/*
* @(#)Integer.java 1.75 06/10/10
*
* Copyright 1990-2008 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* This program 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 at /legal/license.txt).
*
* 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 Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*
*/
package java.lang;
/**
* The <code>Integer</code> 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 1.67 11/10/00
* @since JDK1.0
*/
public final class Integer extends Number implements Comparable {
/**
* A constant holding the minimum value an <code>int</code> can
* have, -2<sup>31</sup>.
*/
public static final int MIN_VALUE = 0x80000000;
/**
* A constant holding the maximum value an <code>int</code> can
* have, 2<sup>31</sup>-1.
*/
public static final int MAX_VALUE = 0x7fffffff;
/**
* The <code>Class</code> instance representing the primitive type
* <code>int</code>.
*
* @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'
};
/**
* 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</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>
* (<code>'\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>
* (<code>'\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><pre>
* 0123456789abcdefghijklmnopqrstuvwxyz
* </pre></blockquote>
* These are <code>'\u0030'</code> through
* <code>'\u0039'</code> and <code>'\u0061'</code> through
* <code>'\u007A'</code>. If <code>radix</code> 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</code>. 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 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.
* <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 <code>'0'</code>
* (<code>'\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><pre>
* 0123456789abcdef
* </pre></blockquote>
* These are the characters <code>'\u0030'</code> through
* <code>'\u0039'</code> and <code>'\u0061'</code> through
* <code>'\u0066'</code>. If uppercase letters are
* desired, the {@link java.lang.String#toUpperCase()} method may
* be called on the result:
* <blockquote><pre>
* Integer.toHexString(n).toUpperCase()
* </pre></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 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.
* <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 <code>'0'</code>
* (<code>'\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><pre>
* 01234567
* </pre></blockquote>
* These are the characters <code>'\u0030'</code> through
* <code>'\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 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.
* <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 <code>'0'</code>
* (<code>'\u0030'</code>); otherwise, the first character of
* the representation of the unsigned magnitude will not be the
* zero character. The characters <code>'0'</code>
* (<code>'\u0030'</code>) and <code>'1'</code>
* (<code>'\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 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 "invariant division by multiplication" to
// accelerate Integer.toString. In particular we want to
// avoid division by 10.
//
// This has roughly the same performance characterists
// as the "classic" Integer.toString code on a non-JIT VM.
// This 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 this
// is considerably faster than the classic code.
//
// NOTE: can also 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 <code>String</code> 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 10.
*/
public static String toString(int i) {
switch(i) {
case Integer.MIN_VALUE: return "-2147483648";
case -3: return "-3";
case -2: return "-2";
case -1: return "-1";
case 0: return "0";
case 1: return "1";
case 2: return "2";
case 3: return "3";
case 4: return "4";
case 5: return "5";
case 6: return "6";
case 7: return "7";
case 8: return "8";
case 9: return "9";
case 10: return "10";
}
char[] buf = (char[])(perThreadBuffer.get());
int charPos = getChars(i, buf);
return new String(buf, charPos, 12 - charPos);
}
// Per-thread buffer for string/stringbuffer conversion
private static ThreadLocal perThreadBuffer = new ThreadLocal() {
protected synchronized Object initialValue() {
return new char[12];
}
};
private static int getChars(int i, char[] buf) {
int q, r;
int charPos = 12;
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
if (sun.misc.BuildFlags.qAssertsEnabled)
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;
}
return charPos;
}
static void appendTo(int i, StringBuffer sb) {
switch(i) {
case Integer.MIN_VALUE:
sb.append("-2147483648");
return;
case -3: sb.append("-3"); return;
case -2: sb.append("-2"); return;
case -1: sb.append("-1"); return;
case 0: sb.append("0"); return;
case 1: sb.append("1"); return;
case 2: sb.append("2"); return;
case 3: sb.append("3"); return;
case 4: sb.append("4"); return;
case 5: sb.append("5"); return;
case 6: sb.append("6"); return;
case 7: sb.append("7"); return;
case 8: sb.append("8"); return;
case 9: sb.append("9"); return;
case 10: sb.append("10"); return;
}
char[] buf = (char[])(perThreadBuffer.get());
int charPos = getChars(i, buf);
sb.append(buf, charPos, 12 - charPos);
}
/**
* 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 <code>NumberFormatException</code> is
* thrown if any of the following situations occurs:
* <ul>
* <li>The first argument is <code>null</code> 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> (<code>'\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</code>.
* </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
* representation to be parsed
* @param radix the radix to be used while parsing <code>s</code>.
* @return the integer represented by the string argument in the
* specified radix.
* @exception NumberFormatException if the <code>String</code>
* does not contain a parsable <code>int</code>.
*/
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 NumberFormatException.forInputString(s);
} else {
result = -digit;
}
}
while (i < max) {
// Accumulating negatively avoids surprises near MAX_VALUE
digit = Character.digit(s.charAt(i++),radix);
if (digit < 0) {
throw NumberFormatException.forInputString(s);
}
if (result < multmin) {
throw NumberFormatException.forInputString(s);
}
result *= radix;
if (result < limit + digit) {
throw NumberFormatException.forInputString(s);
}
result -= digit;
}
} else {
throw NumberFormatException.forInputString(s);
}
if (negative) {
if (i > 1) {
return result;
} else { /* Only got "-" */
throw NumberFormatException.forInputString(s);
}
} else {
return -result;
}
}
/**
* 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>
* (<code>'\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</code> containing the <code>int</code>
* 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 <code>Integer</code> object holding the value
* extracted from the specified <code>String</code> 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</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><code>
* new Integer(Integer.parseInt(s, radix))
* </code></blockquote>
*
* @param s the string to be parsed.
