Hi, Thanks Mark!
I do have the same question as Alixandre. How do I get the content of the document instead of the document id? Thanks. Regards, Lee Li Bin -----Original Message----- From: Alixandre Santana [mailto:[EMAIL PROTECTED] Sent: Tuesday, July 03, 2007 12:55 AM To: java-user@lucene.apache.org Subject: Re: Pagination Mark, The ScoreDoc[] contains only the IDs of each lucene document. what would be the best way of getting the entire (lucene)document ? Should i do a new search with the ID retrivied by hpc.getScores() - (searcher.doc(idDoc))? thanks. Alixandre On 7/2/07, mark harwood <[EMAIL PROTECTED]> wrote: > The Hits class is OK but can be inefficient due to re-running the query unnecessarily. > > The class below illustrates how to efficiently retrieve a particular page of results and lends itself to webapps where you don't want to retain server side state (i.e. a Hits object) for each client. > It would make sense to put an upper limit on the "start" parameter (as Google etc do) to avoid consuming to much RAM per client request. > > Cheers, > Mark > > [Begin code] > > > > > package lucene.pagination; > > import org.apache.lucene.index.Term; > import org.apache.lucene.search.HitCollector; > import org.apache.lucene.search.IndexSearcher; > import org.apache.lucene.search.Query; > import org.apache.lucene.search.ScoreDoc; > import org.apache.lucene.search.TermQuery; > import org.apache.lucene.util.PriorityQueue; > > /** > * A HitCollector that retrieves a specific page of results > * @author maharwood > */ > public class HitPageCollector extends HitCollector > { > //Demo code showing pagination > public static void main(String[] args) throws Exception > { > IndexSearcher s=new IndexSearcher("/indexes/nasa"); > HitPageCollector hpc=new HitPageCollector(1,10); > Query q=new TermQuery(new Term("contents","sea")); > s.search(q,hpc); > ScoreDoc[] sd = hpc.getScores(); > System.out.println("Hits "+ hpc.getStart()+" - "+ hpc.getEnd()+" of "+hpc.getTotalAvailable()); > for (int i = 0; i < sd.length; i++) > { > System.out.println(sd[i].doc); > } > s.close(); > } > > int nDocs; > PriorityQueue hq; > float minScore = 0.0f; > int totalHits = 0; > int start; > int maxNumHits; > int totalInThisPage; > > public HitPageCollector(int start, int maxNumHits) > { > this.nDocs = start + maxNumHits; > this.start = start; > this.maxNumHits = maxNumHits; > hq = new HitQueue(nDocs); > } > > public void collect(int doc, float score) > { > totalHits++; > if((hq.size()<nDocs)||(score >= minScore)) > { > ScoreDoc scoreDoc = new ScoreDoc(doc,score); > hq.insert(scoreDoc); // update hit queue > minScore = ((ScoreDoc)hq.top()).score; // reset minScore > } > totalInThisPage=hq.size(); > } > > > public ScoreDoc[] getScores() > { > //just returns the number of hits required from the required start point > /* > So, given hits: > 1234567890 > and a start of 2 + maxNumHits of 3 should return: > 234 > or, given hits > 12 > should return > 2 > and so, on. > */ > if (start <= 0) > { > throw new IllegalArgumentException("Invalid start :" + start+" - start should be >=1"); > } > int numReturned = Math.min(maxNumHits, (hq.size() - (start - 1))); > if (numReturned <= 0) > { > return new ScoreDoc[0]; > } > ScoreDoc[] scoreDocs = new ScoreDoc[numReturned]; > ScoreDoc scoreDoc; > for (int i = hq.size() - 1; i >= 0; i--) // put docs in array, working backwards from lowest count > { > scoreDoc = (ScoreDoc) hq.pop(); > if (i < (start - 1)) > { > break; //off the beginning of the results array > } > if (i < (scoreDocs.length + (start - 1))) > { > scoreDocs[i - (start - 1)] = scoreDoc; //within scope of results array > } > } > return scoreDocs; > } > > public int getTotalAvailable() > { > return totalHits; > } > > public int getStart() > { > return start; > } > > public int getEnd() > { > return start+totalInThisPage-1; > } > > public class HitQueue extends PriorityQueue > { > public HitQueue(int size) > { > initialize(size); > } > public final boolean lessThan(Object a, Object b) > { > ScoreDoc hitA = (ScoreDoc)a; > ScoreDoc hitB = (ScoreDoc)b; > if (hitA.score == hitB.score) > return hitA.doc > hitB.doc; > else > return hitA.score < hitB.score; > } > } > } > > > > ----- Original Message ---- > From: Lee Li Bin <[EMAIL PROTECTED]> > To: java-user@lucene.apache.org > Sent: Monday, 2 July, 2007 9:59:14 AM > Subject: RE: Pagination > > Hi, > > I still have no idea of how to get it done. Can give me some details? > > The web application is in jsp btw. > > Thanks a lot. > > > Regards, > Lee Li Bin > -----Original Message----- > From: Chris Lu [mailto:[EMAIL PROTECTED] > Sent: Saturday, June 30, 2007 2:21 AM > To: java-user@lucene.apache.org > Subject: Re: Pagination > > After search, you will just get an object Hits, and go through all of the > documents by hits.doc(i). > > The pagination is controlled by you. Lucene is pre-caching first 200 > documents and lazy loading the rest by batch size 200. > > -- > Chris Lu > ------------------------- > Instant Scalable Full-Text Search On Any Database/Application > site: http://www.dbsight.net > demo: http://search.dbsight.com > Lucene Database Search in 3 minutes: > http://wiki.dbsight.com/index.php?title=Create_Lucene_Database_Search_in_3_m > inutes > > On 6/29/07, Lee Li Bin <[EMAIL PROTECTED]> wrote: > > > > Hi, > > > > does anyone knows how to do pagination on jsp page using the number of > > hits > > return? Or any other solutions? > > > > > > > > Do provide me with some sample coding if possible or a step by step guide. > > Sry if I'm asking too much, I'm new to lucene. > > > > > > > > Thanks > > > > > > > > > > > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > > ___________________________________________________________ > Yahoo! Answers - Got a question? Someone out there knows the answer. Try it > now. > http://uk.answers.yahoo.com/ > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > -- Alixandre Santana --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
