content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * Licensed 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 com.alibaba.nacos.config.server.utils;
  
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.ThreadFactory;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicInteger;
  
  /**
   * Simple Flow data
   *
   * @author Nacos
   */
  public class SimpleFlowData {
      private int index = 0;
      private AtomicInteger[] data;
      private int average;
      private int slotCount;
  
      @SuppressWarnings("PMD.ThreadPoolCreationRule")
      private ScheduledExecutorService timer = Executors.newSingleThreadScheduledExecutor(new ThreadFactory() {
  
          @Override
          public Thread newThread(Runnable r) {
              Thread t = new Thread(r);
              t.setName("nacos flow control thread");
              t.setDaemon(true);
              return t;
          }
  
      });
  
      public SimpleFlowData(int slotCount, int interval) {
          this.slotCount = slotCount;
          data = new AtomicInteger[slotCount];
          for (int i = 0; i < data.length; i++) {
              data[i] = new AtomicInteger(0);
          }
          timer.scheduleAtFixedRate(new Runnable() {
  
              @Override
              public void run() {
                  rotateSlot();
              }
  
          }, interval, interval, TimeUnit.MILLISECONDS);
      }
  
      public int addAndGet(int count) {
          return data[index].addAndGet(count);
      }
  
      public int incrementAndGet() {
          return data[index].incrementAndGet();
      }
  
      public void rotateSlot() {
          int total = 0;
  
          for (int i = 0; i < slotCount; i++) {
              total += data[i].get();
          }
  
          average = total / slotCount;
  
          index = (index + 1) % slotCount;
          data[index].set(0);
      }
  
      public int getCurrentCount() {
          return data[index].get();
      }
  
      public int getAverageCount() {
          return this.average;
      }
  
      public int getSlotCount() {
          return this.slotCount;
      }
  
      public String getSlotInfo() {
          StringBuilder sb = new StringBuilder();
  
          int index = this.index + 1;
  
          for (int i = 0; i < slotCount; i++) {
              if (i > 0) {
                  sb.append(" ");
              }
              sb.append(this.data[(i + index) % slotCount].get());
          }
          return sb.toString();
      }
  
      public int getCount(int prevStep) {
          prevStep = prevStep % this.slotCount;
          int index = (this.index + this.slotCount - prevStep) % this.slotCount;
          return this.data[index].intValue();
      }
  
  }
  