content: /*
   * Copyright (C) 2010-2101 Alibaba Group Holding Limited.
   *
   * 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.otter.shared.arbitrate.impl.setl.monitor;
  
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ScheduledFuture;
  import java.util.concurrent.ScheduledThreadPoolExecutor;
  import java.util.concurrent.ThreadPoolExecutor;
  import java.util.concurrent.TimeUnit;
  
  import com.alibaba.otter.shared.common.utils.thread.NamedThreadFactory;
  
  /**
   * monitor调度程序,定时调度{@linkplain Monitor}对象
   * 
   * @author jianghang 2011-9-19 下午08:55:42
   * @version 4.0.0
   */
  public class MonitorScheduler {
  
      private static final Long                    DEFAULT_PERIOD = 60 * 1000L;
      private static final int                     DEFAULT_POOL   = 10;
      private static ScheduledThreadPoolExecutor   scheduler      = new ScheduledThreadPoolExecutor(
                                                                                                    DEFAULT_POOL,
                                                                                                    new NamedThreadFactory(
                                                                                                                           "Arbitrate-Monitor"),
                                                                                                    new ThreadPoolExecutor.CallerRunsPolicy());
  
      private static Map<Monitor, ScheduledFuture> register       = new ConcurrentHashMap<Monitor, ScheduledFuture>(10);
  
      /**
       * 注册对应的Monitor对象
       * 
       * @param monitor
       */
      public static void register(final Monitor monitor) {
          register(monitor, DEFAULT_PERIOD);
      }
  
      /**
       * 注册对应的Monitor对象
       * 
       * @param monitor
       */
      public static void register(final Monitor monitor, Long delay) {
          register(monitor, delay, DEFAULT_PERIOD);
      }
  
      /**
       * 注册对应的Monitor对象
       * 
       * @param monitor
       * @param period 调度周期，单位ms
       */
      public static void register(final Monitor monitor, Long delay, Long period) {
          ScheduledFuture future = scheduler.scheduleAtFixedRate(new Runnable() {
  
              public void run() {
                  monitor.reload();
              }
          }, delay, period, TimeUnit.MILLISECONDS);
  
          register.put(monitor, future);
      }
  
      /**
       * 取消注册对应的Monitor对象
       * 
       * @param monitor
       */
      public static void unRegister(Monitor monitor) {
          ScheduledFuture future = register.remove(monitor);
          if (future != null) {
              future.cancel(true);// 打断
          }
      }
  }
  