UNDEF
public static final TriStateBoolean UNDEF
- Special
TriStateBoolean
object representing an
uninitialized value. This is needed to support the
aggregate()
operation. Using the UNDEF
value
is analogous to saying "no value". When UNDEF
is used
in a TriStateBoolean
operation, it is essentially ignored,
the result of the operation is determined by the other operand. If
both operands are UNDEF
then UNDEF
is
returned.
getState
public static TriStateBoolean getState(boolean state)
getState
public static TriStateBoolean getState(java.lang.Boolean state)
isTrue
public boolean isTrue()
- Returns
true
if this instance represents
TRUE
; returns false
otherwise.
isTriState
public boolean isTriState()
- Returns
true
if this instance represents
TRI_STATE
; returns false
otherwise.
isFalse
public boolean isFalse()
- Returns
true
if this instance represents
FALSE
; returns false
otherwise.
isUndef
public boolean isUndef()
- Returns
true
if this instance represents
UNDEF
; returns false
otherwise.
booleanValue
public boolean booleanValue()
- Returns
true
if this instance represents
TRUE
. Returns false
if this instance
represents false
. Throws an
IllegalStateException
if this instance represents
TRI_STATE
.
toggle
public TriStateBoolean toggle()
- This method defines the "toggle" operation as follows:
- Toggling
TRUE
returns FALSE
.
- Toggling
TRI_STATE
returns FALSE
.
- Toggling
FALSE
returns TRUE
.
aggregate
public TriStateBoolean aggregate(TriStateBoolean b)
- This method is used to help determine if a set of
TriStateBoolean
values are all the same or have some
difference. It implements the following unusual truth table:
Truth table for tri-state AND operator
AGG | true | false | tri |
true | true | tri | tri |
false | tri | false | tri |
tri | tri | tri | tri |
and
public TriStateBoolean and(TriStateBoolean b)
Truth table for tri-state AND operator
AND | true | false | tri |
true | true | false | tri |
false | false | false | tri |
tri | tri | tri | tri |
or
public TriStateBoolean or(TriStateBoolean b)
Truth table for tri-state OR operator
OR | true | false | tri |
true | true | true | tri |
false | true | false | tri |
tri | tri | tri | tri |
not
public TriStateBoolean not()
- NOT true => false.
NOT false => true.
NOT tri => tri.
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