/*
* 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 java.io.File;
import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.NoSuchElementException;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import org.apache.mahout.cf.taste.common.Refreshable;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.common.AbstractLongPrimitiveIterator;
import org.apache.mahout.cf.taste.impl.common.FastIDSet;
import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
import org.apache.mahout.cf.taste.impl.model.GenericItemPreferenceArray;
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.apache.mahout.common.iterator.FileLineIterable;
public final class NetflixFileDataModel implements DataModel {
private final File dataDirectory;
public NetflixFileDataModel(File dataDirectory) {
Preconditions.checkArgument(dataDirectory != null && dataDirectory.exists() && dataDirectory.isDirectory(),
"%s is not a directory", dataDirectory);
this.dataDirectory = dataDirectory;
}
@Override
public LongPrimitiveIterator getUserIDs() {
throw new UnsupportedOperationException(); // TODO
}
@Override
public PreferenceArray getPreferencesFromUser(long id) {
throw new UnsupportedOperationException(); // TODO
}
@Override
public LongPrimitiveIterator getItemIDs() {
return new MovieIDIterator();
}
@Override
public FastIDSet getItemIDsFromUser(long userID) {
throw new UnsupportedOperationException(); // TODO
}
@Override
public Float getPreferenceValue(long userID, long itemID) {
throw new UnsupportedOperationException(); // TODO
}
@Override
public Long getPreferenceTime(long userID, long itemID) {
throw new UnsupportedOperationException(); // TODO
}
@Override
public PreferenceArray getPreferencesForItem(long itemID) throws TasteException {
StringBuilder itemIDPadded = new StringBuilder(5);
itemIDPadded.append(itemID);
while (itemIDPadded.length() < 5) {
itemIDPadded.insert(0, '0');
}
List<Preference> prefs = Lists.newArrayList();
File movieFile = new File(new File(dataDirectory, "training_set"), "mv_00" + itemIDPadded + ".txt");
try {
for (String line : new FileLineIterable(movieFile, true)) {
int firstComma = line.indexOf(',');
Integer userID = Integer.valueOf(line.substring(0, firstComma));
int secondComma = line.indexOf(',', firstComma + 1);
float rating = Float.parseFloat(line.substring(firstComma + 1, secondComma));
prefs.add(new GenericPreference(userID, itemID, rating));
}
} catch (IOException ioe) {
throw new TasteException(ioe);
}
return new GenericItemPreferenceArray(prefs);
}
@Override
public int getNumItems() {
return MovieIDIterator.COUNT;
}
/**
* @throws UnsupportedOperationException
*/
@Override
public int getNumUsers() {
throw new UnsupportedOperationException();
}
/**
* @throws UnsupportedOperationException
*/
@Override
public int getNumUsersWithPreferenceFor(long itemID) {
throw new UnsupportedOperationException();
}
@Override
public int getNumUsersWithPreferenceFor(long itemID1, long itemID2) {
throw new UnsupportedOperationException();
}
/**
* @throws UnsupportedOperationException
*/
@Override
public void setPreference(long userID, long itemID, float value) {
throw new UnsupportedOperationException();
}
/**
* @throws UnsupportedOperationException
*/
@Override
public void removePreference(long userID, long itemID) {
throw new UnsupportedOperationException();
}
@Override
public void refresh(Collection<Refreshable> alreadyRefreshed) {
// do nothing
}
@Override
public boolean hasPreferenceValues() {
return true;
}
@Override
public float getMaxPreference() {
return 0.0f; // TODO
}
@Override
public float getMinPreference() {
return 0.0f; // TODO
}
@Override
public String toString() {
return "NetflixFileDataModel";
}
private static final class MovieIDIterator extends AbstractLongPrimitiveIterator {
static final int COUNT = 17770;
private int next = 1;
@Override
public long nextLong() {
if (next <= COUNT) {
return next++;
}
throw new NoSuchElementException();
}
@Override
public long peek() {
if (next <= COUNT) {
return next;
}
throw new NoSuchElementException();
}
@Override
public boolean hasNext() {
return next <= COUNT;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public void skip(int n) {
next += n;
}
}
}