* @param radix the radix to be used in interpreting <code>s</code>
* @return an <code>Integer</code> object holding the value
* represented by the string argument in the specified
* radix.
* @exception NumberFormatException if the <code>String</code>
* does not contain a parsable <code>int</code>.
*/
public static Integer valueOf(String s, int radix) throws NumberFormatException {
return new Integer(parseInt(s,radix));
}
/**
* Returns an <code>Integer</code> object holding the
* value of the specified <code>String</code>. 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</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><code>
* new Integer(Integer.parseInt(s))
* </code></blockquote>
*
* @param s the string to be parsed.
* @return an <code>Integer</code> 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));
}
/**
* The value of the <code>Integer</code>.
*
* @serial
*/
private int value;
/**
* Constructs a newly allocated <code>Integer</code> object that
* represents the specified <code>int</code> value.
*
* @param value the value to be represented by the
* <code>Integer</code> object.
*/
public Integer(int value) {
this.value = value;
}
/**
* Constructs a newly allocated <code>Integer</code> object that
* represents the <code>int</code> value indicated by the
* <code>String</code> parameter. The string is converted to an
* <code>int</code> value in exactly the manner used by the
* <code>parseInt</code> 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 <code>Integer</code> as a
* <code>byte</code>.
*/
public byte byteValue() {
return (byte)value;
}
/**
* Returns the value of this <code>Integer</code> as a
* <code>short</code>.
*/
public short shortValue() {
return (short)value;
}
/**
* Returns the value of this <code>Integer</code> as an
* <code>int</code>.
*/
public int intValue() {
return value;
}
/**
* Returns the value of this <code>Integer</code> as a
* <code>long</code>.
*/
public long longValue() {
return (long)value;
}
/**
* Returns the value of this <code>Integer</code> as a
* <code>float</code>.
*/
public float floatValue() {
return (float)value;
}
/**
* Returns the value of this <code>Integer</code> as a
* <code>double</code>.
*/
public double doubleValue() {
return (double)value;
}
/**
* Returns a <code>String</code> object representing this
* <code>Integer</code>'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 hash code for this <code>Integer</code>.
*
* @return a hash code value for this object, equal to the
* primitive <code>int</code> value represented by this
* <code>Integer</code> 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 <code>null</code>, or if the property does not have
* the correct numeric format, then <code>null</code> is returned.
* <p>
* In other words, this method returns an <code>Integer</code>
* object equal to the value of:
*
* <blockquote><code>
* getInteger(nm, null)
* </code></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 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>
* 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
* <code>null</code>.
* <p>
* In other words, this method returns an <code>Integer</code> object
* equal to the value of:
* <blockquote><code>
* getInteger(nm, new Integer(val))
* </code></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 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</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 by 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 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</code>.
*
* @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 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</code> <i>HexDigits</i>
* <dd><i>Sign<sub>opt</sub></i> <code>0X</code> <i>HexDigits</i>
* <dd><i>Sign<sub>opt</sub></i> <code>#</code> <i>HexDigits</i>
* <dd><i>Sign<sub>opt</sub></i> <code>0</code> <i>OctalDigits</i>
* <p>
* <dt><i>Sign:</i>
* <dd><code>-</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">§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>",
* "<code>0X</code>", "<code>#</code>", or
* leading zero) is parsed as by the <code>Integer.parseInt</code>
* 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</code> is the
* minus sign. No whitespace characters are permitted in the
* <code>String</code>.
*
* @param nm the <code>String</code> to decode.
* @return a <code>Integer</code> object holding the <code>int</code>
* value represented by <code>nm</code>
* @exception NumberFormatException if the <code>String</code> does not
* contain a parsable integer.
* @see java.lang.Integer#parseInt(java.lang.String, int)
* @since 1.2
*/
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 <code>Integer</code> objects numerically.
*
* @param anotherInteger the <code>Integer</code> to be compared.
* @return the value <code>0</code> if this <code>Integer</code> is
* equal to the argument <code>Integer</code>; a value less than
* <code>0</code> if this <code>Integer</code> is numerically less
* than the argument <code>Integer</code>; and a value greater
* than <code>0</code> if this <code>Integer</code> is numerically
* greater than the argument <code>Integer</code> (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 <code>Integer</code> object to another object.
* If the object is an <code>Integer</code>, this function behaves
* like <code>compareTo(Integer)</code>. Otherwise, it throws a
* <code>ClassCastException</code> (as <code>Integer</code>
* objects are only comparable to other <code>Integer</code>
* objects).
*
* @param o the <code>Object</code> to be compared.
* @return the value <code>0</code> if the argument is a
* <code>Integer</code> numerically equal to this
* <code>Integer</code>; a value less than <code>0</code>
* if the argument is a <code>Integer</code> numerically
* greater than this <code>Integer</code>; and a value
* greater than <code>0</code> if the argument is a
* <code>Integer</code> numerically less than this
* <code>Integer</code>.
* @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;
}