com.google.javascript.rhino.jstype

Enum TernaryValue

java.lang.Object

java.lang.Enum<TernaryValue>

com.google.javascript.rhino.jstype.TernaryValue

All Implemented Interfaces:

Serializable, Comparable<TernaryValue>

public enum TernaryValue
extends Enum<TernaryValue>

An enum for ternary logic. The TRUE and FALSE values are equivalent to typical booleans, and the UNKNOWN value plays the role of a placeholder, which can be either TRUE or FALSE.

A ternary value expression evaluates to TRUE or FALSE only if all replacements of UNKNOWN in this expression yield the same result. Therefore, the ternary logic coincides with typical Boolean logic if the UNKNOWN value is not present in an expression.

See Also:

Ternary Logic

Enum Constant Summary

Enum Constants

Enum Constant and Description
FALSE false
TRUE true
UNKNOWN unknown, it represents lack of knowledge about whether this value is true or false.

Method Summary

Methods

Modifier and Type	Method and Description
abstract TernaryValue	and(TernaryValue that) Gets the and of this and that.
static TernaryValue	forBoolean(boolean val) Gets the TernaryValue for the given boolean.
abstract TernaryValue	not() Gets the not of this.
abstract TernaryValue	or(TernaryValue that) Gets the or of this and that.
abstract boolean	toBoolean(boolean unknown) Converts this ternary value to boolean.
static TernaryValue	valueOf(String name) Returns the enum constant of this type with the specified name.
static TernaryValue[]	values() Returns an array containing the constants of this enum type, in the order they are declared.
abstract TernaryValue	xor(TernaryValue that) Gets the xor of this and that.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

FALSE

public static final TernaryValue FALSE

false

TRUE

public static final TernaryValue TRUE

true

UNKNOWN

public static final TernaryValue UNKNOWN

unknown, it represents lack of knowledge about whether this value is true or false.

Method Detail

values

public static TernaryValue[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (TernaryValue c : TernaryValue.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static TernaryValue valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

and

public abstract TernaryValue and(TernaryValue that)

Gets the and of this and that.

not

public abstract TernaryValue not()

Gets the not of this.

or

public abstract TernaryValue or(TernaryValue that)

Gets the or of this and that.

xor

public abstract TernaryValue xor(TernaryValue that)

Gets the xor of this and that.

toBoolean

public abstract boolean toBoolean(boolean unknown)

Converts this ternary value to boolean. The #TRUE and #FALSE values are simply converted to true and false respectively, whilst the UNKNOWN is converted to the specified unknown value.

Parameters:

unknown - the boolean value to which the UNKNOWN value is converted

Returns:

return
     this == TRUE ? true :
     this == FALSE ? false :
     unknown

forBoolean

public static TernaryValue forBoolean(boolean val)

Gets the TernaryValue for the given boolean.