java - Access the submitted object from within a ThreadPoolExecutor -

public void execute(runnable command)

this command object contains submitted object, seems have been wrapped.

how can access submitted object within custom thread pool executor? or not such idea try , access submitted object inside threadpoolexecutor's before/after/execute methods?

don't use execute, use submit, returns future, handle task. here's example code:

executorservice service = executors.newcachedthreadpool();  callable<string> task = new callable<string>() {     public string call() throws exception {         return "hello world";     } };  future<string> future = service.submit(task); 

although can't access task directly, can still interact it:

future.cancel(); // won't start task if not started string result = future.get(); // blocks until thread has finished calling task.call() , returns result future.isdone(); // true if complete 

you can interact service:

service.shutdown(); //etc     

edited incorporate comments:

if want logging, use anonymous class override afterexecute() method, this:

    threadpoolexecutor executor = new threadpoolexecutor(1, 1, 1, timeunit.seconds, new arrayblockingqueue<runnable>(1)) {         @override         protected void afterexecute(runnable r, throwable t)         {             // logging here             super.afterexecute(r, t);         }     }; 

override other methods required.

quick plug: imho, bible subject java concurrency in practice - recommend buy , read it.