/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.mahout.cf.taste.impl.recommender;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.common.FastIDSet;
import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
import org.apache.mahout.cf.taste.model.DataModel;
public final class AllUnknownItemsCandidateItemsStrategy extends AbstractCandidateItemsStrategy {
/**
* return all items the user has not yet seen
*/
@Override
protected FastIDSet doGetCandidateItems(long[] preferredItemIDs, DataModel dataModel) throws TasteException {
FastIDSet possibleItemIDs = new FastIDSet(dataModel.getNumItems());
LongPrimitiveIterator allItemIDs = dataModel.getItemIDs();
while (allItemIDs.hasNext()) {
possibleItemIDs.add(allItemIDs.nextLong());
}
possibleItemIDs.removeAll(preferredItemIDs);
return possibleItemIDs;
}
}