is it right to call ejb bean from thread by ThreadPoolExecutor?

Posted by kislo_metal on Stack Overflow See other posts from Stack Overflow or by kislo_metal
Published on 2010-04-08T08:36:22Z Indexed on 2010/04/08 13:33 UTC
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I trying to call some ejb bean method from tread. and getting error :

(as is glassfish v3)

Log Level

SEVERE Logger
javax.enterprise.system.std.com.sun.enterprise.v3.services.impl Name-Value Pairs
{_ThreadName=Thread-1, _ThreadID=42} Record Number 928 Message ID
java.lang.NullPointerException at ua.co.rufous.server.broker.TempLicService.run(TempLicService.java Complete Message 35) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:637)

here is tread

public class TempLicService implements Runnable {

    String hash;
//it`s Stateful bean
    @EJB
    private LicActivatorLocal lActivator;


    public TempLicService(String hash) {
        this.hash= hash;
    }


    @Override
    public void run() {


       lActivator.proccessActivation(hash);
    }

}

my ThreadPoolExecutor

public class RequestThreadPoolExecutor extends ThreadPoolExecutor {

    private boolean isPaused;
    private ReentrantLock pauseLock = new ReentrantLock();
    private Condition unpaused = pauseLock.newCondition();


    private static RequestThreadPoolExecutor threadPool;

    private RequestThreadPoolExecutor() {
        super(1, Integer.MAX_VALUE, 10, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
        System.out.println("RequestThreadPoolExecutor created");
    }

    public static RequestThreadPoolExecutor getInstance() {
        if (threadPool == null)
            threadPool = new RequestThreadPoolExecutor();
        return threadPool;
    }
    public void runService(Runnable task) {

        threadPool.execute(task);


    }


    protected void beforeExecute(Thread t, Runnable r) {
        super.beforeExecute(t, r);
        pauseLock.lock();
        try {
            while (isPaused) unpaused.await();
        } catch (InterruptedException ie) {
            t.interrupt();
        } finally {
            pauseLock.unlock();
        }
    }

    public void pause() {
        pauseLock.lock();
        try {
            isPaused = true;
        } finally {
            pauseLock.unlock();
        }
    }

    public void resume() {
        pauseLock.lock();
        try {
            isPaused = false;
            unpaused.signalAll();
        } finally {
            pauseLock.unlock();
        }
    }


    public void shutDown() {
        threadPool.shutdown();
    }
//<<<<<< creating thread here
    public void runByHash(String hash) {
        Runnable service = new TempLicService(hash);
        threadPool.runService(service);
    }
}

and method where i call it (it is gwt servlet, but there is no proble to call thread that not contain ejb) :

 @Override
    public Boolean submitHash(String hash) {
        System.out.println("submiting hash");
        try {

            if (tBoxService.getTempLicStatus(hash) == 1) {
//<<< here is the call
                    RequestThreadPoolExecutor.getInstance().runByHash(hash);
                    return true;
                }
            } catch (NoResultException e) {
                e.printStackTrace();
            }
            return false;
        }

I need to organize some pool of submitting hash to server (calls of LicActivator bean), is ThreadPoolExecutor design good idea and why it is not working in my case? (as I know we can`t create thread inside bean, but could we call bean from different threads? ). If No, what is the bast practice for organize such request pool?

Thanks.


  1. << Answer: I am using DI (EJB 3.1) soo i do not need any look up here. (application packed in ear and both modules in it (web module and ejb), it works perfect for me). But I can use it only in managed classes.

So..

2.Can I use manual look up in Tread ?

  1. Could I use Bean that extends ThreadPoolExecutor and calling another bean that implements Runnable ? Or it is not allowed ?

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