} else if (name.equals("Evidence")) {
// redefinition of evidence so clear out evidence context
evidenceContext = null;
if (qv == null || "".equals(qv.getText().trim())) {
addError(new InvalidEvidenceException(an.getLine(), an.getCharPositionInLine()));
} else {
evidenceContext = new BELEvidence(qv.getText());
}
}