code: package cic.cs.unb.ca.weka;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import weka.core.Attribute;
  import weka.core.FastVector;
  import weka.core.Instance;
  import weka.core.Instances;
  import weka.core.converters.CSVLoader;
  import weka.filters.Filter;
  import weka.filters.unsupervised.attribute.PrincipalComponents;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.Enumeration;
  
  /**
   * Created by yzhang29 on 02/01/18.
   */
  public class WekaFactory {
  
      protected static final Logger logger = LoggerFactory.getLogger(WekaFactory.class);
  
      private static WekaFactory instanceFactory = new WekaFactory();
  
      //private Instances mEmptyFlowInstances;
  
  
      public static final String DIMENREDUCE_TSNE = "t-sne";
      public static final String DIMENREDUCE_WEKA_PCA = "weka-pca";
  
      public static final Attribute DRATTRX = new Attribute("X");
      public static final Attribute DRATTRY = new Attribute("Y");
  
  
      public static WekaFactory getFactory() {
          return instanceFactory;
      }
  
      public WekaFactory init() {
  
          /*List<FlowFeature> featureList = FlowFeature.getFeatureList();
          FastVector fastVector = new FastVector();
          for (FlowFeature feature : featureList) {
              Attribute attribute = feature2attr(feature.getName(),feature.isNumeric());
              fastVector.addElement(attribute);
          }
          mEmptyFlowInstances = new Instances("cic_flow_feature",fastVector,0);
          logger.debug("{}",mEmptyFlowInstances.toSummaryString());*/
  
          return instanceFactory;
      }
  
      /*public Instances createEmptyFlowInstances() {
          return new Instances(mEmptyFlowInstances,0);
      }
  
      public int numAttributesOfFlowInstances() {
          return mEmptyFlowInstances.numAttributes();
      }*/
  
      public static Instances loadURLCsv(File file) {
          logger.debug("loadURLCsv {}",file.getPath());
          Instances instances=null;
  
          CSVLoader loader = new CSVLoader();
  
          try {
              loader.setSource(file);
              instances = loader.getDataSet();
  
              //logger.info("loadURLCsv org->> {}",instances.toSummaryString());
              instances.deleteAttributeType(Attribute.NOMINAL);
  
              Enumeration<Attribute> enuAttr = instances.enumerateAttributes();
              while(enuAttr.hasMoreElements()) {
                  instances.deleteWithMissing(enuAttr.nextElement());
              }
              logger.debug("loadURLCsv summary-> {}",instances.toSummaryString());
  
          } catch (IOException e) {
              logger.debug(e.getMessage());
          }
  
          return instances;
      }
  
      public static Instances loadFlowCsv(File file) {
          logger.debug("loadFlowCsv {}",file.getPath());
          Instances instances=null;
  
          CSVLoader loader = new CSVLoader();
          try {
              loader.setSource(file);
              instances = loader.getDataSet();
  
              Enumeration<Attribute> enuAttr = instances.enumerateAttributes();
              while(enuAttr.hasMoreElements()) {
                  instances.deleteWithMissing(enuAttr.nextElement());
              }
              logger.debug("loadFlowCsv summary-> {}",instances.toSummaryString());
  
          }catch(IOException e) {
              logger.debug(e.getMessage());
          }
          return instances;
      }
  
      private static Instances createEmptyDimReInstances(String dimReAlgorithm) {
          FastVector fv = new FastVector();
          fv.addElement(DRATTRX);
          fv.addElement(DRATTRY);
          Instances insts = new Instances(dimReAlgorithm,fv,0);
          //logger.info("{}",insts.toSummaryString());
          return insts;
      }
  
      private static DimenReduce getDimenReduceMethod(String arg) {
  
          DimenReduce dr=null;
  
          switch(arg) {
              case DIMENREDUCE_TSNE:
                  //dr =  new DimReImplTSNE();
                  break;
          }
          return dr;
      }
  
      public static Instances dimReduce(final Instances org, String arg) {
  
          Instances instances = createEmptyDimReInstances(arg);
  
          DimenReduce dr = getDimenReduceMethod(arg);
  
          if(arg==null||arg.equals(DIMENREDUCE_WEKA_PCA)||dr==null) {
              try {
                  PrincipalComponents pca = new PrincipalComponents();
                  pca.setMaximumAttributes(2);
                  pca.setInputFormat(org);
                  instances = Filter.useFilter(org, pca);
              }catch(Exception e) {
                  logger.debug(e.getMessage());
              }
          }else{
              double[][] orgData = instances2doubleArray(org);
  
              double[][] newData = dr.dimensionReduce(orgData);
  
              for(int i=0;i<newData.length;i++) {
                  Instance inst = new Instance(instances.numAttributes());
                  inst.setValue(DRATTRX, newData[i][0]);
                  inst.setValue(DRATTRY, newData[i][1]);
                  instances.add(inst);
              }
          }
          logger.debug("{}",instances.toSummaryString());
          return instances;
      }
  
      public static double[][] instances2doubleArray(final Instances instances){
  
          int num = instances.numInstances();
  
          double[][] ret  = new double[num][];
  
          for(int i=0;i<num;i++) {
              Instance inst = instances.instance(i);
              ret[i] = inst.toDoubleArray();
          }
          return ret;
      }
  
      public static Attribute feature2attr(String featurename,boolean isNumeric){
          Attribute attr;
          if(isNumeric) {
              attr = new Attribute(featurename);
          }else {
              attr = new Attribute(featurename, (FastVector) null);
          }
          return attr;
      }
  
  }
  