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Boolean.java
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1998-09-22
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/*
* @(#)Boolean.java 1.28 98/07/07
*
* Copyright 1995-1998 by Sun Microsystems, Inc.,
* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
* All rights reserved.
*
* This software is the confidential and proprietary information
* of Sun Microsystems, Inc. ("Confidential Information"). You
* shall not disclose such Confidential Information and shall use
* it only in accordance with the terms of the license agreement
* you entered into with Sun.
*/
package java.lang;
/**
* The Boolean class wraps a value of the primitive type
* <code>boolean</code> in an object. An object of type
* <code>Boolean</code> contains a single field whose type is
* <code>boolean</code>.
* <p>
* In addition, this class provides many methods for
* converting a <code>boolean</code> to a <code>String</code> and a
* <code>String</code> to a <code>boolean</code>, as well as other
* constants and methods useful when dealing with a
* <code>boolean</code>.
*
* @author Arthur van Hoff
* @version 1.28, 07/07/98
* @since JDK1.0
*/
public final
class Boolean implements java.io.Serializable {
/**
* The <code>Boolean</code> object corresponding to the primitive
* value <code>true</code>.
*
* @since JDK1.0
*/
public static final Boolean TRUE = new Boolean(true);
/**
* The <code>Boolean</code> object corresponding to the primitive
* value <code>false</code>.
*
* @since JDK1.0
*/
public static final Boolean FALSE = new Boolean(false);
/**
* The Class object representing the primitive type boolean.
*
* @since JDK1.1
*/
public static final Class TYPE = Class.getPrimitiveClass("boolean");
/**
* The value of the Boolean.
*/
private boolean value;
/** use serialVersionUID from JDK 1.0.2 for interoperability */
private static final long serialVersionUID = -3665804199014368530L;
/**
* Allocates a <code>Boolean</code> object representing the
* <code>value</code> argument.
*
* @param value the value of the <code>Boolean</code>.
* @since JDK1.0
*/
public Boolean(boolean value) {
this.value = value;
}
/**
* Allocates a <code>Boolean</code> object representing the value
* <code>true</code> if the string argument is not <code>null</code>
* and is equal, ignoring case, to the string <code>"true"</code>.
* Otherwise, allocate a <code>Boolean</code> object representing the
* value <code>false</code>.
*
* @param s the string to be converted to a <code>Boolean</code>.
* @since JDK1.0
*/
public Boolean(String s) {
this(toBoolean(s));
}
/**
* Returns the value of this Boolean object as a boolean.
*
* @return the primitive <code>boolean</code> value of this object.
* @since JDK1.0
*/
public boolean booleanValue() {
return value;
}
/**
* Returns the boolean value represented by the specified String.
* A new <code>Boolean</code> object is constructed. This
* <code>Boolean</code> contains the value <code>true</code> if the
* string argument is not <code>null</code> and is equal, ignoring
* case, to the string <code>"true"</code>.
*
* @param s a string.
* @return the <code>Boolean</code> value represented by the string.
* @since JDK1.0
*/
public static Boolean valueOf(String s) {
return new Boolean(toBoolean(s));
}
/**
* Returns a String object representing this Boolean's value.
* If this object contains the value <code>true</code>, a string equal
* to <code>"true"</code> is returned. Otherwise, a string equal to
* <code>"false"</code> is returned.
*
* @return a string representation of this object.
* @since JDK1.0
*/
public String toString() {
return value ? "true" : "false";
}
/**
* Returns a hash code for this Boolean.
*
* @return a hash code value for this object.
* @since JDK1.0
*/
public int hashCode() {
return value ? 1231 : 1237;
}
/**
* Returns <code>true</code> if and only if the argument is not
* <code>null</code> and is a <code>Boolean </code>object that
* contains the same <code>boolean</code> value as this object.
*
* @param obj the object to compare with.
* @return <code>true</code> if the objects are the same;
* <code>false</code> otherwise.
* @since JDK1.0
*/
public boolean equals(Object obj) {
if ((obj != null) && (obj instanceof Boolean)) {
return value == ((Boolean)obj).booleanValue();
}
return false;
}
/**
* Returns is <code>true</code> if and only if the system property
* named by the argument exists and is equal to the string
* <code>"true"</code>. (Beginning with Java 1.0.2, the test of
* this string is case insensitive.) A system property is accessible
* through <code>getProperty</code>, a method defined by the
* <code>System</code> class.
*
* @param name the system property name.
* @return the <code>boolean</code> value of the system property.
* @see java.lang.System#getProperty(java.lang.String)
* @see java.lang.System#getProperty(java.lang.String, java.lang.String)
* @since JDK1.0
*/
public static boolean getBoolean(String name) {
SecurityManager sm = System.getSecurityManager();
if (sm != null)
sm.checkPropertyAccess(name);
return toBoolean(System.getProperty(name));
}
private static boolean toBoolean(String name) {
return ((name != null) && name.toLowerCase().equals("true"));
}
}