| // Copyright 2016 The Bazel Authors. All Rights Reserved. |
| // |
| // 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.google.testing.junit.runner.util; |
| |
| /** |
| * A time source; returns a time value representing the number of nanoseconds elapsed since some |
| * fixed but arbitrary point in time. |
| * |
| * <p><b>Warning:</b> this interface can only be used to measure elapsed time, not wall time. |
| */ |
| public abstract class Ticker { |
| /** |
| * Constructor for use by subclasses. |
| */ |
| protected Ticker() {} |
| |
| /** |
| * Returns the number of nanoseconds elapsed since this ticker's fixed point of reference. |
| */ |
| public abstract long read(); |
| |
| /** |
| * A ticker that reads the current time using {@link System#nanoTime}. |
| * |
| * @since 10.0 |
| */ |
| public static Ticker systemTicker() { |
| return SYSTEM_TICKER; |
| } |
| |
| private static final Ticker SYSTEM_TICKER = |
| new Ticker() { |
| @Override |
| public long read() { |
| return System.nanoTime(); |
| } |
| }; |
| } |