Hadoop源码分析10: IPC流程(5) Atomic

1.Class类的running 

用于主线程的Client    和若干 ClientConnection 线程之间 共享Client的running变量

public class Client {

  public AtomicBoolean running = newAtomicBoolean(true); // if client runs

  public void stop() {

  ...............

    if(! running. compareAndSet(true, false)) {

      return;

    }

  .................

  }

  private ClientConnection getConnection(ClientConnectionId remoteId,

                                    ClientCallcall)

                                    throwsIOException, InterruptedException {

    if(! running. get()) {

      //the client is stopped

      thrownew IOException("The client is stopped");

    }

}

public class ClientConnection extends Thread {

    private synchronizedboolean waitForWork() {

      if(calls.isEmpty() && !shouldCloseConnection.get()  && client.running.get())  {

        long timeout = maxIdleTime-

              (System.currentTimeMillis()-lastActivity.get());

        if (timeout>0) {

          try {

            wait(timeout);

          } catch (InterruptedExceptione) {}

        }

      }

    if (!calls.isEmpty()&& !shouldCloseConnection.get() && client.running. get()) {

        return true;

      } 

      。。。。。。。。。。。。。。

}

public class ClientConnectionPingInputStream extendsFilterInputStream {

    private void handleTimeout(SocketTimeoutException e) throws IOException{

      if(clientConnection.shouldCloseConnection.get() ||! clientConnection.client.running.get()   ||clientConnection.rpcTimeout > 0) {

        throw e;

      }else {

        sendPing();

      }

    }

。。。。。。

}

2.  ClientConnection的 lastActivity

用于若干ClientConnection线程之间共享lastActivity

public class ClientConnection extends Thread {

    private AtomicLonglastActivity = new AtomicLong();// last I/O activity time

     

   

    private void touch() {

      lastActivity. set(System.currentTimeMillis());

    }

 

    private synchronizedboolean waitForWork() {

      if(calls.isEmpty() && !shouldCloseConnection.get()  && client.running.get())  {

        long timeout = maxIdleTime-

              (System.currentTimeMillis()- lastActivity.get());

        if (timeout>0) {

          try {

            wait(timeout);

          } catch (InterruptedExceptione) {}

        }

      }

    }

}

3.   ClientConnection  的 shouldCloseConnection  

用于若干ClientConnection 线程之间共享shouldCloseConnection  

public class ClientConnection extends Thread {

    AtomicBoolean shouldCloseConnection = new AtomicBoolean(); 

    // indicate if theconnection is closed

    public synchronizedboolean addCall(ClientCall call) {

      if( shouldCloseConnection.get())

        return false;

      calls.put(call.id, call);

      notify();

      return true;

    }

    public synchronized void setupIOstreams() throws InterruptedException {

      if(socket != null || shouldCloseConnection.get()) {

        return;

      }

      .........

    }

    private synchronizedboolean waitForWork() {

      if(calls.isEmpty() && ! shouldCloseConnection.get()  && client.running.get())  {

        long timeout = maxIdleTime-

              (System.currentTimeMillis()-lastActivity.get());

        if (timeout>0) {

          try {

            wait(timeout);

          } catch (InterruptedExceptione) {}

        }

      }

       

      if(!calls.isEmpty() && ! shouldCloseConnection.get()&& client.running.get()) {

        return true;

      }else if ( shouldCloseConnection.get()) {

        return false;

      }else if (calls.isEmpty()) { // idle connection closed orstopped

        markClosed(null);

        return false;

      }else { // get stopped but there are still pendingrequests 

        markClosed((IOException)newIOException().initCause(

            newInterruptedException()));

        return false;

      }

    }

    public void sendParam(ClientCall call) {

      if( shouldCloseConnection.get()) {

        return;

      }

    }

    private void receiveResponse() {

      if( shouldCloseConnection.get()) {

        return;

      }

      touch();

    }

   

    private synchronizedvoid markClosed(IOException e) {

      if( shouldCloseConnection.compareAndSet(false, true)) {

        closeException = e;

        notifyAll();

      }

    }

     

   

    private synchronizedvoid close() {

      if(! shouldCloseConnection.get()) {

          return;

      }

    }

}

publicclass  ClientConnectionPingInputStream extendsFilterInputStream {

    privatevoid  handleTimeout(SocketTimeoutExceptione) throws IOException {

      if( clientConnection.shouldCloseConnection.get() ||!clientConnection.client.running.get()    ||clientConnection.rpcTimeout > 0) {

        throw e;

      }else {

        sendPing();

      }

    }

。。。。。。

}