1/* 2 * Copyright (c) 1994, 2015, 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 26package 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 defined 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 1.0 54 */ 55public abstract class Number implements java.io.Serializable { 56 /** 57 * Returns the value of the specified number as an {@code int}. 58 * 59 * @return the numeric value represented by this object after conversion 60 * to type {@code int}. 61 */ 62 public abstract int intValue(); 63 64 /** 65 * Returns the value of the specified number as a {@code long}. 66 * 67 * @return the numeric value represented by this object after conversion 68 * to type {@code long}. 69 */ 70 public abstract long longValue(); 71 72 /** 73 * Returns the value of the specified number as a {@code float}. 74 * 75 * @return the numeric value represented by this object after conversion 76 * to type {@code float}. 77 */ 78 public abstract float floatValue(); 79 80 /** 81 * Returns the value of the specified number as a {@code double}. 82 * 83 * @return the numeric value represented by this object after conversion 84 * to type {@code double}. 85 */ 86 public abstract double doubleValue(); 87 88 /** 89 * Returns the value of the specified number as a {@code byte}. 90 * 91 * <p>This implementation returns the result of {@link #intValue} cast 92 * to a {@code byte}. 93 * 94 * @return the numeric value represented by this object after conversion 95 * to type {@code byte}. 96 * @since 1.1 97 */ 98 public byte byteValue() { 99 return (byte)intValue(); 100 } 101 102 /** 103 * Returns the value of the specified number as a {@code short}. 104 * 105 * <p>This implementation returns the result of {@link #intValue} cast 106 * to a {@code short}. 107 * 108 * @return the numeric value represented by this object after conversion 109 * to type {@code short}. 110 * @since 1.1 111 */ 112 public short shortValue() { 113 return (short)intValue(); 114 } 115 116 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 117 private static final long serialVersionUID = -8742448824652078965L; 118} 119