/*
* Hibernate Search, full-text search for your domain model
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.search.spatial.impl;
import org.apache.lucene.index.AtomicReader;
import org.apache.lucene.index.AtomicReaderContext;
import org.apache.lucene.index.DocsEnum;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.DocIdSet;
import org.apache.lucene.search.DocIdSetIterator;
import org.apache.lucene.search.Filter;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.OpenBitSet;
import java.io.IOException;
import java.util.List;
/**
* Lucene Filter for filtering documents which have been indexed with Hibernate Search Spatial SpatialFieldBridge
* Use denormalized spatial hash cell ids to return a sub set of documents near the center
*
* @author Nicolas Helleringer <nicolas.helleringer@novacodex.net>
* @see org.hibernate.search.spatial.SpatialFieldBridgeByHash
* @see org.hibernate.search.spatial.Coordinates
*/
public final class SpatialHashFilter extends Filter {
private final List<String> spatialHashCellsIds;
private final String fieldName;
public SpatialHashFilter(List<String> spatialHashCellsIds, String fieldName) {
this.spatialHashCellsIds = spatialHashCellsIds;
this.fieldName = fieldName;
}
/**
* Returns Doc Ids by searching the index for document having the correct spatial hash cell id at given grid level
*
* @param reader reader to the index
*/
@Override
public DocIdSet getDocIdSet(AtomicReaderContext context, Bits acceptDocs) throws IOException {
if ( spatialHashCellsIds.size() == 0 ) {
return null;
}
final AtomicReader atomicReader = context.reader();
OpenBitSet matchedDocumentsIds = new OpenBitSet( atomicReader.maxDoc() );
Boolean found = false;
for ( int i = 0; i < spatialHashCellsIds.size(); i++ ) {
Term spatialHashCellTerm = new Term( fieldName, spatialHashCellsIds.get( i ) );
DocsEnum spatialHashCellsDocs = atomicReader.termDocsEnum( spatialHashCellTerm );
if ( spatialHashCellsDocs != null ) {
while ( true ) {
final int docId = spatialHashCellsDocs.nextDoc();
if ( docId == DocIdSetIterator.NO_MORE_DOCS ) {
break;
}
else {
if ( acceptDocs == null || acceptDocs.get( docId ) ) {
matchedDocumentsIds.fastSet( docId );
found = true;
}
}
}
}
}
if ( found ) {
return matchedDocumentsIds;
}
else {
return null;
}
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
sb.append( "SpatialHashFilter" );
sb.append( "{spatialHashCellsIds=" ).append( spatialHashCellsIds );
sb.append( ", fieldName='" ).append( fieldName ).append( '\'' );
sb.append( '}' );
return sb.toString();
}
}