How to access thread objects inside custom threadpool executor's methods?

Question

I want to access the data inside the runnable objects which I have in the custom threadpool executor. If I tried to access in the before/after execute methods I am getting class cast exception. How do i resolve this scenario.

public class MyThread implements Runnable 
{
  String key;

  public void run(){ /* Do something */}  
}

public class MyExecutor extends ThreadPoolExecutor
{

  @Override
  protected void beforeExecute(Thread paramThread, Runnable paramRunnable)
  {
             MyThread mt = (mt)paramRunnable; 

  }

  @Override
  protected void afterExecute(Runnable paramRunnable, Throwable paramThrowable) 
 {
       MyThread mt = (mt)paramRunnable; 
    /* Need to access "key" inside MyThread */    
 }

Answer 1

If get ClassCastException that means you pass in Thread implementations that are not MyThread or subclass of MyThread also into your MyExecutor . So in order to fix it you just do a instanceof check before casting.

public class MyExecutor extends ThreadPoolExecutor
{

  @Override
  protected void beforeExecute(Thread paramThread, Runnable paramRunnable)
  {
         if(paramRunnable instanceof MyThread) {
             MyThread mt = (MyThread)paramRunnable; 
         }

  }

  @Override
  protected void afterExecute(Runnable paramRunnable, Throwable paramThrowable) 
 {
       if(paramRunnable instanceof MyThread) {
           MyThread mt = (MyThread)paramRunnable; 
       }
       /* Need to access "key" inside MyThread */    
 }

Answer 2

The solution is to use my thread as callable, and get the response in the futuretask response. The below implementation solved my solution.

    protected void afterExecute(Runnable paramRunnable, Throwable paramThrowable) {

    super.afterExecute(paramRunnable, paramThrowable);
    FutureTask<String> task = (FutureTask<String>) paramRunnable;
    try {
        String a = task.get();
    } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (ExecutionException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}