content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.flink.streaming.connectors.pinot;
  
  import org.apache.flink.streaming.connectors.pinot.filesystem.FileSystemAdapter;
  import org.apache.flink.streaming.connectors.pinot.filesystem.FileSystemUtils;
  
  import java.io.File;
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.nio.file.Files;
  import java.util.List;
  
  import static org.apache.flink.util.Preconditions.checkNotNull;
  
  /**
   * The LocalFileSystemAdapter is used when sharing files via the local filesystem.
   * Keep in mind that using this FileSystemAdapter requires running the Flink app on a single node.
   */
  public class LocalFileSystemAdapter implements FileSystemAdapter {
  
      private final String tempDirPrefix;
  
      public LocalFileSystemAdapter(String tempDirPrefix) {
          this.tempDirPrefix = checkNotNull(tempDirPrefix);
      }
  
      /**
       * Writes a list of serialized elements to the local filesystem.
       *
       * @param elements List of serialized elements
       * @return Path identifying the written file
       * @throws IOException
       */
      @Override
      public String writeToSharedFileSystem(List<String> elements) throws IOException {
          File tempDir = Files.createTempDirectory(tempDirPrefix).toFile();
          return FileSystemUtils.writeToLocalFile(elements, tempDir).getAbsolutePath();
      }
  
      /**
       * Reads a previously written list of serialized elements from the local filesystem.
       *
       * @param path Path returned by {@link #writeToSharedFileSystem}
       * @return List of serialized elements read from the local filesystem
       * @throws IOException
       */
      @Override
      public List<String> readFromSharedFileSystem(String path) throws IOException {
          File dataFile = new File(path);
          return Files.readAllLines(dataFile.toPath(), Charset.defaultCharset());
      }
  
      /**
       * Deletes a file from the local filesystem
       *
       * @param path Path returned by {@link #writeToSharedFileSystem}
       * @throws IOException
       */
      @Override
      public void deleteFromSharedFileSystem(String path) {
          new File(path).delete();
      }
  }
  