content: /*
   * Copyright (C) 2017 The Android Open Source Project
   *
   * 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 androidx.test.espresso.base;
  
  /**
   * An internal interface UiControllerImpl uses to communicate with sources of idleness.
   *
   * @param <CB> the callback type which receives notification of idleness.
   */
  interface IdleNotifier<CB> {
  
    /** Indicates the resources backed by this notifier are idle now. */
    boolean isIdleNow();
  
    /** De-registers any currently registered callback. */
    void cancelCallback();
  
    /**
     * Registers a callback to be invoked when the resources backed by the notifier go idle.
     *
     * @param callback an object that the notifier will use to inform us about the idle state of the
     *     resources.
     */
    void registerNotificationCallback(CB callback);
  }
  