content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.kafka.common.utils;
  
  import org.apache.kafka.common.errors.TimeoutException;
  
  import java.util.concurrent.CopyOnWriteArrayList;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicLong;
  import java.util.function.Supplier;
  
  /**
   * A clock that you can manually advance by calling sleep
   */
  public class MockTime implements Time {
  
      public interface Listener {
          void onTimeUpdated();
      }
  
      /**
       * Listeners which are waiting for time changes.
       */
      private final CopyOnWriteArrayList<Listener> listeners = new CopyOnWriteArrayList<>();
  
      private final long autoTickMs;
  
      // Values from `nanoTime` and `currentTimeMillis` are not comparable, so we store them separately to allow tests
      // using this class to detect bugs where this is incorrectly assumed to be true
      private final AtomicLong timeMs;
      private final AtomicLong highResTimeNs;
  
      public MockTime() {
          this(0);
      }
  
      public MockTime(long autoTickMs) {
          this(autoTickMs, System.currentTimeMillis(), System.nanoTime());
      }
  
      public MockTime(long autoTickMs, long currentTimeMs, long currentHighResTimeNs) {
          this.timeMs = new AtomicLong(currentTimeMs);
          this.highResTimeNs = new AtomicLong(currentHighResTimeNs);
          this.autoTickMs = autoTickMs;
      }
  
      public void addListener(Listener listener) {
          listeners.add(listener);
      }
  
      @Override
      public long milliseconds() {
          maybeSleep(autoTickMs);
          return timeMs.get();
      }
  
      @Override
      public long nanoseconds() {
          maybeSleep(autoTickMs);
          return highResTimeNs.get();
      }
  
      private void maybeSleep(long ms) {
          if (ms != 0)
              sleep(ms);
      }
  
      @Override
      public void sleep(long ms) {
          timeMs.addAndGet(ms);
          highResTimeNs.addAndGet(TimeUnit.MILLISECONDS.toNanos(ms));
          tick();
      }
  
      @Override
      public void waitObject(Object obj, Supplier<Boolean> condition, long deadlineMs) throws InterruptedException {
          Listener listener = () -> {
              synchronized (obj) {
                  obj.notify();
              }
          };
          listeners.add(listener);
          try {
              synchronized (obj) {
                  while (milliseconds() < deadlineMs && !condition.get()) {
                      obj.wait();
                  }
                  if (!condition.get())
                      throw new TimeoutException("Condition not satisfied before deadline");
              }
          } finally {
              listeners.remove(listener);
          }
      }
  
      public void setCurrentTimeMs(long newMs) {
          long oldMs = timeMs.getAndSet(newMs);
  
          // does not allow to set to an older timestamp
          if (oldMs > newMs)
              throw new IllegalArgumentException("Setting the time to " + newMs + " while current time " + oldMs + " is newer; this is not allowed");
  
          highResTimeNs.set(TimeUnit.MILLISECONDS.toNanos(newMs));
          tick();
      }
  
      private void tick() {
          for (Listener listener : listeners) {
              listener.onTimeUpdated();
          }
      }
  }
  