/*
* 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.example.grouplens;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import org.apache.mahout.cf.taste.common.Refreshable;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.recommender.CachingRecommender;
import org.apache.mahout.cf.taste.impl.recommender.slopeone.SlopeOneRecommender;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.recommender.IDRescorer;
import org.apache.mahout.cf.taste.recommender.RecommendedItem;
import org.apache.mahout.cf.taste.recommender.Recommender;
/**
* A simple {@link Recommender} implemented for the GroupLens demo.
*/
public final class GroupLensRecommender implements Recommender {
private final Recommender recommender;
public GroupLensRecommender() throws IOException, TasteException {
this(new GroupLensDataModel());
}
/**
* <p>Alternate constructor that takes a {@link DataModel} argument, which allows this {@link Recommender}
* to be used with the {@link org.apache.mahout.cf.taste.eval.RecommenderEvaluator} framework.</p>
*
* @param dataModel data model
* @throws TasteException if an error occurs while initializing this
*/
public GroupLensRecommender(DataModel dataModel) throws TasteException {
recommender = new CachingRecommender(new SlopeOneRecommender(dataModel));
}
@Override
public List<RecommendedItem> recommend(long userID, int howMany) throws TasteException {
return recommender.recommend(userID, howMany);
}
@Override
public List<RecommendedItem> recommend(long userID, int howMany, IDRescorer rescorer) throws TasteException {
return recommender.recommend(userID, howMany, rescorer);
}
@Override
public float estimatePreference(long userID, long itemID) throws TasteException {
return recommender.estimatePreference(userID, itemID);
}
@Override
public void setPreference(long userID, long itemID, float value) throws TasteException {
recommender.setPreference(userID, itemID, value);
}
@Override
public void removePreference(long userID, long itemID) throws TasteException {
recommender.removePreference(userID, itemID);
}
@Override
public DataModel getDataModel() {
return recommender.getDataModel();
}
@Override
public void refresh(Collection<Refreshable> alreadyRefreshed) {
recommender.refresh(alreadyRefreshed);
}
@Override
public String toString() {
return "GroupLensRecommender[recommender:" + recommender + ']';
}
}