Example usage for org.apache.mahout.cf.taste.impl.recommender RandomRecommender recommend

Introduction

In this page you can find the example usage for org.apache.mahout.cf.taste.impl.recommender RandomRecommender recommend.

Prototype

@Override
public List<RecommendedItem> recommend(long userID, int howMany) throws TasteException 

Source Link

Document

Default implementation which just calls Recommender#recommend(long,int,org.apache.mahout.cf.taste.recommender.IDRescorer) , with a org.apache.mahout.cf.taste.recommender.Rescorer that does nothing.

Usage

From source file:com.thegoodlife2015.servlet.recServlet.java

/**
 * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
 * methods.// w  w  w . ja  v  a2s  .  c  om
 *
 * @param request servlet request
 * @param response servlet response
 * @throws ServletException if a servlet-specific error occurs
 * @throws IOException if an I/O error occurs
 * @throws org.apache.mahout.cf.taste.common.TasteException
 */
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException, TasteException {
    response.setContentType("text/html;charset=UTF-8");
    PrintWriter out = response.getWriter();

    //specifying the number of recommendations to be generated
    int noOfRecommendations = 20;

    String fbID = request.getParameter("fbID");
    long fbIDL = Long.parseLong(fbID);

    // Specifications tables  
    String tablename = "rating";
    String col1 = "fbID";
    String col2 = "offerID";
    String col3 = "rate";

    //Input for database connections
    // grab environment variable
    String host = System.getenv("OPENSHIFT_MYSQL_DB_HOST");
    String servername;
    String username;
    String password;
    String dbname;
    String port;
    String PROPS_FILENAME = "/connection.properties";

    if (host != null) {
        // this is production environment
        // obtain database connection properties from environment variables
        servername = host;
        port = System.getenv("OPENSHIFT_MYSQL_DB_PORT");
        dbname = System.getenv("OPENSHIFT_APP_NAME");
        username = System.getenv("OPENSHIFT_MYSQL_DB_USERNAME");
        password = System.getenv("OPENSHIFT_MYSQL_DB_PASSWORD");
        //out.println(servername + " " + port + " " + dbname + " " + username + " " + password);

    } else {

        try {
            // Retrieve properties from connection.properties via the CLASSPATH
            // WEB-INF/classes is on the CLASSPATH
            InputStream is = ConnectionManager.class.getResourceAsStream(PROPS_FILENAME);
            Properties props = new Properties();
            props.load(is);

            // load database connection details
            servername = props.getProperty("db.host");
            port = props.getProperty("db.port");
            dbname = props.getProperty("db.name");
            username = props.getProperty("db.user");
            password = props.getProperty("db.password");

            //out.println(servername + " " + port + " " + dbname + " " + username + " " + password);
        } catch (Exception ex) {
            // unable to load properties file
            String message = "Unable to load '" + PROPS_FILENAME + "'.";

            out.println(message);
            Logger.getLogger(ConnectionManager.class.getName()).log(Level.SEVERE, message, ex);
            throw new RuntimeException(message, ex);
        }
    }

    //setup for second connection
    java.sql.Connection conn = null;
    java.sql.Statement stmt = null;
    ResultSet rs = null;
    boolean hasRec = false;

    try {
        ///Initialize connection for Mahout input
        MysqlDataSource dataSource = new MysqlDataSource();
        dataSource.setServerName(servername);
        dataSource.setUser(username);
        dataSource.setPassword(password);
        dataSource.setDatabaseName(dbname);

        MySQLJDBCDataModel dataModel = new MySQLJDBCDataModel(dataSource, tablename, col1, col2, col3, null);

        /*Specifies the Similarity algorithm*/
        ItemSimilarity itemSimilarity = new LogLikelihoodSimilarity(dataModel);

        /*Initalizing the recommender */
        ItemBasedRecommender recommender = new GenericItemBasedRecommender(dataModel, itemSimilarity);
        List<RecommendedItem> recommendations = null;

        try {
            recommendations = recommender.recommend(fbIDL, noOfRecommendations);
        } catch (Exception e) {
            RandomRecommender rRecommender = new RandomRecommender(dataModel);
            recommendations = rRecommender.recommend(fbIDL, noOfRecommendations);
        } finally {
            //                if (recommendations.size() < noOfRecommendations) {
            //                    int randomInt = noOfRecommendations - recommendations.size();
            //                    RandomRecommender rRecommender = new RandomRecommender(dataModel);
            //                    recommendations.addAll(rRecommender.recommend(fbIDL, randomInt));
            //                }
            while (recommendations.size() < noOfRecommendations) {
                int randomInt = noOfRecommendations - recommendations.size();
                RandomRecommender rRecommender = new RandomRecommender(dataModel);
                recommendations.addAll(rRecommender.recommend(fbIDL, randomInt));
                recommendations = new ArrayList<>(new HashSet<>(recommendations));
            }
        }
        if (recommendations.size() >= 0) {
            JSONObject jsonObject = getJsonFromMyFormObject(recommendations, fbIDL);
            hasRec = true;
            out.println(jsonObject);
        }

    } catch (Exception e) {
        e.printStackTrace();

    } finally {
        try {
            if (rs != null) {
                rs.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {
            if (stmt != null) {
                stmt.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {
            if (conn != null) {
                conn.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    //        if(!hasRec) {
    //            out.println("{\"error\":\"user has no records\"}");
    //        }
}

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