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™ 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