2013-01-10 36 views
2

现在基本上我创建了三个类。如何将这些新消息传递给另一个类

public void run() { 
int seqId = 0; 
while(true) { 
    List<KamMessage> list = null; 
    try { 
     list = fullPoll(seqId); 
    } catch (Exception e1) { 
     e1.printStackTrace(); 
    } 
    if (!list.isEmpty()) { 
     seqId = list.get(0).getSequence(); 
     incomingMessages.addAll(list); 
     System.out.println("waiting 3 seconds"); 
     System.out.println("new incoming message"); 
    } 
    try { 
     Thread.sleep(3000); 
     System.out.println("new incoming message"); 
    } catch (InterruptedException e) { 
     e.printStackTrace(); 
    } 
    } 
} 
public List<KamMessage> fullPoll(int lastSeq) throws Exception { 
Statement st = dbConnection.createStatement(); 
ResultSet rs = st.executeQuery("select * from msg_new_to_bde where ACTION = 804 and SEQ >" + 
lastSeq + "order by SEQ DESC");   
List<KamMessage> pojoCol = new ArrayList<KamMessage>(); 
    while (rs.next()) { 
    KamMessage filedClass = convertRecordsetToPojo(rs); 
    pojoCol.add(filedClass); 
    } 
for (KamMessage pojoClass : pojoCol) { 
    System.out.print(" " + pojoClass.getSequence()); 
    System.out.print(" " + pojoClass.getTableName()); 
    System.out.print(" " + pojoClass.getAction()); 
    System.out.print(" " + pojoClass.getKeyInfo1()); 
    System.out.print(" " + pojoClass.getKeyInfo2()); 
    System.out.println(" " + pojoClass.getEntryTime()); 
    }    
return pojoCol; 
    } 

下面是类: 1.Poller-确实轮询和从分贝通行证新的数据到控制器

2.Controller-这个类有一个线程池,其同时调用轮询并且具有要从处理器请求的新数据

3.处理器 - 该类必须查找新数据,处理它并将其返回给控制器。

所以现在我的问题是如何实现第三阶段...

这里是我的控制器类:

public class RunnableController { 

/** Here This Queue initializes the DB and have the collection of incoming message 
*      
*/ 
    private static Collection<KpiMessage> incomingQueue = new ArrayList<KpiMessage>(); 
    private Connection dbConncetion; 
    public ExecutorService threadExecutor; 
    private void initializeDb() 
    { 
    //catching exception must be adapted - generic type Exception prohibited 
    DBhandler conn = new DBhandler(); 
    try { 
     dbConncetion = conn.initializeDB(); 
    } catch (Exception e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
    } 


private void initialiseThreads() 
{   
    try { 

     threadExecutor = Executors.newFixedThreadPool(10); 
      PollingSynchronizer read = new PollingSynchronizer(incomingQueue, dbConncetion); 
     threadExecutor.submit(read); 

    }catch (Exception e){ 
    e.printStackTrace(); 
    } 

} 

@SuppressWarnings("unused") 
private void shutDownThreads() 
{   
    try { 
     threadExecutor.shutdown(); 
     //DB handling should be moved to separate DB class 
     dbConncetion.close(); 

    }catch (Exception e){ 
    e.printStackTrace(); 
    } 

} 

/** Here This Queue passes the messages and have the collection of outgoing message 
* 
*/ 

//private Collection<KpiMessage> outgingQueue = new ArrayList<KpiMessage>(); 
//have to implement something here for future 

    public static void main(String[] args) throws InterruptedException { 
    RunnableController controller = new RunnableController(); 

    System.out.println(incomingQueue.size()); 

    controller.initializeDb(); 
    controller.initialiseThreads(); 

    Thread.sleep(3000); 
    System.out.println("Polling"); 

    } 

} 

回答

4

我会建议使用的BlockingQueue这样做,而不是一个简单的ArrayList 。只需更改您的incomingQueue变量的类型。然后你就可以有另一个线程(或线程池)做这样的事情

//pseudocode 
while (true) { 
    // it polls data from the incomingQueue that shares with the producers 
    KpiMessage message = this.incomingQueue.take() 

    //Then process the message and produces an output... you can put that output in a different queue as well for other part of the code to pick it up 
} 

上BlockingQueues一个很好的例子可以在这里找到http://www.javamex.com/tutorials/blockingqueue_example.shtml

+1

顺便说一句,你是一个典型的生产者 - 消费者问题。只需谷歌了解如何在java 5中解决它(以前的sdks上没有队列,并且使用监视器是相当烦人的),你会得到大量的例子。 – Claudio

+0

谢谢你的意思是说,我应该使用队列而不是我的Poller类中的列表... !! – Babu

+1

是的,原因很多: 1 - 常用数组列表不是线程安全的,因此除非您同步它,否则您将遇到竞争条件问题 2-消费者可以阻止和被动地等待新消息由制片人放在队列中 – Claudio