/*
* LensKit, an open source recommender systems toolkit.
* Copyright 2010-2014 LensKit Contributors. See CONTRIBUTORS.md.
* Work on LensKit has been funded by the National Science Foundation under
* grants IIS 05-34939, 08-08692, 08-12148, and 10-17697.
*
* This program 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 program 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 General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.grouplens.lenskit.util;
import it.unimi.dsi.fastutil.longs.LongOpenHashSet;
import it.unimi.dsi.fastutil.longs.LongSet;
import it.unimi.dsi.fastutil.longs.LongSets;
import org.grouplens.lenskit.scored.ScoredId;
import org.grouplens.lenskit.scored.ScoredIdListBuilder;
import org.grouplens.lenskit.scored.ScoredIds;
import org.grouplens.lenskit.vectors.MutableSparseVector;
import java.util.Collections;
import java.util.List;
/**
* Scored item accumulator with no upper bound.
*
* @author <a href="http://www.grouplens.org">GroupLens Research</a>
*/
public final class UnlimitedScoredItemAccumulator implements ScoredItemAccumulator {
private ScoredIdListBuilder scores;
public UnlimitedScoredItemAccumulator() {}
@Override
public boolean isEmpty() {
return scores == null || scores.size() == 0;
}
@Override
public int size() {
return scores == null ? 0 : scores.size();
}
@Override
public void put(long item, double score) {
if (scores == null) {
scores = ScoredIds.newListBuilder();
}
scores.add(item, score);
}
@Override
public List<ScoredId> finish() {
if (scores == null) {
return Collections.emptyList();
}
List<ScoredId> list = scores.sort(ScoredIds.scoreOrder().reverse()).finish();
scores = null;
return list;
}
@Override
public MutableSparseVector finishVector() {
if (scores == null) {
return MutableSparseVector.create();
}
MutableSparseVector vec = scores.buildVector().mutableCopy();
scores.clear();
scores = null;
return vec;
}
@Override
public LongSet finishSet() {
if (scores == null) {
return LongSets.EMPTY_SET;
}
LongSet set = new LongOpenHashSet(scores.size());
for (ScoredId id: finish()) {
set.add(id.getId());
}
return set;
}
}