Question

I have developed an application which is intended to allow users to execute queries.Once the user enters the query and clicks on execute button the control is passed to RMI server which in turn starts the thread.

User should be able to execute other quesries one after the other and each query will b executed in different thread.

I am not able to stop the execution of the thread. I want to stop the execution while it is executing or on the button click event based on the thread id passed.
I am trying below code

public class AcQueryExecutor implements Runnable {  
    private volatile boolean paused = false;     
    private volatile boolean finished = false;  
    String request_id="",usrnamee="",pswd="",driver="",url="";   

    public AcQueryExecutor(String request_id,String usrnamee,String pswd,String driver,String url) {  
        this.request_id=request_id;   
        this.usrnamee=usrnamee;   
        this.pswd=pswd;   
        this.url=url;   
        this.driver=driver;   
    }   

    public void upload() throws InterruptedException {   
        //some code                
        stop();
        //some more code
    }   

    public void run() {   
        try {   
            while(!finished) {   
                upload();   
            }
        } catch (InterruptedException e) {   
            e.printStackTrace();   
        }   
    }   

    public void stop() {
        finished = true; 
    }
}  

RMI server class from where I start the thread

        public class ExecutorServer extends UnicastRemoteObject implements ExecutorInterface

        {
        public ExecutorServer()throws RemoteException
        {
        System.out.println("Server is in listening mode");
        }
        public void executeJob(String req_id,String usrname,String pwd,String driver,String url)throws RemoteException  
{
    try{
    System.out.println("Inside executeJob.wew..");
    AcQueryExecutor a=new AcQueryExecutor(req_id,usrname,pwd,driver,url);
    Thread t1 = new Thread(a);
    t1.start();
    }
    catch(Exception e)
    {
        System.out.println("Exception " + e);
    }

}           
        public void killJob(String req_id)throws RemoteException{
            logger.debug("Kill task");  
            AcQueryExecutor a=new AcQueryExecutor(req_id,"","","","");
    a.stop();
                    }


        public static void main(String arg[])
        {
        try{
            LocateRegistry.createRegistry(2007);
        ExecutorServer p=new ExecutorServer();
        Naming.rebind("//localhost:2007/exec1",p);
        System.out.println ("Server is connected and ready for operation.");
        }catch(Exception e)
        {
        System.out.println("Exception occurred : "+e.getMessage());
        e.printStackTrace();
        }
        }
               }

RMI client

 ExecutorInterface p=(ExecutorInterface)Naming.lookup("//localhost:2007/exec1");
            System.out.println("Inside client.."+ p.toString());
                   p.executeJob(id, usrname, pswd);
                 p.killJob(id);
            }

Till my knowlegde p.killJob() will wont be invoked untill executeJob() is finished.
I want to stop the execution while it is running

Answer 1

The problem appears to be that you are allocating a fresh instance of the Runnable AcQueryExecutor for each thread. This means each is seeing its own finished flag. Setting one in killJob will not lead to any other thread exiting because no other thread shares this flag.

You’ll need to share Runnables or else make the finish field static. The latter will cause all threads to exit whenever any instance’s stop is called, so may not be what you want.