public Goal execute() throws Failure {
class ObserverEqualValue extends Observer {
@Override
public Object master() {
return ConstraintExpEqualsValue.this;
}
@Override
public int subscriberMask() {
return EventOfInterest.VALUE | EventOfInterest.MIN | EventOfInterest.MAX;
}
@Override
public String toString() {
return "ObserverEqualValue";
}
@Override
public void update(Subject exp, EventOfInterest interest) throws Failure {
// Debug.on();Debug.print("ObserverEqualValue:
// "+interest);Debug.off();
IntEvent event = (IntEvent) interest;
if ((event.isValueEvent() && event.min() != _value)
|| (event.isMaxEvent() && event.max() < _value)
|| (event.isMinEvent() && event.min() > _value)) {
exp.constrainer().fail("from ObserverEqualValue");
}
_exp.setValue(_value);
}
} // ~ ObserverEqualValue
_exp.setValue(_value); // may fail
_exp.attachObserver(new ObserverEqualValue());
return null;
}
