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.csp.sentinel.demo.flow.param;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ThreadLocalRandom;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicLong;
  
  import com.alibaba.csp.sentinel.Entry;
  import com.alibaba.csp.sentinel.EntryType;
  import com.alibaba.csp.sentinel.SphU;
  import com.alibaba.csp.sentinel.slots.block.BlockException;
  import com.alibaba.csp.sentinel.util.StringUtil;
  import com.alibaba.csp.sentinel.util.TimeUtil;
  
  /**
   * A traffic runner to simulate flow for different parameters.
   *
   * @author Eric Zhao
   * @since 0.2.0
   */
  class ParamFlowQpsRunner<T> {
  
      private final T[] params;
      private final String resourceName;
      private int seconds;
      private final int threadCount;
  
      private final Map<T, AtomicLong> passCountMap = new ConcurrentHashMap<>();
      private final Map<T, AtomicLong> blockCountMap = new ConcurrentHashMap<>();
  
      private volatile boolean stop = false;
  
      public ParamFlowQpsRunner(T[] params, String resourceName, int threadCount, int seconds) {
          assertTrue(params != null && params.length > 0, "Parameter array should not be empty");
          assertTrue(StringUtil.isNotBlank(resourceName), "Resource name cannot be empty");
          assertTrue(seconds > 0, "Time period should be positive");
          assertTrue(threadCount > 0 && threadCount <= 1000, "Invalid thread count");
          this.params = params;
          this.resourceName = resourceName;
          this.seconds = seconds;
          this.threadCount = threadCount;
  
          for (T param : params) {
              assertTrue(param != null, "Parameters should not be null");
              passCountMap.putIfAbsent(param, new AtomicLong());
              blockCountMap.putIfAbsent(param, new AtomicLong());
          }
      }
  
      private void assertTrue(boolean b, String message) {
          if (!b) {
              throw new IllegalArgumentException(message);
          }
      }
  
      /**
       * Pick one of provided parameters randomly.
       *
       * @return picked parameter
       */
      private T generateParam() {
          int i = ThreadLocalRandom.current().nextInt(0, params.length);
          return params[i];
      }
  
      void simulateTraffic() {
          for (int i = 0; i < threadCount; i++) {
              Thread t = new Thread(new RunTask());
              t.setName("sentinel-simulate-traffic-task-" + i);
              t.start();
          }
      }
  
      void tick() {
          Thread timer = new Thread(new TimerTask());
          timer.setName("sentinel-timer-task");
          timer.start();
      }
  
      private void passFor(T param) {
          passCountMap.get(param).incrementAndGet();
          // System.out.println(String.format("Parameter <%s> passed at: %d", param, TimeUtil.currentTimeMillis()));
      }
  
      private void blockFor(T param) {
          blockCountMap.get(param).incrementAndGet();
      }
  
      final class RunTask implements Runnable {
  
          @Override
          public void run() {
  
              while (!stop) {
                  Entry entry = null;
                  T param = generateParam();
                  try {
                      entry = SphU.entry(resourceName, EntryType.IN, 1, param);
                      // Add pass for parameter.
                      passFor(param);
                  } catch (BlockException e) {
                      // block.incrementAndGet();
                      blockFor(param);
                  } catch (Exception ex) {
                      // biz exception
                      ex.printStackTrace();
                  } finally {
                      // total.incrementAndGet();
                      if (entry != null) {
                          entry.exit(1, param);
                      }
                  }
  
                  sleep(ThreadLocalRandom.current().nextInt(0, 10));
              }
          }
      }
  
      private void sleep(int timeMs) {
          try {
              TimeUnit.MILLISECONDS.sleep(timeMs);
          } catch (InterruptedException e) {
              // ignore
          }
      }
  
      final class TimerTask implements Runnable {
          @Override
          public void run() {
              long start = System.currentTimeMillis();
              System.out.println("Begin to run! Go go go!");
              System.out.println("See corresponding metrics.log for accurate statistic data");
  
              Map<T, Long> map = new HashMap<>(params.length);
              for (T param : params) {
                  map.putIfAbsent(param, 0L);
              }
              while (!stop) {
                  sleep(1000);
  
                  // There may be a mismatch for time window of internal sliding window.
                  // See corresponding `metrics.log` for accurate statistic log.
                  for (T param : params) {
  
                      System.out.println(String.format(
                          "[%d][%d] Parameter flow metrics for resource %s: "
                              + "pass count for param <%s> is %d, block count: %d",
                          seconds, TimeUtil.currentTimeMillis(), resourceName, param,
                          passCountMap.get(param).getAndSet(0), blockCountMap.get(param).getAndSet(0)));
                  }
                  System.out.println("=============================");
                  if (seconds-- <= 0) {
                      stop = true;
                  }
              }
  
              long cost = System.currentTimeMillis() - start;
              System.out.println("Time cost: " + cost + " ms");
              System.exit(0);
          }
      }
  }
  