Cool! Only one question: if we have
class RelevanceAndDistanceCollector extends
HitCollector
{
public ScoreDoc[] getMatches(int start, int size)
{
...
}
}
and a call of getMatches(10000, 25); would not cache
as many as 10000+ docs, would it? Remember this is the
whole point of this exercise -- scalability -- just
want to make sure.
Thanks,
-James
--- markharw00d <[EMAIL PROTECTED]> wrote:
> Here's an example I put together to illustrate the
> point.
>
>
> package distance;
>
> import java.io.IOException;
> import java.util.ArrayList;
>
> import org.apache.lucene.analysis.Analyzer;
> import
> org.apache.lucene.analysis.WhitespaceAnalyzer;
> import org.apache.lucene.document.Document;
> import org.apache.lucene.document.Field;
> import org.apache.lucene.index.IndexReader;
> import org.apache.lucene.index.IndexWriter;
> import org.apache.lucene.queryParser.ParseException;
> import org.apache.lucene.queryParser.QueryParser;
> 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.store.RAMDirectory;
> import org.apache.lucene.util.PriorityQueue;
>
> public class TestDistance
> {
>
> private static QueryParser parser;
> private static IndexReader reader;
> private static Location[] locsCache;
> private static IndexSearcher searcher;
> /**
> * @param args
> */
> public static void main(String[] args) throws
> Exception
> {
> Analyzer analyzer=new WhitespaceAnalyzer();
> RAMDirectory dir=new RAMDirectory();
> IndexWriter writer=new
> IndexWriter(dir,analyzer,true);
> addDoc(writer,"the faraway mouse", 500,500);
> addDoc(writer,"the semilocal cat", 50,50);
> addDoc(writer,"the local dog", 20,20);
> writer.close();
> searcher=new IndexSearcher(dir);
> parser=new QueryParser("description",
> analyzer);
>
> //create location cache
> reader = searcher.getIndexReader();
> ArrayList allLocs=new ArrayList();
> int docCount=reader.numDocs();
> for (int i = 0; i < docCount; i++)
> {
> Document doc=reader.document(i);
> allLocs.add(new Location(
>
> Float.parseFloat(doc.get("lat")),
>
> Float.parseFloat(doc.get("lon"))
> )
> );
> }
> locsCache=new Location[reader.numDocs()];
> locsCache= (Location[]) allLocs.toArray(new
> Location[allLocs.size()]);
>
> //example search 1
> runSearch("the cat");
>
> runSearch("the dog");
>
> runSearch("the mouse");
>
>
> }
>
> private static void runSearch(String
> queryString) throws
> ParseException, IOException
> {
> System.out.println("query:"+queryString);
> Query query=parser.parse(queryString);
> Location queryLocation=new Location(1f,1f);
> RelevanceAndDistanceCollector collector=new
> RelevanceAndDistanceCollector(10,
> queryLocation,locsCache);
> searcher.search(query,collector);
> ScoreDoc[] results = collector.getMatches();
> for (int i = 0; i < results.length; i++)
> {
> Document
> doc=reader.document(results[i].doc);
>
> System.out.print("["+results[i].doc+"]");
>
> System.out.print("("+results[i].score+")");
>
> System.out.println("\t"+doc.get("description"));
> }
> System.out.println("");
> }
>
>
> public static void addDoc(IndexWriter
> writer,String description,
> float lat, float lon) throws IOException
> {
> Document doc=new Document();
> doc.add(Field.UnIndexed("lat", ""+lat));
> doc.add(Field.UnIndexed("lon", ""+lon));
>
> doc.add(Field.Text("description",description));
> writer.addDocument(doc);
> }
> static class Location
> {
> float lat;
> float lon;
> public Location(float lat, float lon)
> {
> this.lat=lat;
> this.lon=lon;
> }
> public float distance(Location loc)
> {
> float latDiff = Math.abs(loc.lat-lat);
> float lonDiff = Math.abs(loc.lon-lon);
> float dist=(float)
> Math.sqrt((latDiff*latDiff)+(lonDiff*lonDiff));
> return dist;
> }
>
> }
> static class RelevanceAndDistanceCollector
> extends HitCollector
> {
> HitQueue hq;
> Location queryLocation;
> float maxDistance=5000;
> private Location[] docLocs;
>
> public RelevanceAndDistanceCollector(int
> numDocs, Location
> queryLocation, Location[] docLocs)
> {
> this.queryLocation=queryLocation;
> this.docLocs=docLocs;
> hq=new HitQueue(numDocs);
> }
> public void collect(int doc, float score)
> {
>
>
score=score*(maxDistance-queryLocation.distance(docLocs[doc]));
> hq.insert(new ScoreDoc(doc,score));
>
> }
> public ScoreDoc[] getMatches()
> {
> ScoreDoc sd[]=new ScoreDoc[hq.size()];
> while(hq.size()>0)
> {
> sd[hq.size()-1]=(ScoreDoc) hq.pop();
> }
> return sd;
> }
> }
> static 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;
> }
> }
>
> }
>
>
>
>
>
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