001    /* Number.java =- abstract superclass of numeric objects
002       Copyright (C) 1998, 2001, 2002, 2005  Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package java.lang;
040    
041    import java.io.Serializable;
042    
043    /**
044     * Number is a generic superclass of all the numeric classes, including
045     * the wrapper classes {@link Byte}, {@link Short}, {@link Integer},
046     * {@link Long}, {@link Float}, and {@link Double}.  Also worth mentioning
047     * are the classes in {@link java.math}.
048     *
049     * It provides ways to convert numeric objects to any primitive.
050     *
051     * @author Paul Fisher
052     * @author John Keiser
053     * @author Warren Levy
054     * @author Eric Blake (ebb9@email.byu.edu)
055     * @since 1.0
056     * @status updated to 1.4
057     */
058    public abstract class Number implements Serializable
059    {
060      /**
061       * Compatible with JDK 1.1+.
062       */
063      private static final long serialVersionUID = -8742448824652078965L;
064    
065      /**
066       * Table for calculating digits, used in Character, Long, and Integer.
067       */
068      static final char[] digits = {
069        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
070        'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
071        'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
072        'u', 'v', 'w', 'x', 'y', 'z',
073      };
074    
075      /**
076       * The basic constructor (often called implicitly).
077       */
078      public Number()
079      {
080      }
081    
082      /**
083       * Return the value of this <code>Number</code> as an <code>int</code>.
084       *
085       * @return the int value
086       */
087      public abstract int intValue();
088    
089      /**
090       * Return the value of this <code>Number</code> as a <code>long</code>.
091       *
092       * @return the long value
093       */
094      public abstract long longValue();
095    
096      /**
097       * Return the value of this <code>Number</code> as a <code>float</code>.
098       *
099       * @return the float value
100       */
101      public abstract float floatValue();
102    
103      /**
104       * Return the value of this <code>Number</code> as a <code>float</code>.
105       *
106       * @return the double value
107       */
108      public abstract double doubleValue();
109    
110      /**
111       * Return the value of this <code>Number</code> as a <code>byte</code>.
112       *
113       * @return the byte value
114       * @since 1.1
115       */
116      public byte byteValue()
117      {
118        return (byte) intValue();
119      }
120    
121      /**
122       * Return the value of this <code>Number</code> as a <code>short</code>.
123       *
124       * @return the short value
125       * @since 1.1
126       */
127      public short shortValue()
128      {
129        return (short) intValue();
130      }
131    }