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Class w3c.www.dsig.Trivalue
java.lang.Object

+w3c.www.dsig.Trivalue
 public final class Trivalue
 extends Object
A class implementing trivalued logic.
Trivalued logic is boolean logic extended by a third state called
'unknown.' More information about trivalued logic TBD.
Objects of this class are inmutable, once generated they cannot
be modified.

TRI_FALSE
 Int value defined to indicate the state false.

TRI_TRUE
 Int value defined to indicate the state true.

TRI_UNKNOWN
 Int value defined to indicate the state unknown.

Trivalue(boolean)
 Construct a trivalue from the given int.

Trivalue(int)
 Construct a trivalue from the given int.

Trivalue(String)
 Construct a trivalue from the given string.

and(Trivalue)
 Return the logic and of this trivalue and the given trivalue
in trivalued logic.

equals(Object)
 Test this trivalue and the given object for equality.

getValue()
 Return the trivalue as an int.

hashCode()
 Return a hash code for this trivalue.

isFalse()
 Return the boolean true if this trivalue is false.

isTrue()
 Return the boolean true if this trivalue is true.

isUnknown()
 Return the boolean true if this trivalue is unknown.

newFalse()
 Return a trivalue with the state true.

newTrue()
 Return a trivalue with the state true.

newUnknown()
 Return a trivalue with the state true.

not()
 Return the logic not of this trivalue in trivalued logic.

or(Trivalue)
 Return the logic and of this trivalue and the given trivalue
in trivalued logic.

toString()
 Return a string representation of this trivalue.

toTrivalue(String)
 Return a trivalue encoded in an int for the string value.

UnknownToFalse()
 'Convert' the Trivalue to boolean treating
unknown as false.

UnknownToTrue()
 'Convert' the Trivalue to boolean treating
unknown as true.
TRI_FALSE
public static final int TRI_FALSE
 Int value defined to indicate the state false.
TRI_TRUE
public static final int TRI_TRUE
 Int value defined to indicate the state true.
TRI_UNKNOWN
public static final int TRI_UNKNOWN
 Int value defined to indicate the state unknown.
Trivalue
public Trivalue(int value)
 Construct a trivalue from the given int. The constants defined
in this class for the int are TRI_FALSE, TRI_TRUE, and TRI_UNKNOWN.
TRI_UNKNOWN and any other value will a trivalue with the state
unknown.
Trivalue
public Trivalue(boolean value)
 Construct a trivalue from the given int. Of course, this will never
lead to a trivalue with the value unknown.
Trivalue
public Trivalue(String value)
 Construct a trivalue from the given string. The string "true"
is mapped to true, "false" to false, all else to unknown.
newTrue
public static Trivalue newTrue()
 Return a trivalue with the state true. This method can be
used as a short hand for 'new Trivalue(Trivalue.TRI_TRUE).'
Additionally, it is more efficient as no new object needs
to be generated.
newFalse
public static Trivalue newFalse()
 Return a trivalue with the state true. This method can be
used as a short hand for 'new Trivalue(Trivalue.TRI_FALSE).'
Additionally, it is more efficient as no new object needs
to be generated.
newUnknown
public static Trivalue newUnknown()
 Return a trivalue with the state true. This method can be
used as a short hand for 'new Trivalue(Trivalue.TRI_UNKNOWN).'
Additionally, it is more efficient as no new object needs
to be generated.
toTrivalue
public int toTrivalue(String value)
 Return a trivalue encoded in an int for the string value.
The string "true" maps to true, "false" to false, all else
to unknown.
getValue
public int getValue()
 Return the trivalue as an int. Possible values for the int are the final
variables TRI_TRUE, TRI_FALSE, and TRI_UNKNOWN defined in this
class.
isTrue
public boolean isTrue()
 Return the boolean true if this trivalue is true.
isFalse
public boolean isFalse()
 Return the boolean true if this trivalue is false.
isUnknown
public boolean isUnknown()
 Return the boolean true if this trivalue is unknown.
UnknownToTrue
public boolean UnknownToTrue()
 'Convert' the Trivalue to boolean treating
unknown as true. That is, return true if this trivalue
is true or unknown, and false if it is false.
UnknownToFalse
public boolean UnknownToFalse()
 'Convert' the Trivalue to boolean treating
unknown as false. That is, return true is this trivalue
is true, and false if it is unknown or false.
not
public Trivalue not()
 Return the logic not of this trivalue in trivalued logic.
true maps to false, false to true, and unknown to unknown.
and
public Trivalue and(Trivalue tvalue)
 Return the logic and of this trivalue and the given trivalue
in trivalued logic. That is, return false if any of the two
is false, true if both are true, and unknown otherwise.
or
public Trivalue or(Trivalue tvalue)
 Return the logic and of this trivalue and the given trivalue
in trivalued logic. That is, return true if any of the two
are true, false if both are false, and unknown otherwise.
equals
public boolean equals(Object obj)
 Test this trivalue and the given object for equality. If the
given object is not null, an instance of the trivalue class
and it represents the same logic state, return true. Otherwise
return false.
 Overrides:
 equals in class Object
hashCode
public int hashCode()
 Return a hash code for this trivalue. Using trivalues as keys in a
hashtable does not make much sense as there are only three distinct
ones, but this method is included anyway just in case someone needs it.
 Overrides:
 hashCode in class Object
toString
public String toString()
 Return a string representation of this trivalue. The state
true is represented by the string "true", false by "false," and
unknown by "unknown."
 Overrides:
 toString in class Object
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