/*
* 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.hadoop;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.mahout.cf.taste.hadoop.item.RecommenderJob;
import org.apache.mahout.math.VarLongWritable;
import java.io.IOException;
import java.util.regex.Pattern;
public abstract class ToEntityPrefsMapper extends
Mapper<LongWritable,Text, VarLongWritable,VarLongWritable> {
public static final String TRANSPOSE_USER_ITEM = ToEntityPrefsMapper.class + "transposeUserItem";
public static final String RATING_SHIFT = ToEntityPrefsMapper.class + "shiftRatings";
private static final Pattern DELIMITER = Pattern.compile("[\t,]");
private boolean booleanData;
private boolean transpose;
private final boolean itemKey;
private float ratingShift;
ToEntityPrefsMapper(boolean itemKey) {
this.itemKey = itemKey;
}
@Override
protected void setup(Context context) {
Configuration jobConf = context.getConfiguration();
booleanData = jobConf.getBoolean(RecommenderJob.BOOLEAN_DATA, false);
transpose = jobConf.getBoolean(TRANSPOSE_USER_ITEM, false);
ratingShift = Float.parseFloat(jobConf.get(RATING_SHIFT, "0.0"));
}
@Override
public void map(LongWritable key,
Text value,
Context context) throws IOException, InterruptedException {
String[] tokens = DELIMITER.split(value.toString());
long userID = Long.parseLong(tokens[0]);
long itemID = Long.parseLong(tokens[1]);
if (itemKey ^ transpose) {
// If using items as keys, and not transposing items and users, then users are items!
// Or if not using items as keys (users are, as usual), but transposing items and users,
// then users are items! Confused?
long temp = userID;
userID = itemID;
itemID = temp;
}
if (booleanData) {
context.write(new VarLongWritable(userID), new VarLongWritable(itemID));
} else {
float prefValue = tokens.length > 2 ? Float.parseFloat(tokens[2]) + ratingShift : 1.0f;
context.write(new VarLongWritable(userID), new EntityPrefWritable(itemID, prefValue));
}
}
}