ゞ沉默是金ゞ

          魚離不開水,但是沒有說不離開哪滴水.
          posts - 98,comments - 104,trackbacks - 0
          Future<?> submit( Runnable r )
          Today in part 4 of the series we will talk about submission of runnable task via executor service. This method can be very beneficial if someone wants to upgrade legacy code from 1.4 to 1.5 onwards.
          As per JAVA version 6.0, ExecutorService Interface has following method -
          Future< ? >  submit( Runnable r ) 
            > Submits a Runnable task for execution and returns a Future representing that task.
            > This method will return NULL on successful completeion of the process, otherwise result will not be null.


          Lets start with Runnable task - As we  know that Runnable interface has following method - public void run()
          So when we say - ExecutorService.submit(Runnable Task) --> It starts a new stack starting with run method of runnable task, but as run method can not return any value so does future object. Due to this reason the signature of submit(Runnable r) is Future< ? >.
          ? --> means anything that extends Object, has no lower limit

          package com.jovialjava.blog.threads;

          import java.util.concurrent.ExecutionException;
          import java.util.concurrent.ExecutorService;
          import java.util.concurrent.Executors;
          import java.util.concurrent.Future;

          public class RunnableExample {
              
              
          private static final ExecutorService executorPool=Executors.newFixedThreadPool(2);
              
              
          public static void main(String[] args) {
                  RunnableTask_1 task_1 
          = new RunnableTask_1();
                  RunnableTask_2 task_2 
          = new RunnableTask_2();
                  
                  
          /**
                   * Submit the first task
                   
          */
                  Future
          <?> fut_1 = executorPool.submit(task_1);
                  Future
          <?> fut_2 = executorPool.submit(task_2);
                  
                  
          try{
                      
          if(fut_1.get() == null){
                          System.out.println(
          "TASK 1 completed SUCCESSFULLY");
                      }
                      
          if(fut_2.get() == null){
                          System.out.println(
          "TASK 2 completed SUCCESSFULLY");
                      }
                  }
          catch(ExecutionException e){            
                      System.out.println(e.getMessage());
                  }
          catch(InterruptedException e){
                      System.out.println(e.getMessage());
                  }
          finally{
                      
          /**====VERY IMPORTANT===
                       * This is required to stop the executor pool to
                       * stop accepting new request.
                       
          */
                      executorPool.shutdown();
                  }

              }

              
              
          /**
               * This task will complete successfully
               
          */
              
          public static class RunnableTask_1 implements Runnable{
                  
          public void run()throws NullPointerException{
                      System.out.println(
          "Hi, Inside Runnable Task 1");            
                  }        

              }
              
              
          /**
               * This task will result in error.
               
          */
              
          public static class RunnableTask_2 implements Runnable{
                  
          public void run()throws NullPointerException{
                      System.out.println(
          "Hi, Inside Runnable Task 2");
                      
          throw new IllegalStateException("Runnable Task Exception");
                  }        

              }
          }
          posted on 2012-08-06 10:33 ゞ沉默是金ゞ 閱讀(780) 評論(0)  編輯  收藏 所屬分類: Java SE
          主站蜘蛛池模板: 阳高县| 龙山县| 壶关县| 两当县| 朔州市| 鄂伦春自治旗| 苏尼特左旗| 乐清市| 博湖县| 揭西县| 平泉县| 驻马店市| 盐池县| 高邮市| 十堰市| 肇庆市| 全椒县| 沙河市| 本溪| 沈阳市| 东丰县| 衢州市| 乐东| 康平县| 阿图什市| 恭城| 西和县| 义马市| 阿城市| 迁安市| 北流市| 镶黄旗| 建水县| 济南市| 新竹县| 新乡县| 中超| 从江县| 台南县| 凤阳县| 新田县|