com.packtpub.mahout.cookbook.chapter01.App.java Source code

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Here is the source code for com.packtpub.mahout.cookbook.chapter01.App.java

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/* 
 *   Copyright [2013] [Piero Giacomelli]
 *
 * Licensed 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.
 *
 *
 * @author Piero Giacomelli
 * @e-mail pgiacome@gmail.com
 * skype:pgiacome
 * twitter:pierogiacomelli
 *   
*/

package com.packtpub.mahout.cookbook.chapter01;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.List;

import org.apache.commons.cli2.OptionException;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.common.LongPrimitiveIterator;
import org.apache.mahout.cf.taste.impl.model.file.FileDataModel;
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.RecommendedItem;

public class App {

    static final String inputFile = "/mnt/new/ml-1m/ratings.dat";
    static final String outputFile = "/mnt/new/ml-1m/ratings.csv";

    public static void main(String[] args) throws IOException, TasteException, OptionException {
        CreateCsvRatingsFile();

        // create data source (model) - from the csv file
        File ratingsFile = new File(outputFile);
        DataModel model = new FileDataModel(ratingsFile);

        // create a simple recommender on our data
        CachingRecommender cachingRecommender = new CachingRecommender(new SlopeOneRecommender(model));

        // for all users
        for (LongPrimitiveIterator it = model.getUserIDs(); it.hasNext();) {
            long userId = it.nextLong();

            // get the recommendations for the user
            List<RecommendedItem> recommendations = cachingRecommender.recommend(userId, 10);

            // if empty write something
            if (recommendations.size() == 0) {
                System.out.print("User ");
                System.out.print(userId);
                System.out.println(": no recommendations");
            }

            // print the list of recommendations for each
            for (RecommendedItem recommendedItem : recommendations) {
                System.out.print("User ");
                System.out.print(userId);
                System.out.print(": ");
                System.out.println(recommendedItem);
            }
        }
    }

    private static void CreateCsvRatingsFile() throws FileNotFoundException, IOException {

        BufferedReader br = new BufferedReader(new FileReader(inputFile));
        BufferedWriter bw = new BufferedWriter(new FileWriter(outputFile));

        String line = null;
        String line2write = null;
        String[] temp;

        int i = 0;
        while ((line = br.readLine()) != null && i < 1000) {
            i++;
            temp = line.split("::");
            line2write = temp[0] + "," + temp[1];
            bw.write(line2write);
            bw.newLine();
            bw.flush();

        }
        br.close();
        bw.close();
    }
}