Improvements on MULTI_SORTED index on 0.9.2

This message was edited 3 times. Last update was at 18/09/2010 15:47:43

Before:

@Override
    public Collection<Object> findUsers(int minAge, int maxAge) {
       
       // Remember that our index is of the type MULTI_SORTED.
       // That's why we are doing this cast here.
       
       MultiSortedMap map = (MultiSortedMap) indexByAge.getMap();
       
       // A multi-sorted-map will store a Map for each key.
       // That's why our index is NON-UNIQUE meaning the same
       // key can be associated with many entries in the map.
       // The map is also sorted by its key, meaning we can
       // perform range searches efficiently.
       
       ConcurrentNavigableMap<Key, Object> subMap = map.subMap(new Key(minAge), true, new Key(maxAge), true);
       
       Collection<Object> users = new ArrayList<Object>(subMap.size() * 3);
       
       Iterator<Object> iter = subMap.values().iterator();
       
       while(iter.hasNext()) {
          
          // our collection here is actually a ConcurrentHashMap!
          
          Map<Object, Boolean> m = (Map<Object, Boolean>) iter.next();
          
          // this is not good as we are transversing the whole list twice!
          // TODO: Create custom iterator for MultiSortedMap to avoid this?
          
          Iterator<Object> iter2 = m.keySet().iterator();
          
          while(iter2.hasNext()) {
             
             users.add(iter2.next());
          }
       }
       
       return users;
    }

NOW:

Simpler and more efficient as you don't need to copy anything. subMapValues returns a collection of users (backed up by a collection of sets) so you can iterate through all elements efficiently.