/*
* 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 org.grouplens.lenskit.vectors.MutableSparseVector;
import org.grouplens.lenskit.vectors.VectorEntry;
import org.grouplens.lenskit.vectors.VectorEntry.State;
import it.unimi.dsi.fastutil.longs.Long2IntMap;
import it.unimi.dsi.fastutil.longs.Long2IntOpenHashMap;
import it.unimi.dsi.fastutil.longs.LongArrayList;
import it.unimi.dsi.fastutil.longs.LongList;
import it.unimi.dsi.fastutil.longs.LongLists;
/**
* Build contiguous 0-based indexes for long IDs.
*
* @author <a href="http://www.grouplens.org">GroupLens Research</a>
* @deprecated Use {@link org.grouplens.lenskit.indexes.MutableIdIndexMapping} instead.
*/
@Deprecated
public class Indexer implements Index {
private static final long serialVersionUID = -8383883342128686850L;
private Long2IntMap indexes;
private LongArrayList ids;
/**
* Construct a new empty indexer. The first interned ID will have index 0.
*/
public Indexer() {
indexes = new Long2IntOpenHashMap();
indexes.defaultReturnValue(-1);
ids = new LongArrayList();
}
@Override
public long getId(int idx) {
return ids.getLong(idx);
}
@Override
public LongList getIds() {
return LongLists.unmodifiable(ids);
}
@Override
public int getIndex(long id) {
return indexes.get(id);
}
@Override
public int getObjectCount() {
return ids.size();
}
/**
* Get an index for an ID, generating a new one if necessary.
*
* @param id The ID.
* @return The index for {@var id}. If the ID has already been interned,
* the old index is returned; otherwise, a new index is generated
* and returned.
*/
public int internId(long id) {
int idx = getIndex(id);
if (idx < 0) {
idx = ids.size();
ids.add(id);
indexes.put(id, idx);
}
return idx;
}
@Override
public MutableSparseVector convertArrayToVector(double[] values) {
if(values.length != getObjectCount()){
throw new IllegalArgumentException("Value array has incorrect length");
}
MutableSparseVector newSparseVector = MutableSparseVector.create(ids);
for(VectorEntry e : newSparseVector.view(State.EITHER)){
final int iid = getIndex(e.getKey());
newSparseVector.set(e, values[iid]);
}
return newSparseVector;
}
}