Showing the changes to java/pkg/java/lang/Boolean.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,282 @@ | ||
| 1 | +/* | |
| 2 | + * Copyright (c) 1994, 2006, 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 Boolean class wraps a value of the primitive type | |
| 30 | + * {@code boolean} in an object. An object of type | |
| 31 | + * {@code Boolean} contains a single field whose type is | |
| 32 | + * {@code boolean}. | |
| 33 | + * <p> | |
| 34 | + * In addition, this class provides many methods for | |
| 35 | + * converting a {@code boolean} to a {@code String} and a | |
| 36 | + * {@code String} to a {@code boolean}, as well as other | |
| 37 | + * constants and methods useful when dealing with a | |
| 38 | + * {@code boolean}. | |
| 39 | + * | |
| 40 | + * @author Arthur van Hoff | |
| 41 | + * @since JDK1.0 | |
| 42 | + */ | |
| 43 | +public final class Boolean implements java.io.Serializable, | |
| 44 | + Comparable<Boolean> | |
| 45 | +{ | |
| 46 | + /** | |
| 47 | + * The {@code Boolean} object corresponding to the primitive | |
| 48 | + * value {@code true}. | |
| 49 | + */ | |
| 50 | + public static final Boolean TRUE = new Boolean(true); | |
| 51 | + | |
| 52 | + /** | |
| 53 | + * The {@code Boolean} object corresponding to the primitive | |
| 54 | + * value {@code false}. | |
| 55 | + */ | |
| 56 | + public static final Boolean FALSE = new Boolean(false); | |
| 57 | + | |
| 58 | + /** | |
| 59 | + * The Class object representing the primitive type boolean. | |
| 60 | + * | |
| 61 | + * @since JDK1.1 | |
| 62 | + */ | |
| 63 | + public static final Class<Boolean> TYPE = Class.getPrimitiveClass("boolean"); | |
| 64 | + | |
| 65 | + /** | |
| 66 | + * The value of the Boolean. | |
| 67 | + * | |
| 68 | + * @serial | |
| 69 | + */ | |
| 70 | + private final boolean value; | |
| 71 | + | |
| 72 | + /** use serialVersionUID from JDK 1.0.2 for interoperability */ | |
| 73 | + private static final long serialVersionUID = -3665804199014368530L; | |
| 74 | + | |
| 75 | + /** | |
| 76 | + * Allocates a {@code Boolean} object representing the | |
| 77 | + * {@code value} argument. | |
| 78 | + * | |
| 79 | + * <p><b>Note: It is rarely appropriate to use this constructor. | |
| 80 | + * Unless a <i>new</i> instance is required, the static factory | |
| 81 | + * {@link #valueOf(boolean)} is generally a better choice. It is | |
| 82 | + * likely to yield significantly better space and time performance.</b> | |
| 83 | + * | |
| 84 | + * @param value the value of the {@code Boolean}. | |
| 85 | + */ | |
| 86 | + public Boolean(boolean value) { | |
| 87 | + this.value = value; | |
| 88 | + } | |
| 89 | + | |
| 90 | + /** | |
| 91 | + * Allocates a {@code Boolean} object representing the value | |
| 92 | + * {@code true} if the string argument is not {@code null} | |
| 93 | + * and is equal, ignoring case, to the string {@code "true"}. | |
| 94 | + * Otherwise, allocate a {@code Boolean} object representing the | |
| 95 | + * value {@code false}. Examples:<p> | |
| 96 | + * {@code new Boolean("True")} produces a {@code Boolean} object | |
| 97 | + * that represents {@code true}.<br> | |
| 98 | + * {@code new Boolean("yes")} produces a {@code Boolean} object | |
| 99 | + * that represents {@code false}. | |
| 100 | + * | |
| 101 | + * @param s the string to be converted to a {@code Boolean}. | |
| 102 | + */ | |
| 103 | + public Boolean(String s) { | |
| 104 | + this(toBoolean(s)); | |
| 105 | + } | |
| 106 | + | |
| 107 | + /** | |
| 108 | + * Parses the string argument as a boolean. The {@code boolean} | |
| 109 | + * returned represents the value {@code true} if the string argument | |
| 110 | + * is not {@code null} and is equal, ignoring case, to the string | |
| 111 | + * {@code "true"}. <p> | |
| 112 | + * Example: {@code Boolean.parseBoolean("True")} returns {@code true}.<br> | |
