LibimsetiRecommender.java

/*
 * Source code for listing 5.5
 * 
 */
package mia.recommender.ch05;

import com.google.common.io.Files;
import com.google.common.io.InputSupplier;
import com.google.common.io.Resources;
import org.apache.mahout.cf.taste.common.Refreshable;
import org.apache.mahout.cf.taste.common.TasteException;
import org.apache.mahout.cf.taste.impl.common.FastIDSet;
import org.apache.mahout.cf.taste.impl.model.file.FileDataModel;
import org.apache.mahout.cf.taste.impl.neighborhood.NearestNUserNeighborhood;
import org.apache.mahout.cf.taste.impl.recommender.GenericUserBasedRecommender;
import org.apache.mahout.cf.taste.impl.similarity.EuclideanDistanceSimilarity;
import org.apache.mahout.cf.taste.model.DataModel;
import org.apache.mahout.cf.taste.neighborhood.UserNeighborhood;
import org.apache.mahout.cf.taste.recommender.IDRescorer;
import org.apache.mahout.cf.taste.recommender.RecommendedItem;
import org.apache.mahout.cf.taste.recommender.Recommender;
import org.apache.mahout.cf.taste.similarity.UserSimilarity;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Collection;
import java.util.List;

public class LibimsetiRecommender implements Recommender {

  private final Recommender delegate;
  private final DataModel model;
  private final FastIDSet men;
  private final FastIDSet women;
  private final FastIDSet usersRateMoreMen;
  private final FastIDSet usersRateLessMen;

  public LibimsetiRecommender() throws TasteException, IOException {
    this(new FileDataModel(readResourceToTempFile("ratings.dat")));
  }

  public LibimsetiRecommender(DataModel model)
      throws TasteException, IOException {
    UserSimilarity similarity = new EuclideanDistanceSimilarity(model);
    UserNeighborhood neighborhood =
        new NearestNUserNeighborhood(2, similarity, model);
    delegate =
        new GenericUserBasedRecommender(model, neighborhood, similarity);
    this.model = model;
    FastIDSet[] menWomen = GenderRescorer.parseMenWomen(readResourceToTempFile("gender.dat"));
    men = menWomen[0];
    women = menWomen[1];
    usersRateMoreMen = new FastIDSet(50000);
    usersRateLessMen = new FastIDSet(50000);
  }

  @Override
  public List<RecommendedItem> recommend(long userID, int howMany)
      throws TasteException {
    IDRescorer rescorer = new GenderRescorer(
        men, women, usersRateMoreMen, usersRateLessMen, userID, model);
    return delegate.recommend(userID, howMany, rescorer);
  }

  @Override
  public List<RecommendedItem> recommend(long userID,
                                         int howMany,
                                         IDRescorer rescorer)
      throws TasteException {
    return delegate.recommend(userID, howMany, rescorer);
  }

  @Override
  public float estimatePreference(long userID, long itemID)
      throws TasteException {
    IDRescorer rescorer = new GenderRescorer(
        men, women, usersRateMoreMen, usersRateLessMen, userID, model);
    return (float) rescorer.rescore(
        itemID, delegate.estimatePreference(userID, itemID));
  }

  @Override
  public void setPreference(long userID, long itemID, float value)
      throws TasteException {
    delegate.setPreference(userID, itemID, value);
  }

  @Override
  public void removePreference(long userID, long itemID)
      throws TasteException {
    delegate.removePreference(userID, itemID);
  }

  @Override
  public DataModel getDataModel() {
    return delegate.getDataModel();
  }

  @Override
  public void refresh(Collection<Refreshable> alreadyRefreshed) {
    delegate.refresh(alreadyRefreshed);
  }

  static File readResourceToTempFile(String resourceName) throws IOException {
    String absoluteResource = resourceName.startsWith("/") ? resourceName : '/' + resourceName;
    InputSupplier<? extends InputStream> inSupplier;
    try {
      URL resourceURL = Resources.getResource(LibimsetiRecommender.class, absoluteResource);
      inSupplier = Resources.newInputStreamSupplier(resourceURL);
    } catch (IllegalArgumentException iae) {
      File resourceFile = new File(resourceName);
      inSupplier = Files.newInputStreamSupplier(resourceFile);
    }
    File tempFile = File.createTempFile("taste", null);
    tempFile.deleteOnExit();
    Files.copy(inSupplier, tempFile);
    return tempFile;
  }

}