java.lang

Class Boolean

public final class Boolean extends Object implements Serializable

The Boolean class wraps a value of the primitive type boolean in an object. An object of type Boolean contains a single field whose type is boolean.

In addition, this class provides many methods for converting a boolean to a String and a String to a boolean, as well as other constants and methods useful when dealing with a boolean.

Since: JDK1.0

Version: 1.45, 06/22/03

Author: Arthur van Hoff

Field Summary
static Boolean	FALSE The `Boolean` object corresponding to the primitive value `false`.
static Boolean	TRUE The `Boolean` object corresponding to the primitive value `true`.
static Class<Boolean>	TYPE The Class object representing the primitive type boolean.

Constructor Summary
	Boolean(boolean value) Allocates a `Boolean` object representing the `value` argument.
	Boolean(String s) Allocates a `Boolean` object representing the value `true` if the string argument is not `null` and is equal, ignoring case, to the string `"true"`.

Method Summary
boolean	booleanValue() Returns the value of this `Boolean` object as a boolean primitive.
boolean	equals(Object obj) Returns `true` if and only if the argument is not `null` and is a `Boolean` object that represents the same `boolean` value as this object.
static boolean	getBoolean(String name) Returns `true` if and only if the system property named by the argument exists and is equal to the string `"true"`.
int	hashCode() Returns a hash code for this `Boolean` object.
static boolean	parseBoolean(String s) Parses the string argument as a boolean.
static String	toString(boolean b) Returns a `String` object representing the specified boolean.
String	toString() Returns a `String` object representing this Boolean's value.
static Boolean	valueOf(boolean b) Returns a `Boolean` instance representing the specified `boolean` value.
static Boolean	valueOf(String s) Returns a `Boolean` with a value represented by the specified String.

Field Detail

FALSE

public static final Boolean FALSE

The Boolean object corresponding to the primitive value false.

TRUE

public static final Boolean TRUE

The Boolean object corresponding to the primitive value true.

TYPE

public static final Class<Boolean> TYPE

The Class object representing the primitive type boolean.

Since: JDK1.1

Constructor Detail

Boolean

public Boolean(boolean value)

Allocates a Boolean object representing the value argument.

Note: It is rarely appropriate to use this constructor. Unless a new instance is required, the static factory Boolean is generally a better choice. It is likely to yield significantly better space and time performance.

Parameters: value the value of the Boolean.

Boolean

public Boolean(String s)

Allocates a Boolean object representing the value true if the string argument is not null and is equal, ignoring case, to the string "true". Otherwise, allocate a Boolean object representing the value false. Examples:

new Boolean("True") produces a Boolean object that represents true.
new Boolean("yes") produces a Boolean object that represents false.

Parameters: s the string to be converted to a Boolean.

Method Detail

booleanValue

public boolean booleanValue()

Returns the value of this Boolean object as a boolean primitive.

Returns: the primitive boolean value of this object.

equals

public boolean equals(Object obj)

Returns true if and only if the argument is not null and is a Boolean object that represents the same boolean value as this object.

Parameters: obj the object to compare with.

Returns: true if the Boolean objects represent the same value; false otherwise.

getBoolean

public static boolean getBoolean(String name)

Returns true if and only if the system property named by the argument exists and is equal to the string "true". (Beginning with version 1.0.2 of the Java^TM platform, the test of this string is case insensitive.) A system property is accessible through getProperty, a method defined by the System class.

If there is no property with the specified name, or if the specified name is empty or null, then false is returned.

Parameters: name the system property name.

Returns: the boolean value of the system property.

See Also: java.lang.System#getProperty(java.lang.String) java.lang.System#getProperty(java.lang.String, java.lang.String)

hashCode

public int hashCode()

Returns a hash code for this Boolean object.

Returns: the integer 1231 if this object represents true; returns the integer 1237 if this object represents false.

parseBoolean

public static boolean parseBoolean(String s)

Parses the string argument as a boolean. The boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string "true".

Parameters: s the String containing the boolean representation to be parsed

Returns: the boolean represented by the string argument

Since: 1.5

toString

public static String toString(boolean b)

Returns a String object representing the specified boolean. If the specified boolean is true, then the string "true" will be returned, otherwise the string "false" will be returned.

Parameters: b the boolean to be converted

Returns: the string representation of the specified boolean

Since: 1.4

toString

public String toString()

Returns a String object representing this Boolean's value. If this object represents the value true, a string equal to "true" is returned. Otherwise, a string equal to "false" is returned.

Returns: a string representation of this object.

valueOf

public static Boolean valueOf(boolean b)

Returns a Boolean instance representing the specified boolean value. If the specified boolean value is true, this method returns Boolean.TRUE; if it is false, this method returns Boolean.FALSE. If a new Boolean instance is not required, this method should generally be used in preference to the constructor Boolean, as this method is likely to to yield significantly better space and time performance.

Parameters: b a boolean value.

Returns: a Boolean instance representing b.

Since: 1.4

valueOf

public static Boolean valueOf(String s)

Returns a Boolean with a value represented by the specified String. The Boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string "true".

Example: Boolean.valueOf("True") returns true.
Example: Boolean.valueOf("yes") returns false.

Parameters: s a string.

Returns: the Boolean value represented by the string.