private void setTOS(ValueNumberFrame vnaFrame, Location location, DefinitelyNullSet fact, boolean isNull)
private void setTOS(ValueNumberFrame vnaFrame, Location location, DefinitelyNullSet fact, NullnessValue nullnessValue)
	private void setTOS(ValueNumberFrame vnaFrame, Location location, DefinitelyNullSet fact, boolean isNull)			throws DataflowAnalysisException {		ValueNumber valueNumber = vnaFrame.getTopValue();		changeNullnessOfValue(valueNumber, location, fact, isNull);	}