int (int parentId, int childrenCount, int slotsToReserve) { int start = myJoinedChildrenList.size(); assert start > 0; for (int i = 0; i < childrenCount; i++) { myJoinedChildrenList.add(parentId + i + 1); } for (int i = 0; i < slotsToReserve; i++) { myJoinedChildrenList.add(0); } myStubData.set(childrenStartIndex(parentId), start); return start; }