPos, buf ) ; 
	}


    
    /**
     * 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> (<code>'\u002d'</code>) to 
     * indicate a negative value. The resulting integer value is returned. 
     * <p>
     * An exception of type <tt>NumberFormatException</tt> is thrown if any 
     * of the following situations occurs:
     * <ul>
     * <li>The first argument is <tt>null</tt> 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 <tt>'-'</tt> 
     * (<tt>'\u002d'</tt>) provided that the string is longer than length 1. 
     * <li>The integer value represented by the string is not a value of type
     * <tt>int</tt>. 
     * </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</code> containing the integer.
     * @param      radix   the radix to be used.
     * @return     the integer represented by the string argument in the
     *             specified radix.
     * @exception  NumberFormatException  if the string does not contain a
     *               parsable integer.

     */
    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, 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 new NumberFormatException(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 new NumberFormatException(s);
		}
		if (result < multmin) {
		    throw new NumberFormatException(s);
		}
		result *= radix;
		if (result < limit + digit) {
		    throw new NumberFormatException(s);
		}
		result -= digit;
	    }
	} else {
	    throw new NumberFormatException(s);
	}
	if (negative) {
	    if (i > 1) {
		return result;
	    } else {	/* Only got "-" */
		throw new NumberFormatException(s);
	    }
	} else {
	    return -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 <code>'-'</code> 
     * (<tt>'\u002d'</tt>) 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 string.
     * @return     the integer 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 a new Integer object initialized to the value of the
     * specified String. 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</code> object that represents the integer value 
     * specified by the string. 
     * <p>
     * In other words, this method returns an <code>Integer</code> object 
     * equal to the value of:
     * <blockquote><pre>
     * new Integer(Integer.parseInt(s, radix))  
     * </pre></blockquote>
     *
     * @param      s   the string to be parsed.
     * @param      radix the radix of the integer represented by string 
     *             <tt>s</tt>
     * @return     a newly constructed <code>Integer</code> initialized to the
     *             value represented by the string argument in the specified
     *             radix.
     * @exception  NumberFormatException  if the String cannot be 
     *             parsed as an <code>int</code>.
     */
    public static Integer valueOf(String s, int radix) throws NumberFormatException {
	return new Integer(parseInt(s,radix));
    }

    /**
     * Returns a new Integer object initialized to 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 
     * <tt>Integer</tt> object that represents the integer value specified 
     * by the string. 
     * <p>
     * In other words, this method returns an <tt>Integer</tt> object equal 
     * to the value of:
     * <blockquote><pre>
     * new Integer(Integer.parseInt(s)) 
     * </pre></blockquote>
     *
     * @param      s   the string to be parsed.
     * @return     a newly constructed <code>Integer</code> initialized to 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));
    }

    /**
     * The value of the Integer.
     *
     * @serial
     */
    private int value;

    /**
     * Constructs a newly allocated <code>Integer</code> object that
     * represents the primitive <code>int</code> argument.
     *
     * @param   value   the value to be represented by the <code>Integer</code>.
     */
    public Integer(int value) {
	this.value = value;
    }

    /**
     * Constructs a newly allocated <code>Integer</code> object that 
     * represents the value represented by the string. The string is 
     * converted to an <tt>int</tt> in exactly the manner used by the 
     * <tt>parseInt</tt> method for radix 10.
     *
     * @param      s   the <code>String</code> to be converted to an
     *                 <code>Integer</code>.
     * @exception  NumberFormatException  if the <code>String</code> 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.
     *
     * @since   JDK1.1
     */
    public byte byteValue() {
	return (byte)value;
    }

    /**
     * Returns the value of this Integer as a short.
     *
     * @since   JDK1.1
     */
    public short shortValue() {
	return (short)value;
    }

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

    /**
     * Returns the value of this Integer as a <tt>long</tt>.
     *
     * @return  the <code>int</code> value represented by this object that is
     *          converted to type <code>long</code> and the result of the
     *          conversion is returned.
     */
    public long longValue() {
	return (long)value;
    }

    /**
     * Returns the value of this Integer as a <tt>float</tt>.
     *
     * @return  the <code>int</code> value represented by this object is
     *          converted to type <code>float</code> and the result of the
     *          conversion is returned.
     */
    public float floatValue() {
	return (float)value;
    }

    /**
     * Returns the value of this Integer as a <tt>double</tt>.
     *
     * @return  the <code>int</code> value represented by this object is
     *          converted to type <code>double</code> and the result of the
     *          conversion is returned.
     */
    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 {@link java.lang.Integer#toString(int)} method.
     *
     * @return  a string representation of the value of this object in
     *          base 10.
     */
    public String toString() {
	return String.valueOf(value);
    }