| 113 | + * Example: {@code Boolean.parseBoolean("yes")} returns {@code false}. | |
| 114 | + * | |
| 115 | + * @param s the {@code String} containing the boolean | |
| 116 | + * representation to be parsed | |
| 117 | + * @return the boolean represented by the string argument | |
| 118 | + * @since 1.5 | |
| 119 | + */ | |
| 120 | + public static boolean parseBoolean(String s) { | |
| 121 | + return toBoolean(s); | |
| 122 | + } | |
| 123 | + | |
| 124 | + /** | |
| 125 | + * Returns the value of this {@code Boolean} object as a boolean | |
| 126 | + * primitive. | |
| 127 | + * | |
| 128 | + * @return the primitive {@code boolean} value of this object. | |
| 129 | + */ | |
| 130 | + public boolean booleanValue() { | |
| 131 | + return value; | |
| 132 | + } | |
| 133 | + | |
| 134 | + /** | |
| 135 | + * Returns a {@code Boolean} instance representing the specified | |
| 136 | + * {@code boolean} value. If the specified {@code boolean} value | |
| 137 | + * is {@code true}, this method returns {@code Boolean.TRUE}; | |
| 138 | + * if it is {@code false}, this method returns {@code Boolean.FALSE}. | |
| 139 | + * If a new {@code Boolean} instance is not required, this method | |
| 140 | + * should generally be used in preference to the constructor | |
| 141 | + * {@link #Boolean(boolean)}, as this method is likely to yield | |
| 142 | + * significantly better space and time performance. | |
| 143 | + * | |
| 144 | + * @param b a boolean value. | |
| 145 | + * @return a {@code Boolean} instance representing {@code b}. | |
| 146 | + * @since 1.4 | |
| 147 | + */ | |
| 148 | + public static Boolean valueOf(boolean b) { | |
| 149 | + return (b ? TRUE : FALSE); | |
| 150 | + } | |
| 151 | + | |
| 152 | + /** | |
| 153 | + * Returns a {@code Boolean} with a value represented by the | |
| 154 | + * specified string. The {@code Boolean} returned represents a | |
| 155 | + * true value if the string argument is not {@code null} | |
| 156 | + * and is equal, ignoring case, to the string {@code "true"}. | |
| 157 | + * | |
| 158 | + * @param s a string. | |
| 159 | + * @return the {@code Boolean} value represented by the string. | |
| 160 | + */ | |
| 161 | + public static Boolean valueOf(String s) { | |
| 162 | + return toBoolean(s) ? TRUE : FALSE; | |
| 163 | + } | |
| 164 | + | |
| 165 | + /** | |
| 166 | + * Returns a {@code String} object representing the specified | |
| 167 | + * boolean. If the specified boolean is {@code true}, then | |
| 168 | + * the string {@code "true"} will be returned, otherwise the | |
| 169 | + * string {@code "false"} will be returned. | |
| 170 | + * | |
| 171 | + * @param b the boolean to be converted | |
| 172 | + * @return the string representation of the specified {@code boolean} | |
| 173 | + * @since 1.4 | |
| 174 | + */ | |
| 175 | + public static String toString(boolean b) { | |
| 176 | + return b ? "true" : "false"; | |
| 177 | + } | |
| 178 | + | |
| 179 | + /** | |
| 180 | + * Returns a {@code String} object representing this Boolean's | |
| 181 | + * value. If this object represents the value {@code true}, | |
| 182 | + * a string equal to {@code "true"} is returned. Otherwise, a | |
| 183 | + * string equal to {@code "false"} is returned. | |
| 184 | + * | |
| 185 | + * @return a string representation of this object. | |
| 186 | + */ | |
| 187 | + public String toString() { | |
| 188 | + return value ? "true" : "false"; | |
| 189 | + } | |
| 190 | + | |
| 191 | + /** | |
| 192 | + * Returns a hash code for this {@code Boolean} object. | |
| 193 | + * | |
| 194 | + * @return the integer {@code 1231} if this object represents | |
| 195 | + * {@code true}; returns the integer {@code 1237} if this | |
| 196 | + * object represents {@code false}. | |
| 197 | + */ | |
