I'm using Lucene's Highlighter to highlight parts of a string. The code below seems to work fine for finding the stemmed words but not for prefix matching.
EnglishAnalyzer analyzer = new EnglishAnalyzer(Version.LUCENE_34);
QueryParser parser = new QueryParser(Version.LUCENE_30, "", analyzer);
Query query = parser.parse(pQuery);
QueryScorer scorer = new QueryScorer(query);
Fragmenter fragmenter = new SimpleSpanFragmenter(scorer, 40);
Highlighter highlighter = new Highlighter(scorer);
highlighter.setTextFragmenter(fragmenter);
String[] frags = highlighter.getBestFragments(analyzer, "", pText, 4);
I've read in a few different places I need to call Query.rewrite to get the prefix matching to work. That method takes an IndexReader arguement though and I'm not sure how to get it. All of the example's I've found that call Query.rewreite don't show where the IndexReader came from. I'll add that that this is the only Lucene code I'm using. I'm not using Lucene to do the searching itself, just for the highlighting.
How do I create an IndexReader and is it possible to create one if I'm using Lucene the way that I am. Or perhaps there's a different way to get it to highlight the prefix matches? I'm very new to Lucene and I'm sure what all of these pieces do or if they're all necessary. I've just copied them from various example's I've found online. So if I've doing anything else wrong please let me know. Thanks.
Suppose you have a query field:abc* . What query.rewrite basically does is: it reads the index(this why you need an IndexReader) finds all terms that start with abc and changes your query as ,for ex., field:abc1 field:abc2 field:abc3. If you know the location of the index, you can use IndexReader.Open to get an IndexReader. If you don't have an index at all, you should search your pText, find all words that start with abc and update your query accordingly.