/**
* Attempt to add a type to the slice, possibly changing the endpoints of some descendant
* intervals.
*
* @param type the type to add to the slice
* @param ancestors the new type's ancestors
* @return if the addition was successful, the event for the endpoint changes, though there might
* be none; if the addition failed, <code>null</code>
*/
public EndpointsChangedEvent add(Constant type, Set<Constant> ancestors) {
Interval<Constant> common = asInterval();
for (Constant ancestor : ancestors) {
Interval<Constant> mask = descendentIntervals.get(ancestor);
if (mask != null) {
common.intersect(mask);
}
}
// empty is okay, as long as we still have location
if (order.compare(common.getMin(), common.getMax()) > 0) {
return null;
}
int surroundMin = 0, surroundMax = 0;
for (Constant ancestor : ancestors) {
Interval<Constant> range = descendentIntervals.get(ancestor);
if (range != null) {
if (order.compare(range.getMin(), common.getMin()) < 0
&& order.compare(range.getMax(), common.getMin()) > 0) {
++surroundMin;
}
if (order.compare(range.getMin(), common.getMax()) < 0
&& order.compare(range.getMax(), common.getMax()) > 0) {
++surroundMax;
}
}
}
if (lambdas.get(common.getMin()) == surroundMin) {
return add(type, common.getMin(), ancestors);
}
if (lambdas.get(common.getMax()) == surroundMax) {
return add(type, common.getMax(), ancestors);
}
//// fast slicing: don't check between min and max
return null;
}
