java.lang

Class Boolean

Contents
  • All Implemented Interfaces:
    Serializable, Comparable<Boolean>

    public final class Boolean
extends Object
implements Serializable, Comparable<Boolean>
    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
    See Also:
    Serialized Form

    • Field Detail

      • TRUE

        public static final Boolean TRUE
        The Boolean object corresponding to the primitive value true.

      • FALSE

        public static final Boolean FALSE
        The Boolean object corresponding to the primitive value false.

      • 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 valueOf(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

      • 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".

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

        Parameters:
        s - the String containing the boolean representation to be parsed
        Returns:
        the boolean represented by the string argument
        Since:
        1.5

      • booleanValue

        public boolean booleanValue()
        Returns the value of this Boolean object as a boolean primitive.
        Returns:
        the primitive boolean value 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(boolean), as this method is likely 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 a true value if the string argument is not null and is equal, ignoring case, to the string "true".
        Parameters:
        s - a string.
        Returns:
        the Boolean value represented by the string.

      • 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.
        Overrides:
        toString in class Object
        Returns:
        a string representation 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.
        Overrides:
        equals in class Object
        Parameters:
        obj - the object to compare with.
        Returns:
        true if the Boolean objects represent the same value; false otherwise.
        See Also:
        Object.hashCode(), HashMap

      • 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 JavaTM 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:
        System.getProperty(java.lang.String), System.getProperty(java.lang.String, java.lang.String)

      • compareTo

        public int compareTo(Boolean b)
        Compares this Boolean instance with another.
        Specified by:
        compareTo in interface Comparable<Boolean>
        Parameters:
        b - the Boolean instance to be compared
        Returns:
        zero if this object represents the same boolean value as the argument; a positive value if this object represents true and the argument represents false; and a negative value if this object represents false and the argument represents true
        Throws:
        NullPointerException - if the argument is null
        Since:
        1.5
        See Also:
        Comparable

      • compare

        public static int compare(boolean x,
          boolean y)
        Compares two boolean values. The value returned is identical to what would be returned by: 
            Boolean.valueOf(x).compareTo(Boolean.valueOf(y))
        Parameters:
        x - the first boolean to compare
        y - the second boolean to compare
        Returns:
        the value 0 if x == y; a value less than 0 if !x && y; and a value greater than 0 if x && !y
        Since:
        1.7

Document created the 11/06/2005, last modified the 04/03/2020
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