/**
* File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/triples/impl/BitmapTriplesIterator.java $
* Revision: $Rev: 191 $
* Last modified: $Date: 2013-03-03 11:41:43 +0000 (dom, 03 mar 2013) $
* Last modified by: $Author: mario.arias $
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Contacting the authors:
* Mario Arias: mario.arias@deri.org
* Javier D. Fernandez: jfergar@infor.uva.es
* Miguel A. Martinez-Prieto: migumar2@infor.uva.es
* Alejandro Andres: fuzzy.alej@gmail.com
*/
package org.rdfhdt.hdt.triples.impl;
import org.rdfhdt.hdt.compact.bitmap.AdjacencyList;
import org.rdfhdt.hdt.enums.ResultEstimationType;
import org.rdfhdt.hdt.enums.TripleComponentOrder;
import org.rdfhdt.hdt.exceptions.NotFoundException;
import org.rdfhdt.hdt.exceptions.NotImplementedException;
import org.rdfhdt.hdt.triples.IteratorTripleID;
import org.rdfhdt.hdt.triples.TripleID;
/**
* @author mario.arias
*
*/
public class BitmapTriplesIterator implements IteratorTripleID {
private BitmapTriples triples;
private TripleID pattern, returnTriple;
private int patX, patY, patZ;
private AdjacencyList adjY, adjZ;
long posY, posZ, minY, minZ, maxY, maxZ;
private long nextY, nextZ;
private int x, y, z;
BitmapTriplesIterator(BitmapTriples triples, TripleID pattern) {
this.triples = triples;
this.returnTriple = new TripleID();
this.pattern = new TripleID();
newSearch(pattern);
}
public void newSearch(TripleID pattern) {
this.pattern.assign(pattern);
TripleOrderConvert.swapComponentOrder(this.pattern, TripleComponentOrder.SPO, triples.order);
patX = this.pattern.getSubject();
patY = this.pattern.getPredicate();
patZ = this.pattern.getObject();
adjY = triples.adjY;
adjZ = triples.adjZ;
// ((BitSequence375)triples.bitmapZ).dump();
findRange();
goToStart();
}
private void updateOutput() {
returnTriple.setAll(x, y, z);
TripleOrderConvert.swapComponentOrder(returnTriple, triples.order, TripleComponentOrder.SPO);
}
private void findRange() {
if(patX!=0) {
// S X X
if(patY!=0) {
// S P X
try {
minY = adjY.find(patX-1, patY);
maxY = minY+1;
if(patZ!=0) {
// S P O
minZ = adjZ.find(minY,patZ);
maxZ = minZ+1;
} else {
// S P ?
minZ = adjZ.find(minY);
maxZ = adjZ.last(minY)+1;
}
} catch (NotFoundException e) {
// Item not found in list, no results.
minY = minZ = maxY = maxZ = 0;
}
} else {
// S ? X
minY = adjY.find(patX-1);
minZ = adjZ.find(minY);
maxY = adjY.last(patX-1)+1;
maxZ = adjZ.find(maxY);
}
x = patX;
} else {
// ? X X
minY=0;
minZ=0;
maxY = adjY.getNumberOfElements();
maxZ = adjZ.getNumberOfElements();
}
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#hasNext()
*/
@Override
public boolean hasNext() {
return posZ<maxZ;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#next()
*/
@Override
public TripleID next() {
z = (int) adjZ.get(posZ);
if(posZ==nextZ) {
posY++;
y = (int) adjY.get(posY);
// nextZ = adjZ.find(posY+1);
nextZ = adjZ.findNext(nextZ)+1;
if(posY==nextY) {
x++;
// nextY = adjY.find(x);
nextY = adjY.findNext(nextY)+1;
}
}
posZ++;
updateOutput();
return returnTriple;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#hasPrevious()
*/
@Override
public boolean hasPrevious() {
return posZ>minZ;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#previous()
*/
@Override
public TripleID previous() {
posZ--;
posY = adjZ.findListIndex(posZ);
z = (int) adjZ.get(posZ);
y = (int) adjY.get(posY);
x = (int) adjY.findListIndex(posY)+1;
nextY = adjY.last(x-1)+1;
nextZ = adjZ.last(posY)+1;
updateOutput();
return returnTriple;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#goToStart()
*/
@Override
public void goToStart() {
posZ = minZ;
posY = adjZ.findListIndex(posZ);
z = (int) adjZ.get(posZ);
y = (int) adjY.get(posY);
x = (int) adjY.findListIndex(posY)+1;
nextY = adjY.last(x-1)+1;
nextZ = adjZ.last(posY)+1;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#estimatedNumResults()
*/
@Override
public long estimatedNumResults() {
return maxZ-minZ;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#numResultEstimation()
*/
@Override
public ResultEstimationType numResultEstimation() {
if(patX!=0 && patY==0 && patZ!=0) {
return ResultEstimationType.UP_TO;
}
return ResultEstimationType.EXACT;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#canGoTo()
*/
@Override
public boolean canGoTo() {
return pattern.isEmpty();
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#goTo(int)
*/
@Override
public void goTo(long pos) {
if(!canGoTo()) {
throw new IllegalAccessError("Cannot goto on this bitmaptriples pattern");
}
if(pos>=adjZ.getNumberOfElements()) {
throw new ArrayIndexOutOfBoundsException("Cannot goTo beyond last triple");
}
posZ = pos;
posY = adjZ.findListIndex(posZ);
z = (int) adjZ.get(posZ);
y = (int) adjY.get(posY);
x = (int) adjY.findListIndex(posY)+1;
nextY = adjY.last(x-1)+1;
nextZ = adjZ.last(posY)+1;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#getOrder()
*/
@Override
public TripleComponentOrder getOrder() {
return triples.order;
}
/* (non-Javadoc)
* @see java.util.Iterator#remove()
*/
@Override
public void remove() {
throw new UnsupportedOperationException();
}
}