/**
* 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.netflix;
import org.apache.mahout.cf.taste.common.Refreshable;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.common.FileLineIterable;
import org.apache.mahout.cf.taste.impl.common.FastIDSet;
import org.apache.mahout.cf.taste.impl.common.FastByIDMap;
import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
import org.apache.mahout.cf.taste.impl.model.GenericDataModel;
import org.apache.mahout.cf.taste.impl.model.GenericPreference;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.model.Preference;
import org.apache.mahout.cf.taste.model.PreferenceArray;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
/**
* <p>This is a {@link DataModel} that reads the Netflix data set, as represented in its
* unpacked file structure. Note that unpacking the distribution entails untarring the main
* archive, then untarring the archive of training set data files.</p>
*/
public final class NetflixDataModel implements DataModel {
private static final Logger log = LoggerFactory.getLogger(NetflixDataModel.class);
private final DataModel delegate;
private final boolean useSubset;
/**
* @param dataDirectory root directory of Netflix data set, unpacked
* @param useSubset if true, will use only a small fraction of the data -- may be useful
* for quick experiments
* @throws IOException
*/
public NetflixDataModel(File dataDirectory, boolean useSubset) throws IOException {
if (dataDirectory == null) {
throw new IllegalArgumentException("dataDirectory is null");
}
if (!dataDirectory.exists() || !dataDirectory.isDirectory()) {
throw new FileNotFoundException(dataDirectory.toString());
}
this.useSubset = useSubset;
log.info("Creating NetflixDataModel for directory: {}", dataDirectory);
log.info("Reading preference data...");
FastByIDMap<PreferenceArray> users = readUsers(dataDirectory);
log.info("Creating delegate DataModel...");
delegate = new GenericDataModel(users);
}
private FastByIDMap<PreferenceArray> readUsers(File dataDirectory) throws IOException {
FastByIDMap<Collection<Preference>> userIDPrefMap = new FastByIDMap<Collection<Preference>>();
int counter = 0;
FilenameFilter filenameFilter = new MovieFilenameFilter();
for (File movieFile : new File(dataDirectory, "training_set").listFiles(filenameFilter)) {
Iterator<String> lineIterator = new FileLineIterable(movieFile, false).iterator();
String line = lineIterator.next();
long movieID = Long.parseLong(line.substring(0, line.length() - 1)); // strip colon
while (lineIterator.hasNext()) {
line = lineIterator.next();
if (++counter % 100000 == 0) {
log.info("Processed {} prefs", counter);
}
int firstComma = line.indexOf((int) ',');
long userID = Long.parseLong(line.substring(0, firstComma));
int secondComma = line.indexOf((int) ',', firstComma + 1);
float rating = Float.parseFloat(line.substring(firstComma + 1, secondComma));
Collection<Preference> userPrefs = userIDPrefMap.get(userID);
if (userPrefs == null) {
userPrefs = new ArrayList<Preference>(2);
userIDPrefMap.put(userID, userPrefs);
}
userPrefs.add(new GenericPreference(userID, movieID, rating));
}
}
return GenericDataModel.toDataMap(userIDPrefMap, true);
}
@Override
public LongPrimitiveIterator getUserIDs() throws TasteException {
return delegate.getUserIDs();
}
@Override
public PreferenceArray getPreferencesFromUser(long id) throws TasteException {
return delegate.getPreferencesFromUser(id);
}
@Override
public FastIDSet getItemIDsFromUser(long userID) throws TasteException {
return delegate.getItemIDsFromUser(userID);
}
@Override
public LongPrimitiveIterator getItemIDs() throws TasteException {
return delegate.getItemIDs();
}
@Override
public PreferenceArray getPreferencesForItem(long itemID) throws TasteException {
return delegate.getPreferencesForItem(itemID);
}
@Override
public Float getPreferenceValue(long userID, long itemID) throws TasteException {
return delegate.getPreferenceValue(userID, itemID);
}
@Override
public int getNumItems() throws TasteException {
return delegate.getNumItems();
}
@Override
public int getNumUsers() throws TasteException {
return delegate.getNumUsers();
}
@Override
public int getNumUsersWithPreferenceFor(long... itemIDs) throws TasteException {
return delegate.getNumUsersWithPreferenceFor(itemIDs);
}
@Override
public void setPreference(long userID, long itemID, float value) {
throw new UnsupportedOperationException();
}
@Override
public void removePreference(long userID, long itemID) {
throw new UnsupportedOperationException();
}
@Override
public void refresh(Collection<Refreshable> alreadyRefreshed) {
// do nothing
}
private class MovieFilenameFilter implements FilenameFilter {
@Override
public boolean accept(File dir, String filename) {
return filename.startsWith(useSubset ? "mv_0000" : "mv_");
}
}
@Override
public String toString() {
return "NetflixDataModel";
}
}