code: /**
   * This file is part of Eclipse Steady.
   *
   * 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.
   *
   * SPDX-License-Identifier: Apache-2.0
   * SPDX-FileCopyrightText: Copyright (c) 2018-2020 SAP SE or an SAP affiliate company and Eclipse Steady contributors
   */
  package org.eclipse.steady.cia.util;
  
  import java.io.BufferedInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.nio.file.Path;
  
  import org.eclipse.steady.shared.json.model.Artifact;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.http.HttpStatus;
  import org.springframework.http.client.ClientHttpRequest;
  import org.springframework.http.client.ClientHttpResponse;
  import org.springframework.web.client.RequestCallback;
  import org.springframework.web.client.ResponseExtractor;
  
  /**
   * <p>ArtifactDownloader class.</p>
   */
  public class ArtifactDownloader {
  
    private static Logger log = LoggerFactory.getLogger(ArtifactDownloader.class);
  
    static class DefaultRequestCallback implements RequestCallback {
      @Override
      public void doWithRequest(ClientHttpRequest request) throws IOException {}
    }
  
    static class FileResponseExtractor implements ResponseExtractor<Path> {
  
      private Artifact artifact = null;
      private Path file = null;
  
      FileResponseExtractor(Artifact _doc, Path _file) {
        this.artifact = _doc;
        this.file = _file;
      }
  
      @Override
      public Path extractData(ClientHttpResponse response) throws IOException {
        // In case of 200, write the bytes to disk
        if (response.getStatusCode().equals(HttpStatus.OK)) {
          try (final FileOutputStream fos = new FileOutputStream(this.file.toFile())) {
            byte[] bytes = new byte[1024];
            int buffer_length = 0;
            try (final BufferedInputStream is = new BufferedInputStream(response.getBody())) {
              while ((buffer_length = is.read(bytes, 0, 1024)) > 0) {
                fos.write(bytes, 0, buffer_length);
                fos.flush();
              }
              fos.flush();
              fos.close();
            }
          }
          return this.file;
        } else {
          log.error(
              "Error "
                  + response.getRawStatusCode()
                  + " when retrieving "
                  + this.artifact.getLibId()
                  + ": "
                  + response.getStatusText());
          return null;
        }
      }
    }
  }
  