// retrieves date and duration of expression
Result node = this.resultStack.popResult();
PeriodNode period = (PeriodNode) node.getBuilt();
Literal begin = period.getBeginning();
Literal end = period.getEnding();
// creates and filter firstDate<= property <= lastDate
Expression property = this.resultStack.popExpression();
And filter = filterFactory.and(filterFactory.lessOrEqual(begin,