content: /*
   * Copyright (C) 2011 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 android.util;
  
  import android.annotation.UnsupportedAppUsage;
  
  /**
   * Interface that provides trusted time information, possibly coming from an NTP
   * server. Implementations may cache answers until {@link #forceRefresh()}.
   *
   * @hide
   */
  public interface TrustedTime {
      /**
       * Force update with an external trusted time source, returning {@code true}
       * when successful.
       */
      @UnsupportedAppUsage
      public boolean forceRefresh();
  
      /**
       * Check if this instance has cached a response from a trusted time source.
       */
      @UnsupportedAppUsage
      public boolean hasCache();
  
      /**
       * Return time since last trusted time source contact, or
       * {@link Long#MAX_VALUE} if never contacted.
       */
      @UnsupportedAppUsage
      public long getCacheAge();
  
      /**
       * Return certainty of cached trusted time in milliseconds, or
       * {@link Long#MAX_VALUE} if never contacted. Smaller values are more
       * precise.
       */
      public long getCacheCertainty();
  
      /**
       * Return current time similar to {@link System#currentTimeMillis()},
       * possibly using a cached authoritative time source.
       */
      @UnsupportedAppUsage
      public long currentTimeMillis();
  }
  