| // 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; |
| |
| import java.time.Duration; |
| import java.time.Instant; |
| |
| /** |
| * A time source used to obtain: |
| * <li>a monotonic timestamp with no relation to a wall time; |
| * <li>a timestamp that can be used to obtain wall time but is not guaranteed to be monotonic. |
| */ |
| public abstract class TestClock { |
| /** Constructor for use by subclasses. */ |
| protected TestClock() {} |
| |
| /** |
| * Returns an immutable value type that contains both a monotonic timestamp (used to measure |
| * relative time but unrelated to wall time) and an EPOCH relative timestamp. |
| */ |
| public TestInstant now() { |
| return new TestInstant(wallTime(), monotonicTime()); |
| } |
| |
| /** |
| * Returns a monotonic timestamp that can only be used to compute relative time. |
| * |
| * <p><b>Warning:</b> the returned timestamp can only be used to measure elapsed time, not wall |
| * time. |
| */ |
| abstract Duration monotonicTime(); |
| |
| /** |
| * A timestamp that may be used to obtain wall time, but is not guaranteed to be monotonic. |
| * |
| * <p><b>Warning:</b> the returned timestamp is not guaranteed to be monotonic, and it may appear |
| * to go back in time in certain cases (e.g. daylight saving time). |
| */ |
| abstract Instant wallTime(); |
| |
| /** |
| * A time source that produces an epoch timestamp using {@link System#currentTimeMillis} and a |
| * monotonic timestamp using {@link System#nanoTime}. |
| */ |
| public static TestClock systemClock() { |
| return SYSTEM_TEST_CLOCK; |
| } |
| |
| private static final TestClock SYSTEM_TEST_CLOCK = |
| new TestClock() { |
| @Override |
| public Duration monotonicTime() { |
| return Duration.ofNanos(System.nanoTime()); |
| } |
| |
| @Override |
| public Instant wallTime() { |
| return Instant.ofEpochMilli(System.currentTimeMillis()); |
| } |
| }; |
| |
| /** |
| * An immutable value type that contains both a monotonic timestamp (used to measure relative time |
| * but unrelated to wall time) and an EPOCH timestamp. |
| */ |
| public static class TestInstant { |
| public static final TestInstant UNKNOWN = new TestInstant(Instant.EPOCH, Duration.ZERO); |
| |
| private final Instant wallTime; |
| private final Duration monotonicTime; |
| |
| public TestInstant(Instant wallTime, Duration monotonicTime) { |
| this.wallTime = wallTime; |
| this.monotonicTime = monotonicTime; |
| } |
| |
| /** |
| * A timestamp that may be used to obtain wall time, but is not guaranteed to be monotonic. |
| * |
| * <p><b>Warning:</b> the returned timestamp is not guaranteed to be monotonic, and it may |
| * appear to go back in time in certain cases (e.g. daylight saving time). |
| */ |
| public Instant wallTime() { |
| return wallTime; |
| } |
| |
| /** |
| * Returns a monotonic timestamp that can only be used to compute relative time. |
| * |
| * <p><b>Warning:</b> the returned timestamp can only be used to measure elapsed time, not wall |
| * time. |
| */ |
| public Duration monotonicTime() { |
| return monotonicTime; |
| } |
| } |
| } |