1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.util; 18 19 /** 20 * Interface that provides trusted time information, possibly coming from an NTP 21 * server. Implementations may cache answers until {@link #forceRefresh()}. 22 * 23 * @hide 24 */ 25 public interface TrustedTime { 26 /** 27 * Force update with an external trusted time source, returning {@code true} 28 * when successful. 29 */ 30 public boolean forceRefresh(); 31 32 /** 33 * Check if this instance has cached a response from a trusted time source. 34 */ 35 public boolean hasCache(); 36 37 /** 38 * Return time since last trusted time source contact, or 39 * {@link Long#MAX_VALUE} if never contacted. 40 */ 41 public long getCacheAge(); 42 43 /** 44 * Return certainty of cached trusted time in milliseconds, or 45 * {@link Long#MAX_VALUE} if never contacted. Smaller values are more 46 * precise. 47 */ 48 public long getCacheCertainty(); 49 50 /** 51 * Return current time similar to {@link System#currentTimeMillis()}, 52 * possibly using a cached authoritative time source. 53 */ 54 public long currentTimeMillis(); 55 } 56
