001/*
002 * Copyright (C) 2008 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.testing;
018
019import static com.google.common.base.Preconditions.checkArgument;
020import static java.util.concurrent.TimeUnit.NANOSECONDS;
021
022import com.google.common.annotations.GwtCompatible;
023import com.google.common.annotations.GwtIncompatible;
024import com.google.common.annotations.J2ktIncompatible;
025import com.google.common.base.Ticker;
026import com.google.errorprone.annotations.CanIgnoreReturnValue;
027import java.time.Duration;
028import java.util.concurrent.TimeUnit;
029import java.util.concurrent.atomic.AtomicLong;
030import org.jspecify.annotations.NullMarked;
031
032/**
033 * A Ticker whose value can be advanced programmatically in test.
034 *
035 * <p>The ticker can be configured so that the time is incremented whenever {@link #read} is called:
036 * see {@link #setAutoIncrementStep}.
037 *
038 * <p>This class is thread-safe.
039 *
040 * @author Jige Yu
041 * @since 10.0
042 */
043@NullMarked
044@GwtCompatible
045public class FakeTicker extends Ticker {
046
047  private final AtomicLong nanos = new AtomicLong();
048  private volatile long autoIncrementStepNanos;
049
050  /** Advances the ticker value by {@code time} in {@code timeUnit}. */
051  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
052  @CanIgnoreReturnValue
053  public FakeTicker advance(long time, TimeUnit timeUnit) {
054    return advance(timeUnit.toNanos(time));
055  }
056
057  /** Advances the ticker value by {@code nanoseconds}. */
058  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
059  @CanIgnoreReturnValue
060  public FakeTicker advance(long nanoseconds) {
061    nanos.addAndGet(nanoseconds);
062    return this;
063  }
064
065  /**
066   * Advances the ticker value by {@code duration}.
067   *
068   * @since 28.0
069   */
070  @GwtIncompatible
071  @J2ktIncompatible
072  @CanIgnoreReturnValue
073  public FakeTicker advance(Duration duration) {
074    return advance(duration.toNanos());
075  }
076
077  /**
078   * Sets the increment applied to the ticker whenever it is queried.
079   *
080   * <p>The default behavior is to auto increment by zero. i.e: The ticker is left unchanged when
081   * queried.
082   */
083  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
084  @CanIgnoreReturnValue
085  public FakeTicker setAutoIncrementStep(long autoIncrementStep, TimeUnit timeUnit) {
086    checkArgument(autoIncrementStep >= 0, "May not auto-increment by a negative amount");
087    this.autoIncrementStepNanos = timeUnit.toNanos(autoIncrementStep);
088    return this;
089  }
090
091  /**
092   * Sets the increment applied to the ticker whenever it is queried.
093   *
094   * <p>The default behavior is to auto increment by zero. i.e: The ticker is left unchanged when
095   * queried.
096   *
097   * @since 28.0
098   */
099  @GwtIncompatible
100  @J2ktIncompatible
101  @CanIgnoreReturnValue
102  public FakeTicker setAutoIncrementStep(Duration autoIncrementStep) {
103    return setAutoIncrementStep(autoIncrementStep.toNanos(), NANOSECONDS);
104  }
105
106  @Override
107  public long read() {
108    return nanos.getAndAdd(autoIncrementStepNanos);
109  }
110}