All primitive type wrappers (including Character and Boolean) now have proper valueOf implementation
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28 import org.apidesign.bck2brwsr.core.JavaScriptBody;
31 * The Boolean class wraps a value of the primitive type
32 * {@code boolean} in an object. An object of type
33 * {@code Boolean} contains a single field whose type is
36 * In addition, this class provides many methods for
37 * converting a {@code boolean} to a {@code String} and a
38 * {@code String} to a {@code boolean}, as well as other
39 * constants and methods useful when dealing with a
42 * @author Arthur van Hoff
45 public final class Boolean implements java.io.Serializable,
49 * The {@code Boolean} object corresponding to the primitive
52 public static final Boolean TRUE = new Boolean(true);
55 * The {@code Boolean} object corresponding to the primitive
56 * value {@code false}.
58 public static final Boolean FALSE = new Boolean(false);
61 * The Class object representing the primitive type boolean.
65 public static final Class<Boolean> TYPE = Class.getPrimitiveClass("boolean");
68 * The value of the Boolean.
72 private final boolean value;
74 /** use serialVersionUID from JDK 1.0.2 for interoperability */
75 private static final long serialVersionUID = -3665804199014368530L;
78 * Allocates a {@code Boolean} object representing the
79 * {@code value} argument.
81 * <p><b>Note: It is rarely appropriate to use this constructor.
82 * Unless a <i>new</i> instance is required, the static factory
83 * {@link #valueOf(boolean)} is generally a better choice. It is
84 * likely to yield significantly better space and time performance.</b>
86 * @param value the value of the {@code Boolean}.
88 public Boolean(boolean value) {
93 * Allocates a {@code Boolean} object representing the value
94 * {@code true} if the string argument is not {@code null}
95 * and is equal, ignoring case, to the string {@code "true"}.
96 * Otherwise, allocate a {@code Boolean} object representing the
97 * value {@code false}. Examples:<p>
98 * {@code new Boolean("True")} produces a {@code Boolean} object
99 * that represents {@code true}.<br>
100 * {@code new Boolean("yes")} produces a {@code Boolean} object
101 * that represents {@code false}.
103 * @param s the string to be converted to a {@code Boolean}.
105 public Boolean(String s) {
110 * Parses the string argument as a boolean. The {@code boolean}
111 * returned represents the value {@code true} if the string argument
112 * is not {@code null} and is equal, ignoring case, to the string
113 * {@code "true"}. <p>
114 * Example: {@code Boolean.parseBoolean("True")} returns {@code true}.<br>
115 * Example: {@code Boolean.parseBoolean("yes")} returns {@code false}.
117 * @param s the {@code String} containing the boolean
118 * representation to be parsed
119 * @return the boolean represented by the string argument
122 public static boolean parseBoolean(String s) {
127 * Returns the value of this {@code Boolean} object as a boolean
130 * @return the primitive {@code boolean} value of this object.
132 public boolean booleanValue() {
137 * Returns a {@code Boolean} instance representing the specified
138 * {@code boolean} value. If the specified {@code boolean} value
139 * is {@code true}, this method returns {@code Boolean.TRUE};
140 * if it is {@code false}, this method returns {@code Boolean.FALSE}.
141 * If a new {@code Boolean} instance is not required, this method
142 * should generally be used in preference to the constructor
143 * {@link #Boolean(boolean)}, as this method is likely to yield
144 * significantly better space and time performance.
146 * @param b a boolean value.
147 * @return a {@code Boolean} instance representing {@code b}.
150 public static Boolean valueOf(boolean b) {
151 return (b ? TRUE : FALSE);
155 * Returns a {@code Boolean} with a value represented by the
156 * specified string. The {@code Boolean} returned represents a
157 * true value if the string argument is not {@code null}
158 * and is equal, ignoring case, to the string {@code "true"}.
161 * @return the {@code Boolean} value represented by the string.
163 public static Boolean valueOf(String s) {
164 return toBoolean(s) ? TRUE : FALSE;
168 * Returns a {@code String} object representing the specified
169 * boolean. If the specified boolean is {@code true}, then
170 * the string {@code "true"} will be returned, otherwise the
171 * string {@code "false"} will be returned.
173 * @param b the boolean to be converted
174 * @return the string representation of the specified {@code boolean}
177 public static String toString(boolean b) {
178 return b ? "true" : "false";
182 * Returns a {@code String} object representing this Boolean's
183 * value. If this object represents the value {@code true},
184 * a string equal to {@code "true"} is returned. Otherwise, a
185 * string equal to {@code "false"} is returned.
187 * @return a string representation of this object.
189 public String toString() {
190 return value ? "true" : "false";
194 * Returns a hash code for this {@code Boolean} object.
196 * @return the integer {@code 1231} if this object represents
197 * {@code true}; returns the integer {@code 1237} if this
198 * object represents {@code false}.
200 public int hashCode() {
201 return value ? 1231 : 1237;
205 * Returns {@code true} if and only if the argument is not
206 * {@code null} and is a {@code Boolean} object that
207 * represents the same {@code boolean} value as this object.
209 * @param obj the object to compare with.
210 * @return {@code true} if the Boolean objects represent the
211 * same value; {@code false} otherwise.
213 public boolean equals(Object obj) {
214 if (obj instanceof Boolean) {
215 return value == ((Boolean)obj).booleanValue();
221 * Returns {@code true} if and only if the system property
222 * named by the argument exists and is equal to the string
223 * {@code "true"}. (Beginning with version 1.0.2 of the
224 * Java<small><sup>TM</sup></small> platform, the test of
225 * this string is case insensitive.) A system property is accessible
226 * through {@code getProperty}, a method defined by the
227 * {@code System} class.
229 * If there is no property with the specified name, or if the specified
230 * name is empty or null, then {@code false} is returned.
232 * @param name the system property name.
233 * @return the {@code boolean} value of the system property.
234 * @see java.lang.System#getProperty(java.lang.String)
235 * @see java.lang.System#getProperty(java.lang.String, java.lang.String)
237 public static boolean getBoolean(String name) {
238 boolean result = false;
240 result = toBoolean(AbstractStringBuilder.getProperty(name));
241 } catch (IllegalArgumentException e) {
242 } catch (NullPointerException e) {
248 * Compares this {@code Boolean} instance with another.
250 * @param b the {@code Boolean} instance to be compared
251 * @return zero if this object represents the same boolean value as the
252 * argument; a positive value if this object represents true
253 * and the argument represents false; and a negative value if
254 * this object represents false and the argument represents true
255 * @throws NullPointerException if the argument is {@code null}
259 public int compareTo(Boolean b) {
260 return compare(this.value, b.value);
264 * Compares two {@code boolean} values.
265 * The value returned is identical to what would be returned by:
267 * Boolean.valueOf(x).compareTo(Boolean.valueOf(y))
270 * @param x the first {@code boolean} to compare
271 * @param y the second {@code boolean} to compare
272 * @return the value {@code 0} if {@code x == y};
273 * a value less than {@code 0} if {@code !x && y}; and
274 * a value greater than {@code 0} if {@code x && !y}
277 public static int compare(boolean x, boolean y) {
278 return (x == y) ? 0 : (x ? 1 : -1);
281 private static boolean toBoolean(String name) {
282 return ((name != null) && name.equalsIgnoreCase("true"));
285 // as last step of initialization, initialize valueOf method
288 @JavaScriptBody(args = { }, body =
289 "vm.java_lang_Boolean(false)" +
290 ".valueOf = function() { return this._value(); };"
292 private native static void initValueOf();