[APEXMALHAR-24] Another Bug in offer(E e) function of com.datatorrent.lib.util.TopNSort.java

• Type: Task
• Status: Closed
• Resolution: Fixed
• Fix Version/s: 0.3.4
• Assignee: Chetan Narsude
• Reporter: gaurav gupta
• Created: 15/Jan/14 00:17
• Updated: 15/Jan/14 00:17
• Resolved: 15/Jan/14 00:17

Description

In the current implementation offer(E e) of TopNSort.java

@SuppressWarnings("unchecked")
public boolean offer(E e)
{
if (q.size() <= qbound) {
return q.offer(e);
}

boolean ret = true;
boolean insert;
Comparable<? super E> head = (Comparable<? super E>)q.peek();

if (ascending) { // means head is the lowest value due to inversion
insert = head.compareTo(e) <= 0; // e >= head
}
else { // means head is the highest value due to inversion
insert = head.compareTo(e) >= 0; // head is <= e
}
if (insert && q.offer(e)) {
ret = true;
q.poll();
}
return ret;
}

In the 1st line the check should be made only for "<" not "<=" i.e. it should as following

if (q.size() < qbound) {
return q.offer(e);
}

For e.g. if you set qbound as 2, with current implementation you end up adding 3 elements in the queue