| 198 | + public int hashCode() { | |
| 199 | + return value ? 1231 : 1237; | |
| 200 | + } | |
| 201 | + | |
| 202 | + /** | |
| 203 | + * Returns {@code true} if and only if the argument is not | |
| 204 | + * {@code null} and is a {@code Boolean} object that | |
| 205 | + * represents the same {@code boolean} value as this object. | |
| 206 | + * | |
| 207 | + * @param obj the object to compare with. | |
| 208 | + * @return {@code true} if the Boolean objects represent the | |
| 209 | + * same value; {@code false} otherwise. | |
| 210 | + */ | |
| 211 | + public boolean equals(Object obj) { | |
| 212 | + if (obj instanceof Boolean) { | |
| 213 | + return value == ((Boolean)obj).booleanValue(); | |
| 214 | + } | |
| 215 | + return false; | |
| 216 | + } | |
| 217 | + | |
| 218 | + /** | |
| 219 | + * Returns {@code true} if and only if the system property | |
| 220 | + * named by the argument exists and is equal to the string | |
| 221 | + * {@code "true"}. (Beginning with version 1.0.2 of the | |
| 222 | + * Java<small><sup>TM</sup></small> platform, the test of | |
| 223 | + * this string is case insensitive.) A system property is accessible | |
| 224 | + * through {@code getProperty}, a method defined by the | |
| 225 | + * {@code System} class. | |
| 226 | + * <p> | |
| 227 | + * If there is no property with the specified name, or if the specified | |
| 228 | + * name is empty or null, then {@code false} is returned. | |
| 229 | + * | |
| 230 | + * @param name the system property name. | |
| 231 | + * @return the {@code boolean} value of the system property. | |
| 232 | + * @see java.lang.System#getProperty(java.lang.String) | |
| 233 | + * @see java.lang.System#getProperty(java.lang.String, java.lang.String) | |
| 234 | + */ | |
| 235 | + public static boolean getBoolean(String name) { | |
| 236 | + boolean result = false; | |
| 237 | + try { | |
| 238 | + result = toBoolean(System.getProperty(name)); | |
| 239 | + } catch (IllegalArgumentException e) { | |
| 240 | + } catch (NullPointerException e) { | |
| 241 | + } | |
| 242 | + return result; | |
| 243 | + } | |
| 244 | + | |
| 245 | + /** | |
| 246 | + * Compares this {@code Boolean} instance with another. | |
| 247 | + * | |
| 248 | + * @param b the {@code Boolean} instance to be compared | |
| 249 | + * @return zero if this object represents the same boolean value as the | |
| 250 | + * argument; a positive value if this object represents true | |
| 251 | + * and the argument represents false; and a negative value if | |
| 252 | + * this object represents false and the argument represents true | |
| 253 | + * @throws NullPointerException if the argument is {@code null} | |
| 254 | + * @see Comparable | |
| 255 | + * @since 1.5 | |
| 256 | + */ | |
| 257 | + public int compareTo(Boolean b) { | |
| 258 | + return compare(this.value, b.value); | |
| 259 | + } | |
| 260 | + | |
| 261 | + /** | |
| 262 | + * Compares two {@code boolean} values. | |
| 263 | + * The value returned is identical to what would be returned by: | |
| 264 | + * <pre> | |
| 265 | + * Boolean.valueOf(x).compareTo(Boolean.valueOf(y)) | |
| 266 | + * </pre> | |
| 267 | + * | |
| 268 | + * @param x the first {@code boolean} to compare | |
| 269 | + * @param y the second {@code boolean} to compare | |
| 270 | + * @return the value {@code 0} if {@code x == y}; | |
| 271 | + * a value less than {@code 0} if {@code !x && y}; and | |
| 272 | + * a value greater than {@code 0} if {@code x && !y} | |
| 273 | + * @since 1.7 | |
| 274 | + */ | |
| 275 | + public static int compare(boolean x, boolean y) { | |
| 276 | + return (x == y) ? 0 : (x ? 1 : -1); | |
| 277 | + } | |
| 278 | + | |
| 279 | + private static boolean toBoolean(String name) { | |
| 280 | + return ((name != null) && name.equalsIgnoreCase("true")); | |
| 281 | + } | |
| 282 | +} | |