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;
  
  /**
   * 根据IP进行流控, 控制单个IP的数量以及IP总量
   *
   * @author leiwen.zh
   */
  @SuppressWarnings("PMD.ClassNamingShouldBeCamelRule")
  public class SimpleIPFlowData {
  
      private AtomicInteger[] data;
  
      private int slotCount;
  
      private int averageCount;
  
      @SuppressWarnings("PMD.ThreadPoolCreationRule")
      private ScheduledExecutorService timer = Executors.newSingleThreadScheduledExecutor(new ThreadFactory() {
  
          @Override
          public Thread newThread(Runnable r) {
              Thread t = new Thread(r);
              t.setName("nacos ip flow control thread");
              t.setDaemon(true);
              return t;
          }
  
      });
  
      class DefaultIPFlowDataManagerTask implements Runnable {
  
          @Override
          public void run() {
              rotateSlot();
          }
  
      }
  
      public SimpleIPFlowData(int slotCount, int interval) {
          if (slotCount <= 0) {
              this.slotCount = 1;
          } else {
              this.slotCount = slotCount;
          }
          data = new AtomicInteger[slotCount];
          for (int i = 0; i < data.length; i++) {
              data[i] = new AtomicInteger(0);
          }
          timer.scheduleAtFixedRate(new DefaultIPFlowDataManagerTask(), interval, interval, TimeUnit.MILLISECONDS);
      }
  
      public int incrementAndGet(String ip) {
          int index = 0;
          if (ip != null) {
              index = ip.hashCode() % slotCount;
          }
          if (index < 0) {
              index = -index;
          }
          return data[index].incrementAndGet();
      }
  
      public void rotateSlot() {
          int totalCount = 0;
          for (int i = 0; i < slotCount; i++) {
              totalCount += data[i].get();
              data[i].set(0);
          }
          this.averageCount = totalCount / this.slotCount;
      }
  
      public int getCurrentCount(String ip) {
          int index = 0;
          if (ip != null) {
              index = ip.hashCode() % slotCount;
          }
          if (index < 0) {
              index = -index;
          }
          return data[index].get();
      }
  
      public int getAverageCount() {
          return this.averageCount;
      }
  }
  