public EventPair treeReduce(EventPair lhs, EventPair rhs) {
EventPair result;
if (lhs.left == null) {
result = rhs;
} else if (rhs.left == null) {
result = lhs;
} else if (lhs.right == null) {
if (rhs.right == null) {
if (canBeMerged(lhs.left, rhs.left))
result =
new EventPair(mergeEvents(lhs.left, rhs.left), null, lhs.intervals, rhs.intervals);
else result = new EventPair(lhs.left, rhs.left, lhs.intervals, rhs.intervals);
} else {
if (canBeMerged(lhs.left, rhs.left))
result =
new EventPair(
mergeEvents(lhs.left, rhs.left), rhs.right, lhs.intervals, rhs.intervals);
else {
if (rhs.left.isReportableEvent()) rhs.intervals.add(rhs.left.getLoc());
result = new EventPair(lhs.left, rhs.right, lhs.intervals, rhs.intervals);
}
}
} else if (rhs.right == null) {
if (canBeMerged(lhs.right, rhs.left))
result =
new EventPair(lhs.left, mergeEvents(lhs.right, rhs.left), lhs.intervals, rhs.intervals);
else {
if (lhs.right.isReportableEvent()) lhs.intervals.add(lhs.right.getLoc());
result = new EventPair(lhs.left, rhs.left, lhs.intervals, rhs.intervals);
}
} else {
if (canBeMerged(lhs.right, rhs.left)) {
Event merge = mergeEvents(lhs.right, rhs.left);
if (merge.isReportableEvent()) lhs.intervals.add(merge.getLoc());
} else {
if (lhs.right.isReportableEvent()) lhs.intervals.add(lhs.right.getLoc());
if (rhs.left.isReportableEvent()) rhs.intervals.add(rhs.left.getLoc());
}
result = new EventPair(lhs.left, rhs.right, lhs.intervals, rhs.intervals);
}
return result;
}
@com.google.java.contract.Requires({"left != null", "right != null"})
private static Event mergeEvents(Event left, Event right) {
left.merge(right);
return left;
}