| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.util; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * Utility methods for getting the time and computing intervals. |
| * |
| * It has the same behavior as {{@link Time}}, with the exception that its |
| * functions can be overridden for dependency injection purposes. |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public class Timer { |
| /** |
| * Current system time. Do not use this to calculate a duration or interval |
| * to sleep, because it will be broken by settimeofday. Instead, use |
| * monotonicNow. |
| * @return current time in msec. |
| */ |
| public long now() { |
| return Time.now(); |
| } |
| |
| /** |
| * Current time from some arbitrary time base in the past, counting in |
| * milliseconds, and not affected by settimeofday or similar system clock |
| * changes. This is appropriate to use when computing how much longer to |
| * wait for an interval to expire. |
| * @return a monotonic clock that counts in milliseconds. |
| */ |
| public long monotonicNow() { return Time.monotonicNow(); } |
| } |