mirror of git://gcc.gnu.org/git/gcc.git
388 lines
11 KiB
Java
388 lines
11 KiB
Java
/* Byte.java -- object wrapper for byte
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Copyright (C) 1998, 2001, 2002, 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.lang;
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/**
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* Instances of class <code>Byte</code> represent primitive <code>byte</code>
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* values.
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*
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* Additionally, this class provides various helper functions and variables
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* useful to bytes.
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*
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* @author Paul Fisher
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* @author John Keiser
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* @author Per Bothner
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* @author Eric Blake (ebb9@email.byu.edu)
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* @since 1.1
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* @status updated to 1.5
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*/
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public final class Byte extends Number implements Comparable
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{
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/**
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* Compatible with JDK 1.1+.
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*/
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private static final long serialVersionUID = -7183698231559129828L;
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/**
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* The minimum value a <code>byte</code> can represent is -128 (or
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* -2<sup>7</sup>).
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*/
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public static final byte MIN_VALUE = -128;
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/**
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* The maximum value a <code>byte</code> can represent is 127 (or
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* 2<sup>7</sup> - 1).
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*/
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public static final byte MAX_VALUE = 127;
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/**
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* The primitive type <code>byte</code> is represented by this
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* <code>Class</code> object.
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*/
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public static final Class TYPE = VMClassLoader.getPrimitiveClass('B');
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/**
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* The number of bits needed to represent a <code>byte</code>.
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* @since 1.5
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*/
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public static final int SIZE = 8;
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// This caches Byte values, and is used by boxing conversions via
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// valueOf(). We're required to cache all possible values here.
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private static Byte[] byteCache = new Byte[MAX_VALUE - MIN_VALUE + 1];
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/**
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* The immutable value of this Byte.
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*
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* @serial the wrapped byte
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*/
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private final byte value;
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/**
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* Create a <code>Byte</code> object representing the value of the
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* <code>byte</code> argument.
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*
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* @param value the value to use
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*/
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public Byte(byte value)
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{
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this.value = value;
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}
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/**
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* Create a <code>Byte</code> object representing the value specified
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* by the <code>String</code> argument
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*
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* @param s the string to convert
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* @throws NumberFormatException if the String does not contain a byte
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* @see #valueOf(String)
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*/
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public Byte(String s)
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{
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value = parseByte(s, 10);
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}
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/**
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* Converts the <code>byte</code> to a <code>String</code> and assumes
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* a radix of 10.
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*
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* @param b the <code>byte</code> to convert to <code>String</code>
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* @return the <code>String</code> representation of the argument
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*/
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public static String toString(byte b)
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{
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return String.valueOf(b);
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}
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/**
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* Converts the specified <code>String</code> into a <code>byte</code>.
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* This function assumes a radix of 10.
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*
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* @param s the <code>String</code> to convert
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* @return the <code>byte</code> value of <code>s</code>
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* @throws NumberFormatException if <code>s</code> cannot be parsed as a
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* <code>byte</code>
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* @see #parseByte(String)
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*/
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public static byte parseByte(String s)
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{
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return parseByte(s, 10);
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}
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/**
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* Converts the specified <code>String</code> into an <code>int</code>
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* using the specified radix (base). The string must not be <code>null</code>
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* or empty. It may begin with an optional '-', which will negate the answer,
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* provided that there are also valid digits. Each digit is parsed as if by
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* <code>Character.digit(d, radix)</code>, and must be in the range
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* <code>0</code> to <code>radix - 1</code>. Finally, the result must be
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* within <code>MIN_VALUE</code> to <code>MAX_VALUE</code>, inclusive.
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* Unlike Double.parseDouble, you may not have a leading '+'.
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*
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* @param s the <code>String</code> to convert
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* @param radix the radix (base) to use in the conversion
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* @return the <code>String</code> argument converted to <code>byte</code>
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* @throws NumberFormatException if <code>s</code> cannot be parsed as a
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* <code>byte</code>
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*/
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public static byte parseByte(String s, int radix)
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{
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int i = Integer.parseInt(s, radix, false);
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if ((byte) i != i)
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throw new NumberFormatException();
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return (byte) i;
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}
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/**
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* Creates a new <code>Byte</code> object using the <code>String</code>
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* and specified radix (base).
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*
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* @param s the <code>String</code> to convert
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* @param radix the radix (base) to convert with
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* @return the new <code>Byte</code>
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* @throws NumberFormatException if <code>s</code> cannot be parsed as a
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* <code>byte</code>
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* @see #parseByte(String, int)
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*/
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public static Byte valueOf(String s, int radix)
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{
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return new Byte(parseByte(s, radix));
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}
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/**
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* Creates a new <code>Byte</code> object using the <code>String</code>,
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* assuming a radix of 10.
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*
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* @param s the <code>String</code> to convert
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* @return the new <code>Byte</code>
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* @throws NumberFormatException if <code>s</code> cannot be parsed as a
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* <code>byte</code>
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* @see #Byte(String)
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* @see #parseByte(String)
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*/
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public static Byte valueOf(String s)
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{
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return new Byte(parseByte(s, 10));
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}
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/**
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* Returns a <code>Byte</code> object wrapping the value.
