/**
* File: $HeadURL: https://hdt-java.googlecode.com/svn/trunk/hdt-java/src/org/rdfhdt/hdt/triples/impl/BitmapTriplesIteratorY.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.NotImplementedException;
import org.rdfhdt.hdt.triples.IteratorTripleID;
import org.rdfhdt.hdt.triples.TripleID;
/**
*
* Iterates over all Y components of a BitmapTriples.
* i.e. In SPO it would iterate over all appearances of a predicate ?P?
*
* @author mario.arias
*
*/
public class BitmapTriplesIteratorY implements IteratorTripleID {
private BitmapTriples triples;
private TripleID pattern, returnTriple;
private int patY;
private AdjacencyList adjY, adjZ;
long posY, posZ;
private long prevY, nextY, prevZ, nextZ;
private int x, y, z;
BitmapTriplesIteratorY(BitmapTriples triples, TripleID pattern) {
this.triples = triples;
this.pattern = new TripleID(pattern);
this.returnTriple = new TripleID();
TripleOrderConvert.swapComponentOrder(this.pattern, TripleComponentOrder.SPO, triples.order);
patY = this.pattern.getPredicate();
if(patY==0) {
throw new IllegalArgumentException("This structure is not meant to process this pattern");
}
adjY = triples.adjY;
adjZ = triples.adjZ;
goToStart();
}
private void updateOutput() {
returnTriple.setAll(x, y, z);
TripleOrderConvert.swapComponentOrder(returnTriple, triples.order, TripleComponentOrder.SPO);
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#hasNext()
*/
@Override
public boolean hasNext() {
return nextY!=-1 || posZ<=nextZ;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#next()
*/
@Override
public TripleID next() {
if(posZ>nextZ) {
prevY = posY;
posY = nextY;
nextY = adjY.findNextAppearance(nextY+1, patY);
posZ = prevZ = adjZ.find(posY);
nextZ = adjZ.last(posY);
x = (int) adjY.findListIndex(posY)+1;
y = (int) adjY.get(posY);
z = (int) adjZ.get(posZ);
} else {
z = (int) adjZ.get(posZ);
}
posZ++;
updateOutput();
return returnTriple;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#hasPrevious()
*/
@Override
public boolean hasPrevious() {
return prevY!=-1 || posZ>=prevZ;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#previous()
*/
@Override
public TripleID previous() {
if(posZ<=prevZ) {
nextY = posY;
posY = prevY;
prevY = adjY.findPreviousAppearance(prevY-1, patY);
posZ = prevZ = adjZ.find(posY);
nextZ = adjZ.last(posY);
x = (int) adjY.findListIndex(posY)+1;
y = (int) adjY.get(posY);
z = (int) adjZ.get(posZ);
} else {
posZ--;
z = (int) adjZ.get(posZ);
}
updateOutput();
return returnTriple;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#goToStart()
*/
@Override
public void goToStart() {
prevY = -1;
posY = adjY.findNextAppearance(0, patY);
nextY = adjY.findNextAppearance(posY+1, patY);
posZ = prevZ = adjZ.find(posY);
nextZ = adjZ.last(posY);
x = (int) adjY.findListIndex(posY)+1;
y = (int) adjY.get(posY);
z = (int) adjZ.get(posZ);
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#estimatedNumResults()
*/
@Override
public long estimatedNumResults() {
return adjZ.getNumberOfElements();
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#numResultEstimation()
*/
@Override
public ResultEstimationType numResultEstimation() {
return ResultEstimationType.UNKNOWN;
}
/* (non-Javadoc)
* @see hdt.iterator.IteratorTripleID#canGoTo()
*/
@Override
public boolean canGoTo() {
return false;
}
/* (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");
}
}
/* (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();
}
}