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 com.alibaba.jstorm.daemon.worker;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Timer;
  import java.util.TimerTask;
  import java.util.concurrent.ArrayBlockingQueue;
  import java.util.concurrent.Future;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  /**
   * @author JohnFang (xiaojian.fxj@alibaba-inc.com).
   */
  public class FlusherPool {
      private final Timer timer = new Timer("flush-trigger", true);
      private final ThreadPoolExecutor threadPool;
      private final HashMap<Long, ArrayList<Flusher>> pendingFlushMap = new HashMap<>();
      private final HashMap<Long, TimerTask> timerTaskMap = new HashMap<>();
  
      public FlusherPool(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit) {
          this.threadPool = new ThreadPoolExecutor(corePoolSize, maximumPoolSize, keepAliveTime, unit,
                  new ArrayBlockingQueue<Runnable>(1024), new ThreadPoolExecutor.DiscardPolicy());
      }
  
      public synchronized void start(Flusher flusher, final long flushInterval) {
          ArrayList<Flusher> pending = pendingFlushMap.get(flushInterval);
          if (pending == null) {
              pending = new ArrayList<>();
              TimerTask t = new TimerTask() {
                  @Override
                  public void run() {
                      invokeAll(flushInterval);
                  }
              };
              pendingFlushMap.put(flushInterval, pending);
              timer.schedule(t, flushInterval, flushInterval);
              timerTaskMap.put(flushInterval, t);
          }
          pending.add(flusher);
      }
  
      private synchronized void invokeAll(long flushInterval) {
          ArrayList<Flusher> tasks = pendingFlushMap.get(flushInterval);
          if (tasks != null) {
              for (Flusher f : tasks) {
                  threadPool.submit(f);
              }
          }
      }
  
      public synchronized void stop(Flusher flusher, long flushInterval) {
          ArrayList<Flusher> pending = pendingFlushMap.get(flushInterval);
          pending.remove(flusher);
          if (pending.size() == 0) {
              pendingFlushMap.remove(flushInterval);
              timerTaskMap.remove(flushInterval).cancel();
          }
      }
  
      public Future<?> submit(Runnable runnable) {
          return threadPool.submit(runnable);
      }
  
      public void shutdown() {
          this.threadPool.shutdown();
          this.timer.cancel();
      }
  
      public void awaitTermination(long timeout, TimeUnit unit) throws InterruptedException {
          this.threadPool.awaitTermination(timeout, unit);
      }
  
  }