public static ObjectFilter simplify(ObjectFilter filter) {
if (filter == null) {
return null;
}
if (filter instanceof AndFilter) {
List<ObjectFilter> conditions = ((AndFilter) filter).getConditions();
AndFilter simplifiedFilter = ((AndFilter) filter).cloneEmpty();
for (ObjectFilter subfilter : conditions) {
if (subfilter instanceof NoneFilter) {
// AND with "false"
return NoneFilter.createNone();
} else if (subfilter instanceof AllFilter) {
// AND with "true", just skip it
} else {
ObjectFilter simplifiedSubfilter = simplify(subfilter);
simplifiedFilter.addCondition(simplifiedSubfilter);
}
}
if (simplifiedFilter.isEmpty()) {
return AllFilter.createAll();
}
return simplifiedFilter;
} else if (filter instanceof OrFilter) {
List<ObjectFilter> conditions = ((OrFilter) filter).getConditions();
OrFilter simplifiedFilter = ((OrFilter) filter).cloneEmpty();
for (ObjectFilter subfilter : conditions) {
if (subfilter instanceof NoneFilter) {
// OR with "false", just skip it
} else if (subfilter instanceof AllFilter) {
// OR with "true"
return AllFilter.createAll();
} else {
ObjectFilter simplifiedSubfilter = simplify(subfilter);
simplifiedFilter.addCondition(simplifiedSubfilter);
}
}
if (simplifiedFilter.isEmpty()) {
return AllFilter.createAll();
}
return simplifiedFilter;
} else if (filter instanceof NotFilter) {
ObjectFilter subfilter = ((NotFilter) filter).getFilter();
ObjectFilter simplifiedSubfilter = simplify(subfilter);
if (subfilter instanceof NoneFilter) {
return AllFilter.createAll();
} else if (subfilter instanceof AllFilter) {
return NoneFilter.createNone();
} else {
NotFilter simplifiedFilter = ((NotFilter) filter).cloneEmpty();
simplifiedFilter.setFilter(simplifiedSubfilter);
return simplifiedFilter;
}
} else {
// Cannot simplify
return filter.clone();
}
}
