(Using 2.1.7)

I have a method making lists of objects distinct by using the suggested new HashSet(originalList) technique... Unfortunately when I've ordered my query in HQL, I believe I'm at risk of losing the order of my elements (since Set doesn't guarantee order).

Has anyone suggested an elegant/efficient method of return a distinct List which retains the order of the original one? I imagine I could write something fairly simple that tromps through the list and deletes duplicates. I wanted to make sure there wasn't a better solution I'd overlooked though.

Also, I don't believe SortedSet implementations will work for me because they require their elements implement comparable. I suppose I could have my entities implement Comparable, but this wouldn't be sufficient for me since I might sort them by a number of different fields for different queries.

Thanks in advance,

Phill

Have you already tried this ?



Simon[/quote]

Wow. I'd overlooked that because it doesn't implement SortedSet. I'm still confused by the documentation as to whether or not I can trust it to retain the order of my original collection. I don't see why it wouldn't work though. It is a bit faster than the other implementation we worked out today, which was:


HashSet set = new HashSet();
ArrayList results = new ArrayList(originalResults.size());

Iterator it = originalResults.iterator();
while (it.hasNext()) {
Object item = it.next();
if (!set.contains(item)) {
set.add(item);
results.add(item);
}
}

return results;