• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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      */
intValue()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      */
longValue()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      */
floatValue()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      */
doubleValue()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      */
byteValue()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      */
shortValue()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 }
125