/*
 * Copyright (c) 2015-present, Parse, LLC.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */
package com.parse;

import java.io.File;

/**
 * A {@code GetFileCallback} is used to run code after a {@link ParseFile} fetches its data on
 * a background thread.
 * <p/>
 * The easiest way to use a {@code GetFileCallback} is through an anonymous inner class.
 * Override the {@code done} function to specify what the callback should do after the fetch is 
 * complete. The {@code done} function will be run in the UI thread, while the fetch happens in a
 * background thread. This ensures that the UI does not freeze while the fetch happens.
 * <p/>
 * <pre>
 * file.getFileInBackground(new GetFileCallback() {
 *   public void done(File file, ParseException e) {
 *     // ...
 *   }
 * });
 * </pre>
 */
public interface GetFileCallback extends ParseCallback2<File, ParseException> {
  /**
   * Override this function with the code you want to run after the fetch is complete.
   *
   * @param file
   *          The data that was retrieved, or {@code null} if it did not succeed.
   * @param e
   *          The exception raised by the fetch, or {@code null} if it succeeded.
   */
  @Override
  void done(File file, ParseException e);
}