content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.clock;
  
  import java.time.Clock;
  import java.time.Duration;
  import java.time.Instant;
  import java.time.ZoneId;
  import java.time.ZoneOffset;
  
  /**
   * A manually set clock useful for testing.
   */
  public final class ManualClock extends Clock {
    private long mTimeMs;
  
    /**
     * Constructs a {@link ManualClock} set to the current system time.
     */
    public ManualClock() {
      this(System.currentTimeMillis());
    }
  
    /**
     * Constructs a {@link ManualClock} set to the specified time.
     *
     * @param time the time to set the clock to
     */
    public ManualClock(long time) {
      mTimeMs = time;
    }
  
    /**
     * Sets the clock to the specified time.
     *
     * @param timeMs the time to set the clock to
     */
    public synchronized void setTimeMs(long timeMs) {
      mTimeMs = timeMs;
    }
  
    /**
     * Moves the clock forward the specified amount of time.
     *
     * @param timeMs the time to add in milliseconds
     */
    public synchronized void addTimeMs(long timeMs) {
      mTimeMs += timeMs;
    }
  
    /**
     * Moves the clock forward the specified duration.
     *
     * @param time the duration to add
     */
    public synchronized void addTime(Duration time) {
      mTimeMs += time.toMillis();
    }
  
    @Override
    public synchronized long millis() {
      return mTimeMs;
    }
  
    @Override
    public ZoneId getZone() {
      return ZoneOffset.UTC;
    }
  
    @Override
    public Clock withZone(ZoneId zone) {
      throw new UnsupportedOperationException("ManualClock only uses UTC");
    }
  
    @Override
    public Instant instant() {
      return Instant.ofEpochMilli(mTimeMs);
    }
  }
  