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.core.cluster;
  
  import com.alibaba.nacos.common.utils.ExceptionUtil;
  import com.alibaba.nacos.core.utils.Loggers;
  
  /**
   * task.
   *
   * @author <a href="mailto:liaochuntao@live.com">liaochuntao</a>
   */
  @SuppressWarnings("PMD.AbstractClassShouldStartWithAbstractNamingRule")
  public abstract class Task implements Runnable {
      
      protected volatile boolean shutdown = false;
      
      @Override
      public void run() {
          if (shutdown) {
              return;
          }
          try {
              executeBody();
          } catch (Throwable t) {
              Loggers.CORE.error("this task execute has error : {}", ExceptionUtil.getStackTrace(t));
          } finally {
              if (!shutdown) {
                  after();
              }
          }
      }
      
      /**
       * Task executive.
       */
      protected abstract void executeBody();
      
      /**
       * after executeBody should do.
       */
      protected void after() {
      
      }
      
      public void shutdown() {
          shutdown = true;
      }
      
  }
  