I'm trying to play with extractTerms() a method of the Query() class[1].  
This method expects a java Set<Term> instance - but instantiating one  
failes with a NotImplementedError. Any clues whats missing:

================================================In [1]: import lucene

In [2]: lucene.initVM()
Out[2]: <jcc.JCCEnv object at 0x005BD3B0>

In [3]: lucene.Se
lucene.Searchable                    lucene.SegmentInfo                    
lucene.SerialMergeScheduler
lucene.Searcher                      lucene.SegmentInfos                  
lucene.Serializable
lucene.SecurityException             lucene.SegmentInfos$FindSegmentsFile  
lucene.Set
lucene.SecurityManager               lucene.SegmentReader                  
lucene.SetBasedFieldSelector

In [3]: lucene.Set
Out[3]: <type 'Set'>

In [4]: lucene.Set()
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
==================================================
thnx, dirk

[1]  
http://lucene.apache.org/java/3_0_1/api/all/org/apache/lucene/search/Query.html#extractTerms(java.util.Set)