diff -r 836adbf7a2cd -r 3317bb8137f4 jdk/src/java.base/share/classes/java/lang/Byte.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/jdk/src/java.base/share/classes/java/lang/Byte.java Sun Aug 17 15:54:13 2014 +0100 @@ -0,0 +1,520 @@ +/* + * Copyright (c) 1996, 2013, 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}. + * + *

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 1.1 + */ +public final class Byte extends Number implements Comparable { + + /** + * A constant holding the minimum value a {@code byte} can + * have, -27. + */ + public static final byte MIN_VALUE = -128; + + /** + * A constant holding the maximum value a {@code byte} can + * have, 27-1. + */ + public static final byte MAX_VALUE = 127; + + /** + * The {@code Class} instance representing the primitive type + * {@code byte}. + */ + @SuppressWarnings("unchecked") + public static final Class TYPE = (Class) 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 '\u005Cu002D'}) to indicate a negative value or an + * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to + * indicate a positive value. The resulting {@code byte} value is + * returned. + * + *

An exception of type {@code NumberFormatException} is + * thrown if any of the following situations occurs: + *

+ * + * @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 '\u005Cu002D'}) to indicate a negative + * value or an ASCII plus sign {@code '+'} + * ({@code '\u005Cu002B'}) 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. + * + *

In other words, this method returns a {@code Byte} object + * equal to the value of: + * + *

+ * {@code new Byte(Byte.parseByte(s, radix))} + *
+ * + * @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. + * + *

In other words, this method returns a {@code Byte} object + * equal to the value of: + * + *

+ * {@code new Byte(Byte.parseByte(s))} + *
+ * + * @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: + * + *
+ *
+ *
DecodableString: + *
Signopt DecimalNumeral + *
Signopt {@code 0x} HexDigits + *
Signopt {@code 0X} HexDigits + *
Signopt {@code #} HexDigits + *
Signopt {@code 0} OctalDigits + * + *
Sign: + *
{@code -} + *
{@code +} + *
+ *
+ * + * DecimalNumeral, HexDigits, and OctalDigits + * are as defined in section 3.10.1 of + * The Java™ Language Specification, + * except that underscores are not accepted between digits. + * + *

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} after + * a widening primitive conversion. + * @jls 5.1.2 Widening Primitive Conversions + */ + public short shortValue() { + return (short)value; + } + + /** + * Returns the value of this {@code Byte} as an {@code int} after + * a widening primitive conversion. + * @jls 5.1.2 Widening Primitive Conversions + */ + public int intValue() { + return (int)value; + } + + /** + * Returns the value of this {@code Byte} as a {@code long} after + * a widening primitive conversion. + * @jls 5.1.2 Widening Primitive Conversions + */ + public long longValue() { + return (long)value; + } + + /** + * Returns the value of this {@code Byte} as a {@code float} after + * a widening primitive conversion. + * @jls 5.1.2 Widening Primitive Conversions + */ + public float floatValue() { + return (float)value; + } + + /** + * Returns the value of this {@code Byte} as a {@code double} + * after a widening primitive conversion. + * @jls 5.1.2 Widening Primitive Conversions + */ + 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} + */ + @Override + public int hashCode() { + return Byte.hashCode(value); + } + + /** + * Returns a hash code for a {@code byte} value; compatible with + * {@code Byte.hashCode()}. + * + * @param value the value to hash + * @return a hash code value for a {@code byte} value. + * @since 1.8 + */ + public static int hashCode(byte value) { + 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: + * 

+     *    Byte.valueOf(x).compareTo(Byte.valueOf(y))
+     *
+ * + * @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; + } + + /** + * Converts the argument to an {@code int} by an unsigned + * conversion. In an unsigned conversion to an {@code int}, the + * high-order 24 bits of the {@code int} are zero and the + * low-order 8 bits are equal to the bits of the {@code byte} argument. + * + * Consequently, zero and positive {@code byte} values are mapped + * to a numerically equal {@code int} value and negative {@code + * byte} values are mapped to an {@code int} value equal to the + * input plus 28. + * + * @param x the value to convert to an unsigned {@code int} + * @return the argument converted to {@code int} by an unsigned + * conversion + * @since 1.8 + */ + public static int toUnsignedInt(byte x) { + return ((int) x) & 0xff; + } + + /** + * Converts the argument to a {@code long} by an unsigned + * conversion. In an unsigned conversion to a {@code long}, the + * high-order 56 bits of the {@code long} are zero and the + * low-order 8 bits are equal to the bits of the {@code byte} argument. + * + * Consequently, zero and positive {@code byte} values are mapped + * to a numerically equal {@code long} value and negative {@code + * byte} values are mapped to a {@code long} value equal to the + * input plus 28. + * + * @param x the value to convert to an unsigned {@code long} + * @return the argument converted to {@code long} by an unsigned + * conversion + * @since 1.8 + */ + public static long toUnsignedLong(byte x) { + return ((long) x) & 0xffL; + } + + + /** + * 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; + + /** + * The number of bytes used to represent a {@code byte} value in two's + * complement binary form. + * + * @since 1.8 + */ + public static final int BYTES = SIZE / Byte.SIZE; + + /** use serialVersionUID from JDK 1.1. for interoperability */ + private static final long serialVersionUID = -7183698231559129828L; +}