Classify music to genre with WEKA

I am struggling to actually implement the classifying part of my investigations into the possibility of classifying music according to some features of music files.

What I have currently produced is code that reads a table of features from the DB and then puts it back into the DB in another table.

The problem is that I do not know how to work with the instances type. Documentation is crap - I have no clue what to do.

What I want to do: I want to use a given set of music files and compute their feature vectors. After this data has been put into arff, I would manually join it with genre data (the gial i.e.). and then save it into a MySQL table.

AFAIU the chain should be like this:

• Read from DB

• Somehow train a K-nearest neighbor classifier on a set of the features (related to genre) per music file for a body of 10 files.

• Use this to classify a set of files with the same features but unknown genre.

• Somehow output results so that they can be machine-readable in the database.

I have found no examples of the output of the data actually being used for further processing so I cannot further haggle :/

After this has been done, I would like to read it back and conduct a classification on a new body of music (the features I have computed by music or using a sample file set). The results should be put back into the DB in yet another new table, detailing what file has which category (assigned).

Here is my code:

package org.tuhh.cpmgg.weka;

import weka.core.*;
import weka.core.converters.*;
import weka.experiment.InstanceQuery;

import java.io.*;
import java.util.ArrayList;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType; 

@Path("/weka2")
public class weka_chain {

  /**
   * loads a dataset from mysql db
   * @param args the commandline arguments
   */
    @GET
    @Produces(MediaType.TEXT_PLAIN)
    public String main() 
            throws Exception {

    java.util.List resultList;

    /*Gets data from DB*/

    InstanceQuery query = new InstanceQuery();
    query.setDatabaseURL("jdbc:mysql://127.2.73.130:3306/cpmgg");
    query.setUsername("adminnNWqHkW");
    query.setPassword("zLlkWsd-NsnQ");
    query.setQuery("SELECT * FROM features"); //Read table
    Instances data = query.retrieveInstances(); //into data
    data.setClassIndex(data.numAttributes() - 1); //sets the number of classes (creates index)

    /*Classifiers */

    String algorithm = "weka.classifiers.bayes.NaiveBayes"; // Sets the type of classifier (many available)

    resultList = new ArrayList();

    Weka1 weka; 
    try {
        weka = new Weka1(algorithm, "lol");
        resultList = weka.weka(algorithm, data); //Essentially what is happening



        /* TODO:
         * Define Output so that it is in table form/instance form
         * This means creating output using the old applet and somehow (?) distilling it into table shape
         */


    /* Saves Results to DB */

    DatabaseSaver save = new DatabaseSaver();
    // save.setUrl("jdbc:mysql://localhost:3306/weka_test");
    save.setUrl("jdbc:mysql://127.2.73.130:3306/cpmgg");
    //save.setUrl("jdbc:mysql://localhost:3306/hibernate");
    save.setUser("AMDINADMIN");
    save.setPassword("PASS_ PASS");
    save.setInstances(data); // define outputtype
    save.setRelationForTableName(false);
    save.setTableName("weka_rslts");
    save.connectToDatabase();
    save.writeBatch();

    return "done";
  }
}