java - Lucene 4 Pagination - Stack Overflow

 java - Lucene 4 Pagination - Stack Overflow

I've been using Lucene 4.8 and have been working on a REST interface which includes pagination. My solution has been to use a TopScoreDocCollector and call the topDocs(int startIndex, int numberOfhits) method. The start index is calculated by multiplying the zero based page number by the number of hits.

...
DirectoryReader reader = DirectoryReader.open(MMapDirectory.open( java.io.File(indexFile) );
IndexSearcher searcher = new IndexSearcher(reader);
TopScoreDocCollector collector = TopScoreDocCollector.create(MAX_RESULTS, true);  // MAX_RESULTS is just an int limiting the total number of hits 
int startIndex = (page -1) * hitsPerPage;  // our page is 1 based - so we need to convert to zero based
Query query = new QueryParser(Version.LUCENE_48, "All", analyzer).parse(searchQuery);
searcher.search(query, collector);
TopDocs hits = collector.topDocs(startIndex, hitsPerPage);
...

So my REST interface accepts the page number and number of hits per page as parameters. So going forward or back is as simple as submitting a new request with the appropriate value for the page

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