org.apache.mahout.cf.taste.hbase.ToEntityPrefsMapper.java Source code

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Here is the source code for org.apache.mahout.cf.taste.hbase.ToEntityPrefsMapper.java

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/*
 * 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.hbase;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.mapreduce.TableMapper;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.mahout.cf.taste.hadoop.EntityPrefWritable;
import org.apache.mahout.cf.taste.hbase.item.RecommenderJob;
import org.apache.mahout.math.VarLongWritable;

import java.io.IOException;
import java.util.NavigableMap;

public abstract class ToEntityPrefsMapper extends TableMapper<VarLongWritable, VarLongWritable> {

    public static final String TRANSPOSE_USER_ITEM = ToEntityPrefsMapper.class + "transposeUserItem";
    public static final String RATING_SHIFT = ToEntityPrefsMapper.class + "shiftRatings";

    private boolean booleanData;
    private float ratingShift;

    private byte[] fcRatings;

    @Override
    protected void setup(Context context) {
        Configuration jobConf = context.getConfiguration();
        booleanData = jobConf.getBoolean(RecommenderJob.BOOLEAN_DATA, false);
        ratingShift = Float.parseFloat(jobConf.get(RATING_SHIFT, "0.0"));

        fcRatings = Bytes.toBytes(jobConf.get(RecommenderJob.PARAM_CF_RATINGS));
    }

    @Override
    protected void map(ImmutableBytesWritable key, Result columns, Context context)
            throws IOException, InterruptedException {

        long userID = Long.valueOf(Bytes.toString(key.get()));

        NavigableMap<byte[], byte[]> colum_map = columns.getFamilyMap(fcRatings);
        for (byte[] colum : colum_map.keySet()) {
            long itemID = Long.valueOf(Bytes.toString(colum));

            if (booleanData) {
                context.write(new VarLongWritable(userID), new VarLongWritable(itemID));
            } else {
                float prefValue;

                try {
                    byte[] pref = columns.getValue(fcRatings, colum);

                    prefValue = Float.parseFloat(Bytes.toString(pref)) + ratingShift;
                } catch (Exception ex) {
                    System.out.println("WARN: the preference valur could not be parsed to float");

                    prefValue = 1.0f;
                }

                context.write(new VarLongWritable(userID), new EntityPrefWritable(itemID, prefValue));
            }
        }
    }

}