jaroslav@86: /* jaroslav@86: * Copyright (c) 1994, 2006, Oracle and/or its affiliates. All rights reserved. jaroslav@86: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. jaroslav@86: * jaroslav@86: * This code is free software; you can redistribute it and/or modify it jaroslav@86: * under the terms of the GNU General Public License version 2 only, as jaroslav@86: * published by the Free Software Foundation. Oracle designates this jaroslav@86: * particular file as subject to the "Classpath" exception as provided jaroslav@86: * by Oracle in the LICENSE file that accompanied this code. jaroslav@86: * jaroslav@86: * This code is distributed in the hope that it will be useful, but WITHOUT jaroslav@86: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or jaroslav@86: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License jaroslav@86: * version 2 for more details (a copy is included in the LICENSE file that jaroslav@86: * accompanied this code). jaroslav@86: * jaroslav@86: * You should have received a copy of the GNU General Public License version jaroslav@86: * 2 along with this work; if not, write to the Free Software Foundation, jaroslav@86: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. jaroslav@86: * jaroslav@86: * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA jaroslav@86: * or visit www.oracle.com if you need additional information or have any jaroslav@86: * questions. jaroslav@86: */ jaroslav@86: jaroslav@86: package java.lang; jaroslav@86: jaroslav@86: /** jaroslav@86: * The Boolean class wraps a value of the primitive type jaroslav@86: * {@code boolean} in an object. An object of type jaroslav@86: * {@code Boolean} contains a single field whose type is jaroslav@86: * {@code boolean}. jaroslav@86: *

jaroslav@86: * In addition, this class provides many methods for jaroslav@86: * converting a {@code boolean} to a {@code String} and a jaroslav@86: * {@code String} to a {@code boolean}, as well as other jaroslav@86: * constants and methods useful when dealing with a jaroslav@86: * {@code boolean}. jaroslav@86: * jaroslav@86: * @author Arthur van Hoff jaroslav@86: * @since JDK1.0 jaroslav@86: */ jaroslav@86: public final class Boolean implements java.io.Serializable, jaroslav@86: Comparable jaroslav@86: { jaroslav@86: /** jaroslav@86: * The {@code Boolean} object corresponding to the primitive jaroslav@86: * value {@code true}. jaroslav@86: */ jaroslav@86: public static final Boolean TRUE = new Boolean(true); jaroslav@86: jaroslav@86: /** jaroslav@86: * The {@code Boolean} object corresponding to the primitive jaroslav@86: * value {@code false}. jaroslav@86: */ jaroslav@86: public static final Boolean FALSE = new Boolean(false); jaroslav@86: jaroslav@86: /** jaroslav@86: * The Class object representing the primitive type boolean. jaroslav@86: * jaroslav@86: * @since JDK1.1 jaroslav@86: */ jaroslav@86: public static final Class TYPE = Class.getPrimitiveClass("boolean"); jaroslav@86: jaroslav@86: /** jaroslav@86: * The value of the Boolean. jaroslav@86: * jaroslav@86: * @serial jaroslav@86: */ jaroslav@86: private final boolean value; jaroslav@86: jaroslav@86: /** use serialVersionUID from JDK 1.0.2 for interoperability */ jaroslav@86: private static final long serialVersionUID = -3665804199014368530L; jaroslav@86: jaroslav@86: /** jaroslav@86: * Allocates a {@code Boolean} object representing the jaroslav@86: * {@code value} argument. jaroslav@86: * jaroslav@86: *

