On Feb 10, 2005, at 4:06 PM, Luke Shannon wrote:
I think I found a pretty good way to do a negative match.
In this query I am looking for all the Documents that have a kcfileupload
field with any value except for jpg.
Query negativeMatch = new WildcardQuery(new Term("kcfileupload",
"*jpg*"));
BooleanQuery typeNegAll = new BooleanQuery();
Query allResults = new WildcardQuery(new Term("kcfileupload", "*"));
IndexSearcher searcher = new IndexSearcher(fsDir);
BooleanClause clause = new BooleanClause(negativeMatch, false,
true);
typeNegAll.add(allResults, true, false);
typeNegAll.add(clause);
Hits hits = searcher.search(typeNegAll);
With the little testing I have done this *seems* to work. Does anyone see a
problem with this approach?
Sure.... do you realize what WildcardQuery does under the covers? It literally expands to a BooleanQuery for all terms that match the pattern. There is an adjustable limit built-in of 1,024 clauses to BooleanQuery. You obviously have not hit that limit ... yet!
You're better off using the advice offered on this thread previously.... create a single dummy field with a fixed value for all documents. Combine a TermQuery for that dummy value with a prohibited clause like y our negativeMatch above.
Erik
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