src/share/classes/java/lang/Number.java

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   1 /*
   2  * Copyright (c) 1994, 2001, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.lang;
  27 
  28 /**
  29  * The abstract class <code>Number</code> is the superclass of classes
  30  * <code>BigDecimal</code>, <code>BigInteger</code>,
  31  * <code>Byte</code>, <code>Double</code>, <code>Float</code>,
  32  * <code>Integer</code>, <code>Long</code>, and <code>Short</code>.
  33  * <p>
  34  * Subclasses of <code>Number</code> must provide methods to convert
  35  * the represented numeric value to <code>byte</code>, <code>double</code>,
  36  * <code>float</code>, <code>int</code>, <code>long</code>, and
  37  * <code>short</code>.










  38  *
  39  * @author      Lee Boynton
  40  * @author      Arthur van Hoff
  41  * @see     java.lang.Byte
  42  * @see     java.lang.Double
  43  * @see     java.lang.Float
  44  * @see     java.lang.Integer
  45  * @see     java.lang.Long
  46  * @see     java.lang.Short
  47  * @since   JDK1.0
  48  */
  49 public abstract class Number implements java.io.Serializable {
  50     /**
  51      * Returns the value of the specified number as an <code>int</code>.
  52      * This may involve rounding or truncation.
  53      *
  54      * @return  the numeric value represented by this object after conversion
  55      *          to type <code>int</code>.
  56      */
  57     public abstract int intValue();
  58 
  59     /**
  60      * Returns the value of the specified number as a <code>long</code>.
  61      * This may involve rounding or truncation.
  62      *
  63      * @return  the numeric value represented by this object after conversion
  64      *          to type <code>long</code>.
  65      */
  66     public abstract long longValue();
  67 
  68     /**
  69      * Returns the value of the specified number as a <code>float</code>.
  70      * This may involve rounding.
  71      *
  72      * @return  the numeric value represented by this object after conversion
  73      *          to type <code>float</code>.
  74      */
  75     public abstract float floatValue();
  76 
  77     /**
  78      * Returns the value of the specified number as a <code>double</code>.
  79      * This may involve rounding.
  80      *
  81      * @return  the numeric value represented by this object after conversion
  82      *          to type <code>double</code>.
  83      */
  84     public abstract double doubleValue();
  85 
  86     /**
  87      * Returns the value of the specified number as a <code>byte</code>.
  88      * This may involve rounding or truncation.



  89      *
  90      * @return  the numeric value represented by this object after conversion
  91      *          to type <code>byte</code>.
  92      * @since   JDK1.1
  93      */
  94     public byte byteValue() {
  95         return (byte)intValue();
  96     }
  97 
  98     /**
  99      * Returns the value of the specified number as a <code>short</code>.
 100      * This may involve rounding or truncation.



 101      *
 102      * @return  the numeric value represented by this object after conversion
 103      *          to type <code>short</code>.
 104      * @since   JDK1.1
 105      */
 106     public short shortValue() {
 107         return (short)intValue();
 108     }
 109 
 110     /** use serialVersionUID from JDK 1.0.2 for interoperability */
 111     private static final long serialVersionUID = -8742448824652078965L;
 112 }
   1 /*
   2  * Copyright (c) 1994, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.lang;
  27 
  28 /**
  29  * The abstract class {@code Number} is the superclass of platform
  30  * classes representing numeric values that are convertible to the
  31  * primitive types {@code byte}, {@code double}, {@code float}, {@code
  32  * int}, {@code long}, and {@code short}.
  33  *
  34  * The specific semantics of the conversion from the numeric value of
  35  * a particular {@code Number} implementation to a given primitive
  36  * type is defined by the {@code Number} implementation in question.
  37  *
  38  * For platform classes, the conversion is often analogous to a
  39  * narrowing primitive conversion or a widening primitive conversion
  40  * as defining in <cite>The Java&trade; Language Specification</cite>
  41  * for converting between primitive types.  Therefore, conversions may
  42  * lose information about the overall magnitude of a numeric value, may
  43  * lose precision, and may even return a result of a different sign
  44  * than the input.
  45  *
  46  * See the documentation of a given {@code Number} implementation for
  47  * conversion details.
  48  *
  49  * @author      Lee Boynton
  50  * @author      Arthur van Hoff
  51  * @jls 5.1.2 Widening Primitive Conversions
  52  * @jls 5.1.3 Narrowing Primitive Conversions




  53  * @since   JDK1.0
  54  */
  55 public abstract class Number implements java.io.Serializable {
  56     /**
  57      * Returns the value of the specified number as an {@code int},
  58      * which may involve rounding or truncation.
  59      *
  60      * @return  the numeric value represented by this object after conversion
  61      *          to type {@code int}.
  62      */
  63     public abstract int intValue();
  64 
  65     /**
  66      * Returns the value of the specified number as a {@code long},
  67      * which may involve rounding or truncation.
  68      *
  69      * @return  the numeric value represented by this object after conversion
  70      *          to type {@code long}.
  71      */
  72     public abstract long longValue();
  73 
  74     /**
  75      * Returns the value of the specified number as a {@code float},
  76      * which may involve rounding.
  77      *
  78      * @return  the numeric value represented by this object after conversion
  79      *          to type {@code float}.
  80      */
  81     public abstract float floatValue();
  82 
  83     /**
  84      * Returns the value of the specified number as a {@code double},
  85      * which may involve rounding.
  86      *
  87      * @return  the numeric value represented by this object after conversion
  88      *          to type {@code double}.
  89      */
  90     public abstract double doubleValue();
  91 
  92     /**
  93      * Returns the value of the specified number as a {@code byte},
  94      * which may involve rounding or truncation.
  95      *
  96      * <p>This implementation returns the result of {@link #intValue} cast
  97      * to a {@code byte}.
  98      *
  99      * @return  the numeric value represented by this object after conversion
 100      *          to type {@code byte}.
 101      * @since   JDK1.1
 102      */
 103     public byte byteValue() {
 104         return (byte)intValue();
 105     }
 106 
 107     /**
 108      * Returns the value of the specified number as a {@code short},
 109      * which may involve rounding or truncation.
 110      *
 111      * <p>This implementation returns the result of {@link #intValue} cast
 112      * to a {@code short}.
 113      *
 114      * @return  the numeric value represented by this object after conversion
 115      *          to type {@code short}.
 116      * @since   JDK1.1
 117      */
 118     public short shortValue() {
 119         return (short)intValue();
 120     }
 121 
 122     /** use serialVersionUID from JDK 1.0.2 for interoperability */
 123     private static final long serialVersionUID = -8742448824652078965L;
 124 }