Note: It is rarely appropriate to use this constructor. jaroslav@86: * Unless a new instance is required, the static factory jaroslav@86: * {@link #valueOf(boolean)} is generally a better choice. It is jaroslav@86: * likely to yield significantly better space and time performance. jaroslav@86: * jaroslav@86: * @param value the value of the {@code Boolean}. jaroslav@86: */ jaroslav@86: public Boolean(boolean value) { jaroslav@86: this.value = value; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Allocates a {@code Boolean} object representing the value jaroslav@86: * {@code true} if the string argument is not {@code null} jaroslav@86: * and is equal, ignoring case, to the string {@code "true"}. jaroslav@86: * Otherwise, allocate a {@code Boolean} object representing the jaroslav@86: * value {@code false}. Examples:

jaroslav@86: * {@code new Boolean("True")} produces a {@code Boolean} object jaroslav@86: * that represents {@code true}.
jaroslav@86: * {@code new Boolean("yes")} produces a {@code Boolean} object jaroslav@86: * that represents {@code false}. jaroslav@86: * jaroslav@86: * @param s the string to be converted to a {@code Boolean}. jaroslav@86: */ jaroslav@86: public Boolean(String s) { jaroslav@86: this(toBoolean(s)); jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Parses the string argument as a boolean. The {@code boolean} jaroslav@86: * returned represents the value {@code true} if the string argument jaroslav@86: * is not {@code null} and is equal, ignoring case, to the string jaroslav@86: * {@code "true"}.

jaroslav@86: * Example: {@code Boolean.parseBoolean("True")} returns {@code true}.
jaroslav@86: * Example: {@code Boolean.parseBoolean("yes")} returns {@code false}. jaroslav@86: * jaroslav@86: * @param s the {@code String} containing the boolean jaroslav@86: * representation to be parsed jaroslav@86: * @return the boolean represented by the string argument jaroslav@86: * @since 1.5 jaroslav@86: */ jaroslav@86: public static boolean parseBoolean(String s) { jaroslav@86: return toBoolean(s); jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns the value of this {@code Boolean} object as a boolean jaroslav@86: * primitive. jaroslav@86: * jaroslav@86: * @return the primitive {@code boolean} value of this object. jaroslav@86: */ jaroslav@86: public boolean booleanValue() { jaroslav@86: return value; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns a {@code Boolean} instance representing the specified jaroslav@86: * {@code boolean} value. If the specified {@code boolean} value jaroslav@86: * is {@code true}, this method returns {@code Boolean.TRUE}; jaroslav@86: * if it is {@code false}, this method returns {@code Boolean.FALSE}. jaroslav@86: * If a new {@code Boolean} instance is not required, this method jaroslav@86: * should generally be used in preference to the constructor jaroslav@86: * {@link #Boolean(boolean)}, as this method is likely to yield jaroslav@86: * significantly better space and time performance. jaroslav@86: * jaroslav@86: * @param b a boolean value. jaroslav@86: * @return a {@code Boolean} instance representing {@code b}. jaroslav@86: * @since 1.4 jaroslav@86: */ jaroslav@86: public static Boolean valueOf(boolean b) { jaroslav@86: return (b ? TRUE : FALSE); jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns a {@code Boolean} with a value represented by the jaroslav@86: * specified string. The {@code Boolean} returned represents a jaroslav@86: * true value if the string argument is not {@code null} jaroslav@86: * and is equal, ignoring case, to the string {@code "true"}. jaroslav@86: * jaroslav@86: * @param s a string. jaroslav@86: * @return the {@code Boolean} value represented by the string. jaroslav@86: */ jaroslav@86: public static Boolean valueOf(String s) { jaroslav@86: return toBoolean(s) ? TRUE : FALSE; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns a {@code String} object representing the specified jaroslav@86: * boolean. If the specified boolean is {@code true}, then jaroslav@86: * the string {@code "true"} will be returned, otherwise the jaroslav@86: * string {@code "false"} will be returned. jaroslav@86: * jaroslav@86: * @param b the boolean to be converted jaroslav@86: * @return the string representation of the specified {@code boolean} jaroslav@86: * @since 1.4 jaroslav@86: */ jaroslav@86: public static String toString(boolean b) { jaroslav@86: return b ? "true" : "false"; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns a {@code String} object representing this Boolean's jaroslav@86: * value. If this object represents the value {@code true}, jaroslav@86: * a string equal to {@code "true"} is returned. Otherwise, a jaroslav@86: * string equal to {@code "false"} is returned. jaroslav@86: * jaroslav@86: * @return a string representation of this object. jaroslav@86: */ jaroslav@86: public String toString() { jaroslav@86: return value ? "true" : "false"; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns a hash code for this {@code Boolean} object. jaroslav@86: * jaroslav@86: * @return the integer {@code 1231} if this object represents jaroslav@86: * {@code true}; returns the integer {@code 1237} if this jaroslav@86: * object represents {@code false}. jaroslav@86: */ jaroslav@86: public int hashCode() { jaroslav@86: return value ? 1231 : 1237; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns {@code true} if and only if the argument is not jaroslav@86: * {@code null} and is a {@code Boolean} object that jaroslav@86: * represents the same {@code boolean} value as this object. jaroslav@86: * jaroslav@86: * @param obj the object to compare with. jaroslav@86: * @return {@code true} if the Boolean objects represent the jaroslav@86: * same value; {@code false} otherwise. jaroslav@86: */ jaroslav@86: public boolean equals(Object obj) { jaroslav@86: if (obj instanceof Boolean) { jaroslav@86: return value == ((Boolean)obj).booleanValue(); jaroslav@86: } jaroslav@86: return false; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Returns {@code true} if and only if the system property jaroslav@86: * named by the argument exists and is equal to the string jaroslav@86: * {@code "true"}. (Beginning with version 1.0.2 of the jaroslav@86: * JavaTM platform, the test of jaroslav@86: * this string is case insensitive.) A system property is accessible jaroslav@86: * through {@code getProperty}, a method defined by the jaroslav@86: * {@code System} class. jaroslav@86: *

