com.google.javascript.rhino.jstype
Enum TernaryValue

java.lang.Object
  extended by java.lang.Enum<TernaryValue>
      extended by 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
FALSE
          false
TRUE
          true
UNKNOWN
          unknown, it represents lack of knowledge about whether this value is true or false.
 
Method Summary
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.