Week4. Additional files

Author: SkyrocketStan

.idea/modules.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library" exported="">
+      <library>
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/../../apache-csv.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/../../apache-csv.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+    <orderEntry type="module-library" exported="">
+      <library>
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/../../courserajava.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES>
+          <root url="jar://$MODULE_DIR$/../../courserajava.jar!/" />
+        </SOURCES>
+      </library>
+    </orderEntry>
+  </component>
+</module>

Week4/Week4.iml

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+/**
+ * Write a description of RaterDatabase here.
+ *
+ * @author (your name)
+ * @version (a version number or a date)
+ */
+import edu.duke.FileResource;
+import org.apache.commons.csv.CSVParser;
+import org.apache.commons.csv.CSVRecord;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class RaterDatabase {
+  private static HashMap<String, Rater> ourRaters;
+
+  private static void initialize() {
+    // this method is only called from addRatings
+    if (ourRaters == null) {
+      ourRaters = new HashMap<String, Rater>();
+    }
+  }
+
+  public static void initialize(String filename) {
+    if (ourRaters == null) {
+      ourRaters = new HashMap<String, Rater>();
+      addRatings("data/" + filename);
+    }
+  }
+
+  public static void addRatings(String filename) {
+    initialize();
+    FileResource fr = new FileResource(filename);
+    CSVParser csvp = fr.getCSVParser();
+    for (CSVRecord rec : csvp) {
+      String id = rec.get("rater_id");
+      String item = rec.get("movie_id");
+      String rating = rec.get("rating");
+      addRaterRating(id, item, Double.parseDouble(rating));
+    }
+  }
+
+  public static void addRaterRating(String raterID, String movieID, double rating) {
+    initialize();
+    Rater rater = null;
+    if (ourRaters.containsKey(raterID)) {
+      rater = ourRaters.get(raterID);
+    } else {
+      rater = new EfficientRater(raterID);
+      ourRaters.put(raterID, rater);
+    }
+    rater.addRating(movieID, rating);
+  }
+
+  public static Rater getRater(String id) {
+    initialize();
+
+    return ourRaters.get(id);
+  }
+
+  public static ArrayList<Rater> getRaters() {
+    initialize();
+    ArrayList<Rater> list = new ArrayList<Rater>(ourRaters.values());
+
+    return list;
+  }
+
+  public static int size() {
+    return ourRaters.size();
+  }
+}

Week4/src/RaterDatabase.java

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+import java.util.ArrayList;
+
+/**
+ * Implement this interface to allow your code to be integrated with our web site.
+ *
+ * <p>When users first visit the recommender website, our code will call the method <code>
+ * getItemsToRate()</code> to get a list of movies to display on the web page for users to rate.
+ *
+ * <p>When a user submits their ratings, our code will call the method <code>
+ * printRecommendationsFor</code> to get your recommendations based on the user's ratings. The ID
+ * given to this method is for a new Rater that we have already added to the RaterDatabase with
+ * ratings for the movies returned by the first method. Whatever is printed from that method will be
+ * displayed on the web page: HTML, plain text, or debugging information.
+ */
+public interface Recommender {
+  /**
+   * This method returns a list of movie IDs that will be used to look up the movies in the
+   * MovieDatabase and present them to users to rate.
+   *
+   * <p>The movies returned in the list will be displayed on a web page, so the number you choose
+   * may affect how long the page takes to load and how willing users are to rate the movies. For
+   * example, 10-20 should be fine, 50 or more would be too many.
+   *
+   * <p>There are no restrictions on the method you use to generate this list of movies: the most
+   * recent movies, movies from a specific genre, randomly chosen movies, or simply your favorite
+   * movies.
+   *
+   * <p>The ratings for these movies will make the profile for a new Rater that will be used to
+   * compare to for finding recommendations.
+   */
+  ArrayList<String> getItemsToRate();
+
+  /**
+   * This method returns nothing, but prints out an HTML table of the movies recommended for the
+   * given rater.
+   *
+   * <p>The HTML printed will be displayed on a web page, so the number you choose to display may
+   * affect how long the page takes to load. For example, you may want to limit the number printed
+   * to only the top 20-50 movies recommended or to movies not rater by the given rater.
+   *
+   * <p>You may also include CSS styling for your table using the &lt;style&gt; tag before you print
+   * the table. There are no restrictions on which movies you print, what order you print them in,
+   * or what information you include about each movie.
+   *
+   * @param webRaterID the ID of a new Rater that has been already added to the RaterDatabase with
+   *     ratings for the movies returned by the method getItemsToRate
+   */
+  void printRecommendationsFor(String webRaterID);
+}