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* In contrast to the <code>Byte</code> constructor, this method
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* will cache some values. It is used by boxing conversion.
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*
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* @param val the value to wrap
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* @return the <code>Byte</code>
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*
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* @since 1.5
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*/
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public static Byte valueOf(byte val)
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{
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synchronized (byteCache)
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{
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if (byteCache[val - MIN_VALUE] == null)
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byteCache[val - MIN_VALUE] = new Byte(val);
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return byteCache[val - MIN_VALUE];
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}
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}
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/**
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* Convert the specified <code>String</code> into a <code>Byte</code>.
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* The <code>String</code> may represent decimal, hexadecimal, or
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* octal numbers.
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*
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* <p>The extended BNF grammar is as follows:<br>
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* <pre>
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* <em>DecodableString</em>:
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* ( [ <code>-</code> ] <em>DecimalNumber</em> )
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* | ( [ <code>-</code> ] ( <code>0x</code> | <code>0X</code>
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* | <code>#</code> ) { <em>HexDigit</em> }+ )
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* | ( [ <code>-</code> ] <code>0</code> { <em>OctalDigit</em> } )
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* <em>DecimalNumber</em>:
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* <em>DecimalDigit except '0'</em> { <em>DecimalDigit</em> }
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* <em>DecimalDigit</em>:
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* <em>Character.digit(d, 10) has value 0 to 9</em>
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* <em>OctalDigit</em>:
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* <em>Character.digit(d, 8) has value 0 to 7</em>
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* <em>DecimalDigit</em>:
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* <em>Character.digit(d, 16) has value 0 to 15</em>
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* </pre>
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* Finally, the value must be in the range <code>MIN_VALUE</code> to
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* <code>MAX_VALUE</code>, or an exception is thrown.
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*
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* @param s the <code>String</code> to interpret
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* @return the value of the String as a <code>Byte</code>
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* @throws NumberFormatException if <code>s</code> cannot be parsed as a
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* <code>byte</code>
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* @throws NullPointerException if <code>s</code> is null
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* @see Integer#decode(String)
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*/
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public static Byte decode(String s)
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{
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int i = Integer.parseInt(s, 10, true);
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if ((byte) i != i)
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throw new NumberFormatException();
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return new Byte((byte) i);
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}
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/**
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* Return the value of this <code>Byte</code>.
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*
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* @return the byte value
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*/
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public byte byteValue()
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{
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return value;
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}
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/**
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* Return the value of this <code>Byte</code> as a <code>short</code>.
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*
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* @return the short value
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*/
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public short shortValue()
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{
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return value;
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}
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/**
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* Return the value of this <code>Byte</code> as an <code>int</code>.
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*
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* @return the int value
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*/
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public int intValue()
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{
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return value;
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}
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/**
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* Return the value of this <code>Byte</code> as a <code>long</code>.
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*
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* @return the long value
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*/
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public long longValue()
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{
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return value;
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}
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/**
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* Return the value of this <code>Byte</code> as a <code>float</code>.
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*
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* @return the float value
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*/
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public float floatValue()
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{
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return value;
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}
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/**
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* Return the value of this <code>Byte</code> as a <code>double</code>.
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*
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* @return the double value
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*/
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public double doubleValue()
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{
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return value;
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}
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/**
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* Converts the <code>Byte</code> value to a <code>String</code> and
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* assumes a radix of 10.
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*
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* @return the <code>String</code> representation of this <code>Byte</code>
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* @see Integer#toString()
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*/
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public String toString()
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{
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return String.valueOf(value);
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}
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/**
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* Return a hashcode representing this Object. <code>Byte</code>'s hash
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* code is simply its value.
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*
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* @return this Object's hash code
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*/
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public int hashCode()
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{
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return value;
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}
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/**
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* Returns <code>true</code> if <code>obj</code> is an instance of
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* <code>Byte</code> and represents the same byte value.
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*
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* @param obj the object to compare
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* @return whether these Objects are semantically equal
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*/
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public boolean equals(Object obj)
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{
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return obj instanceof Byte && value == ((Byte) obj).value;
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}
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/**
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* Compare two Bytes numerically by comparing their <code>byte</code> values.
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* The result is positive if the first is greater, negative if the second
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* is greater, and 0 if the two are equal.
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*
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* @param b the Byte to compare
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* @return the comparison
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* @since 1.2
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*/
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public int compareTo(Byte b)
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{
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return value - b.value;
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}
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/**
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* Behaves like <code>compareTo(Byte)</code> unless the Object
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* is not a <code>Byte</code>.
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*
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* @param o the object to compare
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* @return the comparison
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* @throws ClassCastException if the argument is not a <code>Byte</code>
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* @see #compareTo(Byte)
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* @see Comparable
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* @since 1.2
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*/
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public int compareTo(Object o)
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{
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return compareTo((Byte) o);
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}
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}
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