How to determine the exact state of a BufferedReader?

Question

I have a BufferedReader (generated by new BufferedReader(new InputStreamReader(process.getInputStream()))). I\'m quite new to the concept of a

Answer 1

This is a pretty fundamental issue with java's blocking I/O API.

I suspect you're going to want to pick one of:

(1) Re-visit the idea of using threading. This doesn't have to be complicated, done properly, and it would let your code escape a blocked I/O read fairly gracefully, for example:

final BufferedReader reader = ...
ExecutorService executor = // create an executor here, using the Executors factory class.
Callable<String> task = new Callable<String> {
   public String call() throws IOException {
      return reader.readLine();
   }
};
Future<String> futureResult = executor.submit(task);
String line = futureResult.get(timeout);  // throws a TimeoutException if the read doesn't return in time

(2) Use java.nio instead of java.io. This is a more complicated API, but it has non-blocking semantics.

Answer 2

Have you confirmed by experiment your assertion that ready() will return false even if the underlying stream is at end of file? Because I would not expect that assertion to be correct (although I haven't done the experiment).