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.beam.sdk.util;
  
  import java.util.concurrent.atomic.AtomicLong;
  import org.junit.rules.ExternalResource;
  import org.junit.rules.TestRule;
  
  /**
   * This object quickly moves time forward based upon how much it has been asked to sleep, without
   * actually sleeping, to simulate the backoff.
   */
  public class FastNanoClockAndSleeper extends ExternalResource
      implements NanoClock, Sleeper, TestRule {
    private AtomicLong fastNanoTime = new AtomicLong();
  
    @Override
    public long nanoTime() {
      return fastNanoTime.get();
    }
  
    @Override
    protected void before() throws Throwable {
      fastNanoTime = new AtomicLong(NanoClock.SYSTEM.nanoTime());
    }
  
    @Override
    public void sleep(long millis) throws InterruptedException {
      fastNanoTime.addAndGet(millis * 1000000L);
    }
  }
  