code: /*
   * Copyright 2015 recommenders.net.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package net.recommenders.rival.examples;
  
  import java.io.File;
  import java.io.IOException;
  import java.net.MalformedURLException;
  import java.net.URL;
  import net.lingala.zip4j.core.ZipFile;
  import net.lingala.zip4j.exception.ZipException;
  import org.apache.commons.io.FileUtils;
  
  /**
   * Class used to download a file and unzips it.
   *
   * @author <a href="http://github.com/alansaid">Alan</a>.
   */
  public class DataDownloader {
  
      /**
       * The URL.
       */
      private String url;
      /**
       * The folder where the file will be unzipped it.
       */
      private String folder;
  
      /**
       * Default constructor.
       *
       * @param theUrl the URL from where the file will be downloaded
       * @param theFolder the folder where the file will be uncompressed
       */
      public DataDownloader(final String theUrl, final String theFolder) {
          this.url = theUrl;
          this.folder = theFolder;
      }
  
      /**
       * Main method.
       *
       * @param args argument (not used)
       */
      public static void main(final String[] args) {
          String url = "http://files.grouplens.org/datasets/movielens/ml-100k.zip";
          String folder = "data3/ml-100k";
          DataDownloader dd = new DataDownloader(url, folder);
          dd.downloadAndUnzip();
      }
  
      /**
       * Downloads the file from the provided url.
       */
      public void download() {
          URL dataURL = null;
          String fileName = folder + "/" + url.substring(url.lastIndexOf("/") + 1);
          if (new File(fileName).exists()) {
              return;
          }
          try {
              dataURL = new URL(url);
          } catch (MalformedURLException e) {
              e.printStackTrace();
          }
  
          File downloadedData = new File(fileName);
          try {
              assert dataURL != null;
              FileUtils.copyURLToFile(dataURL, downloadedData);
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
  
      /**
       * Downloads the file from the provided url and uncompresses it to the given
       * folder.
       */
      public void downloadAndUnzip() {
          URL dataURL = null;
          String fileName = folder + "/" + url.substring(url.lastIndexOf("/") + 1);
          File compressedData = new File(fileName);
          if (!new File(fileName).exists()) {
              try {
                  dataURL = new URL(url);
              } catch (MalformedURLException e) {
                  e.printStackTrace();
              }
              try {
                  assert dataURL != null;
                  FileUtils.copyURLToFile(dataURL, compressedData);
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
          try {
              ZipFile zipFile = new ZipFile(compressedData);
              File dataFolder = new File(folder);
              zipFile.extractAll(dataFolder.getCanonicalPath());
          } catch (ZipException | IOException e) {
              e.printStackTrace();
          }
      }
  }
  