Question

I am trying to read in data from an input stream, but if the program does not receive data for X amount of time, I would like to terminate the attempt and return a -1. I was previously using Thread.sleep( X ) but then realized that thats a completely incorrect approach. If anyone has any ideas please let me know. Here is my code for reading from the input stream…

            try {
                // Read from the InputStream
                bytes = mmInStream.read(buffer, 0, length);

                // Send the obtained bytes to the UI Activity
                mHandler.obtainMessage(MainMenu.MESSAGE_READ, bytes, -1, buffer)
                        .sendToTarget();
            } catch (IOException e) {
                Log.e(TAG, "disconnected", e);
                connectionLost();
                // Start the service over to restart listening mode
                BluetoothService.this.start();
                //break;
            }

Answer 1

You can use Future to do this.

First, you need a class which will be returned as “future” value:

public class ReadResult {
    public final int size;
    public final byte[] buffer;

    public ReadResult(int size, byte[] buffer) {
         this.size = size;
         this.buffer = buffer;
    }
}

Then you need to use executor service and use get(long timeout, TimeUnit unit) like this:

        ExecutorService service = Executors.newSingleThreadExecutor();
        Future<ReadResult> future = service.submit(new Callable<ReadResult>() {

            @Override
            public ReadResult call() throws Exception {
                bytes = mInStream.read(buffer, 0, length);
                return new ReadResult(bytes, buffer);
            }
        });

        ReadResult result = null;
        try {
            result = future.get(10, TimeUnit.SECONDS);
        } catch (InterruptedException e1) {
            // Thread was interrupted
            e1.printStackTrace();
        } catch (ExecutionException e1) {
            // Something bad happened during reading
            e1.printStackTrace();
        } catch (TimeoutException e1) {
            // read timeout
            e1.printStackTrace();
        }

        if (result != null) {
            // here you can use it
        }

In that way you will be able to achieve your goal. Plz note that its better to subclass Callable class which will accept inputstream as constructor argument then using class variables.