468 lines · 16.8 KB · Java
RawDownload
/* * Copyright (c) 1996, 2009, Oracle and/or its affiliates. All rights reserved. * 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 * or visit www.oracle.com if you need additional information or have any * questions. */ package java.lang; /** * The {@code Short} class wraps a value of primitive type {@code * short} in an object.  An object of type {@code Short} contains a * single field whose type is {@code short}. * * <p>In addition, this class provides several methods for converting * a {@code short} to a {@code String} and a {@code String} to a * {@code short}, as well as other constants and methods useful when * dealing with a {@code short}. * * @author  Nakul Saraiya * @author  Joseph D. Darcy * @see     java.lang.Number * @since   JDK1.1 */public final class Short extends Number implements Comparable<Short> {     /**     * A constant holding the minimum value a {@code short} can     * have, -2<sup>15</sup>.     */    public static final short   MIN_VALUE = -32768;     /**     * A constant holding the maximum value a {@code short} can     * have, 2<sup>15</sup>-1.     */    public static final short   MAX_VALUE = 32767;     /**     * The {@code Class} instance representing the primitive type     * {@code short}.     */    public static final Class<Short>    TYPE = (Class<Short>) Class.getPrimitiveClass("short");     /**     * Returns a new {@code String} object representing the     * specified {@code short}. The radix is assumed to be 10.     *     * @param s the {@code short} to be converted     * @return the string representation of the specified {@code short}     * @see java.lang.Integer#toString(int)     */    public static String toString(short s) {        return Integer.toString((int)s, 10);    }     /**     * Parses the string argument as a signed {@code short} 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 or an     * ASCII plus sign {@code '+'} (<code>'&#92;u002B'</code>) to     * indicate a positive value.  The resulting {@code short} 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>) or plus sign     * {@code '+'} (<code>'&#92;u002B'</code>) provided that the     * string is longer than length 1.     *     * <li> The value represented by the string is not a value of type     * {@code short}.     * </ul>     *     * @param s         the {@code String} containing the     *                  {@code short} representation to be parsed     * @param radix     the radix to be used while parsing {@code s}     * @return          the {@code short} represented by the string     *                  argument in the specified radix.     * @throws          NumberFormatException If the {@code String}     *                  does not contain a parsable {@code short}.     */    public static short parseShort(String s, int radix)        throws NumberFormatException {        int i = Integer.parseInt(s, radix);        if (i < MIN_VALUE || i > MAX_VALUE)            throw new NumberFormatException(                "Value out of range. Value:\"" + s + "\" Radix:" + radix);        return (short)i;    }     /**     * Parses the string argument as a signed decimal {@code     * short}. 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 or an ASCII plus sign {@code '+'}     * (<code>'&#92;u002B'</code>) to indicate a positive value.  The     * resulting {@code short} value is returned, exactly as if the     * argument and the radix 10 were given as arguments to the {@link     * #parseShort(java.lang.String, int)} method.     *     * @param s a {@code String} containing the {@code short}     *          representation to be parsed     * @return  the {@code short} value represented by the     *          argument in decimal.     * @throws  NumberFormatException If the string does not     *          contain a parsable {@code short}.     */    public static short parseShort(String s) throws NumberFormatException {        return parseShort(s, 10);    }     /**     * Returns a {@code Short} 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 {@code short} in     * the radix specified by the second argument, exactly as if the     * argument were given to the {@link #parseShort(java.lang.String,     * int)} method. The result is a {@code Short} object that     * represents the {@code short} value specified by the string.     *     * <p>In other words, this method returns a {@code Short} object     * equal to the value of:     *     * <blockquote>     *  {@code new Short(Short.parseShort(s, radix))}     * </blockquote>     *     * @param s         the string to be parsed     * @param radix     the radix to be used in interpreting {@code s}     * @return          a {@code Short} object holding the value     *                  represented by the string argument in the     *                  specified radix.     * @throws          NumberFormatException If the {@code String} does     *                  not contain a parsable {@code short}.     */    public static Short valueOf(String s, int radix)        throws NumberFormatException {        return valueOf(parseShort(s, radix));    }     /**     * Returns a {@code Short} object holding the     * value given by the specified {@code String}. The argument     * is interpreted as representing a signed decimal     * {@code short}, exactly as if the argument were given to     * the {@link #parseShort(java.lang.String)} method. The result is     * a {@code Short} object that represents the     * {@code short} value specified by the string.     *     * <p>In other words, this method returns a {@code Short} object     * equal to the value of:     *     * <blockquote>     *  {@code new Short(Short.parseShort(s))}     * </blockquote>     *     * @param s the string to be parsed     * @return  a {@code Short} object holding the value     *          represented by the string argument     * @throws  NumberFormatException If the {@code String} does     *          not contain a parsable {@code short}.     */    public static Short valueOf(String s) throws NumberFormatException {        return valueOf(s, 10);    }     private static class ShortCache {        private ShortCache(){}         static final Short cache[] = new Short[-(-128) + 127 + 1];         static {            for(int i = 0; i < cache.length; i++)                cache[i] = new Short((short)(i - 128));        }    }     /**     * Returns a {@code Short} instance representing the specified     * {@code short} value.     * If a new {@code Short} instance is not required, this method     * should generally be used in preference to the constructor     * {@link #Short(short)}, as this method is likely to yield     * significantly better space and time performance by caching     * frequently requested values.     *     * This method will always cache values in the range -128 to 127,     * inclusive, and may cache other values outside of this range.     *     * @param  s a short value.     * @return a {@code Short} instance representing {@code s}.     * @since  1.5     */    public static Short valueOf(short s) {        final int offset = 128;        int sAsInt = s;        if (sAsInt >= -128 && sAsInt <= 127) { // must cache            return ShortCache.cache[sAsInt + offset];        }        return new Short(s);    }     /**     * Decodes a {@code String} into a {@code Short}.     * 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 -}     * <dd>{@code +}     * </dl>     * </blockquote>     *     * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>     * are as defined in section 3.10.1 of     * <cite>The Java&trade; Language Specification</cite>,     * except that underscores are not accepted between digits.     *     * <p>The sequence of characters following an optional     * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",     * "{@code #}", or leading zero) is parsed as by the {@code     * Short.parseShort} 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    a {@code Short} object holding the {@code short}     *            value represented by {@code nm}     * @throws    NumberFormatException  if the {@code String} does not     *            contain a parsable {@code short}.     * @see java.lang.Short#parseShort(java.lang.String, int)     */    public static Short decode(String nm) throws NumberFormatException {        int i = Integer.decode(nm);        if (i < MIN_VALUE || i > MAX_VALUE)            throw new NumberFormatException(                    "Value " + i + " out of range from input " + nm);        return valueOf((short)i);    }     /**     * The value of the {@code Short}.     *     * @serial     */    private final short value;     /**     * Constructs a newly allocated {@code Short} object that     * represents the specified {@code short} value.     *     * @param value     the value to be represented by the     *                  {@code Short}.     */    public Short(short value) {        this.value = value;    }     /**     * Constructs a newly allocated {@code Short} object that     * represents the {@code short} value indicated by the     * {@code String} parameter. The string is converted to a     * {@code short} value in exactly the manner used by the     * {@code parseShort} method for radix 10.     *     * @param s the {@code String} to be converted to a     *          {@code Short}     * @throws  NumberFormatException If the {@code String}     *          does not contain a parsable {@code short}.     * @see     java.lang.Short#parseShort(java.lang.String, int)     */    public Short(String s) throws NumberFormatException {        this.value = parseShort(s, 10);    }     /**     * Returns the value of this {@code Short} as a     * {@code byte}.     */    public byte byteValue() {        return (byte)value;    }     /**     * Returns the value of this {@code Short} as a     * {@code short}.     */    public short shortValue() {        return value;    }     /**     * Returns the value of this {@code Short} as an     * {@code int}.     */    public int intValue() {        return (int)value;    }     /**     * Returns the value of this {@code Short} as a     * {@code long}.     */    public long longValue() {        return (long)value;    }     /**     * Returns the value of this {@code Short} as a     * {@code float}.     */    public float floatValue() {        return (float)value;    }     /**     * Returns the value of this {@code Short} as a     * {@code double}.     */    public double doubleValue() {        return (double)value;    }     /**     * Returns a {@code String} object representing this     * {@code Short}'s value.  The value is converted to signed     * decimal representation and returned as a string, exactly as if     * the {@code short} value were given as an argument to the     * {@link java.lang.Short#toString(short)} method.     *     * @return  a string representation of the value of this object in     *          base&nbsp;10.     */    public String toString() {        return Integer.toString((int)value);    }     /**     * Returns a hash code for this {@code Short}; equal to the result     * of invoking {@code intValue()}.     *     * @return a hash code value for this {@code Short}     */    public int hashCode() {        return (int)value;    }     /**     * Compares this object to the specified object.  The result is     * {@code true} if and only if the argument is not     * {@code null} and is a {@code Short} object that     * contains the same {@code short} 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 Short) {            return value == ((Short)obj).shortValue();        }        return false;    }     /**     * Compares two {@code Short} objects numerically.     *     * @param   anotherShort   the {@code Short} to be compared.     * @return  the value {@code 0} if this {@code Short} is     *          equal to the argument {@code Short}; a value less than     *          {@code 0} if this {@code Short} is numerically less     *          than the argument {@code Short}; and a value greater than     *           {@code 0} if this {@code Short} is numerically     *           greater than the argument {@code Short} (signed     *           comparison).     * @since   1.2     */    public int compareTo(Short anotherShort) {        return compare(this.value, anotherShort.value);    }     /**     * Compares two {@code short} values numerically.     * The value returned is identical to what would be returned by:     * <pre>     *    Short.valueOf(x).compareTo(Short.valueOf(y))     * </pre>     *     * @param  x the first {@code short} to compare     * @param  y the second {@code short} to compare     * @return the value {@code 0} if {@code x == y};     *         a value less than {@code 0} if {@code x < y}; and     *         a value greater than {@code 0} if {@code x > y}     * @since 1.7     */    public static int compare(short x, short y) {        return x - y;    }     /**     * The number of bits used to represent a {@code short} value in two's     * complement binary form.     * @since 1.5     */    public static final int SIZE = 16;     /**     * Returns the value obtained by reversing the order of the bytes in the     * two's complement representation of the specified {@code short} value.     *     * @return the value obtained by reversing (or, equivalently, swapping)     *     the bytes in the specified {@code short} value.     * @since 1.5     */    public static short reverseBytes(short i) {        return (short) (((i & 0xFF00) >> 8) | (i << 8));    }     /** use serialVersionUID from JDK 1.1. for interoperability */    private static final long serialVersionUID = 7515723908773894738L;}