1 /*
2  * Copyright 2017, OpenCensus Authors
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 io.opencensus.common;
18 
19 /**
20  * Interface for getting the current time.
21  *
22  * @since 0.5
23  */
24 public abstract class Clock {
25 
26   /**
27    * Obtains the current instant from this clock.
28    *
29    * @return the current instant.
30    * @since 0.5
31    */
now()32   public abstract Timestamp now();
33 
34   /**
35    * Returns a time measurement with nanosecond precision that can only be used to calculate elapsed
36    * time.
37    *
38    * @return a time measurement with nanosecond precision that can only be used to calculate elapsed
39    *     time.
40    * @since 0.5
41    */
nowNanos()42   public abstract long nowNanos();
43 }
44