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

    /**
     * Compares this object to the specified object.
     * The result is <code>true</code> if and only if the argument is not
     * <code>null</code> and is an <code>Integer</code> object that contains
     * the same <code>int</code> value as this object.
     *
     * @param   obj   the object to compare with.
     * @return  <code>true</code> if the objects are the same;
     *          <code>false</code> 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.
     * <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</code> object representing this value is 
     * returned. Details of possible numeric formats can be found with 
     * the definition of <code>getProperty</code>. 
     * <p>
     * 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 <code>null</code> is returned. In other words, this method
     * returns an <code>Integer</code> object equal to the value of:
     * <blockquote><pre>
     * getInteger(nm, null)
     * </pre></blockquote>
     *
     * @param   nm   property name.
     * @return  the <code>Integer</code> 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.
     * <p>
     * The first argument is treated as the name of a system property. 
     * System properties are accessible through <code>getProperty</code>, 
     * a method defined by the <code>System</code> class. The 
     * string value of this property is then interpreted as an integer 
     * value and an <code>Integer</code> object representing this value is 
     * returned. Details of possible numeric formats can be found with 
     * the definition of <code>getProperty</code>. 
     * <p>
     * The second argument is the default value. An <code>Integer</code> 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.
     * <p>
     * In other words, this method returns an <code>Integer</code> object 
     * equal to the value of:
     * <blockquote><pre>
     * getInteger(nm, new Integer(val))
     * </pre></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</code> 
     * object when the default value is not needed. 
     *
     * @param   nm   property name.
     * @param   val   default value.
     * @return  the <code>Integer</code> 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 <code>getProperty</code>, 
     * a method defined by the <code>System</code> class. The string value of
     * this property is then interpreted as an integer value, as per the
     * <code>Integer.decode</code> method, and an <code>Integer</code> object
     * representing this value is returned.
     * <p>
     * <ul><li>If the property value begins with the two ASCII characters 
     *         <code>0x</code> or the ASCII character <code>#</code>, not 
     *      followed by a minus sign, then the rest of it is parsed as a 
     *      hexadecimal integer exactly as for the method 
     *      {@link #valueOf(java.lang.String, int)} with radix 16. 
     * <li>If the property value begins with the ASCII character 
     *     <code>0</code> followed by another character, it is parsed as an 
     *     octal integer exactly as for the method 
     *     {@link #valueOf(java.lang.String, int) with radix 8. 
     * <li>Otherwise, the property value is parsed as a decimal integer 
     * exactly as for 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 null.
     *
     * @param   nm   property name.
     * @param   val   default value.
     * @return  the <code>Integer</code> 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 <code>String</code> into an <code>Integer</code>.  Accepts
     * decimal, hexadecimal, and octal numbers, in the following formats:
     * <pre>
     *     [-]        decimal constant
     *     [-] 0x     hex constant
     *     [-] #      hex constant
     *     [-] 0      octal constant
     * </pre>
     *
     * The constant following an (optional) negative sign and/or "radix
     * specifier" is parsed as by the <code>Integer.parseInt</code> method
     * with the specified radix (10, 8 or 16).  This constant must be positive
     * or a NumberFormatException will result.  The result is made negative if
     * first character of the specified <code>String</code> is the negative
     * sign.  No whitespace characters are permitted in the
     * <code>String</code>.
     *
     * @param     nm the <code>String</code> to decode.
     * @return    the <code>Integer</code> represented by the specified string.
     * @exception NumberFormatException  if the <code>String</code> does not
     *            contain a parsable integer.
     * @see java.lang.Integer#parseInt(String, int)
     */
    public static Integer decode(String nm) throws NumberFormatException {
        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;
    }

    /**
     * Compares two Integers numerically.
     *
     * @param   anotherInteger   the <code>Integer</code> to be compared.
     * @return  the value <code>0</code> if the argument Integer is equal to
     *          this Integer; a value less than <code>0</code> if this Integer
     *          is numerically less than the Integer argument; and a
     *          value greater than <code>0</code> if this Integer is
     *          numerically greater than the Integer argument
     *		(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));
    }

    /**
     * Compares this Integer to another Object.  If the Object is a Integer,
     * this function behaves like <code>compareTo(Integer)</code>.  Otherwise,
     * it throws a <code>ClassCastException</code> (as Integers are comparable
     * only to other Integers).
     *
     * @param   o the <code>Object</code> to be compared.
     * @return  the value <code>0</code> if the argument is a Integer
     *		numerically equal to this Integer; a value less than
     *		<code>0</code> if the argument is a Integer numerically
     *		greater than this Integer; and a value greater than
     *		<code>0</code> if the argument is a Integer numerically
     *		less than this Integer.
     * @exception <code>ClassCastException</code> if the argument is not an
     *		  <code>Integer</code>.
     * @see     java.lang.Comparable
     * @since   1.2
     */
    public int compareTo(Object o) {
	return compareTo((Integer)o);
    }

    /** use serialVersionUID from JDK 1.0.2 for interoperability */
    private static final long serialVersionUID = 1360826667806852920L;
}