Question

How do i assign Status with CallMe() using isFinish() to have returned value true?

public static boolean isFinish ()
{    
  boolean Status = false;
  new Thread(new Runnable()
  {
    public void run()
    {
      /* This shell return true or false 
       * How do you keep it in Status
       */
      CallMe(); 
    }
  }).start();

  /* How can i get the true or false exactly from CallMe? here */
  return Status;
}

public static boolean CallMe()
{
  /* some heavy loads ... */
  return true;
}

Answer 1

There are two ways of doing this.
The first is to use a future computation result and the other is to have a shared variable.
I think that the first method is much cleaner than the second, but sometimes you need to push values to the thread too.

• Using a RunnableFuture.

FutureTask implements a RunnableFuture. So you create that task which, once executed, will have a value.

RunnableFuture f = new FutureTask(new Callable<Boolean>() {
  // implement call
});
// start the thread to execute it (you may also use an Executor)
new Thread(f).start();
// get the result
f.get();

• Using a holder class

You create a class holding a value and share a reference to that class. You may create your own class or simply use the AtomicReference.
By holder class, I mean a class that has a public modifiable attribute.

// create the shared variable
final AtomicBoolean b = new AtomicBoolean();
// create your thread
Thread t = new Thread(new Runnable() {
  public void run() {
    // you can use b in here
  }
});
t.start();
// wait for the thread
t.join();
b.get();