}
public String addEntry() {
FacesContext fc = FacesContext.getCurrentInstance();
VariableResolver vr = fc.getApplication().getVariableResolver();
AdvancedFilter af = (AdvancedFilter) vr.resolveVariable(fc, "advancedFilter");
DataFilterEntry entry = af.getEntry();
if (entry.getOperator() == null) {
fc.addMessage("msg", new FacesMessage("Operator is not filled!"));
} else if (entry.getOperator().needsValue() && Utilities.isEmpty(entry.getValue())) {