jaroslav@86: * If there is no property with the specified name, or if the specified jaroslav@86: * name is empty or null, then {@code false} is returned. jaroslav@86: * jaroslav@86: * @param name the system property name. jaroslav@86: * @return the {@code boolean} value of the system property. jaroslav@86: * @see java.lang.System#getProperty(java.lang.String) jaroslav@86: * @see java.lang.System#getProperty(java.lang.String, java.lang.String) jaroslav@86: */ jaroslav@86: public static boolean getBoolean(String name) { jaroslav@86: boolean result = false; jaroslav@86: try { jaroslav@104: result = toBoolean(AbstractStringBuilder.getProperty(name)); jaroslav@86: } catch (IllegalArgumentException e) { jaroslav@86: } catch (NullPointerException e) { jaroslav@86: } jaroslav@86: return result; jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Compares this {@code Boolean} instance with another. jaroslav@86: * jaroslav@86: * @param b the {@code Boolean} instance to be compared jaroslav@86: * @return zero if this object represents the same boolean value as the jaroslav@86: * argument; a positive value if this object represents true jaroslav@86: * and the argument represents false; and a negative value if jaroslav@86: * this object represents false and the argument represents true jaroslav@86: * @throws NullPointerException if the argument is {@code null} jaroslav@86: * @see Comparable jaroslav@86: * @since 1.5 jaroslav@86: */ jaroslav@86: public int compareTo(Boolean b) { jaroslav@86: return compare(this.value, b.value); jaroslav@86: } jaroslav@86: jaroslav@86: /** jaroslav@86: * Compares two {@code boolean} values. jaroslav@86: * The value returned is identical to what would be returned by: jaroslav@86: * 

jaroslav@86:      *    Boolean.valueOf(x).compareTo(Boolean.valueOf(y))
jaroslav@86:      *
jaroslav@86: * jaroslav@86: * @param x the first {@code boolean} to compare jaroslav@86: * @param y the second {@code boolean} to compare jaroslav@86: * @return the value {@code 0} if {@code x == y}; jaroslav@86: * a value less than {@code 0} if {@code !x && y}; and jaroslav@86: * a value greater than {@code 0} if {@code x && !y} jaroslav@86: * @since 1.7 jaroslav@86: */ jaroslav@86: public static int compare(boolean x, boolean y) { jaroslav@86: return (x == y) ? 0 : (x ? 1 : -1); jaroslav@86: } jaroslav@86: jaroslav@86: private static boolean toBoolean(String name) { jaroslav@86: return ((name != null) && name.equalsIgnoreCase("true")); jaroslav@86: } jaroslav@86: }