content: /*
   * Copyright (C) 2016 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 com.android.server.twilight;
  
  import android.annotation.NonNull;
  import android.os.Handler;
  
  /**
   * This class provides sunrise/sunset information based on the device's current location.
   */
  public interface TwilightManager {
      /**
       * Register a listener to be notified whenever the twilight state changes.
       *
       * @param listener the {@link TwilightListener} to be notified
       * @param handler the {@link Handler} to use to notify the listener
       */
      void registerListener(@NonNull TwilightListener listener, @NonNull Handler handler);
  
      /**
       * Unregisters a previously registered listener.
       *
       * @param listener the {@link TwilightListener} to be unregistered
       */
      void unregisterListener(@NonNull TwilightListener listener);
  
      /**
       * Returns the last {@link TwilightState}, or {@code null} if not available.
       */
      TwilightState getLastTwilightState();
  }
  