| /* |
| * 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 Byte} class wraps a value of primitive type {@code byte} |
| * in an object. An object of type {@code Byte} contains a single |
| * field whose type is {@code byte}. |
| * |
| * <p>In addition, this class provides several methods for converting |
| * a {@code byte} to a {@code String} and a {@code String} to a {@code |
| * byte}, as well as other constants and methods useful when dealing |
| * with a {@code byte}. |
| * |
| * @author Nakul Saraiya |
| * @author Joseph D. Darcy |
| * @see java.lang.Number |
| * @since JDK1.1 |
| */ |
| public final class Byte extends Number implements Comparable<Byte> { |
| |
| /** |
| * A constant holding the minimum value a {@code byte} can |
| * have, -2<sup>7</sup>. |
| */ |
| public static final byte MIN_VALUE = -128; |
| |
| /** |
| * A constant holding the maximum value a {@code byte} can |
| * have, 2<sup>7</sup>-1. |
| */ |
| public static final byte MAX_VALUE = 127; |
| |
| /** |
| * The {@code Class} instance representing the primitive type |
| * {@code byte}. |
| */ |
| public static final Class<Byte> TYPE = (Class<Byte>) Class.getPrimitiveClass("byte"); |
| |
| /** |
| * Returns a new {@code String} object representing the |
| * specified {@code byte}. The radix is assumed to be 10. |
| * |
| * @param b the {@code byte} to be converted |
| * @return the string representation of the specified {@code byte} |
| * @see java.lang.Integer#toString(int) |
| */ |
| public static String toString(byte b) { |
| return Integer.toString((int)b, 10); |
| } |
| |
| private static class ByteCache { |
| private ByteCache(){} |
| |
| static final Byte cache[] = new Byte[-(-128) + 127 + 1]; |
| |
| static { |
| for(int i = 0; i < cache.length; i++) |
| cache[i] = new Byte((byte)(i - 128)); |
| } |
| } |
| |
| /** |
| * Returns a {@code Byte} instance representing the specified |
| * {@code byte} value. |
| * If a new {@code Byte} instance is not required, this method |
| * should generally be used in preference to the constructor |
| * {@link #Byte(byte)}, as this method is likely to yield |
| * significantly better space and time performance since |
| * all byte values are cached. |
| * |
| * @param b a byte value. |
| * @return a {@code Byte} instance representing {@code b}. |
| * @since 1.5 |
| */ |
| public static Byte valueOf(byte b) { |
| final int offset = 128; |
| return ByteCache.cache[(int)b + offset]; |
| } |
| |
| /** |
| * Parses the string argument as a signed {@code byte} 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>'\u002D'</code>) to indicate a negative value or an |
| * ASCII plus sign {@code '+'} (<code>'\u002B'</code>) to |
| * indicate a positive value. The resulting {@code byte} 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>'\u002D'</code>) or plus sign |
| * {@code '+'} (<code>'\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 byte}. |
| * </ul> |
| * |
| * @param s the {@code String} containing the |
| * {@code byte} |
| * representation to be parsed |
| * @param radix the radix to be used while parsing {@code s} |
| * @return the {@code byte} value represented by the string |
| * argument in the specified radix |
| * @throws NumberFormatException If the string does |
| * not contain a parsable {@code byte}. |
| */ |
| public static byte parseByte(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 (byte)i; |
| } |
| |
| /** |
| * Parses the string argument as a signed decimal {@code |
| * byte}. The characters in the string must all be decimal digits, |
| * except that the first character may be an ASCII minus sign |
| * {@code '-'} (<code>'\u002D'</code>) to indicate a negative |
| * value or an ASCII plus sign {@code '+'} |
| * (<code>'\u002B'</code>) to indicate a positive value. The |
| * resulting {@code byte} value is returned, exactly as if the |
| * argument and the radix 10 were given as arguments to the {@link |
| * #parseByte(java.lang.String, int)} method. |
| * |
| * @param s a {@code String} containing the |
| * {@code byte} representation to be parsed |
| * @return the {@code byte} value represented by the |
| * argument in decimal |
| * @throws NumberFormatException if the string does not |
| * contain a parsable {@code byte}. |
| */ |
| public static byte parseByte(String s) throws NumberFormatException { |
| return parseByte(s, 10); |
| } |
| |
| /** |
| * Returns a {@code Byte} 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 byte} in |
| * the radix specified by the second argument, exactly as if the |
| * argument were given to the {@link #parseByte(java.lang.String, |
| * int)} method. The result is a {@code Byte} object that |
| * represents the {@code byte} value specified by the string. |
| * |
| * <p> In other words, this method returns a {@code Byte} object |
| * equal to the value of: |
| * |
| * <blockquote> |
| * {@code new Byte(Byte.parseByte(s, radix))} |
| * </blockquote> |
| * |
| * @param s the string to be parsed |
| * @param radix the radix to be used in interpreting {@code s} |
| * @return a {@code Byte} 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 byte}. |
| */ |
| public static Byte valueOf(String s, int radix) |
| throws NumberFormatException { |
| return valueOf(parseByte(s, radix)); |
| } |
| |
| /** |
| * Returns a {@code Byte} object holding the value |
| * given by the specified {@code String}. The argument is |
| * interpreted as representing a signed decimal {@code byte}, |
