Shagheyegh: I'm hardly the lucene expert, but I don't think you can search just a portion of the index. But that's effectively what you're doing if you restrict the search to "son and.....".
However, depending on your problem space, you could build separate indexes. To continue the example, you could build 4 indexes, "mother", "father", "son", "daughter" and only search the relevant ones. You should still be able to aggregate the results. That is, you could search over all 4 indexes when you needed to and combine the results into a single response. Then you could only search a subset of them at other times. I admit that I haven't yet had to use a MultiSearcher, but that sure looks like what you want if you adopt this approach <G>... Note: I'm looking at the 2.0 documentation.... But I also have to ask, why are you trying to "search only a portion of the index"? If you haven't encountered a bottleneck that's forcing you into this option (or don't have a *very* high expectation that you will encounter such a bottleneck), this strikes me as work you shouldn't be doing until there's a demonstrated need. The eXtreme Programming folks look at it this way "make it work, make it right, make it fast".
From Tony Hoare and Donald Knuth... "We should forget about small
efficiencies, say about 97% of the time: premature optimization is the root of all evil." Best Erick
