/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.lang;
import java.io.Serializable;
/**
* The wrapper for the primitive type {@code boolean}.
*
* @since 1.0
*/
public final class Boolean implements Serializable, Comparable<Boolean> {
private static final long serialVersionUID = -3665804199014368530L;
/**
* The boolean value of the receiver.
*/
private final boolean value;
/**
* The {@link Class} object that represents the primitive type {@code
* boolean}.
*/
@SuppressWarnings("unchecked")
public static final Class<Boolean> TYPE
= (Class<Boolean>) boolean[].class.getComponentType();
// Note: Boolean.TYPE can't be set to "boolean.class", since *that* is
// defined to be "java.lang.Boolean.TYPE";
/**
* The {@code Boolean} object that represents the primitive value
* {@code true}.
*/
public static final Boolean TRUE = new Boolean(true);
/**
* The {@code Boolean} object that represents the primitive value
* {@code false}.
*/
public static final Boolean FALSE = new Boolean(false);
/**
* Constructs a new {@code Boolean} with its boolean value specified by
* {@code string}. If {@code string} is not {@code null} and is equal to
* "true" using a non-case sensitive comparison, the result will be a
* Boolean representing the primitive value {@code true}, otherwise it will
* be a Boolean representing the primitive value {@code false}.
*
* @param string
* the string representing a boolean value.
*/
public Boolean(String string) {
this(parseBoolean(string));
}
/**
* Constructs a new {@code Boolean} with the specified primitive boolean
* value.
*
* @param value
* the primitive boolean value, {@code true} or {@code false}.
*/
public Boolean(boolean value) {
this.value = value;
}
/**
* Gets the primitive value of this boolean, either {@code true} or
* {@code false}.
*
* @return this object's primitive value, {@code true} or {@code false}.
*/
public boolean booleanValue() {
return value;
}
/**
* Compares this instance with the specified object and indicates if they
* are equal. In order to be equal, {@code o} must be an instance of
* {@code Boolean} and have the same boolean value as this object.
*
* @param o
* the object to compare this boolean with.
* @return {@code true} if the specified object is equal to this
* {@code Boolean}; {@code false} otherwise.
*/
@Override
@FindBugsSuppressWarnings("RC_REF_COMPARISON_BAD_PRACTICE_BOOLEAN")
public boolean equals(Object o) {
return (o == this) || ((o instanceof Boolean) && (((Boolean) o).value == value));
}
/**
* Compares this object to the specified boolean object to determine their
* relative order.
*
* @param that
* the boolean object to compare this object to.
* @return 0 if the value of this boolean and the value of {@code that} are
* equal; a positive value if the value of this boolean is
* {@code true} and the value of {@code that} is {@code false}; a
* negative value if the value if this boolean is {@code false} and
* the value of {@code that} is {@code true}.
* @see java.lang.Comparable
* @since 1.5
*/
public int compareTo(Boolean that) {
return compare(value, that.value);
}
/**
* Compares two {@code boolean} values.
* @return 0 if lhs = rhs, less than 0 if lhs < rhs, and greater than 0 if lhs > rhs.
* (Where true > false.)
* @since 1.7
*/
public static int compare(boolean lhs, boolean rhs) {
return lhs == rhs ? 0 : lhs ? 1 : -1;
}
/**
* Returns an integer hash code for this boolean.
*
* @return this boolean's hash code, which is {@code 1231} for {@code true}
* values and {@code 1237} for {@code false} values.
*/
@Override
public int hashCode() {
return value ? 1231 : 1237;
}
/**
* Returns a string containing a concise, human-readable description of this
* boolean.
*
* @return "true" if the value of this boolean is {@code true}, "false"
* otherwise.
*/
@Override
public String toString() {
return String.valueOf(value);
}
/**
* Returns the {@code boolean} value of the system property identified by
* {@code string}.
*
* @param string
* the name of the requested system property.
* @return {@code true} if the system property named by {@code string}
* exists and it is equal to "true" using case insensitive
* comparison, {@code false} otherwise.
* @see System#getProperty(String)
*/
public static boolean getBoolean(String string) {
if (string == null || string.length() == 0) {
return false;
}
return (parseBoolean(System.getProperty(string)));
}
/**
* Parses the specified string as a {@code boolean}.
*
* @param s
* the string representation of a boolean value.
* @return {@code true} if {@code s} is not {@code null} and is equal to
* {@code "true"} using case insensitive comparison, {@code false}
* otherwise.
* @since 1.5
*/
public static boolean parseBoolean(String s) {
return "true".equalsIgnoreCase(s);
}
/**
* Converts the specified boolean to its string representation.
*
* @param value
* the boolean to convert.
* @return "true" if {@code value} is {@code true}, "false" otherwise.
*/
public static String toString(boolean value) {
return String.valueOf(value);
}
/**
* Parses the specified string as a boolean value.
*
* @param string
* the string representation of a boolean value.
* @return {@code Boolean.TRUE} if {@code string} is equal to "true" using
* case insensitive comparison, {@code Boolean.FALSE} otherwise.
* @see #parseBoolean(String)
*/
public static Boolean valueOf(String string) {
return parseBoolean(string) ? Boolean.TRUE : Boolean.FALSE;
}
/**
* Returns a {@code Boolean} instance for the specified boolean value.
* <p>
* If it is not necessary to get a new {@code Boolean} instance, it is
* recommended to use this method instead of the constructor, since it
* returns its static instances, which results in better performance.
*
* @param b
* the boolean to convert to a {@code Boolean}.
* @return {@code Boolean.TRUE} if {@code b} is equal to {@code true},
* {@code Boolean.FALSE} otherwise.
*/
public static Boolean valueOf(boolean b) {
return b ? Boolean.TRUE : Boolean.FALSE;
}
}