Question

i have implemented a Runnable interface to load the image tiles and i want to call the Main thread from this secondary thread for displaying the tiles.
can anybody tell me how to call a Main thread from a Runnable Interface thread in Java.

thanks.

Answer 1

Instead of Runnable you can use Callable<Set<Image>> which returns a set of loaded images. Submit this callable task to an executor, get the Future<Set<Image>> and wait for the loading thread to finish its job.

For example:

Future<Set<Image>> future =
  Executors.newSingleThreadExecutor().submit(new Callable<Set<Image>>()
    {
      @Override
      public Set<Image> call() throws Exception
      {
        return someServiceThatLoadsImages.load();
      }
    });

try
{
  Set<Image> images = future.get();
  display(images);
} catch (Exception e)
{
  logger.error("Something bad happened", e);
}