private Set<String> findMultiProperty(OrImpl or) {
Set<String> values = newLinkedHashSet();
for (ConstraintImpl constraint : or.getConstraints()) {
if (constraint instanceof ComparisonImpl) {
ComparisonImpl comparison = (ComparisonImpl) constraint;
if (isIndexed(comparison.getOperand1())
&& comparison.getOperator() == Operator.EQUAL) {
values.addAll(encode(comparison.getOperand2().currentValue()));
} else {
return null;
}
} else if (constraint instanceof InImpl) {
InImpl in = (InImpl) constraint;