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.trogdor.workload;
  
  import org.apache.kafka.common.utils.Time;
  
  public class Throttle {
      private final int maxPerPeriod;
      private final int periodMs;
      private int count;
      private long prevPeriod;
      private long lastTimeMs;
  
      Throttle(int maxPerPeriod, int periodMs) {
          this.maxPerPeriod = maxPerPeriod;
          this.periodMs = periodMs;
          this.count = maxPerPeriod;
          this.prevPeriod = -1;
          this.lastTimeMs = 0;
      }
  
      public synchronized boolean increment() throws InterruptedException {
          boolean throttled = false;
          while (true) {
              if (count < maxPerPeriod) {
                  count++;
                  return throttled;
              }
              lastTimeMs = time().milliseconds();
              long curPeriod = lastTimeMs / periodMs;
              if (curPeriod <= prevPeriod) {
                  long nextPeriodMs = (curPeriod + 1) * periodMs;
                  delay(nextPeriodMs - lastTimeMs);
                  throttled = true;
              } else {
                  prevPeriod = curPeriod;
                  count = 0;
              }
          }
      }
  
      public synchronized long lastTimeMs() {
          return lastTimeMs;
      }
  
      protected Time time() {
          return Time.SYSTEM;
      }
  
      protected synchronized void delay(long amount) throws InterruptedException {
          if (amount > 0) {
              wait(amount);
          }
      }
  }
  