| * exactly as if the argument were given to the {@link |
| * #parseByte(java.lang.String)} method. The result is a |
| * {@code Byte} object that represents the {@code byte} |
| * value specified by the string. |
| * |
| * <p> In other words, this method returns a {@code Byte} object |
| * equal to the value of: |
| * |
| * <blockquote> |
| * {@code new Byte(Byte.parseByte(s))} |
| * </blockquote> |
| * |
| * @param s the string to be parsed |
| * @return a {@code Byte} object holding the value |
| * represented by the string argument |
| * @throws NumberFormatException If the {@code String} does |
| * not contain a parsable {@code byte}. |
| */ |
| public static Byte valueOf(String s) throws NumberFormatException { |
| return valueOf(s, 10); |
| } |
| |
| /** |
| * Decodes a {@code String} into a {@code Byte}. |
| * 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™ 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 |
| * Byte.parseByte} 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 Byte} object holding the {@code byte} |
| * value represented by {@code nm} |
| * @throws NumberFormatException if the {@code String} does not |
| * contain a parsable {@code byte}. |
| * @see java.lang.Byte#parseByte(java.lang.String, int) |
| */ |
| public static Byte 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((byte)i); |
| } |
| |
| /** |
| * The value of the {@code Byte}. |
| * |
| * @serial |
| */ |
| private final byte value; |
| |
| /** |
| * Constructs a newly allocated {@code Byte} object that |
| * represents the specified {@code byte} value. |
| * |
| * @param value the value to be represented by the |
| * {@code Byte}. |
| */ |
| public Byte(byte value) { |
| this.value = value; |
| } |
| |
| /** |
| * Constructs a newly allocated {@code Byte} object that |
| * represents the {@code byte} value indicated by the |
| * {@code String} parameter. The string is converted to a |
| * {@code byte} value in exactly the manner used by the |
| * {@code parseByte} method for radix 10. |
| * |
| * @param s the {@code String} to be converted to a |
| * {@code Byte} |
| * @throws NumberFormatException If the {@code String} |
| * does not contain a parsable {@code byte}. |
| * @see java.lang.Byte#parseByte(java.lang.String, int) |
| */ |
| public Byte(String s) throws NumberFormatException { |
| this.value = parseByte(s, 10); |
| } |
| |
| /** |
| * Returns the value of this {@code Byte} as a |
| * {@code byte}. |
| */ |
| public byte byteValue() { |
| return value; |
| } |
| |
| /** |
| * Returns the value of this {@code Byte} as a |
| * {@code short}. |
| */ |
| public short shortValue() { |
| return (short)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Byte} as an |
| * {@code int}. |
| */ |
| public int intValue() { |
| return (int)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Byte} as a |
| * {@code long}. |
| */ |
| public long longValue() { |
| return (long)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Byte} as a |
| * {@code float}. |
| */ |
| public float floatValue() { |
| return (float)value; |
| } |
| |
| /** |
| * Returns the value of this {@code Byte} as a |
| * {@code double}. |
| */ |
| public double doubleValue() { |
| return (double)value; |
| } |
| |
| /** |
| * Returns a {@code String} object representing this |
| * {@code Byte}'s value. The value is converted to signed |
| * decimal representation and returned as a string, exactly as if |
| * the {@code byte} value were given as an argument to the |
| * {@link java.lang.Byte#toString(byte)} method. |
| * |
| * @return a string representation of the value of this object in |
| * base 10. |
| */ |
| public String toString() { |
| return Integer.toString((int)value); |
| } |
| |
| /** |
| * Returns a hash code for this {@code Byte}; equal to the result |
| * of invoking {@code intValue()}. |
| * |
| * @return a hash code value for this {@code Byte} |
| */ |
| 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 Byte} object that |
| * contains the same {@code byte} 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 Byte) { |
| return value == ((Byte)obj).byteValue(); |
| } |
| return false; |
| } |
| |
| /** |
| * Compares two {@code Byte} objects numerically. |
| * |
| * @param anotherByte the {@code Byte} to be compared. |
| * @return the value {@code 0} if this {@code Byte} is |
| * equal to the argument {@code Byte}; a value less than |
| * {@code 0} if this {@code Byte} is numerically less |
| * than the argument {@code Byte}; and a value greater than |
| * {@code 0} if this {@code Byte} is numerically |
| * greater than the argument {@code Byte} (signed |
| * comparison). |
| * @since 1.2 |
| */ |
| public int compareTo(Byte anotherByte) { |
| return compare(this.value, anotherByte.value); |
| } |
| |
| /** |
| * Compares two {@code byte} values numerically. |
| * The value returned is identical to what would be returned by: |
| * <pre> |
| * Byte.valueOf(x).compareTo(Byte.valueOf(y)) |
| * </pre> |
| * |
| * @param x the first {@code byte} to compare |
| * @param y the second {@code byte} 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(byte x, byte y) { |
| return x - y; |
| } |
| |
| /** |
| * The number of bits used to represent a {@code byte} value in two's |
| * complement binary form. |
| * |
| * @since 1.5 |
| */ |
| public static final int SIZE = 8; |
| |
| /** use serialVersionUID from JDK 1.1. for interoperability */ |
| private static final long serialVersionUID = -7183698231559129828L; |
| } |
