Resource streaming status trick

gistfile1.java

// Inside a Restlet Resource's represent(...) method

PipedInputStream pi = new PipedInputStream();
PipedOutputStream po = new PipedOutputStream(pi);
Representation ir = new OutputRepresentation(MediaType.TEXT_PLAIN){
  @Override
  public void write(OutputStream realOutput) throws IOException {
    byte[] b = new byte[8];
    int read;
    while ((read = pi.read(b)) != -1) {  
      realOutput.write(b, 0, read);  
      realOutput.flush();
    }  
  }
};
OutputStreamWriter ow = new OutputStreamWriter(po);
PrintWriter out = new PrintWriter(ow,true);

// ...

try {
  new Thread(new LongRunningBeast(out)).start();
  return ir;
} catch (Exception e) {
  // return some error representation
}