code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC 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.openqa.selenium.remote;
  
  import java.io.File;
  import java.util.logging.Logger;
  
  /** Detects files on the local disk. */
  public class LocalFileDetector implements FileDetector {
  
    private static final Logger LOG = Logger.getLogger(LocalFileDetector.class.getName());
  
    @Override
    public File getLocalFile(CharSequence... keys) {
      StringBuilder builder = new StringBuilder();
      for (CharSequence chars : keys) {
        builder.append(chars);
      }
  
      String filepath = builder.toString();
  
      // If empty string, no file is meant to be sent
      if (filepath.isEmpty()) {
        return null;
      }
  
      File file = new File(filepath);
  
      // It turns out that files in the CWD may not have a parent file.
      File parentDir = file.getParentFile();
      if (parentDir == null) {
        parentDir = new File(".");
      }
      File toUpload = new File(parentDir, file.getName());
  
      LOG.fine("Detected local file: " + toUpload.exists());
  
      return toUpload.exists() && toUpload.isFile() ? toUpload : null;
    }
  }
  